ST-138 Controller User Manual - ftp.piacton.comftp.piacton.com/Public/Manuals/Princeton...

4411-0088 Version 2.A

December 3, 2002

*4411-0088*

Copyright 2001-02 Roper Scientific, Inc. 3660 Quakerbridge Rd Trenton, NJ 08619 TEL: 609-587-9797 FAX: 609-587-1970 All rights reserved. No part of this publication may be reproduced by any means without the written permission of Roper Scientific, Inc.

Printed in the United States of America.

Macintosh is a registered trademark of Apple Computer, Inc.

TAXI is a registered trademark of AMD Corporation

Windows 95 is a registered trademark of Microsoft Corporation in the United States and/or other countries.

The information in this publication is believed to be accurate as of the publication release date. However, Roper Scientific, Inc. does not assume any responsibility for any consequences including any damages resulting from the use thereof. The information contained herein is subject to change without notice. Revision of this publication may be issued to incorporate such change.

iii

Table of Contents

Chapter 1 Overview..............................................................................................9

Introduction......................................................................................................................... 9

Chapter 2 Controller Setup................................................................................13

Introduction....................................................................................................................... 13 Unpacking the Controller ................................................................................................. 13 Equipment and Parts Inventory......................................................................................... 13 Precautions........................................................................................................................ 14 Environmental Requirements ........................................................................................... 14 Power Input....................................................................................................................... 14

Power Cord Plug ........................................................................................................ 14 Power Module ............................................................................................................ 15 Voltage Setting and Fuse Replacement...................................................................... 15

Computer Requirements ................................................................................................... 17 Host Computer Type .................................................................................................. 17

ST-138 Features................................................................................................................ 17 Front panel functions ................................................................................................. 17 Rear panel functions................................................................................................... 18

Software Installation......................................................................................................... 19 Jumper Settings................................................................................................................. 19 Camera Setup.................................................................................................................... 19 Service Note...................................................................................................................... 19

Chapter 3 Installing the Computer Interface...................................................21

Introduction....................................................................................................................... 21 PCI Serial Buffer Board.................................................................................................... 21

Introduction ................................................................................................................ 21 Installing the PCI Card............................................................................................... 21 Power-On Checks................................................................................................ 24 Apple Macintosh ........................................................................................................ 21

ISA Serial Card................................................................................................................. 26 Checking the ISA Serial Board Jumpers.................................................................... 26 Installation.................................................................................................................. 26 Power-On Checks....................................................................................................... 28

Chapter 4 First Light ..........................................................................................29

Introduction....................................................................................................................... 29 Procedure .......................................................................................................................... 29

iv ST-138 Controller Operation manual Version 2.A

Chapter 5 Temperature Control ........................................................................33

Chapter 6 Experiment Timing............................................................................35

Synchronous or Asynchronous ......................................................................................... 36 Store Strobe Option .......................................................................................................... 38 Standard Triggering Modes .............................................................................................. 40

Freerun timing............................................................................................................ 41 External Sync timing.................................................................................................. 42 Continuous Cleans timing .......................................................................................... 44

Special Triggering Modes................................................................................................. 46 Frame transfer timing................................................................................................. 46 Kinetics timing ........................................................................................................... 48

Chapter 7 Exposure and Readout.....................................................................51

Exposure ........................................................................................................................... 51 Exposure with a mechanical shutter........................................................................... 52 Exposure with an image intensifier............................................................................ 53 Continuous exposure (no shuttering) ......................................................................... 53 Saturation ................................................................................................................... 54 Dark charge ................................................................................................................ 54

Readout of the Array ........................................................................................................ 55 Full frame readout ...................................................................................................... 55 Image readout with binning........................................................................................ 58 Single spectrum readout with binning........................................................................ 59 Binning in software .................................................................................................... 62 Frame transfer readout ............................................................................................... 63 Kinetics mode readout................................................................................................ 64

Digitization ....................................................................................................................... 65 Dual A/D converters .................................................................................................. 65 Lookup table............................................................................................................... 65 Accumulator ............................................................................................................... 65

Appendix A Specifications ................................................................................67

General.............................................................................................................................. 67 Input Ports......................................................................................................................... 67 Output Ports ...................................................................................................................... 68

Appendix B J5 Data Port Configuration...........................................................69

Appendix C Cleaning Instructions....................................................................71

Controller and Camera...................................................................................................... 71 Optical Surfaces................................................................................................................ 71

Table of Contents v

Figures Figure 1. ST-138 camera controller................................................................................... 9 Figure 2. Some of the cameras that can be used with the ST-138 Controller ................. 10 Figure 3. Typical AC power cord plug............................................................................ 15 Figure 4. Power Module Assembly ................................................................................. 15 Figure 5. ST-138 front panel .......................................................................................... 17 Figure 6. ST-138 rear panel ............................................................................................ 18 Figure 7. PCI serial board................................................................................................ 22 Figure 8. Removing the expansion slot cover on an AT type computer ......................... 23 Figure 9. PCI expansion slots in typical computer .......................................................... 23 Figure 10. ISA board switch and jumper settings............................................................ 27 Figure 11. Computer expansion slots for installing an ISA Buffer card ......................... 28 Figure 12. Removing the expansion slot cover on an AT type computer ....................... 28 Figure 13. System connection diagram............................................................................ 30 Figure 14. Temperature dial set to -15°C and to -110°C................................................. 33 Figure 15. Chart of Asynchronous and Synchronous operation...................................... 37 Figure 16. Store Strobe timing diagram........................................................................... 38 Figure 17. Store Strobe timing chart, part of the chart in Figure 15 ............................... 39 Figure 18. Possible cable connections for timing modes ................................................ 40 Figure 19. Freerun timing chart, part of the chart in Figure 17....................................... 41 Figure 20. Freerun timing diagram.................................................................................. 41 Figure 21. Chart showing two External Sync timing options, part of chart in Figure 17 .......42 Figure 22. Timing diagram for the External Sync mode ................................................. 43 Figure 23. Continuous Cleans operation flow chart, part of the chart in Figure 17........ 44 Figure 24. Continuous Cleans timing diagram................................................................ 45 Figure 25. Frame Transfer where texp + tw1 + tc < tR...................................................... 46 Figure 26. Frame Transfer where texp + tw1 + tc > tR...................................................... 47 Figure 27. Frame Transfer where pulse arrives after readout ......................................... 48 Figure 28. Single Trigger Kinetics .................................................................................. 49 Figure 29. Multiple Trigger Kinetics............................................................................... 49

Warranty & Service ............................................................................................73 Limited Warranty: Roper Scientific Analytical Instrumentation...................................... 73

Basic Limited One (1) Year Warranty ....................................................................... 73 Limited One (1) Year Warranty on Refurbished or Discontinued Products .............. 73 Shutter Limited One Year Warranty .......................................................................... 73 VersArray (XP) Vacuum Chamber Limited Lifetime Warranty................................ 74 Sealed Chamber Integrity Limited 24 Month Warranty............................................. 74 Vacuum Integrity Limited 24 Month Warranty ......................................................... 74 Image Intensifier Detector Limited One Year Warranty............................................ 74 X-Ray Detector Limited One Year Warranty ............................................................ 74 Software Limited Warranty........................................................................................ 75 Owner's Manual and Troubleshooting ....................................................................... 75 Your Responsibility.................................................................................................... 75

Contact Information.......................................................................................................... 76

Index ....................................................................................................................77

vi ST-138 Controller Operation manual Version 2.A

Figure 30. Block diagram of light path in system............................................................ 51 Figure 31. Exposure of the CCD with shutter compensation .......................................... 52 Figure 32. Diagram of an MCP image intensifier ........................................................... 53 Figure 33. Full frame at full resolution............................................................................ 56 Figure 34. 2 x 2 binning for images................................................................................. 59 Figure 35. Perpendicular mode binning........................................................................... 60 Figure 36. Parallel mode binning..................................................................................... 61 Figure 37. Frame Transfer readout .................................................................................. 63 Figure 38. Kinetics readout ............................................................................................. 64 Figure 39. JP5 data port pin configuration ...................................................................... 69 Figure 40. Suggested test schematic for J5 data port ...................................................... 69

Tables Table 1. Camera timing modes ........................................................................................ 35 Table 2. Shutter compensation time ................................................................................ 52 Table 3. Typical timing values for some CCD arrays ..................................................... 57 Table 4. Possible A/D settings for the Model ST-138 Controller ................................... 65

Table of Contents vii

viii ST-138 Controller Operation manual Version 2.A

Safety Related Symbols Used in This Manual

Caution! The use of this symbol on equipment indicates that one or more nearby items should not be operated without first consulting the manual. The same symbol appears in the manual adjacent to the text that discusses the hardware item(s) in question.

Caution! Risk of electric shock! The use of this symbol on equipment indicates that one or more nearby items pose an electric shock hazard and should be regarded as potentially dangerous. This same symbol appears in the manual adjacent to the text that discusses the hardware item(s) in question.

9

Chapter 1 Overview

Introduction Overview: The Princeton Instruments® Model ST-138 is a high performance full-featured CCD Camera Controller available from Roper Scientific. Designed for demanding image acquisition, it offers dual A/D converters for optimized image collection at high speed or at high precision. Up to 14-bit data transfer at speeds up to 1 MHz is achieved via a high-speed serial link to DMA.

Function: Able to operate with a variety of different cameras and CCD arrays, with support for several popular computer platforms and application software packages, the ST-138 Controller allows you to assemble an image acquisition system precisely tailored to your specific needs. In operation, analog data acquired by the camera is routed to the controller where it is converted to digital data by specially designed, low-noise electronics. Two complete analog channels, each with its own A/D converter (precision A/D converter optional), are available. The ST-138 Controller enables both high-speed and high-precision readout capabilities. 16-bit data acquisition is possible at speeds as high as 430 kHz (pixels per second). In the high-speed mode, 14-bit images can be acquired at rates as high as 1 million pixels per second (1 MHz). Switching between the two channels is completely under software control for total experiment automation.

Cameras Supported: The Model ST-138 Camera Controller supports type RTE/CCD, TE/CCD, LN/CCD and ICCD detectors. See the CCD Camera Catalog for complete information on these cameras.

Figure 1. ST-138 camera

controller

10 ST-138 Controller Operation manual Version 2.A

Flexible Readout: The flexible programming of the ST-138 allows the following common readout modes:

• Readout and digitization of the whole array at full resolution.

• Readout and digitization of a rectangular subsection of the array at full resolution. This results in a higher readout rate and is useful for focusing or viewing a region of interest (ROI).

• Readout with N × M binning. This increases the readout rate but reduces resolution. Because N × M binning combines the charges from many pixels, the apparent sensitivity of the camera is increased, allowing shorter exposure times to be used.

• Readout and digitization of rectangular bands of pixels, binned to give a one-dimensional output. This mode of readout offers fast cross section read-outs.

• Readout with patterned row and column skipping. This allows the whole CCD or a part of it to be read out with lower resolution, but without binning.

When working with live images, this last option allows you to zoom in and out on a large CCD array without changing exposure levels to compensate for binning. It also allows a large CCD array to be read out to a window on your computer screen, at a frame rate of that is determined by the window size and not by the CCD size. For focusing and alignment, this keeps the frame rate high, even as you zoom in and out on the image.

High Speed Data Transfer: Data is transferred directly to the host computer memory via a high-speed serial link. A proprietary Interface card places the data from the controller directly into the host computer RAM using Direct Memory Access (DMA). The DMA transfer process ensures that the data arrives at sufficiently high speed to keep up with even the fastest frame rate.

Fast Image Display: The ST-138 Camera Controller uses digital circuitry to compute the minimum and maximum value of each frame in real time, and then uses a downloadable lookup table to convert pixel data from 16 bits per pixel to 8 bits. This allows images to be displayed on computer screens in real time with digital intensity

Figure 2. Some of the cameras

that can be used with the

ST-138 Controller

Chapter 1 Overview 11

autoscaling. Because the process is entirely digital, it does not introduce any noise as analog gain controls can. Because the minimum and maximum are determined exactly, the entire range of the display is used.

This digital approach is also better than an analog gain-control because the scaling is known precisely: there is no question of calibration of the relative analog levels. The researcher is also not limited to a few fixed gain levels provided by the manufacturer or to an unknown calibration. Because it is so fast, this mechanism can be used to adjust the intensity scaling on every frame, for automatic image-by-image optimization.

Kinetics Mode: Charge can be shifted on a CCD array much faster than it can be read out. The ST-138 takes advantage of this characteristic via its Kinetics mode, in which only a small region of a CCD is illuminated. Multiple exposures are made rapidly, with just enough time between exposures to shift the charge aside. Once the entire CCD area is filled with these images, the series is read out with high precision. This allows a burst of images to be taken at very high frame rates, while still providing the high sensitivity, low noise, and high dynamic range of a slow-scan CCD camera.

Frame Transfer Operation: The ST-138 Controller supports operation of CCD detectors in frame transfer mode, where the array is divided into two equal sections, an image area that is exposed and a storage area that is masked. After each exposure period, the charge in the image area is rapidly shifted to the storage area. Once this is done, the next exposure period begins. During this exposure, the charge in the storage area is read out (only the storage area of the CCD is clocked).

Since frame transfer operation allows read-out to be concurrent with exposure, the exposure duty cycle can become nearly 100%, a sensitivity advantage when taking sequences of images or for continuous operation.

Applications: With its fully integrated design, support for a variety of cameras, CCD arrays, and computers, together with temperature control, advanced exposure control timing, and sophisticated readout capabilities, the ST-138 Controller is well suited to a wide range of general macro imaging and microscopy applications.


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13

Chapter 2 Controller Setup

Introduction This chapter explains the initial steps in setting up your ST-138 Controller. In addition to descriptions of such basics as unpacking and grounding safety, the chapter includes discussions of the requirements that have to be met before the camera can be switched on. Included are environmental, power, hardware, and software requirements. Also provided are descriptions of the front and rear panels.

Unpacking the Controller During unpacking, check the controller for possible signs of shipping damage. If there are any, notify Roper Scientific and file a claim with the carrier. If damage is not apparent but controller specifications cannot be achieved, internal damage may have occurred in shipment.

Equipment and Parts Inventory A complete system consists of a computer, an ST-138 Controller, a TE/CCD, RTE/CCD, LN/CCD, or ICCD series camera, and a gate pulser (optional). Also required are the following:

• Camera to controller cable: 6 ft. standard for most cameras. Lengths up to 20 feet with RF shielding are available for most cameras.

• Controller to computer cable: 25 ft. standard. Lengths up to 165 feet are available. Optional fiber optic transducers can be used with standard controllers and cameras, extending this distance up to 2 km.

• System Dependent Interface Components:

Note: In the following operating-procedure discussion, this manual refers to a PC equipped with a PCI high-speed interface card and using the Princeton Instrument’s WinView/32 software. Interface components as follows could be required.

• PC Systems: High Speed PCI Interface Board*

Note: Computers purchased from Roper Scientific will be shipped with the board already installed.

• Intensified cameras may require a high-voltage power supply or gate pulser.

* High-Speed ISA Interface may be available as special purchase.


Precautions The apparatus described in this manual is of Class I category as defined in IEC Publication 348 (Safety Requirements for Electronic Measuring Apparatus). It is designed for indoor operation only. Before turning on the controller, the ground prong of the power cord plug must be properly connected to the ground connector of the wall outlet. The wall outlet must have a third prong, or must be properly connected to an adapter that complies with these safety requirements.

If equipment is damaged, the protective grounding could be disconnected. Do not use damaged equipment until safety has been verified by authorized personnel. Disconnecting the protective earth terminal (inside or outside the apparatus) or any tampering with its operation is also prohibited.

Inspect the supplied power cord. If it is not compatible with the power socket, replace the cord with one that has suitable connectors on both ends.

Replacement power cords or power plugs must have the same polarity as that of the original ones to avoid hazard due to electrical shock.

Environmental Requirements Storage temperature -20° C to 55° C; Operating temperature range over which specifications can be met is 18° C to 23° C; Relative humidity <80% noncondensing.

Power Input The standard ST-138 Controller can operate from any one of four different nominal line voltages: 100, 120, 220, or 240 V AC. The power consumption averages 300 watts and the line frequency can range from 47 to 63 Hz.

HIVAC: In the case of an ST-138 that has been modified for use with the HIVAC camera, there are only two line voltages available, 120 V and 240 V AC. Also, note that the HIVAC temperature range will be moderately reduced if operated with a standard ST-138.

X-Ray Taper Camera: Although a system containing the X-Ray Taper Camera includes a modified ST-138 Controller, the camera is powered by a separate power supply, which operates from the same nominal line voltages as a standard controller.

Power Cord Plug The plug on the line cord supplied with the controller should be compatible with the line-voltage outlets in common use in the region to which the controller is shipped. If the line cord plug should prove to be incompatible, a compatible plug should be installed, taking care to maintain the proper polarity to protect the equipment and assure user safety.

WARNING

WARNING

Chapter 2 Controller Setup 15

LN

E

L = LINE OR ACTIVE CONDUCTOR(ALSO CALLED "LIVE" OR "HOT")

N = NEUTRAL OR IDENTIFIED CONDUCTOR

E = EARTH OR SAFETY GROUND

Power Module The power module, located on the back panel, contains the voltage selector card line fuse and the power cord connector. The operating voltage is set by the voltage selector card. There are four possible orientations for the card, each corresponding to a different line voltage setting. The available choices are 100 V, 120 V, 220 V, and 240 V. Each setting defines a range and you should select the setting that is closest to the actual line voltage, with the limitation that 100 V is the lowest allowable voltage.

FUSEPULL

Voltage Selector Card

Fuse ReleaseLever

FuseSliding Cover

Both Sides ofVoltage Selector Card

Voltage Setting and Fuse Replacement Prior to operation, the voltage selector card on the controller must be set to match the line voltage of the wall outlet. This setting is 100, 120, 220, or 240 V, at either 50 or 60 Hz. Incorrect setting may damage the apparatus. The selected voltage can be seen on the card, directly below the fuse and to the left of the fuse release lever. All four voltages are printed on the card, but only the selected voltage is visible when the card is installed.

Figure 3. Typical AC power cord

plug

Figure 4. Power Module

Assembly


Line Voltage Fuse Rating

100 ~ 3.0A - T (S.B.)

120 ~ 3.0A - T (S.B.)

220 ~ 1.5A - T (S.B.)

240 ~ 1.5A - T (S.B.)

To check and/or change the voltage setting or fuse, proceed as follows.

Turn off the controller.

Remove the power cord.

Slide the clear plastic fuse cover on the Power Module to the left.

Move the fuse release lever (lower right) to the left, until the fuse is ejected from the fuseholder.

If you are changing the voltage setting, pull out the setting card and reinsert it with the correct number showing. If the selected line voltage is 220, the number 220 should be visible on the topside of the card and to the left of the fuse release lever.

Check that the fuse rating of the fuse to be inserted matches the requirement for the voltage setting. Refer to the table printed on the panel to the right of the power module or to the table at the beginning of this section.

If the fuse rating is correct, put the fuse into the fuseholder, slide the cover to the right, and reinsert the power cord.

The correct fuse for the country where the ST-138 is to be shipped is installed at the factory.

Be sure to use the proper fuse. The controller and camera will not be properly protected if the fuse rating is too high. If it is too low, the fuse will fail.

Line Voltage and Fuse

Requirements

WARNING


Computer Requirements

Host Computer Type Note: The following information is only intended to give an approximate indication of the computer requirements. Please contact the factory to determine your specific needs.

PC Type: Pentium (or better) PC.

Memory (RAM): Minimum of 32 Mbytes; possibly more depending on experiment design and size of CCD Array.

Operating System: Windows 95® or later.

Interface: High-Speed PCI Serial I/O card. Computers purchased from Roper Scientific for use with the ST-138 Controller are shipped with the card installed.

Note: If the application calls for controlling multiple controllers from a single computer, a separate PCI Interface cards would have to be installed in the computer for each controller.

Computer Monitor: Super VGA monitor with 256 color graphics card and at least 512 kbytes of memory.

Mouse: Two-button Microsoft compatible serial mouse or Logitech three-button serial/bus mouse.

ST-138 Features

DETECTOR CONTROLLER

12

3

4

5 67

8

Front panel functions 1. Cooler power switch

2. Cooler power indicator (yellow)

3. Cooler status (yellow) indicates that the camera is not yet thermostated

4. Cooler status (green) indicates that the camera is thermostated to within ±0.05°C of the set temperature

5. Warning indicator (red) if temperature is set too low

Figure 5. ST-138 front

panel


6. Temperature setting potentiometer, calibrated in minus °C

7. Power on indicator (yellow)

8. Controller power switch

1

2

3

4

5

19

20 2122

WARNING: NO OPERATOR SERVICEABLE COMPONENTSINSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.

CAUTION: FOR CONTINUED PROTECTION AGAINST FIRE,REPLACE ONLY WITH FUSE OF THE SPECIFIEDVOLTAGE AND CURRENT RATINGS.

10

11

12

13

7

6

9

8

14

15

16

17

18

FUSE100-120V220-240V300W MAX

3.0A T (S.B.)1.5A T (S.B.)50 60 HZ

Rear panel functions Label Function

1. J6 Digital sync for frame grabber board

2. J5 Auxiliary port (34-pin), 8-bit software programmable digital I/O port, see Appendix B

3. IEEE-488 Not used with the ST-138.

4. DETECTOR Detector head cable connector: DB-37-M

5. RS-232 Serial port for communicating via RS232C

6. CRT X X-ramp signal for multisync monitor

7. TRIGGER OUT TTL low (negative edge) during data acquisition

8. NORMALIZE 1 Not Used

9. NORMALIZE 2 Shutter monitor (optional)

10. CRT Y Video out monitor: 0-10 V

11. TRIGGER IN External trigger input: TTL low level activated

12. NOTSCAN TTL low when sensor is being read; TTL high indicates sensor currently being exposed

13. NORMALIZE 3 Kinetics Timing (see page 49)

14. CRT Z Negative blanking signals for XYZ monitor

15. EXT SYNC External sync input: TTL low level activated

16. SHUTTER External shutter control; TTL level; TTL low forces shutter open. In certain timing modes, complete control of shutter is possible.

17. NORM 4/VIDEO 0-1.3 V normalized video out for frame grabber board

Figure 6. ST-138 rear

panel


18. J7 Connector for communicating with Serial Buffer Board inside computer

19. AC power cord slot

20. Fuse

21. Fuse release lever

22. Voltage selector card

Software Installation It is necessary to install the application software before the controller can be operated and data acquired. The installation procedure will vary according to the computer type, operating controller, and type of application software. See your software manual for detailed software installation and software-operation information.

Jumper Settings Users who have purchased only one camera and one shutter should never need to change the jumpers and switches within the controller. Your equipment is tested as a complete system at the factory, and all of these settings have been verified.

If you plan to use more than one camera or more than one shutter with this controller, the jumpers and switches may need to be changed for each camera. Contact factory Tech Support for guidance (page Error! Bookmark not defined.).

Camera Setup Since each type of camera has its own specifications and warnings, the setup instructions for your camera are contained in a separate manual.

Service Note There are no user-serviceable components inside the ST-138. Refer servicing to qualified personnel and contact the factory Technical Support for guidance. Contact information is provided on page Error! Bookmark not defined. of the manual.

21

Chapter 3 Installing the Computer Interface

Introduction If a computer was ordered as a component of your system, a PCI Serial card will have been already installed at the factory. If you are going to use a different computer, then it will be necessary to install a PCI card per the directions in this chapter.

This chapter will lead you through the process of installing the Computer Interface. Following these steps explicitly will help insure proper connection to your computer.

PCI Serial Buffer Board

Introduction If the computer is a PCI bus PC, it must be equipped with a PCI Serial Buffer board. Information about the installation and operation of this board follows.

A PCI Serial board must be installed in an x86 type computer having a motherboard with at least one free PCI slot. The PCI Serial card must be plugged into a PCI slot. If using WinView/32 or WinSpec/32 software, High Speed PCI must be the selected Interface type. This selection is accessed from the Hardware Setup dialog box.

A screwdriver may be needed to remove screws from the computer (the type varies from computer to computer). A small, flat-bladed screwdriver is needed to connect both ends of the serial cable.

Installing the PCI Card 1. Remove the expansion slot cover on the rear panel of the I/O slot selected (see

Figure 12).

2. Insert the PCI Serial Interface card as far as possible into the appropriate PCI socket (see Figure 9). Then secure the Serial Buffer Board by reinstalling the expansion slot cover screw.

Apple Macintosh The PCI card can be installed and operated in any Macintosh having a PCI bus, allowing the ST-138 to be controlled via user software from the Macintosh.

CAUTION


Memory Overflow Indicator LED

To Controller High-Speed Serial Port

Connect the standard TAXI® serial cable to the 9-pin cable connector on the PCI Serial Buffer Board mounting panel as shown in Figure 10. The other end of the serial cable connects to the Controller’s high-speed serial output connector. Take care to tighten the screws at both ends of the cable using a small, flat-bladed screwdriver.

Figure 7. PCI serial

board

Chapter 3 Installing the Computer Interface 23

ISA Slot ISA Slot ISA Slot

PCI Slot PCI Slot PCI Slot

ISA Slots

Figure 8. Removing the

expansion slot cover on an AT type computer

Figure 9. PCI expansion slots in typical

computer


Power-On Checks Introduction Before proceeding, be sure the PCI Serial card is firmly mounted in the slot. Replace the cover of the computer and turn on the computer only. If an error occurs at bootup, either the PCI serial card was not installed properly or there is an address or interrupt conflict.

Conflicts One of the many advantages that PCI offers over ISA is that the whole issue of address and interrupt assignments is user transparent and under BIOS control. As a result, users typically do not have to be concerned about jumpers or switches when installing a PCI card. Nothing more should be required than to plug in the card, make the connections, and operate the system. As it turns out, however, in certain situations conflicts may nevertheless occur and user intervention will be required to resolve them.

Typical PCI motherboards have both ISA and PCI slots and will have both PCI and ISA cards installed. In the case of the ISA cards, the I/O address and Interrupt assignments will have been made by the user and the BIOS will not know which addresses and interrupts have been user assigned. When a PCI card is installed, the BIOS checks for available addresses and interrupt levels and automatically assigns them so that there are no PCI address or interrupt conflicts. However, because the BIOS doesn't know about the user-assigned ISA I/O address and interrupt level assignments, it is possible that a PCI card will be assigned an address or interrupt that is already assigned to an ISA card. If this happens, improper operation will result. Specifically, the problems could range from erratic operation under specific conditions to complete system failure. If such a conflict occurs, because the user has no control over the PCI address and interrupt assignments, there will be no recourse but to examine the ISA assignments and change them to values that do not conflict. Most (but by no means all) ISA cards make provision for selecting alternative I/O addresses and interrupt levels so that conflicts can be resolved. Software is available to help identify specific conflicts.

The following example may serve to illustrate the problem. Suppose you had a system with an ISA network card, a PCI video card and an ISA sound card. Further suppose that you were then going to install a PCI Serial Buffer card. Before installing the PCI Serial card, the I/O address and interrupt assignments for the installed cards might be as follows.

I/O Address & Interrupt Assignments Before Installing Serial Card

Slot Type Status I/O Address Interrupt

1 (ISA) ISA Network Card 200-210 11

2 (PCI) PCI Video Card FF00-FFFF 15

3 (ISA) ISA Sound Card 300-304 9

4 (PCI) Empty N/A N/A

As shown, there are no conflicts, allowing the three peripheral cards to operate properly. If the PCI Serial card were then installed, the BIOS would interrogate the PCI cards and may reassign them new address and interrupt values as follows.


I/O Address & Interrupt Assignments After Installing Serial Card

Slot Type Status I/O Address(s) Interrupt

1 (ISA) ISA Network Card 200-210 11

2 (PCI) PCI Video Card FE00-FEFF 11

3 (ISA) ISA Sound Card 300-304 9

4 (PCI) Princeton Instruments PCI Serial Card

FF80-FFFF 15

As indicated, there is now an interrupt conflict between the ISA Network Card and the PCI Video card (both cards have been assigned Interrupt 11), causing the computer to no longer function normally. This doesn't mean that the PCI Serial card is defective because the computer stops functioning properly when the Serial card is installed. What it does mean is that there is an interrupt conflict that can be resolved by changing the interrupt level on the conflicting Network card in this example. It is up to the user to consult the documentation for any ISA cards to determine how to make the necessary change.

Note: Changing the order of the PCI cards, that is, plugging them into different slots, could change the address and interrupt assignments and possibly resolve the conflict. However, this would be a trial and error process with no guarantee of success.

Diagnostics Software Many diagnostics programs, both shareware and commercial, are available to help resolve conflicts. In addition, a Macro-Basic routine that runs under WinView is currently being developed. Most often, all that's required is a program that will read and report the address and interrupt assignments for each PCI device in the computer. One such program available from Roper Scientific's Technical Support department is called PCICHECK. When the program is run, it reports the address and interrupt assignments for the first PCI device it finds. Each time the spacebar is pressed, it moves on to the next one and reports the address and interrupt assignments for that one as well. In a few moments this information can be obtained for every PCI device in the computer. Note that, even though there are generally only three PCI slots, the number of PCI devices reported may be larger because some PCI devices may be built onto the motherboard. A good strategy for using the program would be to run it before installing the PCI Serial card. Then run it again after installing the card and note any address or interrupt assignments that may have changed. This will allow you to easily focus on the ones that may be in conflict with address or interrupt assignments on ISA cards. It might be noted that there are many programs, such as the MSD program supplied by Microsoft, that are designed to read and report address and interrupt assignments, including those on ISA cards. Many users have had mixed results at best using these programs.

Operation There are no operating considerations that are unique to the PCI Serial card. The card can easily accept data as fast as any Princeton Instruments system now available can send it. The incoming data is temporarily stored in the card’s memory, and then transferred to the main computer memory when the card gains access to the bus. The PCI bus arbitration scheme assures that, as long as every PCI card conforms to the PCI guidelines, the on-board memory will never overflow.


Unfortunately, there are some PCI peripheral cards that do not fully conform to the PCI guidelines and that take control of the bus for longer periods than the PCI specification allows. Certain video cards (particularly those that use the S3 video chip) are notorious in this respect. Usually you will be able to recognize when memory overflow occurs because the displayed video will assume a split-screen appearance. At the same time, the LED on the upper edge of the PCI Serial card will light.

Users are thus advised not to take any actions that would worsen the possibility of memory overflow occurring when taking data. In that regard, avoid multitasking while taking data. Specific operations to avoid include multitasking (pressing ALT TAB or ALT ESC to start another program), or running a screensaver program.

ISA Serial Card ISA Serial boards were available before the PCI board, now standard, was developed. ISA Serial Buffer boards are still supported and may be available on special order.

A screwdriver may be needed to remove screws from the computer (the type varies from computer to computer). A small, flat-bladed screwdriver is needed to connect both ends of the serial cable.

Checking the ISA Serial Board Jumpers Before installing an ISA Interface Board, its address should be confirmed. The factory default address is 0A00. This address can be confirmed or changed by comparing the 8 dipswitches found on the board with Figure 10. The ISA Serial Buffer board is set to interrupt level 10 and uses DMA channels 5 and 6. The interrupt level can be changed by the user, as long as both hardware and software are set to the same interrupt. Figure 10 shows all possible configurations. If the default DMA channels present a problem, contact the factory for more information.

Since interrupts and DMA channels cannot be shared, make sure no other boards in your computer use this interrupt or these DMA channels.

Installation 1. Remove the expansion slot cover on the rear panel of the I/O slot selected (see

Figure 12).

2. Insert the ISA Serial Interface card as far as possible into an unused ISA socket. Then secure the Serial Buffer Board by reinstalling the expansion slot cover screw.

Note: EISA bus computers have largely been replaced by PCI technology. However, it may be possible to operate an ISA Serial Buffer board in an EISA slot. Contact the factory for guidance if this is your intention.

ATTENTION

CAUTION


3. Connect the serial cable to the 9-pin cable on the ISA Serial Buffer Board mounting panel. The other end of the serial cable connects to the SERIAL COM connector on the Interface Control Module panel. Take care to tighten the screws at both ends of the cable using a small, flat-bladed screwdriver.

These are factory set andshould not be disturbed.

Figure 10. ISA board switch and

jumper settings


Power-On Checks Replace the cover of the computer and turn on the computer only. If an error occurs at boot up, either the Serial Buffer Board is not installed properly or there is an address or interrupt conflict. Turn off the computer, try a new address or interrupt and reinstall the card. Be sure the Serial Buffer Board is firmly mounted in the slot.

Figure 11. Computer

expansion slots for installing an ISA Buffer card

Figure 12. Removing the

expansion slot cover on an AT type computer

29

Chapter 4 First Light

Introduction This chapter provides a step-by-step procedure for placing the system in operation the first time. At this point a lens should be mounted on the camera or the camera mounted on a microscope. See your camera manual for mounting instructions. A suggested procedure for operating the system and viewing your first images follows. Note that the intent of this simple procedure is to help you gain basic familiarity with the operation of your ST-138 based system and to demonstrate that it is functioning properly. Once basic familiarity has been established, then operation with other operating configurations, ones with more complex timing modes, can be established as described in Chapter 6, Experiment Timing.

To carry out this procedure, it will be necessary to have a basic grasp of the applications software. Refer to your software manual for the required information.

Before You Start, if your system includes a microscope Xenon or Hg arc lamp, it is CRITICAL to turn off all electronics adjacent to the arc lamp, especially your digital camera system and your computer hardware (monitors included) before turning on the lamp power.

Powering up a microscope Xenon or Hg arc lamp causes a large EMF spike to be produced that can cause damage to electronics that are running in the vicinity of the lamp. We advise that you place a clear warning sign on the power button of your arc lamp reminding all workers to follow this procedure. While Roper Scientific has taken great care to isolate its sensitive circuitry from EMF sources, we cannot guarantee that this protection will be sufficient for all EMF bursts. Therefore, in order to fully guarantee the performance of your system, you must follow this startup procedure.

Procedure 1. If the system cables haven’t as yet been installed, connect them as follows (system

power off). See Figure 13.

• Connect the 25-pin cable from the DETECTOR connector on the back of the ST-138 to the mating connector at the camera. Be sure to secure the cable at both ends.

WARNING


DETECTOR CONTROLLER

J7

DETECTOR

Connects to DB-25 connector on back of camera

Connects to DB-9connector J7 onback of controller

Connects to DB-9connector on serialinterface card panel

Connects to DB-37 connectoron back of controller

• Connect one end of the 9-pin serial cable to J7 on the back of the ST-138. Connect the other end of the cable to the DB-9 connector on the panel of the serial interface card.

• Connect the line cord from the Power Input assembly on the back of the controller to a suitable source of AC power.

2. If you haven’t already done so, install a lens on the camera or connect it to your microscope or other system optics, whichever applies. See the manual for your particular camera. The initial lens settings aren’t important but it may prove convenient to set the focus to approximately the anticipated distance and to begin with a small aperture setting.

3. After reviewing the operating directions for your particular software and camera, follow the directions in those manuals and begin a data acquisition. Take care to observe all equipment and personnel safety requirements as outlined in your camera manual.

4. Adjust the lens aperture, intensity scaling, and focus for the best image. Some imaging tips follow.

5. Begin with the lens blocked off. Set the lens at the smallest possible aperture (largest f-stop number).

Figure 13. System

connection diagram

Chapter 4 First Light 31

If using an intensified camera, it is critical to follow the procedures in the camera manual precisely, and to comply with the requirements of all the manual cautions and warnings. When powered, an intensified camera can be destroyed in a few seconds by light overload.

6. Place a suitable target in front of the lens. An object with text or graphics works best. If working with a microscope, use any easily viewed specimen. It is generally not advisable to attempt fluorescence imaging during this Getting Started phase of operation.

7. Set the focus adjustment of the lens for maximum sharpness in the viewed image.

8. In the case of a camera with an F-mount, the camera lens adapter itself also has a focus adjustment. If necessary, this focus can be changed to bring the image into range of the lens focus adjustment. See your camera manual for instructions on how to do this.

9. Once optimum focus and aperture have been achieved, you can switch from focusing to standard data-acquisition operation.

This completes First Light. If the system functioned as described, you can be reasonably sure it has arrived in good working order. In addition, you should have a basic understanding of how the system hardware is used. Other topics, which are important under certain conditions, are discussed in the following chapters.

WARNING

33

Chapter 5 Temperature Control

Temperature control is done via Temperature knob on the front panel of the ST-138. Figure 14 shows the dial settings for two different temperatures. Once the cooler power is turned on and the desired array temperature has been set, the ST-138 controls the thermoelectric cooling circuits in the camera so as to reduce the array temperature to the set value. On reaching that temperature, the control loop locks to the set temperature for stable and reproducible performance. The green Temperature Status indicator on the front panel lights to indicate that temperature lock has been reached (temperature within 0.05°C of set value). If using WinView, there will also be a Temperature Locked YES indication in the Detector Temperature dialog box (accessed from the Setup menu). This on-screen indication allows easy verification of temperature lock in experiments where the computer and controller are widely separated. There is also provision for reading out the actual temperature at the computer so that the progress of the cooldown can be monitored.

Locking tab

×100°C

×1°C

Temperature set to -15°C

Locking tab

×100°C

×1°C

Temperature set to -110°C

There is additionally a red warning temperature indicator. Specifically, it lights if the temperature is set below -75°C with a type TE detector or below -140°C with a type LN detector. Clearly, if the red indicator is lighted, it will be impossible to achieve temperature lock. However, depending on the camera model, array type and other factors, it will probably not be possible to achieve lock at temperatures well above those required to light the red indicator.

As protection against damage from overheating, Princeton Instruments cameras are equipped with a thermal-protection switch that interrupts power to the cooler circuits if the internal temperature exceeds +50°C. This protection is effective for temperature settings down to approximately -270°C

Do not operate with temperature settings outside the range of your particular camera! At temperature settings below approximately -270°C, an overheating condition will occur that could cause internal damage to the camera after an extended period of operation.

Figure 14. Temperature

dial set to -15°C and to

-110°C

WARNING


Because the control loop is designed to achieve temperature lock as quickly as possible, overshoot may occur. If this happens, the green Temperature Status indicator will light, then extinguish briefly during the overshoot, then light again and remain lighted as stable control is re-established. This is normal behavior and should not be a cause for concern. Should a low temperature be set initially and then a higher one, this overshoot would probably not occur because the temperature control loop doesn’t drive the temperature higher, but rather waits passively for temperature rise to occur. Optimum noise performance is achieved by operating at the lowest temperature at which temperature lock can be maintained. Typical values for the lowest temperature can vary over a wide range and will depend on a number of factors, including the camera and array type, as discussed in the individual camera manuals.

Temperature lock to a temperature in the normal operating range for a type TE or RTE camera should typically take about ten minutes. However, the time required to achieve lock can vary over a considerable range, depending on such factors as the camera type, CCD array type, type of cooling, etc. Also, if the lab is particularly warm, achieving temperature lock might take a little longer (30 minutes maximum), or the lowest temperature at which lock can be achieved could be a little higher. Once lock occurs, it’s okay to begin focusing. However, you should wait an additional twenty minutes before taking quantitative data so that the system has time to achieve optimum thermal stability.

35

Chapter 6 Experiment Timing

The Princeton Instruments system has been designed to allow the greatest possible flexibility when synchronizing data collection with an experiment. Below are listed the different timing configurations.

TE/CCD, LN/CCD, and ICCD users can apply any of the timing modes below to their experimental setup. ICCD users also have the option of using a HV pulser, which offers additional gating modes. These gating modes are described in the pulser manual.

The chart below lists all of the timing mode combinations. Use this chart in combination with the detailed descriptions in this chapter to determine the optimal timing configuration.

Mode Store Enable Shutter

Freerun Off Normal

Freerun On Normal

External Sync Off Normal

External Sync Off Preopen

External Sync On Normal

External Sync On Preopen

Continuous Cleans Off Normal

Continuous Cleans Off Preopen

Continuous Cleans On Normal

Continuous Cleans On Preopen

Table 1. Camera timing

modes


Synchronous or Asynchronous The parameter determining overall control of the experiment timing is called Synchronous by the software. When Synchronous is not selected, the controller is operating in Asynchronous mode.

Figure 15 is a flowchart comparing the Synchronous and Asynchronous modes. In Synchronous mode, the controller runs according to the timing of the experiment, with no interruptions from the computer. In Asynchronous mode the computer processes each frame as it is received. The controller cannot collect a new frame until the previous frame has been completely processed.

Synchronous mode is primarily for collection of “real” experimental data, where timing is critical and events cannot be missed. Once the controller is sent the STARTACQ command from the computer, all frames are collected by the controller without further intervention from the computer. A Trigger Out pulse from the controller indicates the beginning of the first exposure (the controller sends only one Trigger Out for the entire series of frames). The advantage of this timing mode is that timing is controlled completely through hardware. A drawback to this mode is that the computer will only display frames when it is not performing other tasks. Image display has a lower priority, so the image on the screen may lag several images behind. A second drawback is that a data overrun may occur if the number of images collected exceeds the amount of allocated RAM.

When collecting more than one frame in Synchronous mode the shutter may open one too many times, or perhaps only open partway on this last exposure. This phenomenon occurs when the controller begins an exposure before the computer issues the STOPACQ command, the command that instructs the controller to stop acquiring data. The extra and/or partial exposure is not digitized or stored, so if the controller is programmed to collect 10 frames, the first 10 exposures are collected and stored.

Asynchronous mode is primarily useful for experiment setup, including alignment and focusing, when it is necessary to have the most current image displayed on the screen. It is also useful when data collection is part of a macro. As seen in Figure 15, in the Asynchronous mode the computer controls when each frame is taken. A Trigger Out pulse from the controller indicates the beginning of each exposure. After each frame is received the controller sends the STOPACQ command to the controller, instructing it to stop acquisition. Once that frame is completely processed and displayed a STARTACQ is sent from the computer to the controller, allowing it to take the next frame. Display is therefore at most only one frame behind the actual data collection.

One disadvantage of the Asynchronous mode is that events may be missed during the experiment, since after each frame the controller is disabled for a short time. The time delay between each frame acquisition is no longer fixed since the software, which has significantly more jitter than the hardware, has full control of data collection.

Chapter 6 Experiment Timing 37

Background orflatfield on?

Start(Asynchronous)

Computer programscontroller with exposureand binning parameters

STARTACQ issued fromcomputer to controller

Cleans performed

1 frame collectedas per timing mode and

store strobe settings

Background and/orflatfield correction

performed

Frame displayed

Framescomplete?

Stop

Yes

Yes

No

No

Background orflatfield on?

Start(Synchronous)

Computer programscontroller with exposureand binning parameters

STARTACQ issued fromcomputer to controller

Cleans performed

1 frame collectedas per timing mode and

store strobe settings

Background and/orflatfield correction

performed

Framescomplete?

Stop

Yes

Yes

No

No

STOPACQ issued fromcomputer to controller

STOPACQ issued fromcomputer to controller

During next acquisitionframes are displayed as

time permits

Figure 15. Chart of

Asynchronous and

Synchronous operation


Store Strobe Option This Store Strobe option is available with the Freerun, External Sync and Continuous Cleans timing modes. It is an option that can be used when frames must be collected at a constant rate, but only selected ones of these frames need to be stored.

The camera continuously repeats the readout/exposure cycle, either with or without external synchronization. At the start of each readout, the controller checks to see if a pulse was received by the External Trigger port on the back of the controller. If an External Trigger was received at any time since the beginning of the previous readout, the digitized data is sent to the computer. If no trigger occurs during this time the digitized data is discarded. Figure 16 shows the basic Store Strobe timing. The signals are TTL logic signals, from 0 to 5 V.

The second trigger pulse in the timing diagram in Figure 16 arrives during a readout. The data that is currently being read out is discarded, but the trigger event is stored in a “latch.” At the beginning of the subsequent readout this latch is checked and reset. Since the latch had recorded a pulse the last readout in the diagram is digitized. In each of the timing mode diagrams, the upper line of text indicates what happens if Store Enable is not selected. The lower line, below the External Trigger plot, is only in the case where Store Enable is selected. This is the case for Figure 20, Figure 22, and Figure 24.

Notscan

External Trigger

Shutter Open Close Open Close Open Close

Read Read Read

First exposureData

storedSecond

exposureData

discardedThird

exposureData

stored

Figure 16. Store Strobe

timing diagram


Once again, this mode is most useful when exposures must always be taken at precise intervals, but only some frames are useful. For data where events are erratic but a background must be subtracted precisely, this option in combination with one of the timing modes below offers the highest performance.

The flow chart in Figure 17 shows details of the frame collection portion of Figure 15. The timing mode part of Figure 17 is detailed later in the flowcharts in Figure 19, Figure 21, and Figure 23. For a discussion and diagrams of array readout, see Readout of the Array, beginning on 55.

Latch=1?(was trigger received)

Store Strobe Off

CCD exposed asper timing mode

CCD datadigitized

Store Strobe On

CCD exposed asper timing mode

Ext. Trigger "latch" isread and reset

CCD data digitizedand discarded

Yes

No

CCD data digitized andtransferred to computer

Figure 17. Store Strobe timing

chart, part of the chart in Figure 15


Standard Triggering Modes The three triggering modes available for any ST-138 based system are Freerun, External Sync, and Continuous Cleans. These timing modes are combined with the Store Enable and Shutter options to provide the widest variety of timing modes for precision experiment synchronization. Cable connections for these timing modes are shown in Figure 18. Not all connections shown may be needed.

To detector

Shutter monitorNotscan

Trigger out

To computer

Power

Trigger in External Sync

The shutter options available include Normal, Preopen, or Disable. Disable simply means that the shutter will not open at all during the experiment. This is only useful for making dark charge measurements, or when no shutter is present in the system. Preopen, available in External Sync or Continuous Cleans mode, opens the shutter as soon as the controller is ready to receive an External Sync pulse but before the pulse is received. This is required if the time between the External Sync pulse and the event is less than the few milliseconds it takes the shutter to open.

The Shutter Monitor output is shown in the timing diagrams for each timing mode below. Except for Freerun, where the modes of shutter operation are identical, both Normal and Preopen lines are shown in the timing diagrams and flow chart. The flow chart in Figure 17 was represented earlier in Figure 15 as a single box with a dotted line.

The timing diagrams are labeled indicating the exposure time (texp), shutter compensation time (tc), and readout time (tR). These parameters are discussed in more detail in Chapter 7.

Figure 18. Possible cable

connections for timing modes


Freerun timing In the Freerun mode the controller does not synchronize with the experiment in any way. The shutter opens as soon as the previous readout is complete, and remains open for the exposure time, texp. Any External Sync or External Trigger signals are ignored. This mode is useful for experiments with a constant light source, such as a CW laser or a DC lamp. Other experiments that can utilize this mode are high repetition studies, where the number of shots that occur during a single shutter cycle is so large that it appears to be continuous illumination.

Shutter opens

Shutter remains openfor preprogrammed

exposure time

System waits whileshutter closes

Other experimental equipment can be synchronized to the controller by using the Trigger Out, Shutter Monitor, or Notscan ports. These signals (synchronous operation) are shown in Figure 20. All are TTL logic signals, from 0 to 5 V.

Notscan

External Trigger

Shutter Open Close Open Close Open Close

Read Read Read

First exposureData

storedSecond

exposureData

discardedThird

exposureData

stored

First exposureData

storedSecond

exposureThird

exposureData

storedData

stored

Trigger Out

texp tRtc

Figure 19. Freerun timing

chart, part of the chart in

Figure 17

Figure 20. Freerun timing

diagram


External Sync timing In this mode all exposures are synchronized to an external source. As shown in the flow chart, Figure 21, this mode can be used in combination with Normal or Preopen Shutter operation. In Normal Shutter mode, the controller waits for an External Sync pulse, then opens the shutter for the programmed exposure period. As soon as the exposure is complete the shutter closes (shutter compensation time is discussed in Chapter 7) and the CCD data are read out. The time required for the shutter to open completely depends on the shutter type, typically 5 ms for a small or remote shutter, and from 16 to 20 ms for a large shutter.

Since the shutter requires up to 10 msec to fully open, the External Sync pulse provided by the experiment must precede the actual signal by at least that much time. If not, the shutter will not be open during the entire signal, or the signal may be missed completely.

Also, since the amount of time from the initialization of the experiment to the first trigger pulse is not fixed, an accurate background subtraction may not be possible for the first readout. In multiple-shot experiments this is easily overcome by simply discarding the first frame.

In the Preopen Shutter mode, on the other hand, shutter operation is only partially synchronized to the experiment. As soon as the controller is ready to collect data the shutter opens. Upon arrival of the first External Sync pulse to the controller, the shutter remains open for the specified exposure period, closes, and the CCD is readout. As soon as readout is complete the shutter re-opens and waits for the next frame.

Shutter opens


exposure time


Shutter opensController waits forExternal Sync pulse

Controller waits forExternal Sync pulse

(shutter preopen) (shutter normal)

Figure 21. Chart showing

two External Sync timing

options, part of chart in Figure

17


The Preopen mode is useful in cases where an External Sync pulse cannot be provided 5-10 msec before the actual signal occurs. Its main drawback is that the CCD is exposed to any ambient light incident on the detector while the shutter is open between frames. If this ambient light is constant, and the triggers occur at regular intervals, this background can also be subtracted, providing that it does not saturate the CCD. As with Normal Shutter mode, accurate background subtraction may not be possible for the first frame.

Also note that in addition to signal from ambient light, dark charge accumulates during the “wait” time (tw). Any variation in trigger frequency also affects the amount of dark charge, even if light is not falling on the CCD during this time.

Notscan

External Trigger

Shutter (Normal) Open Close Open Close Open Close

Read Read Read

First waitand exposure

Datastored

Second waitand exposure

Datadiscarded

Third waitand exposure

Shutter (Preopen) Open Close Open Close Open Close

External Sync

Datastored

First waitand exposure

Datastored

Second waitand exposure

Third waitand exposure

Datastored

Datastored

Trigger Out

texp tc tRtw1

Figure 22. Timing diagram for the External

Sync mode


Continuous Cleans timing The third timing mode available with the ST-138 Controller is called Continuous Cleans. In addition to the standard “cleaning” of the array, which occurs after the controller is enabled, Continuous Cleans will remove any charge from the array until the moment the External Sync pulse is received. This continuous cleaning is accomplished by driving both the vertical and horizontal clocks of the chip simultaneously.

Shutter opens


exposure time


Shutter opensCCD is continuously

cleaned until External Syncpulse is received

(shutter preopen) (shutter normal)

CCD is continuouslycleaned until External Sync

pulse is received

Once the External Sync pulse is received, cleaning of the array stops as soon as the current row is shifted, and frame collection begins. With Normal Shutter operation the shutter is opened for the set exposure time. With Preopen Shutter operation the shutter is open during the continuous cleaning, and once the External Sync pulse is received the shutter remains open for the set exposure time, then closes.

Figure 23. Continuous

Cleans operation flow

chart, part of the chart in

Figure 17


If the vertical rows are shifted midway when the External Sync pulse arrives, the pulse is saved until the row shifting is completed, to prevent the CCD from getting “out of step.” As expected, the response latency is on the order of one vertical shift time, from 1-30 µsec depending on the array. This latency does not prevent the incoming signal from being detected, since photo generated electrons are still collected over the entire active area. However, if the signal arrival is coincident with the vertical shifting, image smearing of up to one pixel is possible. The amount of smearing is a function of the signal duration compared to the single vertical shift time.

Notscan

External Trigger

Shutter (Normal) Open Close Open Close Open Close

Read Read Read

Exp.Data

stored

Datadiscarded

Shutter (Preopen) Open Close Open Close Open Close

External Sync

Cont.cleans

Cont.cleans

Cont.cleansExp. Exp.

Datastored

Datastored

Datastored

Datastored

Trigger Out

Figure 24 shows only Synchronous operation, in which only one Trigger Out pulse is sent from the controller. This pulse occurs at the start of the first exposure. In Asynchronous mode (not shown), each exposure produces its own Trigger Out pulse.

Figure 24. Continuous

Cleans timing diagram


Special Triggering Modes Several specialized triggering modes are available with only the Model ST-138 Controller. These include frame transfer and kinetics timing modes. Readout of these modes is described in Chapter 7. The sections below describe how the timing of these modes operates.

Frame transfer timing Frame transfer operation assumes that half of the CCD is used for sensing light, and the other half is used for storage and readout. Not all CCD arrays are capable of readout in this mode, as it requires that charge can be shifted in the two halves of the array independently. Arrays such as those manufactured by Kodak, for example, do not have this capability and therefore cannot be operated in frame transfer mode. For a discussion of frame-transfer array readout, including frame-transfer shift diagrams, see Frame Transfer Readout on page 63.

The camera head must also have certain circuitry for frame transfer operation. Currently LN/CCD cameras do not operate in frame transfer mode. TE/CCD and ICCD cameras are capable of frame transfer operation only if ordered as a frame transfer camera. Frame transfer cameras can be operated in full frame mode, but if masking is present, then only half of the array will detect signal.

There are two timing options available in frame transfer mode, Freerun or External Sync. Both are similar to their counterparts in full frame (standard) operation, except that in frame transfer operation a shutter is not generally used. Because there is no shutter (or the shutter is only closed after the detector has collected a series of frames), shutter Normal, Preopen, or Disable have no physical meaning here. The exposure time setting affects the Shutter Monitor output, as shown in Figure 27.

In Freerun, Frame Transfer mode the detector exposes for the set exposure time (texp), and then quickly shifts the charge into the other half of the array. As soon as this shifting is complete (typically a few milliseconds) the next exposure immediately begins. During the exposure charge is read out of the storage half of the array. The minimum exposure time is equal to the amount of time needed to read out the storage half of the array. If the Exposure is set to less than the readout time the exact length of the exposure will vary depending on when the External Sync pulse is received. Figure 25 shows an example where texp + tw1 + tc < tR. The time the controller waits for the first pulse is tw1.

Notscan

Shutter monitor

Read Read Read

External Sync

Trigger Out

Read

Data notstored Shift Shift Shift Shift

Datastored

Datastored

Datastored

texptw1 tRts

Figure 25. Frame Transfer

where texp + tw1 + tc < tR


In External Sync, Frame Transfer mode the detector reads out one frame for every External Sync pulse received, providing that the frequency does not exceed the maximum rep rate possible with the system. As shown in Figure 25, the first readout is discarded, since these data are already in the storage half of the array when the first External Sync pulse was received and thus contain no information. From the second frame on every frame is digitized and stored.

Although in Figure 25 and Figure 26 the shutter monitor is low before the External Sync pulse is received, remember that in most cases there is no mechanical shutter present, so light is falling on the array during the entire readout (whenever Notscan is low). The actual exposure is therefore somewhat longer than the Shutter Monitor indicates. Figure 26 shows the timing of the experiment if the exposure time is set to a value greater than the readout time (texp + tw1 + tc > tR).

Notscan

Shutter monitor

Read Read Read

External Sync

Trigger Out

Read

ShiftData

storedData

storedData

storedShift Shift Shift

texptw1 tRts

Figure 26 shows a case where the External Sync pulse arrives during the readout of the array. Depending on the frequency of this signal and the frame rate of the detector, this pulse could also arrive after the readout. Figure 27 shows the timing under these conditions. Notice that the Shutter Monitor signal is shown in both Normal and Preopen modes. Although a shutter is not usually used during frame transfer mode, the Shutter Monitor port can be used to activate other aspects of an experiment.


where texp + tw1 + tc > tR


Notscan

Shutter (normal)

Read Read Read

External Sync

Trigger Out

Read

Datanot

stored ShiftData

storedData

storedData

storedShift Shift

Shutter (preopen)

texptw1

tRts

Kinetics timing Charge can be shifted on the surface of a CCD array much faster than it can be read out. If only a small area of a CCD is illuminated, the charge from several exposures can be shifted along the surface, in much the same way that a long strip of film is passed through a traditional photographic camera to record a series of images. Instead of moving the film, the Princeton Instruments camera moves only the charge along the surface of the array, and this makes it very fast. This type of readout is described in more detail in Chapter 7.

Kinetics mode operates with three timing modes: Freerun, Single Trigger, and Multiple Trigger. In the Freerun Kinetics mode the controller takes a series of images each with the Exposure set through the software, with only a few hundred microseconds between frames. The exact number of frames depends on the Window Size selected by the user. The number of frames is the Window Size divided by the number of pixels perpendicular to the shift register (Nx in the terminology of Chapter 7).

Single Trigger Kinetics mode takes an entire series of images with each External Sync pulse. After the series is complete the shutter closes and the CCD is read out normal speeds. Once the readout is complete the detector is ready for the next series of exposures. This timing is shown in Figure 28, where a single External Sync pulse is used to collect a burst of 8 frames. Note the signal provided at the NORM3 BNC connector. It can be used to enable an experiment light source, such as a laser. It is desirable that the light source only be activated during the exposure time. This is particularly true with lasers that have a long recovery time after each operation. The way to accomplish this is to only enable the light source when the NORM3 signal is high. When the NORM3 signal is low, the light source should be inhibited.


where pulse arrives after

readout


Notscan

Shutter monitor

External Sync

Trigger Out

Read

Norm3 Out

ExposureShift

Exposure

Shift

Multiple Trigger Kinetics takes a single image in the series for each External Sync pulse received by the controller. Once the series is complete the shutter closes and readout begins. Since the shutter is open during the entire series of images, if the External Sync pulses are irregularly spaced then the exposures will be of different lengths. Once the series has been read out the detector is ready for the next series. This timing is shown in Figure 29, where a series of 8 frames is collected with 8 External Sync pulses. Again, the NORM3 Output can be used to enable/inhibit the light source.

Notscan

Shutter monitor

External Sync

Trigger Out

Read

Norm3 Out

ExposureShift

Wait Exposure

ShiftWait

Figure 28. Single Trigger

Kinetics

Figure 29. Multiple Trigger Kinetics

51

Chapter 7 Exposure and Readout

Before each image from the CCD detector appears on the computer screen, it must first be read, digitized, and transferred to the computer. A block diagram of the path of the image signal is shown in Figure 30.

Image intensifier

CCD

Preamp

Cable driver

Incoming photons

Up/down integrator

Fast A/D

HS serial buffer board

Display

Camera

Controller

Computer

ICCDTE/CCDLN/CCD

Slow A/D

Lookup table

HS serial interface

Storage

8 bit 32 bit

Accumulator

16 bit 12/14 bit

16 bit12/14 bit

The sections below describe the exposure, readout, and digitization of the image. Included are descriptions of binning for imaging or spectroscopy applications, and the specialized timing modes available only with the ST-138 Controller.

Exposure Charge coupled devices can be roughly thought of as a two-dimensional grid of individual photodiodes (called pixels), each connected to its own charge storage “well.” Each pixel senses the intensity of light falling on its collection area, and stores a proportional amount of charge in its associated “well”. Once enough charge accumulates, the pixels are read out serially.

CCD arrays perform three essential functions: photons are transduced to electrons, integrated and stored, and finally read out. CCDs are very compact, rugged, and unintensified, uncoated CCDs can withstand direct exposure to relatively high light

Figure 30. Block diagram of light path in

system


levels and magnetic and RF radiation. They are easily cooled and can be precisely thermostated to within a few tens of millidegrees.

Because CCD detectors, like film and other media, are always sensitive to light, light must not be allowed to fall on the array during readout. Unintensified CCD detectors, including the TE/CCD and LN/CCD models, use a mechanical shutter to prevent light from reaching the CCD during readout. ICCD (intensified) models use an image intensifier to gate the light on and off.

Princeton Instruments software allows the user to set the length of time the detector is allowed to integrate the incoming light, called the exposure. During each scan, the shutter or intensifier is enabled for the duration of the exposure period, allowing the pixels to register light.

Exposure with a mechanical shutter Unintensified CCD detectors, including TE/CCD and LN/CCD models, use a mechanical shutter to control the exposure of the CCD. The following chart lists the appropriate mechanical shutter compensation time (tc), the delay allowed after the exposure (texp) for the shutter to close. These values are for detector-mounted shutters only.

CCD Array Compensation time, msec

576 × 384, 768 × 512, 1317 × 1035 6.75

All other CCDs 26.75

The diagram in Figure 31 shows how the exposure period is measured. Either the Notscan or the Shutter Monitor port on the back of the controller can be used to monitor the exposure and readout cycle (tR). Both of these signals are also shown in Figure 31.

Notscan

Shutter Monitor

Mechanical Shutter

Acquire Readout

ClosedOpen

Exposure time Shutter compensationtexp tc

Notscan is low during readout, high during exposure, and high during shutter compensation time. Shutter Monitor is high during exposure, low during shutter compensation, and low during readout.

Since most shutters behave like an iris, the opening and closing of the shutter will cause the center of the CCD to be exposed slightly longer than the edges. It is important to realize this physical limitation, particularly when using short exposures.

Table 2. Shutter

compensation time

Figure 31. Exposure of the

CCD with shutter

compensation

Chapter 7 Exposure and Readout 53

Exposure with an image intensifier ICCD (intensified) cameras use an image intensifier both to gate light on and off and to greatly increase the brightness of the image. In these cameras the image intensifier detects and amplifies the light, and the CCD is used for readout. The coupling between the CCD and the intensifier can be either fiber optic, which is the most sensitive, or with a relay lens, a more flexible camera arrangement. With a fiber coupled camera, the combined high gain of the image intensifier and the low readout noise of the CCD array result in a camera capable of responding to a single photoelectron.

The exposure programmed by software in this case refers to duration of gating of the intensifier. Our standard (fiber coupled) ICCD when operated with only a controller is capable of exposures as short as 5 msec. Because the controller is used to control the exposure the shutter compensation time, as shown in Figure 31, is 1.75 msec. For shorter exposures, a Princeton Instruments pulser is required.

Photocathode

Quartz window

MCP electron intensifier

PhosphorFiber-optic coupler

CCDCold finger

The MCP (microchannel plate) of the intensifier is composed of more than 106 individual miniature electron multipliers with an excellent input to output spatial geometric accuracy. Intensifier gain is varied by adjusting the voltage across the MCP or the voltage across the MCP output and the phosphor. This second parameter is a factory adjustment, as it affects both the gain and the resolution of the intensifier.

Detection of extremely weak CW signals, e.g., luminescence and Raman scattering from solid state samples, is typically limited by the dark current of the intensifier’s photocathode, usually referred to as the equivalent brightness intensity (EBI). All standard Princeton Instruments intensified cameras have the lowest EBI values possible.

Continuous exposure (no shuttering) Unlike video rate CCD cameras, slow scan scientific cameras require a shutter to prevent “smearing” of features during readout. This is because during readout, charge is moved

Figure 32. Diagram of an

MCP image intensifier


horizontally or vertically across the surface of the CCD. If light is falling on the CCD during readout then charge will continue to accumulate, blurring the image along one direction only.

For some experimental applications a shutter is not required because no light falls on the CCD during readout. If the light source can be controlled electronically, outputs such as Trigger Out can produce the signal, and the CCD can be read out in darkness. For some specialized cameras, such as those for some X-ray applications, no shutter is available, and electronic control of the signal is necessary. If a shutter is present it can be held open for short periods of time using the External Shutter Control on the rear of the controller.

In other cases a shutter is not required because “smearing” is not an issue. For spectroscopy applications where only a single spectrum is acquired and the CCD is set up in “parallel” mode (described in the readout section below), smearing of the signal along the slit direction does not cause any loss of information, since no relevant information is contained along the slit axis. By removing or disabling the shutter the highest spectral rates are possible.

Finally, cameras with frame transfer capability may be used with or without a shutter. Although this closely resembles the operation of video rate cameras, the high dynamic range and slower readout may still make the smearing non-negligible. For example, on an 8-bit video rate camera 1% smearing results in only about 2 counts of smearing per pixel. On a 16-bit slow scan camera, the same 1% results in over 600 counts of smearing.

Saturation When signal levels in some part of the image or spectrum are very high, charge generated in one pixel may exceed the “well capacity” of the pixel, spilling over into adjacent pixels in a process called “blooming.” In this case a more frequent readout is advisable, with signal averaging to enhance S/N accomplished through the software.

For signal levels low enough to be readout-noise limited, longer exposure times, and therefore longer signal accumulation in the CCD, improves the S/N ratio approximately linearly with the length of exposure time. There is, however, a maximum time limit for on-chip averaging, determined by either the saturation of the CCD by the signal or the loss of dynamic range due to the buildup of dark charge in the pixels (see below).

Dark charge Dark charge (or dark current) is the thermally induced buildup of charge in the CCD over time. The statistical noise associated with this charge is known as dark noise. Dark charge values vary widely from one CCD array to another and are exponentially temperature dependent. At the typical operating temperature of an RTE/CCD camera, for example, dark charge is reduced by a factor of ~2 for every 6º reduction in temperature. At -50ºC, a non-MPP CCD will have an average dark charge value of approximately 0.5 counts/pixel/second (approximately 3-6 electrons). This represents approximately 0.003% of a 14-bit A/D (16,000:1). In the case of cameras such as the RTE/CCD-768-K and RTE/CCD-1317-K, which have MPP type arrays, the average dark charge is extremely small. However, the dark-charge distribution is such that a significant number of pixels may exhibit a much higher dark charge, limiting the maximum practical exposure. Dark charge effect is more pronounced in the case of cameras having a non-MPP array.


With the light into the camera completely blocked, the CCD will collect a dark charge pattern, dependent on the exposure time and camera temperature. The longer the exposure time and the warmer the camera, the larger and less uniform this background will appear. Thus, to minimize dark-charge effects, you should operate with the lowest CCD temperature possible.

Note: Do not be concerned about either the DC level of this background or its shape unless it is very high, i.e., > 1000 counts with 16-bit A/D or 300 counts with a 12-bit A/D. What you see is not noise. It is a fully subtractable readout pattern. Each CCD has its own dark charge pattern, unique to that particular device. Simply acquire and save a dark charge “background image” under conditions identical to those used to acquire the “actual” image. Subtracting the background image from the actual image will significantly reduce dark-charge effects.

Note that the offset level is more likely to require readjustment if the controller and camera weren’t calibrated and tested as a system at the factory.

If you observe a sudden change in the baseline signal you may have excessive humidity in the vacuum enclosure of the camera. See your camera manual for information on repumping the vacuum.

Readout of the Array In this section, a simple 6 × 4 pixel CCD is used to demonstrate how charge is shifted and digitized. As described below, three different types of readout are available. Full frame readout, for full frame CCDs, reads out the entire CCD surface at the same time. Frame transfer operation assumes half of the CCD is for data collection and half of the array is a temporary storage area. Finally, kinetics operation assumes only a small part of the array is for data collection, and the remainder is for temporarily storing a limited number of frames.

Full frame readout The upper left drawing in Figure 33 represents a CCD after exposure but before the beginning of readout. The capital letters represent different amounts of charge, including both signal and dark charge. This section explains readout at full resolution, where every pixel is digitized separately.

CAUTION


1 2

3 4

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5 A6

B4 B5 B6

C4 C5 C6

D4 D5 D6

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5 A6

B4 B5 B6

C4 C5 C6

D4 D5 D6

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5

A6

B4 B5

B6

C4 C5

D4 D5

C6

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5

A6B4 B5

B6C4 C5

C6D4 D5

D6

Readout of the CCD begins with the simultaneous shifting of all pixels one column toward the “shift register,” in this case the column on the far right. The shift register is a single line of pixels along one side of the CCD, not sensitive to light and used for readout only. Typically the shift register pixels hold twice as much charge as the pixels in the imaging area of the CCD.

After the first column is moved into the shift register, the charge now in the shift register is shifted toward the output node, located at one end of the shift register. As each value is “emptied” into this node it is sent to the controller and digitized. Only after all pixels in the first column are digitized is the second column moved into the shift register. The order of shifting in our example is therefore D6, C6, B6, A6, D5, C5, B5, A5, D4....

After charge is shifted out of each pixel the remaining charge is zero, meaning that the array is immediately ready for the next exposure.

Below are the equations that determine the rate at which the CCD is read out.

The time needed to take a full frame at full resolution is:

tR + texp + tc (1)

where tR is the CCD readout time,

texp is the exposure time, and

tc is the shutter compensation time.

Figure 33. Full frame at

full resolution


The readout time is given by:

tR = [Nx · Ny · (tsr + tv)] + (Nx · ti) (2)

where

Nx is the smaller dimension of the CCD (except for the 1152 × 298, 1152 × 770, and 576 × 384 CCDs, where you should use the larger of the two dimensions)

Ny is the larger dimension of the CCD

tsr is the time needed to shift one pixel out of the shift register

tv is the time needed to digitize a pixel

ti is the time needed to shift one line into the shift register

(ts, the time needed to discard a pixel, appears below and in later equations)

Timing values appear below for some CCD arrays. All clock values are given in microseconds. The numbers below are subject to change, and are therefore not a guarantee that your particular detector will run at a given A/D rate. These values are given as a guideline only.

Manufacturer A/D

(kHz) 50 100 150 200 430 500 1000

SITe TE front illum. ti 9.6 9.6 9.6 9.6 9.6 9.6 N/A

SITe LN front illum. ti 19.2 19.2 19.2 19.2 19.2 19.2 N/A

All SITe back illum ti 153.6 153.6 153.6 153.6 153.6 153.6 N/A

All SITe tsr 0.6 0.6 0.6 0.6 0.6 0.6 N/A

All SITe tv 17.6 8.8 6.0 4.4 1.7 1.4 N/A

All SITe ts 1.6 0.8 0.4 0.4 0.5 0.4 N/A

All EEV ti 15.0 15.0 15.0 15.0 15.0 15.0 15.0

All EEV tsr 0.6 0.6 0.6 0.3 0.3 0.3 0.2

All EEV tv 18.4 9.2 6.2 4.7 2.0 1.7 0.9

All EEV ts 1.6 0.8 0.4 0.4 0.6 0.6 0.5

Reticon TE ti 12.0 12.0 12.0 12.0 12.0 12.0 N/A

Reticon LN ti 25.2 25.2 25.2 25.2 25.2 25.2 N/A

All Reticon tsr 0.6 0.6 0.6 0.6 0.6 0.6 N/A

All Reticon tv 17.6 8.8 6.0 4.4 2.0 1.5 N/A

All Reticon ts 1.6 0.8 0.4 0.4 0.5 0.5 N/A

Kodak 768 ti 19.2 19.2 19.2 19.2 19.2 19.2 19.2

Kodak 1280, 1317 ti 38.4 38.4 38.4 38.4 38.4 38.4 38.4

Kodak 2033, 3072 ti 48.0 48.0 48.0 48.0 48.0 48.0 48.0

All Kodak tsr 0.4 0.4 0.4 0.4 0.4 0.2 0.1

All Kodak tv 18.4 9.2 6.2 4.6 1.9 1.6 0.9

All Kodak ts 1.6 0.8 0.4 0.4 0.4 0.5 0.5

Table 3. Typical timing

values for some CCD arrays


Manufacturer A/D (kHz)

50 100 150 200 430 500 1000

All PI * ti 48.0 48.0 N/A N/A N/A N/A N/A

All PI tsr 6.4 6.4 N/A N/A N/A N/A N/A

All PI tv 20.8 10.4 N/A N/A N/A N/A N/A

All PI ts 0.4 0.4 N/A N/A N/A N/A N/A

A subsection of the CCD can be read out at full resolution, dramatically increasing the readout rate while retaining the highest resolution in the region of interest (ROI). To approximate the readout rate of an ROI, in Equation 2 substitute the x and y dimensions of the ROI in place of the dimensions of the full CCD. A small amount of overhead time is required to read out and discard the unwanted pixels.

Image readout with binning Binning is the process of adding the data from adjacent pixels together to form a single pixel (sometimes called a super-pixel), and it can be accomplished in either hardware or software. Rectangular groups of pixels of any size may be binned together, subject to some hardware and software limitations.

Hardware binning is performed before the signal is read out by the preamplifier. For signal levels that are readout noise limited this method improves S/N ratio linearly with the number of pixels grouped together. For signals large enough to render the detector photon shot noise limited, and for all fiber-coupled ICCD detectors, the S/N ratio improvement is roughly proportional to the square-root of the number of pixels binned.

Figure 34 shows an example of 2 × 2 binning. Each pixel of the image displayed by the software represents 4 pixels of the CCD array. Rectangular bins of any size are possible.

* PI stands for Princeton Instruments


1 2

3 4

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5 A6

B4 B5 B6

C4 C5 C6

D4 D5 D6

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5+A6

B4 B5+B6

C4 C5+C6

D4 D5+D6

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4

B4

C4

D4

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4

A5+A6

B4

B5+B6

C4

D4

C5+C6+D5+D6

A5+A6+B5+B6

Binning also reduces readout time and the burden on computer memory, but at the expense of resolution. Since shift register pixels typically hold only twice as much charge as image pixels, the binning of large sections may result in saturation and “blooming”, or spilling of charge back into the image area.

The readout rate for n × n binning is calculated using a more general version of the full resolution equation. The modified equation is:

(3)

Single spectrum readout with binning Depending on the physical structure of the CCD, spectroscopic readout is either achieved in “perpendicular” or “parallel” mode. Perpendicular mode is needed when the shift register is along the shorter axis of the CCD, as is the case with 576 × 384, 1152 × 298, and 1152 × 770 formats. All other rectangular formats operate in parallel mode. Square arrays such as the 1024 × 1024 when used for spectroscopic applications can be operated in either perpendicular or parallel mode. See below for a discussion of advantages of both methods.

Perpendicular (slow) mode is best for high light levels, when readout speed is not a factor. Charge cannot “spill” back into the shift register or the image area. Also, the output node can contain ~2-3 times as much charge as an imaging pixel, allowing a

Figure 34. 2 x 2 binning

for images


larger dynamic range. Finally, readout rate is reduced, since time is required to “empty” the shift register after each vertical shift.

With these arrays each spectral line is first moved to the shift register, then grouped together in the output node and digitized. For the case of our simplified CCD model, shifting proceeds as shown in Figure 35.

1 2

3 4

A1 A2 A3

B1 B2 B3

A4 A5 A6

B4 B5 B6

A1 A2 A3

B1 B2 B3

A4 A5 A6

B4 B5 B6

A1 A2 A3

B1 B2 B3

A4 A5

B4 B5

A1 A2 A3

B1 B2 B3

A4 A5

A6+B6

B4 B5

For the perpendicular mode, the equation for binning a single spectrum is:

(4)

where ts is the time needed to discard a pixel (no digitization)

The parallel (fast) mode is used with arrays where the shift register is parallel to the spectral dispersion. Although the dynamic range is now limited by the well capacity of the pixels of the shift register, there is a dramatic increase in speed, since the shift register is only “emptied” once. Figure 36 is a simple example of this mode.

Figure 35. Perpendicular mode binning


1 2

3 4

A1 A2 A3

B1 B2 B3

A4 A5 A6

B4 B5 B6

A1 A2 A3

B1 B2 B3

A4 A5 A6

B4 B5 B6

A1+

B1

A2+

B2

A3+

B3

A4+

B4

A5+

B5

A6+

B6

A1+

B1

A2+

B2

A3+

B3

A4+

B4

A5+

B5

A6+

B6

In the parallel mode, the equation for binning a single spectrum becomes

(5)

Figure 36. Parallel mode

binning


Binning in software One limitation of hardware binning is that the shift register pixels and the output node are typically only 2-3 times the size of imaging pixels. Imaging pixels have a well capacity of approximately 5 × 105 electrons, while shift registers and “binning” capacitors hold approximately 106 electrons. Consequently, if the total charge binned together exceeds the capacity of the shift register or output node, the data will be lost.

This restriction strongly limits the number of pixels that may be binned in cases where there is a small signal superimposed on a large background, such as in the case of Raman spectroscopy of signals with a large fluorescence. Ideally, one would like to bin many pixels to increase the S/N ratio of the weak peaks but cannot, since the fluorescence will quickly saturate the CCD.

The solution is to perform the binning in software. Limited hardware binning may be used when reading out the CCD. Additional binning is accomplished in software, producing a result that represents many more photons than was possible using hardware binning.

Software averaging can improve the S/N ratio by as much as the square root of the number of scans. Unfortunately with a high number of scans, i.e., above 100, detector 1/f noise may reduce the actual S/N ratio to slightly below this theoretical value. Also, if the light source used is photon flicker rather than photon shot noise limited, this theoretical signal improvement cannot be fully realized. Again, background subtraction from the raw data is necessary.

This technique is also useful in high light level experiments, where the detector is again photon shot noise limited. Summing multiple pixels in software corresponds to collecting more photons, and results in a better S/N ratio in the measurement.


Frame transfer readout The ST-138 Controller fully supports frame transfer readout of detectors capable of this mode. Operation in this mode is very similar to the operation of video rate detectors. Half of the CCD is exposed continuously, raising the exposure duty cycle to nearly 100%. The other half of the CCD is masked to prevent exposure, and it is here that the image is “stored” until it can be read out.

Figure 37 shows the readout of a masked version of our sample 4 × 6 CCD. The shading represents the masked area (masking may be on the array, mechanical, or optical).

1 2

3 4

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5 A6

B4 B5 B6

C4 C5 C6

D4 D5 D6

A1 A2

A3

B1 B2

B3

C1 C2

D1 D2

C3

A1 A2 A3

B1 B2 B3

C1 C2 C3

D1 D2 D3

A4 A5 A6

B4 B5 B6

C4 C5 C6

D4 D5 D6

A1

B1

C1

D1

D2

A2

B2

C2

Only the exposed region collects charge. At the end of the exposure, the charge is quickly shifted into the masked region. Since the shifting is accomplished in a short time, i.e., a few milliseconds, the incident light causes only minimal “smearing” of the signal. While the exposed region continues collecting data, the masked region is read out and digitized. The percentage of smearing is given by the equation below, simply the time needed to shift all rows from the imaging area divided by the exposure time.

(6)


readout


Kinetics mode readout Kinetics mode uses the CCD to store a limited number of images in rapid succession. The time it takes to shift each line on the CCD is as short as a few microseconds, depending on the CCD. Therefore the time between images can be as short as a few hundred microseconds.

Returning to our 4 × 6 CCD example, in this case 2/3 of the array is masked, either mechanically or optically. The shutter opens to expose a 4 × 2 region. While the shutter remains open charge is quickly shifted just under the mask, and the exposure repeated. After a third image is collected the shutter is closed and the CCD is read out. Since the CCD can be read out slowly, very high dynamic range is achieved. Shifting and readout are shown in Figure 38.

1 2

3 4

5 6

A1 A2A3

B1 B2B3

C1 C2C3

D1 D2D3

A4A5 A6

B4B5 B6

C4C5 C6

D4D5 D6

A1

A2

A3

B1

B2

B3

C1

C2

C3

D1

D2

D3

A4A5 A6

B4B5 B6

C4C5 C6

D4D5 D6

A1 A2A3

B1 B2B3

C1 C2C3

D1 D2D3

A4

B4

C4

D4

A1 A2A3

B1 B2B3

C1 C2C3

D1 D2D3

A4

B4

C4

D4

A1 A2

B1 B2

C1 C2

D1 D2

A1 A2

B1 B2

C1 C2

D1 D2

Figure 38. Kinetics readout


Digitization During readout, an analog signal representing the charge of each pixel (or binned group of pixels) is sent to the controller and digitized. The number of bits per pixel is based on both the hardware and the settings programmed into the controller through the software. The ST-138 Controller can contain up to two A/D converters, and some of the converters allow different readout rates settable through software. A lookup table option is also available for the fastest possible image display, “movie mode”. Finally, on-board memory may be used for the accumulation of many images together in hardware.

Dual A/D converters The ST-138 Controller can contain up to two A/D converters. System configurations differ widely, with A/D rates ranging from 50 kHz (50,000 pixels per second) to 1 MHz (1 million pixels per second).

In situations where the fastest possible data acquisition is needed, the fast A/D is used. The software can quickly switch to the slower A/D when higher dynamic range data is required. To switch between the two A/D, simply set the converter type and speed in the software. If a fast speed is selected, the controller will automatically use the fast A/D. For slower speeds the higher dynamic range A/D will be used.

A/D converter(s) in Controller Possible A/D rates

1 MHz 12 bits 1 MHz only 1 MHz 14 bits 1 MHz only 1 MHz 12 bits; 430 kHz 16 bits 1 MHz and one of 430, 200, 100 or 50 kHz,

(not user selectable, factory set) 1 MHz 14 bits; 430 kHz 16 bits 1 MHz and one of 430, 200, 100 or 50 kHz,

(not user selectable, factory set) 500 kHz 12 bits 500, 200, 100, or 50 kHz, user selectable 500 kHz 12 bits; 150 kHz 16 bits 500, 200, 150, 100, or 50 kHz, user selectable 430 kHz 16 bits 430 or 200 kHz, user selectable 430 kHz 16 bits; 150 kHz 16 bits 430, 200, 150, 100, or 50 kHz, user selectable 150 kHz 16 bits 150, 100, or 50 kHz, user selectable

Lookup table The ST-138 Controller has a built in Lookup Table for real time display of images, called Movie mode. In this mode, the controller autoscales and converts each two-byte pixel value to 8 bits in hardware before transferring this data to the computer. The 8-bit data can then be sent directly to the monitor for display, resulting in a display rate up to several frames per second, several times faster than systems without this option.

Accumulator The ST-138 Controller also offers optional Accumulator memory, for adding multiple images together in hardware. The Accumulator requires four bytes of memory per pixel, and is activated through the software. As frames are collected the results are accumulated, pixel-by-pixel, so that the final result is a single image with 32 bits per pixel. Not only does this hardware allow summing of thousands of frames at full speed, but it can also be used to temporarily store images if more than one ST-138 Controller is connected to the same computer. Contact the factory for information on this option.

Table 4. Possible A/D

settings for the Model ST-138

Controller

67

Appendix A Specifications

General Thermostating precision: ±0.05°C

A/D converter range: 12, 14-16 bits

Linearity: better than 1%.

Exposure (integration time): 5 msec to 23 hours (full frame or frame transfer), 0.2 µsec to 1 sec (kinetics)

Accumulator memory width: 32 bits (4.29 × 109 counts) per pixel

Readout rate: 50, 100, 150, 200, 430, 500 kHz, 1 MHz, depending on converter

Readout noise: 1-1.2 counts RMS on standard systems

Dimensions: 7″ h, 17″ w, 16″ d; rack mounts available

Weight: 18 kg

Power Requirements: 100, 120, 220, or 240 V at 50 or 60 Hz, approximately 250 W

TTL Requirements: Rise time ≤ 40 nsec, Duration ≥ 100 nsec.

Environmental Requirements: Storage temperature -20° C to 55° C; Operating temperature range over which specifications can be met is 18° C to 23° C; Relative humidity <80% noncondensing.

Input Ports External Synchronization: TTL low; up to 1/tR.

Trigger In: TTL low

External Shutter Control: TTL low to open shutter, high to close.

Software Programmable Inputs: (8) TTL low or high.


Output Ports Trigger Out: TTL low at start of data acquisition

Notscan: TTL high during exposure; low during readout.

Shutter Monitor Out: TTL high when energized; low when de-energized.

Software Programmable Outputs: (4) TTL low or high, (4) high voltage (60 V, 0.5 A) for use with relays, etc.

69

Appendix B J5 Data Port Configuration

The J5 data port, located on the rear panel of the controller, can be used for digital I/O. Figure 39 and the pin configuration listing both appear below.

J5 Pin 1

Pin 18

Pin 17

Pin 34 1 2 3 DIG GND 4 DATA IN 7 5 DATA IN 5 6 DATA IN 3 7 DATA IN 1 8 DIG GND 9 10 DATA OUT 3 11 DATA OUT 1 12 13 DIG GND 14 DATA OUT 4* 15 DATA OUT 5* 16 DATA OUT 6* 17 DATA OUT 7*

18 19 20 DIG GND 21 DATA IN 6 22 DATA IN 4 23 DATA IN 2 24 DATA IN 0 25 DIG GND 26 27 DATA OUT 2 28 DATA OUT 0 29 30 DIG GND 31 DATA OUT 4 RTN 32 DATA OUT 5 RTN 33 DATA OUT 6 RTN 34 DATA OUT 7 RTN

The “*” above denotes negative assertion. These upper 4 bits work as FET switches (maximum 60 V, 0.5 A). See the suggested test schematic in Figure 40.

J5-17

Output

J5-34

J5-16

J5-33

J5-15

J5-32

J5-14

J5-31

J5-10

J5-27

J5-11

J5-28

J5-4

J5-21

J5-5

J5-22

J5-6

J5-23

J5-7

J5-24

InputAll R = 51 Ω

Figure 39. JP5 data port pin configuration

Figure 40. Suggested test schematic for

J5 data port

71

Appendix C Cleaning Instructions

Turn off all power to the equipment and secure all covers before cleaning the units. Otherwise, damage to the equipment or injury to yourself could occur.

Controller and Camera Although there is no periodic maintenance that must be performed on the ST-138 Controller and Camera, users are advised to clean these components from time to time by wiping them down with a clean damp cloth. This operation should only be done on the external surfaces and with all covers secured. In dampening the cloth, use clean water only. No soap, solvents or abrasives should be used. Not only are they not required, but they could damage the finish of the surfaces on which they are used.

Optical Surfaces Optical surfaces may need to be cleaned due to the accumulation of atmospheric dust. We advise that the drag-wipe technique be used. This involves dipping a clean cellulose lens tissue into clean anhydrous methanol, and then dragging the dampened tissue over the optical surface to be cleaned. Do not allow any other material to touch the optical surfaces.

WARNING

73

Warranty & Service

Limited Warranty: Roper Scientific Analytical Instrumentation Roper Scientific, Inc. (“Roper Scientific,” us,” “we,” “our”) makes the following limited warranties. These limited warranties extend to the original purchaser (“You”, “you”) only and no other purchaser or transferee. We have complete control over all warranties and may alter or terminate any or all warranties at any time we deem necessary.

Basic Limited One (1) Year Warranty Roper Scientific warrants this product against substantial defects in materials and / or workmanship for a period of up to one (1) year after shipment. During this period, Roper Scientific will repair the product or, at its sole option, repair or replace any defective part without charge to you. You must deliver the entire product to the Roper Scientific factory or, at our option, to a factory-authorized service center. You are responsible for the shipping costs to return the product. International customers should contact their local Roper Scientific authorized representative/distributor for repair information and assistance, or visit our technical support page at www.roperscientific.com.

Limited One (1) Year Warranty on Refurbished or Discontinued Products Roper Scientific warrants, with the exception of the CCD imaging device (which carries NO WARRANTIES EXPRESS OR IMPLIED), this product against defects in materials or workmanship for a period of up to one (1) year after shipment. During this period, Roper Scientific will repair or replace, at its sole option, any defective parts, without charge to you. You must deliver the entire product to the Roper Scientific factory or, at our option, a factory-authorized service center. You are responsible for the shipping costs to return the product to Roper Scientific. International customers should contact their local Roper Scientific representative/distributor for repair information and assistance or visit our technical support page at www.roperscientific.com.

Shutter Limited One Year Warranty Roper Scientific warrants for a period of up to one (1) year after shipment the standard, factory-installed camera shutter of all our products that incorporate an integrated shutter. This limited warranty applies to the standard shutter installed in the camera system at the time of manufacture. Non-standard shutters, special product request (SPR) shutters, and third-party shutter drive equipment carry NO WARRANTIES EXPRESSED OR IMPLIED. Roper Scientific will supply, at no cost to the customer, up to one (1) replacement shutter during the warranty period. Roper Scientific will, at Roper Scientific's option, either ship a ready-to-install shutter to the customer site for installation by the customer according to the instructions in the product User Manual or arrange with the customer to return the camera system (or portion of the camera system) to the factory (or factory-authorized service center) for shutter replacement by us or a Roper Scientific-authorized agent. Responsibility for shipping charges is as described above under our Limited One (1) Year Warranty.


VersArray (XP) Vacuum Chamber Limited Lifetime Warranty Roper Scientific warrants that the cooling performance of the system will meet our specifications over the lifetime of the VersArray (XP) detector or Roper Scientific will, at its sole option, repair or replace any vacuum chamber components necessary to restore the cooling performance back to the original specifications at no cost to the original purchaser. Any failure to “cool to spec” beyond our Basic (1) year limited warranty from date of shipment, due to a non-vacuum-related component failure (e.g., any components that are electrical/electronic) is NOT covered and carries NO WARRANTIES EXPRESSED OR IMPLIED. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Sealed Chamber Integrity Limited 24 Month Warranty Roper Scientific warrants the sealed chamber integrity of all our products for a period of twenty-four (24) months after shipment. If, at anytime within twenty-four (24) months from the date of delivery, the detector should experience a sealed chamber failure, all parts and labor needed to restore the chamber seal will be covered by us. Open chamber products carry NO WARRANTY TO THE CCD IMAGING DEVICE, EXPRESSED OR IMPLIED. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Vacuum Integrity Limited 24 Month Warranty Roper Scientific warrants the vacuum integrity of all our products for a period of up to twenty-four (24) months from the date of shipment. We warrant that the detector head will maintain the factory-set operating temperature without the requirement for customer pumping. Should the detector experience a Vacuum Integrity failure at anytime within twenty-four (24) months from the date of delivery all parts and labor needed to restore the vacuum integrity will be covered by us. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Image Intensifier Detector Limited One Year Warranty All image intensifier products are inherently susceptible to Phosphor and/or Photocathode burn (physical damage) when exposed to high intensity light. Roper Scientific warrants, with the exception of image intensifier products that are found to have Phosphor and/or Photocathode burn damage (which carry NO WARRANTIES EXPRESSED OR IMPLIED), all image intensifier products for a period of one (1) year after shipment. See additional Limited One (1) year Warranty terms and conditions above, which apply to this warranty. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

X-Ray Detector Limited One Year Warranty Roper Scientific warrants, with the exception of CCD imaging device and fiber optic assembly damage due to X-rays (which carry NO WARRANTIES EXPRESSED OR IMPLIED), all X-ray products for one (1) year after shipment. See additional Basic Limited One (1) year Warranty terms and conditions above, which apply to this warranty. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Warranty & Service 75

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Software Limited Warranty Roper Scientific warrants all of our manufactured software discs to be free from substantial defects in materials and / or workmanship under normal use for a period of one (1) year from shipment. Roper Scientific does not warrant that the function of the software will meet your requirements or that operation will be uninterrupted or error free. You assume responsibility for selecting the software to achieve your intended results and for the use and results obtained from the software. In addition, during the one (1) year limited warranty. The original purchaser is entitled to receive free version upgrades. Version upgrades supplied free of charge will be in the form of a download from the Internet. Those customers who do not have access to the Internet may obtain the version upgrades on a CD-ROM from our factory for an incidental shipping and handling charge. See Item 12 in the following section of this warranty ("Your Responsibility") for more information.

Owner's Manual and Troubleshooting You should read the owner’s manual thoroughly before operating this product. In the unlikely event that you should encounter difficulty operating this product, the owner’s manual should be consulted before contacting the Roper Scientific technical support staff or authorized service representative for assistance. If you have consulted the owner's manual and the problem still persists, please contact the Roper Scientific technical support staff or our authorized service representative. See Item 12 in the following section of this warranty ("Your Responsibility") for more information.

Your Responsibility The above Limited Warranties are subject to the following terms and conditions:

1. You must retain your bill of sale (invoice) and present it upon request for service and repairs or provide other proof of purchase satisfactory to Roper Scientific.

2. You must notify the Roper Scientific factory service center within (30) days after you have taken delivery of a product or part that you believe to be defective. With the exception of customers who claim a “technical issue” with the operation of the product or part, all invoices must be paid in full in accordance with the terms of sale. Failure to pay invoices when due may result in the interruption and/or cancellation of your one (1) year limited warranty and/or any other warranty, expressed or implied.

3. All warranty service must be made by the Roper Scientific factory or, at our option, an authorized service center.

4. Before products or parts can be returned for service you must contact the Roper Scientific factory and receive a return authorization number (RMA). Products or parts returned for service without a return authorization evidenced by an RMA will be sent back freight collect.

5. These warranties are effective only if purchased from the Roper Scientific factory or one of our authorized manufacturer's representatives or distributors.

6. Unless specified in the original purchase agreement, Roper Scientific is not responsible for installation, setup, or disassembly at the customer’s location.


7. Warranties extend only to defects in materials or workmanship as limited above and do not extend to any product or part which has:

• been lost or discarded by you;

• been damaged as a result of misuse, improper installation, faulty or inadequate maintenance or failure to follow instructions furnished by us;

• had serial numbers removed, altered, defaced, or rendered illegible;

• been subjected to improper or unauthorized repair; or

• been damaged due to fire, flood, radiation, or other “acts of God” or other contingencies beyond the control of Roper Scientific.

8. After the warranty period has expired, you may contact the Roper Scientific factory or a Roper Scientific-authorized representative for repair information and/or extended warranty plans.

9. Physically damaged units or units that have been modified are not acceptable for repair in or out of warranty and will be returned as received.

10. All warranties implied by state law or non-U.S. laws, including the implied warranties of merchantability and fitness for a particular purpose, are expressly limited to the duration of the limited warranties set forth above. With the exception of any warranties implied by state law or non-U.S. laws, as hereby limited, the forgoing warranty is exclusive and in lieu of all other warranties, guarantees, agreements, and similar obligations of manufacturer or seller with respect to the repair or replacement of any parts. In no event shall Roper Scientific’s liability exceed the cost of the repair or replacement of the defective product or part.

11. This limited warranty gives you specific legal rights and you may also have other rights that may vary from state to state and from country to country. Some states and countries do not allow limitations on how long an implied warranty lasts, when an action may be brought, or the exclusion or limitation of incidental or consequential damages, so the above provisions may not apply to you.

12. When contacting us for technical support or service assistance, please refer to the Roper Scientific factory of purchase, contact your authorized Roper Scientific representative or reseller, or visit our technical support page at www.roperscientific.com.

Contact Information Roper Scientific's manufacturing facility for this product is located at the following address:

Roper Scientific 3660 Quakerbridge Road Trenton, NJ 08619 (USA)

Tel: 609-587-9797 Fax: 609-587-1970

Technical Support E-mail: [email protected]

For technical support and service outside the United States, see our web page at www.roperscientific.com. An up-to-date list of addresses, telephone numbers, and e-mail addresses of Roper Scientific's overseas offices and representatives is maintained on the web page.

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Index AC power requirements, 14 Background DC level, 55 Baseline signal, 55

excessive humidity, 55 sudden change in, 55

Binning software, 62

Blooming. see Smearing Buffer board

PCI, 21 Cables, 13 Camera setup, 19 Cautions

DMA and Interrupt, 26 excessive humidity in CCD chamber, 55 PCI Serial board installation, 21

CCD arrays dark charge effects, 54

Cleaning, 71 Cleaning optical surfaces, 71 Computer interface

installation, 21 Computer requirements, 17 Contact information, 75 Continuous Cleans timing, 44 Cooler power indicator, 17 Cooler power switch, 17 Cooler status indicators, 17 CRT X connector, 18 CRT Y connector, 18 CRT Z connector, 18 Dark charge

definition of, 54 pattern, 55 temperature dependence, 54 typical values, 54

Dark current, 54 DETECTOR connector, 18 Detector Temperature dialog box, 33 Dual A/D converters, 65 EMF spike, 29 Excessive humidity, 55 Exposure, 52 EXT SYNC connector, 18 External shutter control, 67 External Sync Normal, 42 External synchronization, 67 First images procedure, 29

First time operation, 29 Focusing procedure, 31 Frame transfer, 63 Freerun, 41 Front panel, 17 Full frame readout, 55 Fuse

line, 16 Fuse (line) requirements, 15 Fuse replacement, 15 Installation

interface PCI, 21

Interface type selection in WinView, 21

ISA Interface card installation, 26 ISA power-on checks, 28 ISA serial card

I/O address, DMA channel, and interrupt level, 26

J5 connector, 18 J6 connector, 18 J7 connector, 19 Kinetics, 64 Kinetics timing, 48 Line cord requirements, 14 Line voltage selection, 15 Lookup table, 65 Maintenance, 71 Memory requirement, 17 Microscopy

arc lamp EMF spike damage warning, 29 Xenon or Hg lamp EMF spike, 29

Monitor requirements, 17 Mouse requirements, 17 NORM 4/VIDEO connector, 18 NORM3 (kinetics timing), 48 NORMALIZE 2 connector, 18 NORMALIZE 3 connector, 18 NOTSCAN, 68 NOTSCAN connector, 18 PCI

diagnostics, 25 PCI installation and operation, 21 Power cord, 14 Power module, 15 Power requirements, 14 Power switch and indicator, 18


Precautions, 14 Procedures

familiarization and checkout, 29 First images, 29 interface installation, 21

RS-232 connector, 18 Saturation, 54 SCSI-2 interface, 17 serial buffer board, 21 SHUTTER connector, 18 Shutter monitor out, 68 Smearing, 53 Specifications, 67 ST-138

introduction and description, 9 System

components of, 13 Technical support, 75 Temperature control

introduction to, 33 overshoot, 34

Temperature dialog box, 33 Temperature lock, 33

time to achieve, 34 Temperature setting potentiometer, 18 Temperature Status indicators, 33 Temperature warning indicator, 17, 33 Thermal protection switch, 33 Trigger in, 67 TRIGGER IN connector, 18 Trigger out, 68

TRIGGER OUT connector, 18 Triggering modes, 40 Unpacking and initial inspection, 13 Voltage setting, 15 Warnings

cleaning equipment, 71 fuse installation, 16 light overload and intensified cameras, 31 loss of over-temperature protection, 33 operation with extreme temperature

settings, 33 protective grounding, 14 replacement power cords/plugs, 14 temperature warning indicator, 33 Xenon and Hg arc lamps, 29

Warranties image intensifier detector, 74 one year, 73 one year on refurbished/discontinued

products, 73 owner's manual and troubleshooting, 75 sealed chamber, 74 shutter, 73 software, 75 vacuum integrity, 74 VersArray (XP) vacuum chamber, 74 x-ray detector, 74 your responsibility, 75

Website, 76 Windows 95, 17 WinView/32, 13

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