21.11.03 Anatoli Konoplyannikov
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Transcript of 21.11.03 Anatoli Konoplyannikov
121.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Overview of the subsystems design
• High voltage system.
• LED monitoring system.
• Cs137 radioactive source calibration system.
Integration of the HV, LED monitoring and radioactive source calibration systems on the HCAL detector
221.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL The Cockcroft-Walton (CW) base for photomultipliers is used for LHCb calorimeters. The PMT chosen for the calorimeters is Hamamatsu photo-multiplier R7899-20. The CW solution has the following advantages over conventional passive divider and transistor bases:
individual gain adjustment;
efficient operation at high rate;
low power dissipation;
low voltage cabling and connectors reducing total cost.
The HCAL high voltage (HV) system consists of:
* about 1500 CW bases, those soldered on the PMT’s leads and placed in each cell of HCAL, * eight 216 – channels DAC boards for HV control voltage distribution, * three power supply units (+80 V, +- 6 V). The DAC boards are placed around the detector and the analogue HV control voltages are distributed to each base by a flat cable.
HCAL CW base circuit diagram.
High voltage system
321.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL High voltage system
Oscillogram of a CW – base voltage ripple on dynode DY10
The gain deviation as function of the DC anode current for three gains 10^4, 10^5, 10^6.
PMT ZL2595 Gain variation (R=500M connected to GND)
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anode current (mkA)
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G10^4
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CW base main characteristics
421.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Photo of HCAL CW base with Hamamatsu PMT.
High voltage system
521.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
The architecture of the subsystem is chosen taking into account following considerations:
* The DAC ICs should be kept in a region with a lowest level of radiation.
* The easy access for board exchange should be foreseen.
* A cable length should be minimized in order to avoid a ground loop voltage shift.
216 – channels DAC board block diagram
The board includes 200 channels of DAC integrated circuit for HV control and 16 channels for LED light intensity control. For readout of the control voltages, the multiplexers and ADC IC are used. An estimated power consumption is about 1.5 W per board and a board size is about 160*250 mm2.
High voltage system
621.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL LED monitoring design
Sketch of the optical part of the LED monitoring system
The LED monitoring system is mainly aimed at:
• a middle term monitoring of the PMT gain stability,
• an ADC sample time calibration and adjustment
The LED monitoring system consists of four functional parts:
•optical mixer and light distribution fibers,
•LED driver with LED and PIN diode with amplifier for a LED light stability monitoring. The PIN diode signal after amplification is sent to the LFB front-end electronics board.
•light intensity control board with DACs ,
•LED triggering pulse distribution board.
721.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL LED monitoring design
LED driver block diagram
The dedicated HCAL versions of the LED driver and PIN diode amplifier were developed. The main LED driver features are:
controlled light intensity
edge sensitive triggering
overshot circuit allows to decrease the trailing edge of a light flash
dimension of the printed board is 40*70 mm*mm
mechanical design is optimised for HCAL
821.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL LED monitoring design
Photo of the light mixer with LED driver and PIN diode amplifier printed circuit boards
921.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
LED monitoring design
Oscillograms of the 50 Gev pions signals and LED signals for clipped and non-clipped cases. Signal clipped on 1.2 m coax with 22 Ohm termination
LED signal50 Gev pions
Comparison the signal shape for 50 GeV pions and LED signal
1021.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Synopsis of LED Trigger Board (LEDTB)
LED monitoring design
For LED trigger pulse distribution a 64 – channels dedicated board has to be developed. It will be placed in to the spare slot of the 9U LFB crate. This crate is connected to TTC and ECS systems.
1121.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL 137Cs radioactive source calibration system
System overview
The reliable and stable calibration method has been developed and tested with HCAL Prototype. Its aim is to monitor the detector properties, like ageing of plastic and fibers, and give an absolute reference for the cell calibration. The radioactive 137Cs gamma-source that has 30 years half-life is used. Three sources encapsulated in the stainless steel pipe were obtained, with activities of 5, 8 and 10 mCi.
The HCAL calibration system incorporates the following parts:
•continuous 8 mm diameter stainless steel pipe that is fed through the middle of all scintillating tiles and filled with a distilled water;
•a computer controlled hydraulic pump and valves that create a reversible water flow in the pipe and therefore move the capsule with a radioactive source throughout the detector;
•an automated garage with a 5 cm thick lead wall, to safely keep the source between calibration runs;
•integrated on-detector electronics to measure the PMT current when the source is moved from cell to cell across the HCAL.
1221.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Photo of the 8 – channels integrator and readout boards
PMT anode current produced by radioactive source is integrated by an electronic integrator with a decay time of order of 2 msec. Readout board collects analog signal from one module phototubes, digitizes them and stores into a local memory (it takes 125 sec/module). Then the data are transferred to a computer through CAN bus interface (it takes about 4 msec). The readout continues till the source run through the module.
Two or five 8 - channel integrator boards (placed into the module) and 520 – channel readout board (placed on the detector) have been developed.
1321.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Photo of the rack with the hydraulic and control electronic crates
Garage for radioactive source storage
1421.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL Integration of the HV, LED monitoring and radioactive source systems on the HCAL detector.
Placement of the electronic boards and connection with ECS
The electronic boards of mentioned systems will be placed partially into the HCAL modules and around the detector. There are two options for the board integration on the detector. Main option is the electronics placement on the top and bottom platforms. In this case one has easy access to all boards, but the cable length of the analog control signals is not minimal. Another option is to distribute the boards on the side of detector. In this case the cable length is minimal, but the access is less convenient. Photo of the internal cabling and CW base
integration into HCAL module
PMT with CW base
1521.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL 2 or 5 (16 or 40 channel HCAL module) 8 contact coax connectors for connection with Front-End crate
5 pin connector for PIN diodes and LED triggering signals
2 of 10 pin connectors for CW base and LED power supply
34 pin connector for Cs calibration system
2 of 40 pin connectors for HV control signals
HCAL module side panel with connectors
1621.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL LFB rack with crates
6U VME size crate for Cs source monitoring, and control electronics
Two boards of HV and LED DAC control voltage + one board of Integrators Readout connected to ECS
33 * 40 wire flat cable
Crate with hydraulic apparatus
LED triggering Board connected to TTC and ECS
850 coax cables of 3 mm diameter
Sketch of the electronic boards and crates integration on the HCAL detector
The estimated cross-sections of the cables integrated on the HCAL side are following:
• coax cables cross-section is about 120 * 120 mm2,
• flat cables cross-section is about 70 * 100 mm2.
1721.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL System Board description Number of boards per half of HCAL
HV 216- channels DAC of the HV and LED control voltage 4Power Supply: + 80 V (1 A) 1 + 6 V (0.2 A) 1 - 6 V (0.2 A) 1
LED monitoring 9U VME 64 – channels LED triggering 1Power Supply: - 40 V (0.1 A) 1 +6 V (0.2 A) 1 - 6 V (7 A) 1
Cs calibration and monitoring 520 – channels Integrators Readout Board 2
16-channels Capsule location sensor (SIN) monitoring board 4Hydraulic control board 1Garage control board 1Power Supply: ~ 220 V (3 A) 1 + 9 V (2 A) 1 + 12 V (5 A) 1 - 12 V (3 A) 1 + 6 V (2 A) 1
The list of the half HCAL electronic boards integrated outside of the detector
1821.11.03 Anatoli Konoplyannikov
Design and integration of HV, LED monitoring and calibration system for
HCAL
Procedure of the PMTs assembly and cabling + needed manpower
• 1500 PMTs and CW base assembly – 3 man-weeks
• 1500 PMT + CW base test and Gain vs HV measurement – 6 man-weeks
• 44 sets of coax and flat cables preparation and installation inside HCAL – 8 man-weeks
• 1500 PMT + CW base installation into modules– 3 man-weeks