Shutter Inspection and Testingfor new Teflon coated blades

Objective:

• To create a shutter timing profile for new double sided Teflon coated shutters under conditions similar to those seen at MRC’s OTF.

• To compare the profile from the new shutters to the old, AlMgF2 coated shutters.

Set up:

• The final setup of the test used the following:– 1050 peak LED from Epitex Inc. (L1050-03)– Two (2) double sided Teflon coated Uni-Blitz shutters

(VS25S2T1)– One (1) AlMgF2 coated Uni-Blitz shutter

(VS25S2ZM0)– Uni-Blitz shutter driver (T132)– Stanford Delay Generator (DG 535)– Fast Focusing Lens– Electro-Optics Technology InGaAs p-i-n

photodetector (ET-3040)– Data read by Tektronix TDS 3054 oscilloscope.

Individual Component Info:

• LED:– Incoherent source– Emits at 1050nm peak (from 1000-1100)– Powered by a standard C 1.5V battery in line

with a 28.7 ohm resistor• Provided 1.64V of power with 57mA of current

– Spec sheet lists radiated power at 2.5 mW typical under these conditions.

Individual Component Info:

• Double Sided Teflon (and AlMgF2 coated) Shutters:– Mounted on a three axis translation mount– Power signal came directly from Uni-Blitz

T132– Entire mount was removed for shutter

exchange, was then replaced and realigned to lens

Individual Component Info:Manufacturer’s standard shutter profile for V25 series taken from Uni-Blitz’s online website

Individual Component Info:

• Shutter Driver (T132)– Triggered externally– Received a triggering pulse from the Stanford

(DG535) connected to the Trig port on the back

– Sent a triggering profile to the oscilloscope from the Pulse Out connection on back.

– Set to have a shutter exposure time of 8ms.

Individual Component Info:

• Stanford Delay Generator (DG 535)– Pulse A was set to fire on T– Pulse B was set to fire at A +.092s (92ms)– Resulted in a 10 Hz frequency with an 8ms

exposure time– Output signal was in the form of A_|---|_B– Reverse signal was sent to oscilloscope

Individual Component Info:

• EOT Photodetector (ET-3040)– Standard InGaAs p-i-n detector– Active area of 1mm

– Has ~.65A/W absolute responsivity at 1050nm

– Biased voltage of 6V

– Ran in linear mode– Output run directly to the oscilloscope

Individual Component Info:

• Tektronix Oscilloscope (TDS 3045)– Capable of 5GS/s

– Used three of four channels• CH1: output from shutter trigger

– 50ohm impedance– Scale of 500mV

• CH2: output from delay generator (A---|_|---B) – 50ohm impedance– Scale of 100mV

• CH3: output direct from detector – 1 Mega ohm impedance– Scale of 5V

• All were DC coupled

– Data could be analyzed directly on the scope or exported as comma separated value files to be plotted with a computer.

Initial Problems

• Hiccups in the shutters opening and closing could be heard at various times

• Most commonly seen at the beginning shortly after shutter initialized.

• Would usually subside and were rarely heard after a prolonged period.

• Using the scope it appeared to be caused by a mis-hap in the Stanford DG 535

• No data collected during these events was used in profiling the shutter

Shutter Hiccup(output from shutter driver)

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

1.30E+00 1.40E+00 1.50E+00 1.60E+00 1.70E+00 1.80E+00 1.90E+00 2.00E+00

Time (s)

Vo

lta

ge

HiccupNormal Pulse

Focus on Second Hiccup Overlap of Both Units

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

1.30E+00

1.35E+00

1.40E+00

1.45E+00

1.50E+00

1.55E+00

1.60E+00

1.65E+00

1.70E+00

1.75E+00

1.80E+00

Time(s)

Vo

ltag

e Hiccup

Normal Pulse

Blue- Shutter DriverMagenta- External Trigger

Shutter Hiccup(Delay generator and shutter driver)

Initial Problems

• Finding a detector that would meet all needs was difficult

• First detector used:– Newport 818-IR photo detector

• Would not respond fast enough• Best rated frequency was 10Hz

• Had large rise time• Did not recharge quickly

-2.50E-001 -2.00E-001 -1.50E-001 -1.00E-001 -5.00E-002 0.00E+000-1

0

1

2

3

4

5

6

7

Primary setupDelay GeneratorShutterDetector (x20)

Time (s)

Ou

tpu

ts

Newport 818-IR Detector

Initial Problems

• Second detector used:– Electro-Optics Technology ET-3020

• InGaAs p-i-n detector• Good responsivity• Rated to a frequency of 2.5 MHz

• Had no bias across it– Would respond in photovoltaic mode with a sharp spike

upon change in incident light.– Quick sharp pulse up and down both upon open and

close of shutter

-1.50E-001 -1.00E-001 -5.00E-002 0.00E+000 5.00E-002 1.00E-001 1.50E-001-3

-2

-1

0

1

2

3

4

5

6

Chart 1

ShutterDelay GenSensor (x20)

TIME (s)

Out

put

ET-3020 Detector

Data Collection

• Data collection began once a suitable detector was found– Used EOT’s ET-3040– Data was collected using the self triggering

mechanism on the scope– Taken in 40ms segments (4ms/division)– Scale was taken to smaller divisions for more

precise measurements– Voltage readings from the sensor were

reduced by a factor of 20

ResultsSn 109917

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-1.20E-02 -8.00E-03 -4.00E-03 0.00E+00 4.00E-03 8.00E-03 1.20E-02

Time (s)

Voltag

e

Shutter Delay Generator Sensor(x 1/20)

344 us 344 us

11.6 ms

2.12 ms

7.12 ms

2.44 ms

1.40ms1.84ms

1.64 ms

Sn 109918

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-1.20E-02 -8.00E-03 -4.00E-03 0.00E+00 4.00E-03 8.00E-03 1.20E-02

Time (s)

Voltag

e

Shutter Delay Generator Sensor(x 1/20)

Results

336us 344us

1.88ms

1.6 ms

7.16 ms

1.36 ms

2.2 ms

11.7 ms

2.44ms

ResultsSn 101959

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

-1.20E-02 -8.00E-03 -4.00E-03 0.00E+00 4.00E-03 8.00E-03 1.20E-02

Time (s)

Vol

tage

Shutter Delay Generator Sensor(x 1/20)

336us 344us

3.44ms

4.32ms

7.44ms

1.74ms

2.68ms2.48ms

14.2ms

Comparing to Manufacturer’s Data

• The timing image from the manufacturer’s website was used as a base for comparison

• The comparison is presented on the following slide.

Time Frame Sn 109917 Sn 109918 Sn 101959 Manufacturer

O-A 1.64 ms 1.88 ms 2.48 ms 3 ms

A-C 2.44 ms 2.44 ms 4.32 ms 3 ms

O-C 4.08 ms 4.32 ms 6.8 ms 6 ms

C-E 7.12 ms^ 7.16 ms^ 7.44 ms^ 2 ms*

E-G 2.12 ms 2.2 ms 2.68 ms 5 ms

A-G 11.6 ms 11.7 ms 14.2 ms 10 ms

^ denotes time spent at max exposer

* denotes min dwell time with min input pulse

Dashed line indicates time for a typical 8 ms exposure pulse

G

E^

Analysis

• It appears that the manufacturer’s data is a compilation of all types of shutters in the VS25 series.

• The Teflon coated shutters had slightly shorter time from start of open to full open the manufacturer’s specs while the AlMgF2 shutters had a slightly longer time.

• The delay from signal to start of open was shorter for all three shutters tested.

• The total close time for all shutters appears to be much faster than the manufacturer given data.– For Teflon coated blades is was less than half

• The total window time for the Teflon blades was around 12 ms while for the AlMgF2 it was 14 ms.