http://ific.uv.es/~cescobar/lasertest.html ific - valencia peter kodys, july 16, 2004, internal...

http://ific.uv.es/~cescobar/lasertest.html

IFIC - Valencia

Peter Kodys, July 16, 2004, internal workshop, status and results 1

Our status, progress and results are summarized on


IFIC – ValenciaJuly 16, 2004

Peter Kodys

With help from: Carlos Escobar and next: Vaso, Salva, Sergio, Pavel, Zdenek, Carlos L., Peter W.P., Carmen, Pepe, Pablo, Luis, Paco (cooperation of IFIC Valencia and CU Prague)


IFIC - Valencia


STATUS

Laser Spot on Threshold Scan(No focused spot, two channel signal, first

historical detection of laser on SCT module in IFIC)

Stable mechanical arrangement. Laser detection in only one side (metal back side of detectors – no transparent for light). Strip position detection working up to 1 minute. Few method of focusing was tuned. Automatic focusing done up to 20 minutes with precision 40um in z and 4 um in x. The bond mixing test done up to 30 minutes per detector – test for production modules. The channels from mask file tested independently using two methods. The channels from external file tested. No effect of interference between chip channels is observed. Pulse shape reconstruction done. Punch through (pin hole) channels test for response done. Testing at low temperatures was tuned and is done up to –20 deg in chillers (4 deg in T-hybrid) in dry air or nitrogen Automatic logbook generate and saved with all important information


IFIC - Valencia


Scheme of arrangement:

Laser parameters and light interaction with silicon:Laser energy of photon: 1.170 eVWavelenght of light: 1060 nmReal part of dielectric const.: 12.65Imag part of dielectric const.: 0.00075Index of refraction: 3.557Imag part of index of refr.: 0Absorption coeficient: 12.07 cm·¹Reflectivity @ 0.6mm Si: 35.2%Transmition @ 0.6mm Si: 24%Absorption @ 0.6mm Si: 40.8%Reflectivity @ 0.27mm Si: 60.35% back side of Si reflected - metalizedTransmition @ 0.27mm Si: 0 % back side of Si reflected - metalizedAbsorption @ 0.27mm Si: 39.65% back side of Si reflected - metalized


IFIC - Valencia


LASER SPOT TUNNING 1

Main conclusion: there is possibility to tune laser focusing to smallest spot using reflectivity from strip metal material to measure decreasing of signal from main testing strip, sensitivity of focusing of our type of laser output is very high, focus range is less 50 µm (from factory is declared good focus range about 1 mm).

Auto focus algorithm: ~ 6 minutes- Based on TriggerBurst Scans in range of variable Z (dynamic focus)- Dynamic Threshold selection based on strip output- In each Z and X distance, we acquire Trigger Burst and Median Charge data. Then, we found the minimum in a 3D plot


IFIC - Valencia


LASER SPOT TUNNING 2

Main conclusion: method independent of starting point in range 3mm from focus give result up to 20 minutes, method use quick scan to find mid of strip in two position (1 minute per position) and find minimum between them with precision 200um. Minimum exist because reflect from strip metal material. Then start fine 2D scan in range 400 x 16 um to find focus point.

Auto focus algorithm: ~ 20 minutesFind mid of channel and current strip pitch

Scan in z to find a minimum (3mm range) Scan in x and z to find a minimum (400 x 16 um range)


IFIC - Valencia


Pulse shape reconstruction vs. interstrip position of laser spot was done. Also quality of laser spot was measured used fit of edges on metal conductive strip and was sigma 3.3+-1.3um, strip width is 23.3+-1.4um.

Laser spot profile reconstruction with sigma ~ 3.3um

Scan of medians in x uncorrected for start point shift

Scan of medians in x – corrected, in middle part is response decreasing based on reflection of light from strip

PULSE SHAPE RECONSTRUCTION


IFIC - Valencia



Laser spot reconstruction

Delay vs. x from pulse shape fit Peaking time vs. x from pulse shape fit

2D graph of medians in time shift vs. x, strip metal part is on point 0 where practically whole light beam is reflected out

Pulse shape fit for all x positions

Strip position


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RE-BONDING SOME CHANNELS

In the results, you can see the differencies...

We re-bond some bonds to different positions to look dependence of chip channel stability base of neighbored high powered channel.

The channels are detected in unexpected positions. We can calculate the bond mixing with presition. This is a good test to check the bonds.

Channels re-bonded


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CHANNEL POSITION SCAN 1 (PRODUCTION TEST)

We use the re-bond module to do all test, so we found in this quick test the incorrect bounded channels.

This test is preliminary and we are working on it. Now, we have good results in ~30 min per side (full channels test).

Dead Chip

Channel signal from Laser


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CHANNEL POSITION SCAN 2 (PRODUCTION TEST)

Response from trigger burst at some threshold over noise threshold, we expect response in range 100-900 counts

This test is for checking of response from all channels using laser spot, neighbours should have not additional response

Results in ~30 min per detector (full channels test), 2 hours per module with 4 detectors.

Using threshold at each channel decreasing of median from noise (threshold without laser spot invoking) 6 bad channels (4 dead and 2 noised)

Special test of only bad channels response from mask file is tuned and is done.


IFIC - Valencia


BAD CHANNEL TEST (FOR PRODUCTION MODULES TEST)

This test is for checking of response from bad channels based on mask file and compare it with neighbours channels

Testing channels normalized to 1 used their neighbours: average of them was reference value, two channels shows some response but in very high level – un-trimm channels

Testing channels (red) with their neighbours (blue), up: response –

noise, bottom: response from channels and noise

(yellow/green)

Map of testing bad channels on module


IFIC - Valencia


PUNCH THROUGH (PIN HOLE) CHANNEL TEST

This test is for checking of response from special channels and compare it with neighbours channels

Testing channels normalized to 1 used their neighbours: average of them was reference value

Testing channels (red) with their neighbours (blue), up: response – noise, bottom: response from channels and noise (yellow/green)

Testing channels – histogram of normalized

channels


IFIC - Valencia


STABILITY AND TEMPERATURE DEPENDENCES

For many tests we need measurement with untrimmed channels (for measurement of un-trimable channels) and unmasked channels (for bad channel tests). For measurement of stability of measurements we use outer unirradiated module with Hamamatsu detectors in dry air atmosphere.

Stability:

1. Measurement of channels response used median point from threshold scan with precision ±5mV

2. Differences between channels (no trimming) are ±17 mV (± 10% of signal from laser)

3. Differences between measurements are ±3 mV (± 2% of signal from laser)

Temperature dependences:

Noise is not depended from temperature in range 6 to 29 °C on Thybrid

Response from channels depend from Thybrid: (2.4 ±0.3)mV/°C


IFIC - Valencia


HOW TO TEST MODULES USING SCTDAQ AND SPECIAL FUNCTIONS

After to set position about 2mm or less from focused point you can find in trigger burst scan laser spot

Typical window after an start laser tests: set right side and initialise L1A Laser Test mode (without calibration pulse)


IFIC - Valencia


HOW TO TEST MODULES USING SCTDAQ AND SPECIAL FUNCTIONS

Computer: Silab05, starting commands:.x ST.cpp();MoveZ(CloseToFocusPoin);Push Button: ´Top/Back side module 0 testing´Push Button: ´Initialization L1A´

Push Button: 1 – 8 to start test you want

To lost laser signal try:Push Button: ´Move TimeBin …´

1a, 7, 8 – working OK in un-focusing .2 – 2.0mm4. Auto Focus – is best and quick6. Median charge scan need setting of delays using delay wires and before scan you must find good focus point and start from it

All test produce log book text file in dir ´data´and program: .x ShowChTestGraphs(FileName,RunNo,SaveGraphs,TypeAnalysis);help you with interpretation of results of main type of tests.

After test, my recommendation, always to restart ROOT session


IFIC - Valencia


PHOTOS 1

First arrangement of workspace

Module in test box with window for laser spot, optical fibre for laser light (yellow cover), insulated plastic support for module

Laser end with focusing lens above module sensor

Black box with 2D stages inside and chiller below them


IFIC - Valencia


PHOTOS 2

Final arrangement of workspace

Black box with module box connecting to cooling and DAQ electronics

General view to laser tests workplace with black box (left) with 2D stages inside and chiller below

them, readout electronics (right) and DAQ computer

Block of connectors for in/out puts of

cooling, air or nitrogen, optical

fibre of laser light and command wires

of position stages


IFIC - Valencia


PHOTOS 3

Final arrangement of workspace

Position stages arrangement

Laser end with focusing lens above module sensor and module test box with two windows

for testing of both sensors (one is closed for save cool dry atmosphere inside)

Production of dry cool air for module


IFIC - Valencia


General summary 1STATUS OF LASER TEST WORKPLACE IN IFIC VALENCIA

Laser Spot on Threshold Scan(No focused spot, two channel signal, first

historical detection of laser on SCT module in IFIC)

Stable mechanical arrangement. Laser detection in only one side (metal back side of detectors – no transparent for light). Strip position detection working up to 1 minute. Few method of focusing was tuned. Automatic focusing done up to 20 minutes with precision 40um in z and 4 um in x. The bond mixing test done up to 30 minutes per detector – test for production modules. The channels from mask file tested independently using two methods. The channels from external file tested. No effect of interference between chip channels is observed. Pulse shape reconstruction done. Punch through (pin hole) channels test for response done. Testing at low temperatures was tuned and is done up to –20 deg in chillers (4 deg in T-hybrid) in dry air or nitrogen Automatic logbook generate and saved with all important information


IFIC - Valencia


CHANNEL POSITION SCAN (FOR PRODUCTION MODULES TEST)

Response from trigger burst at some threshold over noise threshold, we expect response in range 100-900 counts

This test is for checking of response from all channels using laser spot, neighbours should have not additional response

Results in ~30 min per detector (full channels test), 2 hours per module with 4 detectors.

Using threshold at each channel decreasing of median from noise (threshold without laser spot invoking) 6 bad channels (4 dead and 2 noised)

Special test of only bad channels response from mask file is tuned and is done.

General summary 2


IFIC - Valencia


BAD CHANNEL TEST (FOR PRODUCTION MODULES TEST)

General summary 3This test is for checking of response from bad channels based on mask file and compare it with neighbours channels

Testing channels normalized to 1 used their neighbours: average of them was reference value, two channels shows some response but in very high level – un-trimm channels

Testing channels (red) with their neighbours (blue), up: response –

noise, bottom: response from channels and noise

(yellow/green)

Map of testing bad channels on module


IFIC - Valencia


General summary 4PUNCH THROUGH (PIN HOLE) CHANNEL TEST

This test is for checking of response from special channels and compare it with neighbours channels

Testing channels normalized to 1 used their neighbours: average of them was reference value

Testing channels (red) with their neighbours (blue), up: response – noise, bottom: response from channels and noise (yellow/green)

Testing channels – histogram of normalized

channels


IFIC - Valencia


General summary 5Pulse shape reconstruction vs. interstrip position of laser spot was done. Also quality of laser spot was measured used fit of edges on metal conductive strip and was sigma 3.3+-1.3um, strip width is 23.3+-1.4um.

Scan of medians in x – corrected, in middle part is response decreasing based on reflection of light from strip

2D graph of medians in time shift vs. x, strip metal part is on point 0 where practically whole light beam is reflected out

Pulse shape fit for all x positions

Strip position

Peaking time (up) and delay (down) vs. x from pulse shape fit



IFIC - Valencia


General summary 6LASER SPOT TUNNING

Main conclusion: method independent of starting point in range 3mm from focus give result up to 20 minutes, method use quick scan to find mid of strip in two position (1 minute per position) and find minimum between them with precision 200um. Minimum exist because reflect from strip metal material. Then start fine 2D scan in range 400 x 16 um to find focus point.

Autofocus algorithm: ~ 20 minutes

Find mid of channel and current strip pitch

Scan in z to find a minimum (3mm range) Scan in x and z to find a minimum (400 x 16 um range)

Detail how sharp is focus point of laser spot


IFIC - Valencia


STABILITY AND TEMPERATURE DEPENDENCES

For many tests we need measurement with untrimmed channels (for measurement of un-trimable channels) and unmasked channels (for bad channel tests). For measurement of stability of measurements we use outer unirradiated module with Hamamatsu detectors in dry air atmosphere.

Stability:

1. Measurement of channels response used median point from threshold scan with precision ±5mV

2. Differences between channels (no trimming) are ±17 mV (± 10% of signal from laser)

3. Differences between measurements are ±3 mV (± 2% of signal from laser)

Temperature dependences:

Noise is not depended from temperature in range 6 to 29 °C on Thybrid

Response from channels depend from Thybrid: (2.4 ±0.3)mV/°C

General summary 7

http://ific.uv.es/~cescobar/lasertest.html ific - valencia peter kodys, july 16, 2004, internal...

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