Pixel Ladder QA manual Software R. Akimoto, A. Shaver. July 2010Email: [email protected].

Pixel Ladder QA manual

Software

R. Akimoto, A. Shaver. July 2010 Email: [email protected]

Check List 1• Interlock

– Temperature of NOVECCheck if the difference from the value in the RIKEN QA is less than 5° C

– Humidity inside test boxCheck if the difference from the value in the RIKEN QA is less than 5%

Relative Humidity (R.H.)• Power supply

– Voltage and current of the power supply for the SPIRO and LADDER are at the operational values.SPIRO: Check that the difference of the current from the value of the

same SPIRO is less than 0.1 ALADDER: Check the difference of the current from the value in the

RIKEN QA is less than 0.1 A– Bias voltage and leakage current at 5 V increments

Check the difference in the leakage current from the value in the RIKEN QA is less than 0.3 μA

2A. Shaver; Aug. 2010

Check List 2

• DAC value– SPIRO S/N

Confirm that the SPD FEM is reading the correct S/N value

– Reference voltage (DAC_REF_VDD, DAC_MID, and GTL_REF) Check the difference from the value of the same SPIRO is less than 2

– Threshold value for each chip Check the difference from the value in the RIKEN QA is less than 10

– Mask pixel Check if there are differences from the results in the RIKEN QA

• β source testing Check the difference in the dead area against the RIKEN QA


Data acquisition

• Data is sent from the SPIRO boards to the FEM via optical fibers and read from the FEM through a USB cable.

• Ops system is used for data acquisition.• User name and password of DAQ PC is

- User name : pixel- Password : pixel*3186


Data Acquisition• Data is sent from the SPIRO board to the FEM via optical fibers and

from the FEM to the computer via USB cable.– Commands are also sent from FEM to SPIRO over optical fibers

• Ops is the program used for data acquisition and FEM control.• User name and password of the computer in the Clean Room is

– User name: pixel– Password: pixel*3186

• Suggested format for filenames:– ladderX_yyyymmdd_description– X is the ladder number, yyyy is the year, mm is the number of the

month, and dd is the day of the month– Description can be things like “calibration,” “calibration19,”

“sourcetest,” “calibration_mask,” etc. It is helpful to write in the lab notebook what the files refer to.

A. Shaver; Aug. 2010 5

Steps in QA testing• This procedure begins after supplying 3.5 V to the Ladder,

and before supplying Bias voltage. (see Hardware manual)1. Set DIAG Registers; Send DACS to SPIRO boards– Measure Reference Voltages

2. Measure Vbias vs. Ileakage (See Hardware manual)3. Set Thresholds4. Run Pulse Test; Noise check5. Source tests

1. 10 minute initial calibration test to find hot pixels2. If needed, 10 minute calibration test(s) at different latency(ies)3. 30 minute - 1 hour calibration test to find “warm” pixels. 4. Run full source test ~2 hours


1.Select USB mode.2.Check the HS channels

which you are using.3.Push “RST” button.4.Push “GO” button.

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Main Window

A. Shaver; Aug. 2010

• These 4 Buttons will direct you to the most commonly used windows within the program

• DIAG takes you to a diagnostics window where you can enter registry values

• DACS takes you to the DAC window where you can make changes to various DAC settings.

• MASK TEST takes you to a window that provides an interface for masking pixels, setting thresholds, and choosing pixels to receive pulse tests

• COSMIC takes you to the test window where the chips on each half ladder are displayed with their hit locations and some simple statistics 8

Main Window


• Set proper values for taking data at some registers.

- ADDR=0x04, 0x14, 0x24 : select the chips where FastOR signals (self trigger signal) are accepted.

✓ If you use readout channel of 0-3 and accept all FastOR signal from them, you have to set 0x04, 0x14=0xff and 0x24=0x0. The first digit of the address represents a specific spiro board. 04 is channels 0,1; 14 is channels 2,3; 24 is channels 3, 4.

✓ DATA Hex: Consider all chips a series of binary digits. Convert that binary value to hex. (e.g. Selecting the First, Third – Fifth, and Eighth chips: 10011101=0x9d; select no chips: 0x00, select all chips: 0xff)

- ADDR=0x60, 0x61 : set the maximum trigger rate

✓ 0x60=0x20 and 0x61=0x0 means the maximum rate is 32Hz

- ADDR=0x62, 0x63 : set trigger mode. (external trigger mode or self trigger mode)

✓ External trigger mode : 0x62=0x0 and 0x63=0x0

✓ Self trigger mode : 0x62=0x1 and 0x63=0x1 (Ladder QA is carried out in self trigger mode.)9

Diagnostics (DIAG) window


1. SET DIAG AND DACS


• Set DAC values (DAC_VDD, DAC_MID, GLT_REF) of analog pilot.

- Set the HS channel which you intend to set DAC values via “HS Channel Number” panel and set proper DAC values via “Set Analog Pilot DACS” panel.

- The DAC values are optimized so that the reference voltage be proper values.

✓ The reference voltages should be measured to be: DAC_REF_VDD=1.93V, DAC_REF_MID=1.085V, GTL_REF=0.93VFollowing slide shows measurement locations, and see appendix for details

✓ The reference voltage can be measured at tester adapters.

- The above values are stored for each SPIRO board in a spreadsheet. The FEM should read off the proper Serial Number (S/N) automatically, but you should confirm that the S/N matches each time you power up the FEM. The second line will “get” the S/N from the board, but it can be wrong. You may want to restart the FEM software or hardware, or manually enter the information on the line above

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DACS window


SPIRO tester adapter guide

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31

GTL


SPIRO tester adapter guide

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31

GTL

Fast-OR A3 A2A1 A0

e.g. A2=Bus A, Chip 2

GTL_REF A

Bus BBus A

DAC_REF_VDD A

DAC_REF_MID A

Fast-OR B3B2 B1B0

GTL_REF B

DAC_REF_MID B

DAC_REF_VDD B

The pins with ‘REF’ are pins to measure Reference value voltages. (see DACS window slide)

FastOR pins can be hooked up to an oscilloscope to read FastOR signals from specific chips (threshold testing)


3. THRESHOLD


Set trigger latency

Set threshold values for each chip

Set mask and test bits

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Mask and Test Bits (MASK TEST) window


Threshold Levels and Values• Note: Threshold DAC value will refer to the setting in the

MASK TEST window, and Threshold level will refer to the actual cut-off. These two words are inversely related. Higher DAC values correspond to lower levels. So if you want to raise your threshold level (to decrease noise), you should decrease your threshold DAC value.

• The threshold level determines some voltage above which, the system will register a hit. A low level will allow for more hits, but also more false hits from noise in voltage levels. A higher level will discriminate against noise more, but may lose some signal. Thus we wish to tune our thresholds to balance these competing effects.

• The default DAC value is 170, and it is a reasonably good working value.


Setting Threshold DAC values

• Connect an oscilloscope probe with the lead connected to a FastOR pin, and the ground attached to the ground connection on the Tester Adapter. (picture following)

• Source should not be present at this time.• The oscilloscope will have a flat low-voltage read if

there are no Fast-ORs firing. • A Fast-OR signal will appear as all or part of a (1-et) rise

in voltage. Example pictures follow.• The goal is to set a Threshold DAC value that is as high

as possible, yet low enough to not send Fast-ORs. Example in next slide


Connecting to Fast-OR on Test Adapter


See DIAG and DACS section for Test Adapter layout

Fast-OR Oscilloscope Examples


Examples of Fast-OR signals on an Oscilloscope

Threshold example• Begin with default 170 DAC value. In this case, no noise was

observed at 170.• DAC value was increased to 190 then 210. Fast-OR was observed

at 210• DAC value was decreased to 200, and Fast-OR was not observed• Increased to 205 and Fast-OR was observed• 200 is a sufficient DAC value, but slightly finer tuning found 202

to have no Fast-OR signal, and 203 to have Fast-OR signal. So 202 is the set threshold DAC value.

• Accuracy to nearest ‘5’ below noise is generally sufficient (eg 195, 200, 205)

• >20 seconds without Fast-OR is usually sufficient to determine that Fast-OR will not occur– There is usually an initial bump as the setting is changed. Ignore it.


4. PULSE TEST, NOISE CHECK


How to set mask or test bits1. Select the chip which has the pixel(s) you want to mask or

send a test pulse to.

2. Select the pixel position.

3. Set mask (test) bit(s).- ALL : Set all the pixels in the chip.

- It is not recommended to send a test pulse to all pixels. Send a pulse to 5 columns at most.

- COL : Set all the pixels in the column.- BIT : Set the pixel in the column and the row.

4. You can save and read the bit information.

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Two dimensional hit map for each chip is shown Take data with external or self trigger

Take data with force trigger (Automatic Pulse Test)

Convert data to an EXCEL file23

Cosmic Test (COSMIC) window


Stop on Event Countbox to enter count, and a check box to select option

DAQ rate is shownStart data taking with external or self trigger

Stop data taking

- Write file:Writes data to a file

- Graph Display:Displays a hit map. If you display a hit map, DAQ rate decrease. It is better not to display when you intend to store data for analysis.

Clear hit maps

This button will begin an Automatic Pulse Test. This takes data with a forced trigger.


Open Excel conversion window: converts and analyzes your data written to a file

EXCEL Convert window


Open Data FileConvert to .csv spreadsheet (EXCEL can open)

% Efficiency(of chip)

% Efficiency(of Ladder)

Saving Test information• In addition to writing the data to a file, it is useful to have visual

representations of the data.– If you have only written the data to file, and not “Graph Display” it is

necessary to use the Display Data File function at the bottom right of the COSMIC screen.• Click SOURCE, open the data file, and click FDR Display.• The COSMIC screen will run through the data file and display the hits as it

sees them. This can take ~20 minutes for a 2 hour test run.• To save the graphs, press ‘SHIFT’ + ‘Print Screen’ on the keyboard.

This copies a picture of the screen to the clipboard.• Open the Paint program and paste the picture of the screen.• Use the ‘rectangle select’ tool to select the area you’re interested in• Copy the selected area, open a new file, and paste the selected

area in the new file. Save this file as a .bmp


Run Pulse Test• Set two columns of test bits– Previous testing often selected columns 11 and 20– It is preferable to select two columns on either side of the

chip, but not on the extreme edge or center.• In COSMIC window, click APT button. Wait for all chips

to respond before starting another APT– Often, not all pixels in a column will respond. Multiple

Pulse Tests are used to determine that a signal is generally coming from the tests. 10 is usually sufficient to demonstrate pulse response.

• There may be some noise present. Threshold settings, bias voltage, and pixel masking may help reduce this but it’s not relevant for this test.


Noise Check• In the COSMIC window make sure ‘Graph Display’

is checked and ‘Write File’ is unchecked.• Click ‘FORCE DATA READ’– Within a minute, any exceptionally noisy pixels will

begin to fire almost continuously. (they may often reach 100 hits or more in this first minute)

– If it’s an isolated pixel or two, then that pixel might be noisy. Mask that pixel.

– If it’s a pixel within a region of other noisy pixels, your threshold values may need readjusting. Sometimes it helps to mask these hottest pixels too, as it sends fewer Fast-ORs and the region ‘cools down’ some.


6. SOURCE TESTING


Initial source testing

• Install the source and begin the motor (see Hardware Manual)

• It is useful to get an understanding of how the Ladder is operating before running a long source test. Short (~10-30 minute) tests help to investigate general features of the Ladder’s operation

• Set the PIXEL DELAY setting in the MASK TEST window to 18. This setting will be referred to as the latency and will be equal to 18 unless otherwise noted

• Repeat the Noise Check from step 5


Calibration Testing• With any observed hot pixels masked, check both the “Write File” and

“Graph Display” boxes. Click “FORCE DATA READ” to begin test.– It will prompt for a file name. Enter one, and click “open.”

• As soon as the first few hits come in, uncheck “Graph Display”– Displaying it initially helps the software form the array appropriately. Writing

to file without initially displaying may cause an error in the data file.– Turning off the display helps increase the data read/write speed.

• Run for 10-15 minutes. ‘E.T.’ is a clock of elapsed time in seconds.• With Graph Display off, the COSMIC window will still display the number

of events, ‘Num Evts’; event rate in events per second, ‘Evts Sec’; and elapsed time ‘E. T.’

• When the time is over, click “EXIT DATA READ.” In ‘Display Data File’ click “SOURCE” and open the file you’ve saved to. Then click FDR display.– The program will populate the graphs with pixel hits

• Then click “EXCEL CONVERT”


EXCEL Analysis• The program can convert its data to a comma-separated value file

(.csv) that can be analyzed using Microsoft EXCEL (and other spreadsheet programs)

• In the Excel Convert window, click “SOURCE” to open your data file, then click “FDR CONVERT”

• Particularly important are the efficiency measurements in the rightmost column. (another slide will explain more of these columns)– If the efficiency is 70%, and the %CORR is high, it may be that there’s a

latency issue.• If you wish to analyze the data more thoroughly, and find

statistically significant hot or cold channels, you can use the Pixel Ladder analysis workbook to help determine pixels to mask.– The goal is to find channels that are many standard deviations above

the others. This is usually a good indication of


Pixel Ladder analysis workbook 1• An Excel workbook has been written that can analyze the data

quickly– Has been optimized to find hot pixels

• The file is write-protected by password to prevent accidentally copying over the initializing dummy data.– If changes need to be made the password is pixel

1. Open the workbook and open the .csv file of your dat– When you open the workbook, click on “Read Only”– You’ll need to have run FDR convert in the Excel Convert window

2. Select all of the data from the .csv file. Copy and paste into the ‘DATA’ worksheet. 1. Click in any cell, and press ‘CTRL’+ ‘END’ on your keyboard to go to the

last cell in the sheet.2. Delete the last row of data (it’s Fast-OR data that will be unreadable

by the workbook)


Pixel Ladder analysis workbook 23. Click on the ‘Analysis’ sheet.4. Click on the ‘Data’ tab at the top of the program. Click the

“Refresh All” button.5. Cell B1 allows you to filter by chip# (0-15). Select the chip you

wish to analyze. The table will be populated with a count of how many events had a hit in a given pixel. – eg if cell G16 has the number 3, there were 3 events with hits in

pixel (5,11)• Further note that it may happen that no hits were recorded in a particular

row or column. There seems to be no way to force the program to display these rows, so always reference the ‘Row Labels’ In Row 4 and the ‘Column Labels’ in Column A to determine the pixel location.

• If you click cell B5 and click the “Freeze panes” option in the ‘View’ tab, the program will keep the first four rows visible to help you see which column a pixel is in when you scroll down the sheet.

– Column AK contains useful quick cuts, and a color legend


Interpreting calibration results• In the 10 minute calibration test, check the efficiency. If part of the

ladder is particularly inefficient, run a calibration test at a new latency setting (often 19 is the best value)– Compare the efficiencies chip by chip. If it’s a latency problem, the sum

of the efficiencies will often be between 90-110% (due to noise and statistical fluctuations

– If the efficiency is still low, Correlation? *to be expanded upon at a later date*

• After investigating latency issues, if any, run a 30-60 minute long calibration.– Here you may find “warm” pixels. These are pixels that are just slightly

‘hot,’ firing at about twice the rate of other pixels. You need a fairly large set of statistics to find warm pixels. Add warm pixels to pixel mask.

– You’ll notice warm pixels by chips appearing largely “blue” colored in the COSMIC window, with the warm pixels being red.

– The Pixel Ladder analysis spreadsheet is really useful here to make cuts


Source Test• After selecting the most efficient latency, and making a good pixel mask,

you’re ready to run the source test.• This test should be approximately 2 hours.

– Often this is ~300000 events. – In the COSMIC window you can select to stop on an event count, so 300000 is

a convenient place to stop if you wish to automate the process.– See the COSMIC window slide

• At the end of the test, divide the number of events by the elapsed time to get an average event rate, and record this value.– You can’t recover the elapsed time from the data, so it’s important to do this

first• Use FDR display on the COSMIC window to display the test

– This can take ~20 minutes to display the whole test– Save a picture of this, it helps in finding hot and dead areas of the pixel

• Use Excel convert to get efficiency statistics.– Usually they aren’t that different than the half-hour source test.


APPENDIX


DAC voltages

• Originally, the voltages listed were for– DAC_REF_VDD = 1.8 V– DAC_REF_MID = 0.955 V– GTL _REF = 0.8 V

• It was determined there was approximately a 0.13 volt drop along the bus, so the voltages have been raised to compensate.


Pixel Ladder QA manual Software R. Akimoto, A. Shaver. July 2010Email: [email protected].

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Transcript of Pixel Ladder QA manual Software R. Akimoto, A. Shaver. July 2010Email: [email protected].