Gray Room Activities Richard Kass with much help from: Marco B., Jacques C., Giovanni M. 12/4/20121R. Kass (Adventures with USBpix)

Many Successes 12/4/20122R. Kass We used USBpix/STcontrol to take data in several modes: SOURCE_SCAN with external trigger: SOURCE_SCAN with USBpix self trigger: Learned how to read.raw files: Modified a program to convert FEI4.raw file to ROOT ntuple Wrote ROOT macros to read the ntuple files & make histograms, etc. Sr90+scintillator based trigger laser diode + pulse generator trigger Sr90 (without scintillator trigger) AM241 (gamma source) 3M triggers 50k triggers 10k triggers 500 triggers

We cleared up a few mysteries… 12/4/20123R. Kass How do we get the “internal” triggers to work? Turn off all of row zero (mask=0) (see slide for how to mask pixels) How do we speed the data taking program up? The program fills up a buffer and “thinks.” It is doing cluster finding which can take a long time This dominates the data collection time. Turn off the clustering histograms speeds up the data collection by > 10X look closely, row 0 is off. The cluster hists are toggled to off.

Future Work 12/4/20124R. Kass Lower the thresholds to 3200e and then even lower (1600e?) There is a “procedure” for doing this: “FEI4 Characterisation”, notes by Kate Doonan We tried it….and the results were confusing: more tuning: two groups, 1500e, 3400e Improve the trigger system eliminate some material (plastic) between source & silicon move source closer to Si and/or collimate the source (lower rate…) get scintillator(s) that better match the geometry of the Si Optimize the mounting of source, card, scint. inside of the box allow us to make reproducible measurements Offline software, save time, do clustering analysis off-line initial: 4700e some tuning: 2500e Note: changing the FE Global parameter Vthin_ALTFine shifts the threshold, e.g. 128= 4700e, 96=3600e 

12/4/20125R. Kass Masking pixels (1) highlight FEI4 in read-out configuration window Choose Edit cfg (2) Choose FE Masks Right click map Choose Display/Edit (3) Use editor to mask individual pixels, rows, columns