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Testbeam 0904 at FNAL. Testbeam Team Marina Artuso, Alessandra Borgia, Torkjell Huse David Hutchcroft, Ray Mountain, Jianchun Wang. The Telescope. VELO. Scint. Pixel. Pixel. Pixel. 120 GeV proton beam. YX. Y. YX. VELO detectors under test
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Testbeam 0904 at FNAL Testbeam Team Marina Artuso, Alessandra Borgia, Torkjell Huse David Hutchcroft, Ray Mountain, Jianchun Wang
The Telescope VELO Scint Pixel Pixel Pixel 120 GeV proton beam YX Y YX • VELO detectors under test • Rf module: setup system, resolution study (0, 4, 8, 12 degrees), starting point for alignment of RR pair with respect to the pixel tracking. • RR Pair: to study VELO performance after irradiation. • Pixel planes provide tracking • Aperture: ~ 3.5cm 3.5cm. • 4 good stations at beginning, with each X Y pair downstream and upstream. • 5th station added later: provides better resolution in Y, validate estimation of projection resolution, a short study of thinned detector (100 mm). • Binary readout at beginning, 2-bit readout at the end. • Scintillation counter provides trigger signal, coincident with clock edge to select VELO events that were sampled at peak. Jianchun Wang
Height Unit nut & washer Annoyance Unit Censored Jianchun Wang
Brilliant ! Jianchun Wang
Beam Profile Y (mm) Beam 120 GeV/c proton ~30-40 K / Spill, ~8 buckets Lateral Spread: s~8 mm, normally spread more in vertical and less in horizontal directions. Tuned a lot based on pixel online monitor. Angular spread: s~ 7 x 10-5 70 mm over 1m. X (mm) X (mm) Y (mm) Jianchun Wang
Data Sets VELO ~ 50 GB data. >~ 5 million events. Pixel ~ 12 GB data. Beetle Setting Chris: faster integration, used in pit. Kazu: slower integration, better for irradiated. Lars: in between Jianchun Wang
VELO Signal ADC Counts ADC Counts Non-irradiated Sensor Tell1 8, p-in-n type Irradiated Sensor Tell1 5, n-in-n type. Jianchun Wang
Synchronization between Two DAQs • Pixel & VELO use independent DAQ systems, write to different data files. • Common BCO clock and trigger pulse BCO/trigger counting as event ID Events matching offline. • A 37.5 MHz BCO clock is generated on the pixel router board. • Scintillation counter signal + BCO clock, with delay and deadtime Trigger pulse. • VELO accepts only software reset Counting start at different time. • We disable trigger pulses before reset to synchronize trigger counting. • Trigger control line = low No trigger pulse is generated • Reset BCO/trigger counting at both systems. • BCO/trigger counting starts from 0. No trigger pulse Trigger counting=0. • Start data taking at both DAQ systems. • Trigger control line = high Same trigger pulses are sent to both systems. • The trigger event ID’s are the same. The BCO event ID’s have a run-dependent offset between two systems, also different for different TELL1s. We rely on trigger event ID and use BCO ID to solve ambiguities. Old Plan Jianchun Wang
Alignment “Strategy” • Central Z position of each detector is measured with rule. • Four chips within a module are assumed to be perfectly aligned. • Six modules within a station (Tbdb) are aligned using overlaps (x, y, f). There is a ~mm bias due to small overlaps and edge effect. • Five (four) stations are primarily aligned by requiring parallel beam (x,y). • VELO stations are manually aligned with respect to pixel tracks (x, y). • Form tracks and align stations (x, y, f, a, b), as well as modules (x, y, f). • Align VELO stations with respect to tracks (x, y, f, a, b). Jianchun Wang
Alignment Between R/F Module and Pixel Tracks Ytrack (mm) Yvelo (mm) Xtrack (mm) Xvelo (mm) VELO at 12 degree, distance between R/Phi not considered yet. Xvelo (mm) Matching VELO R/phi hit pairs and pixel tracking projections Xtrack (mm) Xvelo– Xtrack – offset (mm) Yvelo (mm) Jianchun Wang Ytrack (mm) Yvelo– Ytrack – offset (mm)
Trigger Count Jump The trigger counts are not perfect. The offset is ~ few counts over 10,000 triggers. We don’t have the redundant BCO counting to correct this ambiguity, due to instability of TELL1 boards. Xtrack (mm) Ytrack (mm) Ytrack (mm) Ytrack (mm) Method to correct For each VELO hit, a best match is searched with a window of 10 trigger count difference. A offset jump is assigned starting from that hit if the majorities (30 hits that follow) agree. For some studies events around the jump will be excluded. Xtrack (mm) Xtrack (mm) Matching Rate Trigger Count Offset Run Period Jianchun Wang Accu. Number of VELO Hits
Alignment Between RR and Tracking 8 degree RR bottom Xtrack (mm) Ytrack (mm) Ytrack (mm) Yvelo (mm) Ytrack (mm) Ytrack (mm) Xvelo (mm) Xtrack (mm) Xtrack (mm) Xtrack (mm) Rvelo (mm) Matching Rate Trigger Count Offset Rvelo– Rtrack, correct (mm) Rtrack, correct (mm) Run Period Accu. Number of VELO Hits Jianchun Wang
More Problem on Trigger Counting Two VELO stations are asynchronous ?! Fortunately they are using the same clock and we can use the ambiguity-solver – BCO count. Might due to higher intensity, bad logic board, or bad TELL1. More headache offline. BCO Diff Trigger Count BCO Diff * Trigger Count BCO Diff = ( BCO5 – BCO8 ) % 4096 BCO Diff * = ( BCO5 – BCO8* ) % 4096 One trigger earlier BCO Difference Jianchun Wang
Summary • It is a quite successful testbeam. • We met many problems. • Quality of TELL1 boards, GBE cards. • Unable to use common clock. • Mechanical and cooling. • Beam issues. • Restaurant close too early. • … • Plan • Finish pixel tracking alignment. • Provide supporting software for VELO study to use tracks. • VELO analysis. • Setup VELO system and finish phase/delay scan. • … Jianchun Wang