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Compton Edet and DAQ

Compton Edet and DAQ. Edet. Short Overview of System Activity since Last Meeting Present Status Proposed Plan for HAPPEX – 3 Short Overview of Old System Proposed Upgrade. DAQ.

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Compton Edet and DAQ

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  1. Compton Edet and DAQ Edet • Short Overview of System • Activity since Last Meeting • Present Status • Proposed Plan for HAPPEX – 3 • Short Overview of Old System • Proposed Upgrade DAQ

  2. Compton scattering ofpolarized electronsfrompolarized photons scatteredelectrons Detect both electrons (Edet) and photons electrons Scattered photons

  3. Compton EdetC. Hyde, A. Camsonne, P. Bertin (ret.), M. Brossard, F. Daudon

  4. Compton Edet Claremont-Ferrand

  5. Microstrip planes In Edet

  6. Looking at Analog Signals Strip 5 Strip 10 Photon trigger

  7. Looking at Analog Signals Same, another event

  8. Correlated Noise Sometimes hits on many strips. JLab environment more noisy than at Claremont.

  9. Conclusions from Analog Signals per. Michel Brossard Interpreted by R. Michaels • Signal ~ 40 mV • Noise ~ 4 mV  S / N ~ 10 • Capacitance 200 pF (longer cables are ok) • Some correlated noise (pickup), tolerable. •  Detector should be efficient !!

  10. Measuring the Efficiency Electron(or something) Initial tests … Microstrips 3-strip method Hit ? Results ~ 8 % hit road (few strips) Later … 2-strip method Hit ? Results ~ 3 %

  11. Oscilloscope checks of Efficiency Results consistent with few % effic. Radioactive source Beta source hit a downstream plane, what hits upstream ? Hit ? Microstrips Trigger electron beam (plus bgr) 5 strips FPGA programmed to output or-of-5 strips on two planes. How often correlated ? Microstrips Trigger

  12. Hypotheses for What is Wrong • Reversed polarity on connection between discriminator and front-end logic. •  fixed, but didn’t improve efficiency • Possible problems with pickup and grounding • (R. Wilson’s note) • Problem in FPGA (many things tried) •  An “unbiased” trigger version prepared but we ran out of time to try it.

  13. ``Unbiased’’ FPGA Version Instead of letting the Edet decide to read itself out, let photon trigger decide. Read whatever is there within generous time window. Electron Microstrips Makes trigger

  14. Try: ``Unbiased’’ FPGA Version Scintillator Microstrips Cosmics Coinc. Trigger Scintillator

  15. Edet: Statusand Plans • Was removed from beamline, on bench for tests PROPOSED PLAN( to Aug 10) -- realistic ideas welcomed • Analog board to get Pulse – height spectrum • Measure discriminator deadtime (pulser input) • Cosmic-ray effic. with “unbiased” FPGA readout(fake photon trigger) • Repair broken planes (possible visit by F. Daudon) • Improved shielding and light-tightness • Re-install Aug 10 • Old Edet ?  if so, some other team to do it.

  16. Compton DAQ • Short Overview • Proposed Upgrade • (see Gregg Franklin’s talk, too)

  17. ROC 1 / 2 : Photon and Electron Detector (the main VME crate)

  18. Software on ROC1 / 2 Acquisition state machine mgt Scaler readout, and informs mailbox read is done Online computing, prepares buffers for event builder DMA mgt of photon & electron data

  19. “ADC0” : a customized card involved in the trigger (no longer an ADC, it has FPGA and NIM I/O)

  20. Compton Integrating DAQ CMU group & me

  21. Proposal : Add the ETROC here ETROC Edet Also need to add BPM info (via v2f)

  22. New, Simpler Compton DAQ ? • Use ETROC in same crate as FADC • Add BPM and other auxiliary info • Develop at CMU during Fall 2009 ? • using old ETROC • using standalone ETROC CRL code • Deploy for PREX in March 2010 • Old system: withers away eventually

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