1. Pions for SoLID May 7 th 2013 SoLID EC meeting A. Camsonne

2. Pi/e separation Online – Reduce trigger rate Offline – Reduce pion contamination

3. Pion trigger Threshold and upper thresold shower – More than 200 MeV – Less than 500 MeV Upper threshold : preshower – Less than 3 MIP Cerenkov – Upper threshold : less than 1 pe Scintillator – Half MIP threshold Need to determine efficiency and rate

4. Clustering Time clustering – Timing resolution at least 4 ns – Most like 1 ns with fit Amplitude clustering – Can separate multiple clusters

5. Tracking Offline – All charged particles have track – Can try to subtract pion from electron cluster – GEM timing : 25 ns sampling – Gas Cerenkov timing : 4ns sampling – Calorimeter timing Concern : GEM occupancy does not include DIS rate ( all Geant process though )

6. Waveform Pion trigger in accidental window

7. Example of waveform treatment for DVCS

9. Waveform data rate Assume 20 samples RateNb samples 6000020 Event size FADCNb channelHeaderTrailerSampleTotal size (Bytes ) Calorimeter6 4480528 Preshower6 4480528 Cerenkov 3 44 80264 Scintillator6 4480528 1848 Bytes/event 110.88 MB/s

10. Data rate GEM PVDIS SectorRateXYBytes3 samples 02346184552 1122496288 2102080240 391872216 Total hits / sector544321296 Data rate / sectorat 60000 KHz2592000077760000 Data rate ( sector Mb/s)25.9277.76 Mb/s

11. Data rate With waveform FADC data size is comparable with GEM At 60 KHz, no choice but to use on board deconvolution from APV25 Rate roughly 200 MB/s at 60 KHz For 30 sectors gives 6 GB/s, need data reduction by about 30

12. L3 Farm Hall D performance – 27 Hz with tracking ( 741 cores for 20 KHz ) – 77 Hz without tracking ( 260 cores for 20 KHz ) Cheap 32 cores server about 5 K$ About 500 K$ for 20 KHz, 1.5 M$ for 60 KHz Need to evaluate speed – Waveform – Clustering – Tracking

13. Tape price Currently 1.5 TB = 75 $ SoLID approved PAC days : 474 days At 250 MB/s about 7 PB of data about 600 K$ Assume double time and double tape for safety : 2.5 M$

14. Conclusion Pion trigger defined but need to evaluate efficiency Waveform recording doable but need to evaluate accurately how many channel fire Waveform has advantage of giving pions though need a larger window size but needs to be studied Cost scales roughly linearly with rate – Prefer to try to keep trigger rate to 20 KHz with coincidence