1. Updates on Using CAEN 1495 as MLU in Trigger Compton DAQ Performance at 440 kHz HV Status R. Michaels, Nov 19, 2013 p. 1 / 5

2. Using CAEN 1495 as MLU in Trigger Memory Lookup Unit Input registers NIM input Output registers NIM output Outputs = function of inputs 10 nsec propagation through unit Negligible time jitter ( << 1 nsec) “2 / 3” trigger [efficiency] (S1.and.C).or.(S2.and.C).or.(S1.and.S2) C = Cerenkov S1,S2 = scint FPGA p. 2 / 5

3. attenuate DC 5V SumAmp V2F Random Pulser Logic OR FADC TI Helicity Compton DAQ at high rate integrate Test Procedure : Trigger with a high-random rate R which has helicity – correlated asymmetry A Results : for f < 300 kHz, DT = 0, asymmetries are “clean”, agree with scaler For f > 300 kHz DT > 0 (pipeline fills up) for some measurements (but can eliminate) Deadtime cuts clean the asymmetries 440 kHz Compton Asymmetry (2.5 %) ~ 2% < 2 MHz Scaler Simulate the Compton process

4. Exploring f > fc ( > 300 kHz) t Busy Signal (scope trace) Normal Pipeline Overflow Put into scaler and read with each event: Busy.AND. Pulser -- deadtime Busy.AND. Helicity.AND. Pulser -- deadtime in helicity window where Pulser = 3 Mhz clock Unstable trailing edge Compton DAQ at high rate p. 4 / 5

5. High Voltage : Works on 2 HRS LeCroy 1458 HV Network new serial card replaces old motherboards (Javier, Jack, Chuck) external 24V supply motherboard emulator Perl script (Brad Sawatzky) Java GUI (Roman Pomatsalyuk) p. 5 / 5 Low-level diagnostics to find bad cards. Software still a bit too slow (working on it ) or Serial