1. Triggering with the RPD E. Burtin, CEA-Saclay COMPASS Hadron run trigger meeting, Feb. 12, 2008

2. Overview of the full project Ring A Ring B

3. Commissioning Calibration (Oct 12 - Nov 5): rot 0°, 30°, 90° Trigger tests (Nov 5 - Nov 11) 6 7 View from Jura side 2007 Upstream 2008 9 5 6 8 Ring A 18 1 2 5 8 10 11 12 13 14 15 16 17 19 20 21 22 23 4 3 0 0 1 2 3 4 7 9 10 11 Ring B Muon beam 0 5 4 3 2 1 6 7

4. Energy loss correlations Tests in 2001 protons   -electrons Thickness A : 4 mm B : 5 cm Thickness A : 5 mm B : 1 cm

5. Trigger condition protons  e Area of interest is : A hi.B low or A low.B hi A low B hi A hi B low Thresholds choice ingredients: - Dynamical range - Attenuation ( =70cm) A : 0.25 B : 0.10 Limitation on B hi to accept high momentum (1GeV/c) proton

6. Proton identification protons  e 275 410 760 MeV/c For protons Limitation: Thickness of Bring elements

7. Proton trigger Trigger timed on A low down Trigger: - At least one A.B pair fired - Done - Only one A.B pair fired - Under study

8. Jitter on signals t up B t do B t up A z B t B t do A z A t A target Z LBLB LALA t do A has ~2ns jitter Leading edges of all signals within 30ns

9. Trigger board : CAEN V1495 Design & Programmation of the FPGA done by Christophe Flouzat « Conduct of operations » : All signal sampled at 400 MHz (2.5ns) Individual delays applied Logic function realized Output of signals on 2 lemo & 64 LVDS A i;down low A i;up low B i hi Trigger 80ns D D D Could fit in 50 ns

10. Trigger latency A down low Trigger Time to produce a trigger < 150 ns Laser signal

11. Trigger signal jitter with BEAM Oscilloscope triggered by the finger trigger signal Scope triggered by hodoscopes signals

12. Conclusions Trigger board : Design validated Jitter of A i B j coincidence is ~2.5 ns (due to the sampling) Each coincidence can be aligned in time Open possibility 32 spare inputs for Forward Hodoscopes if needed 64 outputs can be used for further processing Needs commissionning with beam …