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

Overview of the full project Ring A Ring B

Commissioning Calibration (Oct 12 - Nov 5): rot 0°, 30°, 90° Trigger tests (Nov 5 - Nov 11) 6 7 View from Jura side 2007 Upstream Ring A Ring B Muon beam

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

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

Proton identification protons  e MeV/c For protons Limitation: Thickness of Bring elements

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

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

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

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

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

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 …