PCB production

1. PCB production • After discussions with Rui and his technicians at CERN a solution was found to manufacture the PCB at CERN in one piece. • The raw material (50  thick polymide + 5  Cu on each side) • has been ordered. Due to the large non-standard width needed (650 mm) this is a custom made order with a minimum order of 30 m2. Expected delivery to CERN beginning of February. • From reception of raw material, Rui will need approximately 4 weeks to manufacture the PCB. • GEM production will cease during PCB production to allow maximum manpower devoted to PCB. We should have by then at least 60 GEMs.

2. PCB final design

3. R2 R2 R2 R2 R R2 HV Resistive chain 3 identical branches • For VGEM = 500V: • Present resistive chain (R1 = 1.2, R2=20, R=5M) • I = 300 A • If a short occurs in one HV segment: • I  301.5 A • voltage across AB  451 V • voltage across damaged GEM  225V • Keep R2 only on segmented face • I  302.7 A • voltage across damaged GEM  411V A B

4. R2 R2 R2 R2 R HV New Resistive chain 3 identical branches • For VGEM = 500V: • Proposed resistive chain: • - Double R1 and R to be able to use LeCroy PS • R1 = 2.4, R = 10 M • - Keep R2 = 20 M only on the segmented face • In normal operation I = 150 A • If a short occurs in one HV segment: • I  152.3 A • voltage across damaged GEM • = VAB = 349 V • If R2 = 80 M I  150.7 A VAB = 451 V A B