Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN HV capacitor Testing

Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN  Two tasks  Capacitor testing (Duke)  Capacitor preparation (Hampton)  Capacitors under testing  Johanson surface mount  1000pf, rated 2000 V, size 821.  Material : X7R  Choices are limited due to space  Capacitors from four different lots (batches).  ~Two years ago, the same capacitors (from different lots) were radiation tested at CERN and the results were mixed.

Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN HV testing  HV cycle  Connect 30 capacitors from each batch to HV=2000 V and discharge.  Measure the total capacitance every 50 discharges.  Number of cycles : 2000  Results  Batch 1  One capacitor –Surface HV breakdown during cycles –Inner HV breakdown during cycles  Batch 2/3/4 : No problem  Conclusion : Pass

Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN  Test setup

Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN

Seog Oh/ Duke University/Oct, 2002 TRT/ ATLAS week at CERN Plan  Repeat the same test with capacitors from HU (encapsulated and legs are attached)  Long term test  30 capacitors from each batch connected to HV=2000 V and current is monitored.  Irradiation test – CERN  Requirement : All capacitors from all batches should pass.  Decision by the end of There should be no problem in getting the capacitors (~6 weeks).  Radiation test on ~100 random samples once the production batch is available  Option in case of failure  Go to lesser capacitance with different material (NPO)