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 1500-1550 cycles

– Inner HV breakdown during 1600-1650 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

HV Test

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Trial/50

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apac

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nf)

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 2002. 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)