HV capacitor Testing

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• HV capacitor Testing

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• 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.

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HV testing

• HV cycle
• Connect 30 capacitors from each batch to HV2000
  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

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• Test setup

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Plan

• Repeat the same test with capacitors from HU
  (encapsulated and legs are attached)
• Long term test
• 30 capacitors from each batch connected to
  HV2000 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)