High%20Voltage%20Plates%20and%20Capacitors

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High Voltage Plates and Capacitors

Jack Fowler
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High Voltage Plate Procurement

• Initial pre series received November 1999
• We determined that the Kapton was too thick and
  redesigned.
• Second pre series was received in May 2000
• Traces on Kapton circuits exhibited cracks after
  flexing
• New Kapton flex circuits ordered in July 2000
• New High Voltage plates received September 2000
• Currently evaluating changes
• Remaining High Voltage Plates to be delivered in
  2000

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High Voltage Plate
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Changes to HV Plate

• Gold plating was removed from the traces, except
  for contact regions
• This was due to the thin layer of Nickel required
  under the gold. It was causing the cracking.
• This was based on several recommendations from
  experts in the field of circuit manufacture.
• Increased radius and added chamfers to areas on
  thick plate where bending will occur
• This was based on recommendations from the
  manufacturer of the Kapton material. (DuPont)

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Changes to Gold Plating
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Changes to Thick Plate
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Consequences of Changes

• Due to the changes in gold plating, portions of
  the Kapton flex circuits had to be remanufactured
• Added 4 weeks to the delivery time
• Cost 15,000 for Type 1 and Type 2 HV Plates
• Type 3 was not affected because only pre-series
  was on order
• Thick plate changes had no effects on price

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Capacitor Procurement

• Johanson X7R dielectric turned to dust after
  radiation testing at CERN
• Identified alternative sources and dielectrics
• Samples have been sent to CERN for evaluation
• Expect 20 to 30 week lead time due to shortage in
  electronics market
• How does this affect module production and
  installation?