SNS Harp Electronics Design

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SNS Harp Electronics Design
SNS Harp Workshop
SNS Harp Workshop March 13, 2003 ORNL by Mike
Plum
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Signal levels from tungsten wires

• If we assume
• A dynamic range of 200 for a given profile,
• That we would like to measure beam profiles for
  beams with peak currents that can vary by a
  factor of 100,
• A factor of four safety margin for estimates of
  signal levels,
• Tungsten wire
• Then
• Need electronics for signal range of 7 nA (7 fC)
  to 8.4 mA (8.4 nC) for 25 micron diameter wire,
  or
• 32 nA (32 fC) to 40 mA (40 nC) for 100 micron
  diameter wire.

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Signal levels from tungsten wires (cont.)
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Harp electronics (cont.)

• Dynamic range is a problem.
• If we really want a dynamic range of 200 for a
  given profile, and want to measure beam profiles
  for beams with peak currents that can vary by a
  factor of 100, were talking about a dynamic
  range of a bit over 1,000,000.
• Gain ranging makes the system more complicated.
• Can we settle for reduced measurement accuracy
  for low beam currents? We do this at LANSCE, and
  it has worked well for us.

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Harp electronics

• Propose design that has been shown to work well
  at LANSCE
• Integrating electronics.
• Gate width of a few microseconds
• Gate initiated by signal from ring extraction
  kickers.
• Differential input to minimize impact of
  electronic noise.

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Harp electronics requirements
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