Flash Measurements in the Main Injector BPM System

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Flash Measurements in the Main Injector BPM System

• Steve Foulkes

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During a Cycle

• As a flash is triggered, the front end notes the
  current filter and the start event
• The front end then waits for data to be
  collected, and moves on.

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End of Beam

• 12000 samples are read out of the 2.5Mhz and
  53Mhz channels of all the Echoteks
• The front end splits up the buffers, choosing
  either the 2.5Mhz or 53Mhz for a particular
  measurement

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First/Last Turn

• The front end uses the start event to determine
  whether a flash was injection or extraction.
• Injection events
• 0x200 (BES), 0x7A, 0xD6, 0xD8, 0x1A4 (Recycler),
  0x1A7 (Recycler), 0x17A (Recycler), 0x1A0
  (Recycler)
• Anything else is treated as an extraction

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Finding the First/Last Turn

• For injection, we start at sample 0, while
  extraction starts at sample 511
• For each BPM, we search through the buffer and
  pick the first sample that has a sum signal over
  250.
• If were not in safe mode, and the first turn is
  found to be sample 0, we set the position to 999.

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Calculating the Average Orbit

• For each BPM, we go through the flash buffer and
  find the mean of the position and intensity
• Only points with sum signal greater than 250 are
  used