Ad-hoc BI-TB on LEIR injection BPM

Europe/Zurich
866/1-A04 (CERN)

866/1-A04

CERN

15
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Issue affecting LEIR injection pickups (electronics based on Low Frequency, high impedance circuitry):

  • Ions & electrons in the beam pipe charging the electrodes (baseline offset)
  • Stray field from neighboring magnets

Attempts to mitigate with solenoids and bias voltage cannot completely solve the problem

  • 7 of the 9 BPMs can be used to give a single position reading at the end of the pulse

New head amplifier with 101MHz output (5 of 9 BPMs equipped) gives promising results when acquired with a scope

Present acquisition system is based on SIS3xx clocked at 100MHz

ACTIONS:

  • M. Bozzolan to confirm with ABP that RF structure is always available
  • M. Bozzolan to measure difference in 101MHz component on first & last pick-up with buncher on & off
  • M. Bozzolan to ask ABP to perform debunching simulations from LN3 exit to LEIR injection to confirm measurements with buncher on & off
  • L. Jensen? to temporarily install VFC with FBCT/diamond FMC for acquisition test
  • M. Wendt, M. Bozzolan & G. Baud to estimate performance, cost & resources (& their availability) required for the following options:
    • Analogue downmixing with SIS3xx acquisition
    • Digital downmixing in FEC with SIS 250MHz acquisition
    • Digital downmixing in FPGA VFC with FBCT/diamond acquisition
    • Digital downmixing in FPGA with VFC & optimised FMC (e.g. 8 channel, 250MSps)

Project meeting at end of August to follow-up on ACTIONS before LIU activity review

 

 

 

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