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