PQB Meeting January 21, 2016

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We will meet in TL 2236 Thursday January 21 at 1:00 pm EST.

For those calling in we'll use the Blue Jeans [1] audio conference system.

Phone number: 1-888-240-2560
Meeting ID: 3528502673#
Meeting URL: http://bluejeans.com/3528502673


  1. Results from December 2015 Hall A beam test (Kent Paschke): media:160121_FallBeamTests.pdf
  2. Spring 2016 Beam Schedule:
    1. Accelerator Restoration: January 28 – February 04
    2. Hall A – 11 GeV, 50 µA polarized beam: February 04 – April 14

Notes from this meeting:

  • Problem with few Hall A BPMs signals observed in December 2015 with CW beam around 30 µA was traced to firmware settings that caused bad readings when switching between High and Low Gain Modes. The EPICS position readback went also bad, not just the S/H card signals.

The "RF Max" and "RF Step" values for Hall A BPMs were changed in CEBAF Element Database (CED) to the same values of Hall C and Injector BPMs where this specific problem was never encountered. After the software updates, Hall A BPMs now have a smooth transition from High to Low Gain Mode of operation without loosing any X/Y positions. Since Hall A reported small signal in IPM1H04A X wire, the RF module for IPM1H04A was tested and it looked fine but was replaced anyway. The RF module for IPM1C12 was also replaced. Many thanks to Pete Francis for solving this problem.

  • During Spring run, there will be dedicated accelerator time for RF recovery with no beam in the accelerator (one shift per week). However, the injector will be available for beam tests; good time for PQB studies in injector.