PREX/CREX Thursday, January 8, 2015 9:30am EDT

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Link to the Meeting page PREX/CREX Teleconferences
Last meeting: PREX/CREX Thursday, December 11, 2014 9:30am EDT

The teleconference info is as follows:
       Phone #: +1-888-240-2560 or +1-408-740-7256 and See International Numbers
       Code: 174599135


  • Discuss PREX/CREX run plans and Configuration Changes

Tyler, Dustin, Bob, Seamus, Caryn, Kent, Nickie, Ciprian, Rakitha, and Guido


  • CREX Target Discussion
    • The goals for the Ca48 Target design are,
      • Chemically isolate to prevent oxidization
      • Not to melt or evaporate
    • Initial proposal was to have a hollow tube to keep the Ca48 and keep DS target window far away to keep out of the acceptance.
    • According to Dave, a method can be devised to ioslate the Ca48 in the scattering chamber vacuum without any isolation chamber like the one we proposed. This is also important to make the PREX/CREX compatible and hence run together one after the other.
    • One idea suggested by Roger to sputter the Ca48 target with few atomic layers of inert material
  • PREX/CREX Collimator Design
    • Implement a long tube or stove pipe to drop down and hoist the collimator + top shielding from the top of the sieve box.
    • This will make the PREX collimator extraction very simple and replace with CREX collimator. This should reduce the wait time to extract either PREX or CREX collimator
    • The CREX collimator will be slightly different from the PREX design. The bore size for the CREX configuration needs to be determined.
    • We need to start the CREX collimator design and background radiation study
  • CREX Septum Design
    • People seems to agree that APEX septum configuration would not suite parity type experiment. The separation of main electron signal from background signals like inelastics is very important to parity experiments where in counting mode experiment like APEX main signal can be separated using tracking detectors.
    • There is also lot of configuration changes and optics checks to make sure this is compatible with PREX or CREX
    • Optic studies are underway to determine the correct CREX optics, target location and HRS optics. This will give us a better idea about the PREX septum compatibility
    • We may be able to use the same coils with higher current with coils water cooled.
  • PREX Shielding Changed to make CREX target design more compatible
    • There is also some concern about the water vessel in the SC raised by Roger and also Dave Meekins would prefer to have more space in the SC. Therefore we may go back to shielding surrounding the SC. There will be some optimization to be done for shielding outside the SC.
  • We would like have a list of requirements for CREX target, collimator, septum tune and HRS tune
  • PREX Radiation Simulation, Things that can be done before the review
    • It would be a plus to have a simulation benchmark from another experiment like HAPPEX-II to get an idea about the radiation dose in the hall.
    • The factor of 10 reduction was proposed to reduce the electron failure rate (for example optical couplers) from once every 2-3 days to much lower rate.
    • Check with Juliette's deuterium target radiation results
    • Discuss with Pavel to get more input about benchmarks
      • For instance the data from different experiments from RadCon detector near the alcove in the hall as a benchmark for PREX simulation
      • Juliette tried to accomplish this sometime back.
    • Use two mini detectors (full absorbent detectors) at around septum area where cryto/magnet power supplies are kept and around HRS electronic hut. to estimate the neutron flux
  • High Energy Neutrons Simulation
    • We need to have an estimate on high energy neutron conversion to low energy neutrons.
    • Lorenzo may have done a study using high Z target with high energy neutrons.
    • What we want is very crude estimation of high energy neutron interactions with 10-30 cm thick iron or concrete


  • Beam parasitic studies needs a to-do list

TO DO Lists

  • We need to have an estimate of how much coulombs used for PREX-I data and an estimate for PREX-II to determine effectively how much more beam time we will use.
  • Have a optic calibration run plan (discussed in 01/16/2014 meeting)
  • It would be nice to have real-time viewer for optics studies in commissioning (disussed in 01/16/2014 meeting)

TO DO Lists link: PREX, CREX