Present: Stepan, Maurik, Nathan, Raphael, John

 

1. Discussion of readiness for ERR.

    Positron Trigger. Stepan noted that we will have to make the case without new simulation. At the collaboration meeting, a strong case was made on the basis of the data, using L6 as a surrogate for the new scintillator hodoscope. We will still need to do detailed simulations to understand backgrounds in the L0 detector, optimal pixel sizes, etc. Orsay has agreed to work on the support structures, designing, building, and funding them. JLAB has the needed scintillator and fibers; UNH can likely supply the PMTs and support readout module construction, and FADCs can be borrowed.

Stepan will post his slides for the overview talk and the positron trigger talk over the weekend. Everyone should look them over and comment as needed. They'll be posted here: https://wiki.jlab.org/hps-run/index.php/HPS_Upgrade_ERR#Jefferson_Lab..2C_June_12.2C_2017

   

   SVT Upgrade. Only two issues were raised. The trigger rate increases with L0. What can we say to assure ERR  (or ourselves) that this is ok? Do we actually have the extra bandwidth? What will the deadtime be? Not clear these issues can be addressed before Monday. A second issue: is 150 um the right choice for detector thickness? These detectors will have less signal and be less mechanically robust. What are we buying by going so thin?

Tim will also post his slides on the ERR wiki, given above. Please comment to Tim.

 

2. Run Plan Discussion

    In his talk at the collaboration meeting, Stepan noted that 70 days on the floor, hopefully in summer or fall of 2018, is what we should be aiming at. It is about the longest believable time slice.

    EC agreed that we want to run at 4.4 GeV for about 4 PAC weeks. We'll need another PAC week for commissioning the beamline, the trigger, and the SVT and an additional  1/2 PAC week for running various diagnostic runs (straight throughs, etc.).

    We agreed it would be useful to know the reach at 6.6 GeV, and how the reach at 4.4 GeV depends on the length of time we run.

    We'll finalize this in the future, but seem to be close to what we want for the Beam Time Request.

 

Respectfully submitted,

 

John

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