[Mott] Mott Run II status

[Joseph Grames]

Folks,

Status for Run II

1. On Friday John and I tested 31MHz e- beam, properties and bunch profile similar as we had in Run I.  We were too cavalier how we ran the expensive laser amplifier in January (think higher peak power at lower rep rate), so we'll ~now operate the amplifier more conservatively which translates into less power.  We'll be able to make ~few uA, not much head room, but suitable for the program.

2. Yesterday Riad and Daniel put beam in Mott for checkout and got a lot done: the DAQ is ready, PMT HV set for 5 MeV, detector delays set so timing fits/cuts similar, hardware veto eliminates dump events, thresholds set to our "low" value OK with timing veto.  Mott spectra and instrumental asymmetries look good, and then...

3. ...they started measurements to quantify background at the Mott generated by testing of two downstream SRF cryomodules (we call them 0L03 and 0L04).  The 0L04 module - one of the new ~100 MV modules - generated a significant background with gradients that will be used for tests next ~couple weeks.  Tonight there is a similar opportunity to measure background from 0L03 as well.  By ~tomorrow we'll have a better estimate of the background landscape for this coming weekend and we'll assess whether Run II is really compatible or not.   A little surprising, but we knew this was a possibility.  Stay tuned...

Joe