[Mott] Mott summary last 24 hours + plan for next 24 hours

[Joseph Grames]

Mott work summary for last 24 hours is shown below. For those off-site you can access electronic logbook (https://logbooks.jlab.org) with your JLAB username and password to view all entries, pictures, plots, etc.

Last 24 hours
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SWING - Recovered KE=5MeV beam to Mott and configured polarization to be nominally vertical (i.e. large L/R asymmetry ~34%, small U/D asymmetry ~2%).  We left that alone temporarily.  Then, we systematically changed KE and measured effective sherman function on 1um gold target (used 5MeV, 4MeV, 3MeV, 6MeV in sequence),  observing clear roll-off at lower energy, higher energy value similar will require little more care in analysis.  Next, we adjusting PHI spin rotator and carefully nulled U/D asymmetry (rotated small amount of horizontal polarization to vertical), finally measuring Py~87% and Px~0.  We then moved to 3 copper foils (1um, 4.1um, 8um) and measured elastic:background contributions with operating currents 1-2uA (1-2kHz) rate suitable for data taking overnight. Measured effective Sherman function to ~few percent and not as bad as gold, so run time (over)estimates in our favor by factors of 3-4.

OWL - Since Seff^2 not a major factor decided to portion 6 hours of run time according to elastic rates.  Overnight operator David Anthony ran (he'll be on shift each OWL this week!) ~3h on 1um, ~2h on 4.1um, and ~1h on 8um.  All the while flipping the half-waveplate.  That run terminated at 6am. 

Next 24 hours
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1. Decode/analyze copper results.

2. Upcoming Mon SWING/Tue OWL we will do the gold measurements (5 ~thick and 2 ~thin), decide on run duration for each and collect data at 5MeV.  We'll roughly spend ~6 hours on thicker foils and ~6 hours on the two 0.05um foils.