[PEPPo] Daily RC Report 5/30

[voutier at lpsc.in2p3.fr]

Daily RC Report

https://positron.jlab.org/wiki/index.php/Wed%2C_May_30%2C_2012_%28Voutier%29

Beam

Efforts have been developped on the reproducibility of an optimized  
positron collection using the T2-cup as a current monitor and  
adjusting S1 and S2 currents at 4 MeV/c momentum selection. The  
optimized setting was found in very good agreement with the tune of  
the previous shift.

A fast test relying on the counting rates in the calorimeter was  
attempted in order to sign the charge of the particles: while the  
sensitivity of the rates to the beam position generates a clear signal  
in electron mode, the same signal is too small in positron mode to be  
conclusive.

Detectors

After the fine tuning of the coincidence between TS1 and PMT5, a BIG  
STEP was achieved with the Compton polarimeter when the expected  
signal from the positron bremstralhung was clearly isolated by  
Jean-Sebastien. The high level of accidental background is motivating  
additional efforts to improve the shielding configuration and to  
optimize the initial electron beam energy.

http://opsweb.acc.jlab.org/CSUEApps/elog/entry/1788496

Next 24 hours:

Wednesday, 5/29 - SWING SL=Arne

    Shielding configuration change
    Annihilation detector measurements
    e+ collection optimization
    Compton polarimeter check-out

Thursday, 5/30 - OWL SL=Jean-Sebastien

    Compton polarimeter measurements

Thursday, 5/30 - DAY, SL=Joe

    Further optimize e- and e+ collection at 6.9 MeV/c incoming electron energy


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