[Halla_running] [New Logentry] Hall A Status

[sanghwa at jlab.org]

Logentry Text:
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Moller measurement suffered from unstable beam (large position and current fluctuations) throughout the measurements. Polarization measurements with 10um Fe with IHWP IN, and Cu target done: ~86.1% polarization from the online analysis (https://logbooks.jlab.org/entry/3772271). Originally planned systematic studies are pushed back, will need to be rescheduled later. 

While trying to come back to production setting from the Moller, LQ2 tripped and was unable to reset. Jessie came in and clear the quench fault with escorted access. We are told to ramp LQ2 in 25 amps increments until further notice (https://logbooks.jlab.org/entry/3772417).

Beam was not restored until around 6am due to the issues of Chopper forward power instability, all halls were down for most of the night. Experts were called in at the MCC. Got beam back around 6am, started beam restoration procedure. Spot size at the target was measured around 150x200um, and verified the raster size (no change). However, we were unable to establish the high current due to the high Moller IC rate, it was reporting >7000 at 10uA. 

Beam has been taken away around 9am for troubleshoot of the Chopper and beam instability (https://logbooks.jlab.org/entry/3772585). Our target is moved to home, for the recovery when we come back. After the straight through beam restored, Yves may also try to tune us through the Compton chicane today.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3772625
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