Well, we hadn't had as much beam as we could expect and the beam quality doesn't meet G0 specifications. Furthermore, a power failure on the main site (outside the fence) occured at 3:15pm. We lost network communication to all CEBAF CUE system and also the telephones were not working anymore. Target and magnet experts were called right away to control as best as we can the magnet and the target which has just been cooled down. Telephone communications were back by 5pm but the network hasn't been operational until 10pm and even then it wasn't fully operational (problem moving run files to analysis machines, silo). We took FR DNL measurement only for 20' (run 18882) because we were told that the beam will be back soon. MCC wasn't hopefully affected by the power outage but during all the time we had network problems they were working on the prebuncher problem in the injector. We had the beam back just before midnight and Kaz was able to go ALL through his parity beam quality program. Kaz's results can be found in g0log entry #72867 and unfortunatly they are not as good as we could have expected, see also g0log entries 72905->72909, 72914. At 9:30, as MCC decided to postpone the beam studies to the afternoon, we started halo measurements on 11mm hole halo target with 5uA, 20uA and 40uA of beam (runs 18898, 18899, 18900 - copy of g0realtimemonitor beam strip charts : entries #72884, #72887). The beam was unstable. We check that the rates from Herbert's Paddle and halo monitors from 20uA to 40uA were scaling linearly. Then we move the halo target to the 6mm hole position and we run with 5uA. The rates on Herbert's paddle were 6 times higher than expected from the 11mm hole and the rates from halo monitors were of the order of MHz. We decided to stop this measurement because from previous Sarah's results the rates should remain the same with 11mm and 6mm holes when running at the same beam current. We then put the empty target in beam with Det. ON (fullgain), Magnet ON and we took some data while the target experts were commissioning the empty target ramping up the beam current from 5uA to 20uA (runs 18902, 18903, 18905, 18906). The at 13:30pm, MCC asked the beam for HallA energy spread and we started FR DNL measuements. We also want to take short runs to commission the 9th DMCH while no beam.
In this pass, the proton yield slopes computed in the first pass has been applied in the regression correction. So only the proton yields/asymmetries in the measurement table are filled. The beam table is also filled, in which I was able to fill the Halo results correctly (finally).
I have changed the halo yield measurement units from counts to (counts/nC) in the DB.
Speaking of code changes, there's a tiny bit change in the NA deadtime correction from Angela, which will apply to this 2nd pass, but wasn't there for the 1st pass. The effect should be very small.
In terms of the selection query in data retrieval, one should add
"analysis.slope_correction='on'".
A copy of this log entry has been emailed to: nakahara@jlab.org, jroche@jlab.org