User name Punjabi
Log entry time 00:09:29 on June10,2000
Entry number 43297
Started shift with run no. 1847
16:00 to 17:25 run 1847 to 1851
lost beam at 17:25 , Cavity problem
17:40 asked for access to fix problem of hole in x-trajectory
spectra in hadron arm. Suspicion is that one of the scintillater paddle in
s1 plane is tilted.
18:30 scintillator s1-6 was rotated to move VDC in. They forgot to put it back in the correct position. All runs from 1823 to 1851 were with this paddle in the wrong position.
18:55 beam back , started run 1852
19:05 beam off for 5 minuites
19:10 beam back, continue with run 1852
19:25 stop run 1852
19:26 start run 1853
19: 49 stop run 1853
Opened collimator in both spectrometer
20:06 started run 1855 . First run with open collimator in both spectrometer.
20:15 stopped run 1855
changed prescale factors because event rate increased due to open collinators.
20:16 started run 1856 with new prescale factors
20:26 stopped run 1856
no beam for about 10 minuites
20:27 started run 1857
20:47 stopped run 1857
20:47 start run 1858
21:00 stopped run 1858
21:01 started run 1859
21:14 stopped run 1859
21:15 started run 1860
21:27 stopped run 1860
21:28 started run 1861
21:41 stopped run 1861
21:42 started run 1862
21:47 stopped run 1862
run 1862 is not a good run
Noticed that event rate jumped sudenly. In trying to find out the reason for this found that helium level in electron Q3 had dropped to 44 % and so there was a quench in this quad. Asked for an access to reset the quench .
22:25 beam back after resetting quad 3 in elrctron arm.
22:25 start run 1863
22:41 stopped run 1863
22:42 start run 1864
22:54 stopped run 1864
22:55 start run 1865
23:07 stop run 1865
23:07 start run 1866
23:19 stop run 1866
23:19 start run 1867
23:34 stop run 1867
23:35 Helium level dropped again in electron quad 3 . So asked for access to reset the quench.
23:55 Zhengwei went to hall to reset the quench.
23:55 Called Mark stevens (Tech on call). He said may be some connections are bad and that is what is causing the problem. He thinks that Q3 quenches first and then helium level drops. We do not know at this time which one happens first, quenching or drop in helium level. He said if problem occurs again, page him and he will come in.
00:10 Quad 3 is reset and it is comming up. We will keep taking data for now until next time the same problem occur.