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User name mercado
Log entry time 11:48:36 on August24,2009
Entry number 285693
keyword=More Lumi commisioning. Attempt at Oversampling.
We took some Lumi data this morning. The beam was 20uA on a Tantalum target.
During run 11546, the HVs were tuned to get a 200K signal out of our 18-bit
Run 11547 is a good run, which lasted 15 minutes and had 2 beam trips for the
purposes of pedestal studies and calibration. For this run, the BCM gains were
LO and the highest signal BCM that didn't saturate was bcm4, with a signal of
Run 11549 is an oversampling run (IT=6600, OS=1). The gain setting of the
18-bit board was changed from (3,0) to (3,1), which has a gain factor of 2. The
BCMs were set to HI gain, and the highest signal BCM for this run was BCM2,
with a signal of ~33K channels.
Run 11550 is an oversampling run (IT=3300, OS=3). The gain setting ofthe 18-bit
board was changed to (3,3), which has a gain factor of about 3.9. BCMs 1, 2 and
4 where set to HI gain, BCM3 was not working while connected to channel 23_2,
so I switched it to channel 23_3, where ot produced a signal of ~39K channels
at LO gain. BCMs 3 and 4 both have decent signals on this run.
NOTE: During this last run, I realized that the Injector crate had not been
responding to GreenMonster. This means that the Injector data, which includes
the helicity data, is probably nonsense, since the IT value for that timing
board remained the same throughout the runs. Because of this, PAN will probably
not be able to calculate proper asymmetries for the lumis for the oversampling
runs. The last two runs should be repeated ASAP.