Nikolas Meitanis, Tavi Filoti, Kevin McIlhany
Smooth running with the usual CODA barfing. A scan of gas flows took place ranging from 1.0
sccm up to 3.0 sccms. The forward start counter was getting about 400kHz at 65 mA, so we backed
off.
Run 614: In order to try to understand the LTOF10 problem (channels piled in 8000), we reduced
the HV from -2100 to -1900 to see what change may occur. The channels dutifully moved down to
2300. Not that this tells us much, but it means the readout is OK, simply the tube is getting
wayyy too much light.
Run 615: We changed the threshold for the CFD in the trigger for channel LTOFtop12 from 31.3mV
up to 73mV in the hope of seeing some different structure other than the current one. This
produced NO CHANGE, so we put it back starting in run 616, althougth HV change from 614 remained
for the rest of the night.
Channel LTOF10 appears from all indications to have a light-leak which requires an access to
fix. Channel LTOF12 (IMHO) shows signs of ringing, which can be traced using the size of the
repeated signal to come from a cable approxiamtely 20 meters in length (2000 channels - or 100
ns).
Tavi continues to try to gain match the cerenkov. I am working on a large-scale eP analysis.
Take a look in ~/commis/phase1/ANALYSES/MCILHANY/_EP/ep2X.C if you would like to see the most
recent incarnation. The main advance here has been to realize that without sparsification in
our data, we readout every channel every time. Some of these show signals where they shouldn't,
so I made a two-pass analysis which in the first pass identifies correctly which tube on each
side of the detector atcually made up the trigger. This allows one to in the second pass
correctly extract the TDCs and ADCs for the eP analysis. Soon, I will have an analysis on the
last 150 runs.
-Kevin
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