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User name roblin
Log entry time 08:18:34 on February 3,2000
Entry number 32188
keyword=EP measurement
After having the beam tuned in EP mode (again, the operators had trouble to find the procedure!) we started data taking. Beam was 5 ua , raster off, otr out and fastfeedback on.
It appears that the photodiode used to measure the target speed is dead. Probably it was fried in radiations (we changed this diode during the shutdown and it was tested ok). Leakage current in the microstrips has increased significantly (around 10-20% of previous values).
run 2935: we had only down triggers.!
I change the settings of the PLU unit to trig with S1.S2.S3 (as opposed to S1.S2.S3.C) and perform run 2936.
here, both down and up events. Conclusion, the Cerenkov photomultiplier for this arm does not work anymore.. Run 2938 was a short rune with S3.C triggering .
I chosed S1.S2.S3 mode and ran run2939.
Upon inspection of the data, it appears that we can extract a reliable value for the beam energy in S1.S2.S3 mode. The counting rate is about 2.3Hz as opposed to the usual 0.4Hz with the cerenkovs. Since there is a massive amount of data to analyse..
Preliminary results : 2.90294 +/- 0.00046 (stat) Gev. Final result will come in a few days as we have to analyse 10K events. (the above result is with 4K results and crude cuts)