[Olympus] Beam time and year review

[Alexander Winnebeck]

Dear colleagues,

2 days ago we had our last beam test for this year. We ran for 24 hours, where the first 3 were used for small repairs, and the rest of the time we took data with electron and positron beams at 2 GeV.
After accomplishing some challenges we took data with all detectors up and running. This allows us to analyze and compare the luminosity of the three detector systems individually with the (beam current x target density) and among each other. This is a very important task for verifying the detector performance/precision as well as having some results to be shown. So I would like to ask again the corresponding groups to perform the analysis and prepare the results until the end of this year.
The TOFs were optimized before this beam time as much as possible without access to the detectors. The rates and spectra look reasonable. However, in the last two days we worked on the weak PMTs and figured out several issues, which were mainly fixed.
We also investigated the noise dependence on the toroidal field. We learned that there are certain ranges with lower noise and together with the MKK people the power supply could be trimmed optimally to the desired current. In parallel there are some modifications planned for January, which in addition will clean up the situation (Large inductors around supply lines, capacitor bank).
To conclude, we could learn quite a bit during the last days but also have some home work to do for January before our first data run.

When looking back this year, I think, we can say we have been very successful with the assembly of the detector, the target improvements, the optimization of the machine, the roll-in in the summer, and various beam tests. I want to thank you all who worked on OLYMPUS and helped to put our experiment from paper into reality.
There is still a way to go to climb the mountain, but we can make it and we will do it.

I wish you a merry christmas and a successful new year 2012,

Alexander    
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Dr. Alexander Winnebeck
winnebeck at mit.edu

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