Virginia Tech Update for Tracking Group, Oct. 18, 2007

Comissioning without beam:
When the drift chambers are mounted in the region 2 rotator, we will want to do extensive testing with cosmic rays to determine the relative wire positions with the chambers mounted in place. (Note to self: need to make sure there is a place designed into the rotator to temporarily mount scintillators for the cosmic ray trigger for these tests.)

Commissioning with beam:
Primarily we will want to study how the chambers behave at different rates. During the low beam current running, we demonstrated that we could get down to about 0.15 nA beam currents easily. That corresponds to about 300- 400 kHz rate in our chambers. If I had been thinking, I would have pushed to try lower beam currents, because ideally we would like to study the behavior of the chambers from relatively low rates (10's of kHz) up to rates above where we nominally plan to run (say 1-2 MHZ). I will look at the numbers and attenuation factors and see if going below 0.15 nA is realistic.

Another option here is to do some commissioning with a hydrogen gas target. That would certainly allow us to get down to low enough rates. The GEM's may appreciate the opportunity to get some data at lower rates, as well. But this would add more to our commissioning time to make the gas target.

I'll think about both these a little further and try to add some real time estimates in the next couple days.