Time-of-Flight/Start-Counter Meeting, April 17, 2009
- Time-of-Flight Status: Paul
- Start Counter Status: Seema
- Role of Start Counter--Design Criteria: all
- Next meeting time
FSU: Paul, Sasha O.
JLab: Beni,Mark I., Elton, Simon, Eugene, Chuck, Tim, Sascha S.
Paul and Sasha O. presented photos and plots from work with their first prototype. There were photos of the test light guides, the test module and the testing box. Sasha showed some initial data from cosmic ray runs with the moudule. See their wiki page for details.
Start Counter Status
Seema reported on current plans. The plan for this summer is to build a prototype. 2, 3, and 5 mm scintillator has been ordered as well as a 1.4 m light guide. The plan is to use a fine-mesh pmt as the photo-detector. They will study light yield and timing. The next step will be to bend the scintillator and compare performance with the straight version and with GEANT4 simulations. They will also work on design of tooling do to the bending.
Read-out will have to include FADC channels in order to incorporate signals into the trigger pipeline.
There was a lot of discussion about various requirements for start counter performance. In general we need to have agreement on the overall goals for the detector. Among these goals are:
- input to trigger
- RF bucket identification
- part of time-of-flight particle ID scheme
- particle ID via dE/dx
These issues had been raised by Werner in a phone conversation with Mark on Thursday.
Start Counter Rates
Seema and Sascha have been studying the electromagnetic background in the start counter. There will be a GlueX note on this subject soon. They see the following:
|inner radius (cm)||rate per counter (kHz)|
recorded by Mark I.