Make New Entry,
Make Followup Entry
User name gaskell
Log entry time 14:31:06 on November 26, 2008
Entry number 250924
keyword=Compton rates vs. slit position
Sirish came in and got the Compton DAQ running in photon mode. We saw
that with Hall B OFF and the slit wide open, there was something like 600
Hz/uA rate in the photon detector (laser off).
MCC closed the slit to "28.0" and adjusted the attenuator to deliver the
same current to Hall A. With the slit more closed, the photon detector
rate dropped to < 50 Hz/uA - terrific.
It's not clear to me why the slit position should make so much difference
- I can only imagine there is some strange tail on the laser pulse as it
strikes the photo-cathode.