• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT
    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.