• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name mjona, feuerbac, saw

    Log entry time 11:53:37 on February 06, 2006

    Entry number 161770

    keyword=F1 reference time and F1 window

    The F1 TDC reference time was not being seen in the data. Looking at the wiring this was becase the reference time was arriving to the TDC at about the same time as the common stop. Because TDC's were programmed to accept hits between 600 and 100 nanoseconds before the common stop, it was missed.

    To put this reference pulse in time, the common stop was delayed by about 80 ns, so that reference pulse arrives before the stop. The F1's window was also changed to between 1050 and 50 ns before the stop, insuring that both neutron bar hits and the reference time will be within the window.

    If we need a narrower tdc window later on, we will program the tdc input with the reference signal to have a different latency than the other inputs. (Since the reference time arrives much later than the inputs from the neutron bars.)

    The reference time signal was also moved from slot 19, channel 0 top slot 13, channel 32. This now leaves 3 F1 tdcs completely unused. These TDC's will be removed before we start running and will be available as spares.