• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT
    Make New Entry, Make Followup Entry

    User name Kai

    Log entry time 02:09:28 on November 9,2009

    Entry number 298488


    keyword=quick access for fixing ps5~8 missing problem

    Ramesh and I went for a quick access to fix the missing of preshower (ps) group 
    5~8 problem. We first went to the back rack to check the 740 analog sum for 
    group5~8 ps. We found there indeed has output signal there. However, we found 
    the offset is -15mv, and do a quick run to check the signal, the fTDC of them 
    is back at least.  but here are two questions:
    1. The offset is -15mv so that it will actually make the ps signal easier to 
    pass the discriminator threshold. As the missing signal is back and MCC is 
    ready to send the beam, so we just left the hall. If this problem happened 
    again, we need to do further check.
    2. Ramesh and I clear the offset of 740 to be all zero just yesterday, and it 
    went to -15mv just in one day. We are thinking if it is necessary to replace 
    all 740 by lecroy 428F of which the offset is stable zero there for several 

    FIGURE 1