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    User name Ramesh/Xiaochao

    Log entry time 15:26:15 on May 28, 2009

    Entry number 277117

    This entry is a followup to: 275271

    Followups:

    keyword=Access activity [PVDIS work]

    During today's access we made the following changes (this also includes the space check for Happex-III detector support):

    1. Found that the ch9 of NIM-ECL 3rd module unplugged; plugged back in. This was the channel which was always giving "Empty Histogram" in TDC histogram-display.

    2. Checked the tagger signal for the pileup/dead-zone technique (we never saw pileup or dead-zone signals before), found that the tagger and pvdis signals were not coincident at the coincident module (PS 758). After the change in tagger scheme during the last time access, we did not check the output from this ANDing module, we better had to. We changed the width of an ANDing module (the one just before the above mentioned ANDing module which ANDs tagger and PVDIS signal) in such a way that the pvdis signal is always within the width of tagger signal.

    3. Also checked whether the PVDIS relay-racks (two of them) pose any problem in repairing left PMTs of S1-scintillator plane (or VDCs). If done carefully, there should not be any problem repairing those detectors.

    4. Also checked the space for supports for the Happex-III detector on the left eye-beam (of RHRS) where the pvdis relay-racks are now sitting. The following is the space available (and occupied) on the eye-beam looking from plateform:

    First 8 inch available

    Next 31 inch occupied by the first pvdis relay-rack

    Next 14 inch available

    Next 15 inch occupied by the 2nd pvdis relay-rack. Remaining space does not belong to PVDIS.



    A copy of this log entry has been emailed to: xiaochao,rom,armd,rsubedi