During the run, the current on D3 was not particulary higher than what it was before. (About 30uA for Anode 1 and 2, 40-50uA in Anode 3). Also, nobody changed any threshold in D3 during the Drift chamber scan. Hiro On Fri, 5 Oct 2001, Flemming Videbaek wrote: > Regarding - T3 problem. Without more details it is hard to draw conclusions from remote (where I am too). > -Clearly from 'normal' events we have seen from 10-30 hits/plane * 30 ~ 900, well below > the limit. > - It is likely related to events with a very large number hits either event related or from the general background that > are causing the general large currents in the DC (T5 in particular) and high singles rates in H2. And as Ian > points out T3 can now 'see' quite far down along the beam towards 12 o'clock. > - It is unlikely the threshold was touched- the scan plan was very specific, as also summarized in the report. > > Since this it not known to all - the main reason for the scans is provide a better understanding for the operation > of the drift chambers, which has a much lower effeciency per chamber for overall track finding than is desireable. > When the scan runs are analyzed (probably already underway) we should get a report. It may well be needed to > perform some more of these in the next couple of days.Until better understanding of the DC operations emerged > we should return to angle and magnet settings where the physics measurements can be carried out primarely with > the Front Forward spectrometer, and not the high momentum settings, that requires DC tracking. > > regards > > ------------------------------------------------------ > Flemming Videbaek > Physics Department > Brookhaven National Laboratory > > tlf: 631-344-4106 > fax 631-344-1334 > e-mail: videbaek@bnl.gov > > >
This archive was generated by hypermail 2b30 : Fri Oct 05 2001 - 15:34:17 EDT