Hi Ramiro, Michael, Thanks for the info. I have been using the 'standard' value of 1.6, so it is good to get a better value, or at least some limits on that value. I'll respin the tapes (oh, wait, we don't do that...I mean extract the data from HPSS...) and see if I can get a more precise measure from the data. Also, you say "someday" the calibration fibers will be added to the FS. Does someday mean someday soon when the machine is off for a couple of days, or does it mean someday between this run and the next run next year? -Ian > -----Original Message----- > From: owner-brahms-l@bnl.gov [mailto:owner-brahms-l@bnl.gov]On Behalf Of > Ramiro Debbe > Sent: Sunday, August 12, 2001 5:37 AM > To: brahms-l@bnl.gov > Subject: Re: tpc drift velocities > > > Let me add something obvious: > DVM1 is connected to TPM1 > DVM2 to TPM2 > DVM3 (DVF1) to T1 > DVM4 (DVF2) to T2 > > The measurements were done downstream of all TPC. All TPC are getting 500 > cc/min of gas flow. > > I made a measurement upstream of all TPCs and the value is consistently > 1.4 cm/musec. > > Something outgases inside the TPCs and lowers the drift velocity. > The value or > values of drift velocity inside the volumes have to be extracted > from data. The > only strong handle seems to be the vertical aperture of the magnet. In the > midrapidity spectrometer we have three fibers to calibrate TPM2. > Someday more > fibers will be added and similar system will be installed in the FFS. > > What we have now are two limits for drift velocity 1.4 and the > values that were > measured last night. The data analysis should stay within those > boundaries. > > > Ramiro > > Michael Murray wrote: > > > Dear Ian, > > your wish is my command! > > DVM1 = 1.329 cm/microsecond > > DVM2 = 1.296 cm/microsecond > > DVM3 = 1.248 cm/microsecond > > DVM4 = 1.332 cm/microsecond > > > > These results have an uncertainty from time measurement of > about 2/1500 for > > DVM1 and .1/1500 for DVM2-4. Of course there are probably other errors. > > > > Let me know if you need more info. I am on shift until Sunday at 8am. > > Michael > > > > Quoting Ian Bearden <bearden@nbi.dk>: > > > > > I read with great delight that the TPCs drift velocities were measured > > > during the > > > 0000-0800 shift, and that the values are recorded in the log book. As > > > the > > > log book (sadly) is not online, could someone please post these values > > > to > > > the list (or to the web)? > > > Thanks, > > > Ian > > > > > > > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899 > > >
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