Re: tpc drift velocities

From: Ramiro Debbe (debbe@sgs1.hirg.bnl.goV)
Date: Sat Aug 11 2001 - 23:36:44 EDT

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    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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