Log entry time 06:12:09 on June22,2004

Entry number 126625

B  eam has tripped and will be off for a few minutes, so
we have ended run 2365, and are going to use the time to
bleed off most of the 44He from the target;
the idea(s) being to take some data with only around 2 atm. 
(vs. the 13 atm we have been running recently) in the racetrack
cell, and see 

  a) does septum heating scale properly with reduced radiation
    length (how much of the heating comes from the He and how 
    much from target windows and possibly other material)
 
  b) do the detector rates and lumi rates (as measured both
    by the ADC amplitudes  and the asymmetry widths) scale in
    a sensible manner with the reduced He density, or are 
    possibly the target windows thicker than we think - this 
    is the oddest way I have ever measured the thickness of an
    Aluminum window!

  Present target conditions after bleed off:
    T_1 = 7.0 K
    T_2 = 7.0 K
    T_3 = 8.0 K
    cell pressure = 39.5 psi (2.7 atm)
    High power heater = 338 W,  CHL flow 16 g/s
       (28 µA of beam)

    start HAPPEX DAQ run 2366