Log entry time 08:15:06 on November 20, 2008

Entry number 249921

  In today owl shift I finished some tests on BB Cherenkov, according to
Brad's plan:
  http://www.jlab.org/~adaq/halog/html/0811_archive/081119233800.html
  However, due to limited beam time, I can only finish part of it..
  
  For empty target:
  beam current: 0.5uA, raster on (3x3)mm
  ---------------------------------------------------------------
  threshold of PMT(V):    0.1        0.3        0.5       0.7
  rates in channel 19:   5.751e3    1.300e3    3.724e2   2.618e2
  rates in channel 20:   2.345e4    5.414e3    1.035e3   5.952e2
  run# 3711 ~0.8M events
  http://www.jlab.org/~adaq/halog/html/0811_archive/081120044105.html
  ########################################################################
  
  For Optics target:
  beam current: 1.0uA, raster off
  ---------------------------------------------------------------
  threshold of PMT(V):    0.1        0.3        0.5       0.7
  rates in channel 19:   1.873e4    4.697e3    1.546e3   9.533e2
  rates in channel 20:   5.734e4    1 554e4    5.185e3   3.091e3
  run# 3713+3714  ~0.7M events
  http://www.jlab.org/~adaq/halog/html/0811_archive/081120052114.html
  http://www.jlab.org/~adaq/halog/html/0811_archive/081120053303.html
  
  
  beam current: 0.5uA, raster off
  ---------------------------------------------------------------
  threshold of PMT(V):    0.1        0.3        0.5       0.7
  rates in channel 19:   1.125e4    2.743e3    8.756e2   5.590e2
  rates in channel 20:   3.555e4    9.236e3    2.743e3   1.667e3
  run# 3716    ~0.34M events.
  http://www.jlab.org/~adaq/halog/html/0811_archive/081120060725.html
  
  
  
  beam current: 0.1uA, raster off
  ---------------------------------------------------------------
  threshold of PMT(V):    0.1        0.3        0.5       0.7
  rates in channel 19:   3.496e3    7.862e2    1.943e2   1.253e2
  rates in channel 20:   1.637e4    1.891e3    6.547e2   3.744e2
  run# 3718     81k   events.
  http://www.jlab.org/~adaq/halog/html/0811_archive/081120063300.html
  
As JP told me we would run 1uA on 3He cell before control access, I
dropped reference cell test. For Optics target, we had some data already.
So I just took few minutes run for compare.

Later I will show some plots about these data.