Radiation Monitor

• Radiation monitor rates versus beam currents:

  

  With protons only the RadMon rate scales linearly with I_p.
  The slope depends on the vacuum base pressure at the right (-z), which in June 2002 is 0.9*10^-8 mbar at pump NR6.0.

  With e⁺ only there is another linear dependence, albeit with unphysical offset. The data are collected from May and June 2002, and conditions may have changed.

  In ep collisions we see the basic HERA problem: synchrotron radiation and electromagnetic heating of the beam pipe create bad vacuum, which increase the proton-beam gas background, so the rates are higher than the sum of the individual rates.
   

• Radiation monitor rates versus vacuum pressure:

  On Sat 29.6. a proton beam of 28.8 mA was stored at 920 GeV.
  Positrons at 12 GeV were filled in 5 steps from PETRA.
  e⁺ current:

  

  Radiation monitor:

  

  Vacuum pressure:

  

  Correlation Radmon vs pressure: