High Resolution Luminosity Monitor for SLAC Experiment E158

摘要

A calorimetric detector based on ionization has been employed as a low-angle luminosity monitor for the parity violation experiment E158 at SLAC. The experiment utilizes a 50 GeV polarized electron beam on a liquid hydrogen target. The detector looks at high energy Mott and Moller scattered electrons, with a per pulse flux of 4 x 10(sup 8) particles. This large signal allows the device to serve the dual role of monitoring target density fluctuations, as well as detecting false asymmetries. In the first physics run of the experiment, the detector has achieved a per-pulse intensity asymmetry resolution of 170 parts per million. The linearity of the device also has been verified to less than or equal to 1%.