PERFORMANCE OF THE HERA-B Target
AND INTERFERENCE WITH HERA OPERATION

K. Ehret, Institut für Physik, Universität Dortmund, D 44221 Dortmund, Germany

Abstract:

HERA-B is a fixed target experiment dedicated to study CP violation in the decay of neutral B mesons into the "gold platted" decay mode . An internal target in the halo of the 820 GeV HERA proton beam provides the source of B mesons in high rate fixed target proton-nucleus interactions. The target collects very efficiently the protons, before they get lost on any aperture limitation, to achieve the required constant interaction rate of 40 MHz. It operates parallel to HERA e-p luminosity data taking without significant disturbance of the other HERA experiments or the beam quality. This paper reviews the requirements and the main functionality of the HERA-B target. The different impacts on the target performance and various measurements are presented.

• Introduction
• HERA
  • HERA Proton Beam Parameter
  • The Proton Collimator System
  • Brief History: HERA and HERA-B Target
• The HERA-B Target
  • Requirements and Environment
  • Scattering on the Target and b Production
  • Basic Impacts on a Halo Target
  • Target Efficiency Simulation
• Experimental Setup
  • Location and Mechanics
  • Counters and DAQ
  • Target Control
• Measurement Examples
  • Halo Target and Target Efficiency
  • Long Term High Rate Operation
  • Rate Stability and Fluctuations
  • Distribution of Interactions along the Wire
  • Individual Bunch Contributions
• Conclusions
• Acknowledgments
• References
• About this document ...