• J. Stiller
  Heidelberg University, Heidelberg
• H.S. Matis, A. Ratti, W.C. Turner
  LBNL, Berkeley, California
• R. Miyamoto
  BNL, Upton, Long Island, New York
• S.M. White
  CERN, Geneva

The LHC BRAN luminosity detector monitors the high luminosity interaction regions (Atlas and CMS). This chamber, which is an Argon gas ionization detector measures the forward neutral particles from collisions the interaction region. To predict and improve the understanding of the detector's performance, we produced a detailed model of the detector and its surroundings in FLUKA. In this paper, we present the model and results of our simulations including the detector's estimated response to interactions for beam energies of 3.5, 5.0, and 7.0 TeV.

• A. Ratti, H.S. Matis, W.C. Turner
  LBNL, Berkeley, California
• E. Bravin, S.M. White
  CERN, Geneva
• R. Miyamoto
  BNL, Upton, Long Island, New York

The Luminosity Monitor for the LHC is ready for operation during the planned 2009-2010 run. The device designed for the high luminosity regions is a gas ionization chamber, that is designed with the ability to resolve bunch by bunch luminosity as well as survive extreme levels of radiation. The devices are installed at the zero degree collision angle in the TAN absorbers ±140m from the IP and monitor showers produced by high energy neutrons from the IP. They are used in real time as a collider operations tool for optimizing the luminosity at ATLAS and CMS. A photo-multiplier based system is used at low luminosities and also available. We will present early test results, noise and background studies and correlation between the gas ionization and the PMT. Comparison with ongoing modeling efforts will be included.