First beam background simulation studies at ir1 for high luminosity LHC

In the High-Luminosity Large Hadron Collider (HL-LHC) Project, the LHC will be significantly upgraded to produce about an order of magnitude more of integrated luminosity per year than what was achieved in Run I (2011 and 2012 data) in ATLAS at IR1 and CMS at IR5. In the view of a successful machine setup as well as a successful physics programme, beam induced background studies at IR1 were performed to investigate sources of particle fluxes to the experimental area. In particular, as a start of the study, two sources forming important contributions were simulated in detail: the first one considers inelastic interactions from beam particles hitting tertiary collimators, the second one from beam interactions with residual gas-molecules in the vacuum pipe close by the experiment, referred to as beamhalo and local beam-gas, respectively. We present these first HL-LHC background studies based on SixTrack and Fluka simulations, highlighting the simulation setup for the design case in the HL-LHC scenario. Results of particle spectra entering the ATLAS detector region are presented for the latest study version of HL-LHC machine layout (2013)