Search

In the High-Luminosity Large Hadron Collider (HL-LHC) Project, the LHC will be significantly upgraded to attain a peak luminosity of up to 8.5 × 10³⁴ cm⁻²s⁻¹, thus almost an order of magnitude higher compared to the nominal machine configuration in ATLAS at IP1 and CMS at IP5. In the view of a successful machine setup as well as a successful physics programme, beam induced background studies at IP1 were performed to investigate sources of particle fluxes to the experimental area. In particular as a start of the study, two sources forming the major 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 beam-halo and local beam-gas, respectively. We will 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)., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of L = 1-2 . 10³³ cm⁻² s^{−1}, with a pileup of 5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

After operation at the nominal luminosity, the LHC is planned to be upgraded to a 5-fold increased luminosity of 5×1034 cm⁻²s^{−1}. The upgrade includes replacement of the IP1/IP5 inner triplet 70-mm NbTi quadrupoles with the 150-mm coil aperture Nb3Sn quadrupoles along with the new 150-mm coil aperture NbTi dipole magnet. A detailed model of the region with these new magnets, field maps, corrector packages, segmented tungsten inner absorbers was built and implemented into the FLUKA and MARS codes. Various aspects of the new design were studied: (i) thicknesses of tungsten absorbers; (ii) beam screen interruption in interconnects; (iii) crossing angle value and orientation, etc. In the optimized configuration, the peak power density averaged over the magnet inner cable width doesn’t exceed 2 mW/cm³, safely below the quench limit. For the integrated luminosity of 3000 fb-1, the highest peak dose of 35 MGy occurs in the corrector package CP, while for other magnets, the peak dose in the innermost insulators ranges from 20 to 30 MGy. Dynamic heat loads to the triplet magnet cold mass are calculated to be on a target 10 W/m level. FLUKA and MARS results agree within 10%., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany