Machine Protection for the Experiments of the LHC

The LHC stored beam contains 362 MJ of energy at the top beam energy of 7 TeV/c, presenting a significant risk to the components of the machine and the detectors. In response to this threat, a sophisticated system of machine protection has been developed to minimize the danger, and detect potentially dangerous situations. In this paper, the protection of the experiments in the LHC from the machine is considered, focusing on pilot beam strikes on the experiments during injection and on the dynamics of hardware failure with a circulating beam, with detailed time-domain calculations performed for LHC ring power converter failures and magnet quenches. The prospects for further integration of the machine protection and experimental protection systems are considered, along with the risk to nearbeam detectors from closed local bumps

Recommended Locations of Beam Loss Monitors for the ATLAS Roman Pots

This note suggests suitable locations to position beam loss monitors to observe losses on the ATLAS Roman Pot station located close to 240m from IP1. This monitoring is envisaged to help to avoid quenches of the super- conducting magnets downstream of the roman pots and to avert damage to either the LHC machine elements or the roman pot detectors. The results presented in this note indicate the locations where the BLMs should be installed. The recommended locations are determined using previous simulation results on BLM response to losses; therefore these results should be considered in conjunction with the previous results. A more detailed note on the topic will follow later

Integration of the Forward Detectors inside the LHC Machine

Several forward detectors have been installed in the LHC long straight sections located on each side of the experimental caverns. Most of these detectors have been designed by the LHC experiments to study the forward physics while some of them are dedicated to the measurement of the LHC luminosity. The integration and the installation of the forward detectors have required an excellent coordination between the experiments and the different CERN groups involved into the design and the installation of the LHC accelerator. In some cases the integration of these detectors has required a modification of the standard beam lines in order to maximise their physics potential. Finally, additional systems have been installed in the LHC tunnel to ensure the operation of the forward detectors in a high radiation environment

Estimation and analysis of the machine-induced background at the TOTEM roman pot detectors in the IR5 of the LHC

The problem of background generation in the experimental insertion IR5 of the LHC during machine operation in the dedicated TOTEM mode with low intensity beams and the specially designed β* = 1540 m optics is discussed. The sources of the machine-induced background in the IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam conditions. The methods for background analysis and rejection are explained

Recommended Locations of Beam Loss Monitors for the TOTEM Roman Pots

This note presents results from simulations of losses on the TOTEM Roman Pot stations located close to 150m and 220m from IP5. These results are used to evaluate suitable locations to position beam loss monitors to monitor these losses, and help to avoid quenches of the super-conducting magnets downstream of the roman pots. The results presented in this note indicate the locations where the BLMs should be installed. A more detailed note on the topic will follow later

Expected Performance of TOTEM BLMS at the LHC

The TOTEM experiment at the LHC will operate down to 10 sigma from the beam in the forward region of the CMS experiment. The associated beam loss monitors (BLMs) are crucial to monitor the position of the detectors and to provide a rapid identification of abnormal beam conditions for machine protection purposes. In this paper, the response of the TOTEM BLMs is considered for nominal machine operation and the protection thresholds are defined, withcalculations made of the expected signal fromprotons grazing the TOTEM pot as a function of pot distance from the beam, and the BLM signal from proton collisions at the CMS beam interaction point

The study of the machine-induced background and its applications at the LHC

We present the recent advances in the analysis of the machine-induced background generation and formation at the LHC. Different aspects of the study of the machine background problem at the LHC are reviewed, including the background production at the different stages of the machine operation, the role and influence on the background from the collimators in the experimental insertions and the background shielding. The potential use of the machine background for the purposes of detector testing and alignment is also discussed