High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility

Marija Cauchi,N Sammut,A Bertarelli,K Cornelis,B Salvachua,R W Assmann,L Lari,S Redaelli,A Rossi,A Dallocchio,P Mollicone,D Deboy,F Carra,O Aberle

doi:10.1103/physrevstab.17.021004

Abstract

The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC). The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat) facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

Highlights

The introduction of new, extremely energetic particle accelerators, such as the Large Hadron Collider (LHC) [1], has established the need for advanced beam cleaning and protection systems in order to be able to safely increase the energy and intensity of particle beams to unprecedented levels [2]
The LHC collimation system consists of 108 collimators, of which 100 are movable collimators, placed in seven out of eight LHC interaction regions as well as in the transfer lines [4]
The collimation system implements a multistage beam cleaning process (Fig. 1) in order to remove particles that would otherwise be lost in the machine, and ensures efficient (>99%) cleaning of the beam halo during the full LHC beam cycle

Summary

Introduction

The introduction of new, extremely energetic particle accelerators, such as the LHC [1], has established the need for advanced beam cleaning and protection systems in order to be able to safely increase the energy and intensity of particle beams to unprecedented levels [2]. The main purpose of the LHC collimation system [3] is, to ensure beam halo cleaning and machine protection. Collimators can be installed in vertical, horizontal, and skew configurations in order to ensure complete cleaning all around the particle beam axis. The collimation system implements a multistage beam cleaning process (Fig. 1) in order to remove particles that would otherwise be lost in the machine, and ensures efficient (>99%) cleaning of the beam halo during the full LHC beam cycle. Being in close proximity to the beam, the collimator jaws are continuously exposed to direct interaction with high energy particles. In normal working conditions, a steady state thermal load is deposited on the collimator jaws as the latter continuously interact with particles belonging to the external beam halo. Continuous beam losses from the halo occur at the primary collimators, with the scattered debris of these low energy density protons subsequently being captured at the secondary and tertiary collimators, respectively

Methods

Results

Conclusion