The impact of synchrotron radiation at the Compact Linear Collider

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 983; no. C; p. 164522
• Main Authors: Arominski, D., Sailer, A., Latina, A., Schulte, D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 11.12.2020; Elsevier
• Subjects: Accelerator Physics; CLIC; Machine–detector interface; Physics; Synchrotron radiation; X-ray reflections; X-ray reflections; CLIC; Synchrotron radiation; Machine–detector interface; beam transport; GEANT; numerical calculations; photon: emission; photon: reflection; CERN CLIC; beam optics; magnet: multipole; photon: interaction
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2020.164522

Synchrotron radiation (SR) emission and interactions with the vacuum chamber walls have the potential to negatively impact the performance of future electron–positron colliders. The Beam Delivery System (BDS) of the Compact Linear Collider (CLIC) contains weak bending and multipole magnets that lead to less intense emissions than at circular colliders with similar centre-of-mass energies. However, the linear geometry more easily allows for multiple reflections of SR photons, that can travel further downstream in the accelerator and impact the detector region. In this study, the results of PLACET and Synrad+ simulations of photon emissions and reflections in the CLIC BDS at two energy stages of 380GeV and 3TeV are presented. Estimates are given for heating and outgassing caused by SR photons interacting with the vacuum chamber in the BDS. The occupancy levels in the tracking detectors coming from full-detector simulations in Geant4 are presented. Optimised beam pipe apertures are proposed for the forward detector region, as well as mitigation methods to ensure the safety and best possible performance of the detector.