Experimental results of crystal-assisted slow extraction at the SPS

TL;DR

This paper reports on experimental results and simulations demonstrating the use of bent silicon crystals for slow extraction of high-energy protons from the SPS, aiming to improve beam steering and reduce activation.

Contribution

It presents new experimental data and analysis on crystal-assisted slow extraction at the SPS, including the use of existing crystals and infrastructure for beam steering.

Findings

Successful extraction of 120 and 270 GeV protons using bent crystals

Simulations align with experimental measurements of beam deflection

Potential for reducing activation in SPS via crystal-assisted extraction

Abstract

The possibility of extracting highly energetic particles from the Super Proton Synchrotron (SPS) by means of silicon bent crystals has been explored since the 1990's. The channelling effect of a bent crystal can be used to strongly deflect primary protons and eject them from the synchrotron. Many studies and experiments have been carried out to investigate crystal channelling effects. The extraction of 120 and 270 GeV proton beams has already been demonstrated in the SPS with dedicated experiments located in the ring. Presently in the SPS, the UA9 experiment is performing studies to evaluate the possibility to use bent silicon crystals to steer particle beams in high energy accelerators. Recent studies on the feasibility of extraction from the SPS have been made using the UA9 infrastructure with a longer-term view of using crystals to help mitigate slow extraction induced activation of the SPS. In this paper, the possibility to eject particles into the extraction channel in LSS2 using the bent crystals already installed in the SPS is presented. Details of the concept, simulations and measurements carried out with beam are presented, before the outlook for the future is discussed.