Double-crystal setup measurements at the CERN SPS

TL;DR

This paper presents a novel experimental setup at CERN's SPS to measure particle deflection using a double-crystal configuration, demonstrating precise efficiency measurements and the ability to investigate various crystal regimes in situ.

Contribution

It introduces a new double-crystal experimental layout at CERN SPS for particle beam characterization, with first-time efficiency measurements and in situ regime investigations.

Findings

Measured particle deflection efficiency of ~0.18 using the second crystal.

Enabled in situ investigation of crystal regimes like channeling and volume reflection.

Demonstrated the setup's capability to measure crystal torsion.

Abstract

In this paper, we discuss an experimental layout for the two-crystals scenario at the Super Proton Synchrotron (SPS) accelerator. The research focuses on a fixed target setup at the circulating machine in a frame of the Physics Beyond Colliders (PBC) project at CERN. The UA9 experiment at the SPS serves as a testbench for the proof of concept, which is planning to be projected onto the Large Hadron Collider (LHC) scale. The presented in the text configuration was used for the quantitative characterization of the deflected particle beam by a pair of bent silicon crystals. For the first time in the double-crystal configuration, a particle deflection efficiency by the second crystal of $0.188 \pm 3 \cdot 10^{-5}$ and $0.179 \pm 0.013$ was measured on the accelerator by means of the Timepix detector and Beam Loss Monitor (BLM) respectively. In this setup, a wide range angular scan allowed a possibility to \textit{in situ} investigate different crystal working regimes (channeling, volume reflection, etc.), and to measure a bent crystal torsion.