The Two-Screen Measurement Setup to Indirectly Measure Proton Beam Self-Modulation in AWAKE

Abstract

The goal of the first phase of the AWAKE \cite{AWAKE1,AWAKE2} experiment at CERN is to measure the self-modulation \cite{SMI} of the ${\sigma }_z=12\mathrm{cm}$ long SPS proton bunch into microbunches after traversing $10\mathrm{m}$ of plasma with a plasma density of $n_{pe}=7\times 10^{14}{electrons/cm}^3$. The two screen measurement setup \cite{Turner2016} is a proton beam diagnostic that can indirectly prove the successful development of the self-modulation of the proton beam by imaging protons that got defocused by the transverse plasma wakefields after passing through the plasma, at two locations downstream the end of the plasma. This article describes the design and realization of the two screen measurement setup integrated in the AWAKE experiment. We discuss the performance and background response of the system based on measurements performed with an unmodulated Gaussian SPS proton bunch during the AWAKE beam commissioning in September and October 2016. We show that the system is fully commissioned and adapted to eventually image the full profile of a self-modulated SPS proton bunch in a single shot measurement during the first phase of the AWAKE experiment.

arXiv comment5 pages 8 figures

References in corpus (5)

• Self-modulation instability of a long proton bunch in plasmas
• AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN
• Path to AWAKE: Evolution of the concept
• Indirect Self-Modulation Instability Measurement Concept for the AWAKE Proton Beam
• Proton Beam Defocusing as a Result of Self-Modulation in Plasma

Cited by in corpus (6)

• Acceleration of electrons in the plasma wakefield of a proton bunch
• AWAKE readiness for the study of the seeded self-modulation of a 400\,GeV proton bunch
• Proton Bunch Self-Modulation in Plasma with Density Gradient
• Upgrade of the Two-Screen Measurement Setup in the AWAKE Experiment
• Signatures of the self-modulation instability of relativistic proton bunches in the AWAKE experiment
• A Method to Determine the Maximum Radius of Defocused Protons after Self-Modulation in AWAKE