Indirect Self-Modulation Instability Measurement Concept for the AWAKE Proton Beam

Abstract

AWAKE, the Advanced Proton-Driven Plasma Wakefield Acceleration Experiment, is a proof-of-principle R&D experiment at CERN using a 400 GeV/c proton beam from the CERN SPS (longitudinal beam size sigma_z = 12 cm) which will be sent into a 10 m long plasma section with a nominal density of approx. 7x10^14 atoms/cm3 (plasma wavelength lambda_p = 1.2mm). In this paper we show that by measuring the time integrated transverse profile of the proton bunch at two locations downstream of the AWAKE plasma, information about the occurrence of the self-modulation instability (SMI) can be inferred. In particular we show that measuring defocused protons with an angle of 1 mrad corresponds to having electric fields in the order of GV/m and fully developed self-modulation of the proton bunch. Additionally, by measuring the defocused beam edge of the self-modulated bunch, information about the growth rate of the instability can be extracted. If hosing instability occurs, it could be detected by measuring a non-uniform defocused beam shape with changing radius. Using a 1 mm thick Chromox scintillation screen for imaging of the self-modulated proton bunch, an edge resolution of 0.6 mm and hence a SMI saturation point resolution of 1.2 m can be achieved.

4 pages, 4 figures, EAAC conference proceedings

References in corpus (2)

• Physics of beam self-modulation in plasma wakefield accelerators
• Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam

Cited by in corpus (7)

• AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN
• AWAKE readiness for the study of the seeded self-modulation of a 400\,GeV proton bunch
• First fully kinetic three-dimensional simulation of the AWAKE baseline scenario
• The Two-Screen Measurement Setup to Indirectly Measure Proton Beam Self-Modulation in AWAKE
• Witness electron beam injection using an active plasma lens for a proton beam-driven plasma wakefield accelerator
• 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