Collective deceleration: toward a compact beam dump

TL;DR

This paper proposes a novel, compact, and non-radioactive beam dump method based on collective deceleration in ionized gas, suitable for high-energy laser-accelerated electron beams, offering advantages over traditional solid targets.

Contribution

It introduces the concept of collective deceleration as an alternative beam dump mechanism, significantly reducing size and radioactivation hazards for high-energy electron beams.

Findings

Collective stopping length can be several orders shorter than traditional methods.

Tenuous gas density minimizes radioactivation.

Effective for short, dense electron bunches from laser wakefield accelerators.

Abstract

With the increasing development of laser accelerators, the electron energy is already beyond GeV and even higher in near future. Conventional beam dump based on ionization or radiation loss mechanism is cumbersome and costly, also has radiological hazards. We revisit the stopping power of high-energy charged particles in matter and discuss the associated problem of beam dump from the point of view of collective deceleration. The collective stopping length in an ionized gas can be several orders of magnitude shorter than the Bethe-Bloch and multiple electromagnetic cascades' stopping length in solid. At the mean time, the tenuous density of the gas makes the radioactivation negligible. Such a compact and non-radioactivating beam dump works well for short and dense bunches, which is typically generated from laser wakefield accelerator.