Strong focusing gradient in a linear active plasma lens

K N Sjobak,M Meisel,E Adli,R Corsini,L Schaper,J Osterhoff,W Farabolini,C A Lindstrøm,A E Dyson,G Boyle,J.-H Röckemann

doi:10.1103/physrevaccelbeams.24.121306

Abstract

Active plasma lenses are compact devices developed as a promising beam-focusing alternative for charged particle beams, capable of short focal lengths for high-energy beams. We have previously shown that linear magnetic fields with gradients of around 0.3 kT/m can be achieved in argon-filled plasma lenses that preserve beam emittance [C.A. Lindstr{\o}m et al., Phys. Rev. Lett. 121, 194801 (2018)]. Here we show that with argon in a 500 {\mu}m diameter capillary, the fields are still linear with a focusing gradient of 3.6 kT/m, which is an order of magnitude higher than the gradients of quadrupole magnets. The current pulses that generate the magnetic field are provided by compact Marx banks, and are highly repeatable. These results establish active plasma lenses as an ideal device for pulsed particle beam applications requiring very high focusing gradients that are uniform throughout the lens aperture.

Highlights

Plasma-based technology promises to pave the way for more compact particle accelerators [1]
We have previously shown that linear magnetic fields with gradients of around 0.3 kT/m can be achieved in argon-filled plasma lenses that preserve beam emittance [C.A
There is a short drift before the beam impinges on an optical transition radiation (OTR) screen mounted at a 45° angle to the beam, used to measure the beam position

Summary

Introduction

Plasma-based technology promises to pave the way for more compact particle accelerators [1]. While much research has been directed toward the use of plasma technology for compact acceleration [2,3,4], there has been less effort directed at compactifying the focusing elements of the accelerator, which is crucial for achieving compact machines. The development of plasma lenses, as discussed here, may establish a superior beam-focusing alternative for charged particle beams in high energy physics applications, as well as for other demanding pulsed-beam applications such as medical applications or photon sources [5,6,7]. Quadrupole magnetic lenses are the conventional choice for focusing of high-energy charged beams [[8] Section 7.2]. Axisymmetric focusing is important for capturing and refocusing beams with high divergence and energy spread, e.g., a beam produced in a plasma-wakefield accelerator [4,13,14]. Implementations of APLs using discharge capillary technology [15] have recently been developed [11,16], and first uses as optical elements for accelerator research applications are reported [17,18,19]

Methods

Discussion

Conclusion