Experimental demonstration of a laser proton accelerator with accurate beam control through image-relaying transport

Jinying Zhu ,K Zhu,T Tajima,Chen Lin ,C E Chen ,Qing Liao ,D Y Li ,D H Wang ,C C Li ,Taoxi Yang ,J J Wang ,Mei Wu ,Yinren Shou ,Yixing Geng ,W J ,Xiaoyi Xu ,Yanying Zhao ,X T He ,Haiyang Lu ,P J Wang ,Xueqing Yan

doi:10.1103/physrevaccelbeams.22.061302

Abstract

A compact laser plasma accelerator (CLAPA) that can stably produce and transport proton ions with different energies less than 10 MeV, $l1%$ energy spread, several to tens of pC charge, is demonstrated. The high current proton beam with continuous energy spectrum and a large divergence angle is generated by using a high contrast laser and micron thickness targets, which later is collected, analyzed and refocused by an image-relaying beam line using a combination of quadrupole and bending electromagnets. It eliminates the inherent defects of the laser-driven beams, realizes precise manipulation of the proton beams with reliability, availability, maintainability and inspectability (RAMI), and takes the first step towards applications of this new generation of accelerator. With the development of high-rep rate Petawatt (PW) laser technology, we can now envision a new generation of accelerator for many applications in the near future soon.

Highlights

The concept of laser acceleration was first invented by Tajima and Dawson [1] in 1979, and was soon extended from accelerating electrons using gas targets to accelerating ions using solid targets
The proton energy demonstrated here is still far from meeting the requirements of some applications, such as cancer therapy, realizing precise manipulation of the monoenergetic proton beams with RAMI is still an important step, which lays the foundation for subsequent experiments, such as precise biological dose deposition, space irradiation environment simulation, measurement of energy stopping in warm dense matter, detection device calibration and measurement of proton beam parameters
Image point at the x axis, while protons with different energies are separated in the x direction. This means that the sector magnet, together with the triplet lens, can efficiently capture and analyze the protons generated in laser acceleration, and the influences of large divergence angle, large energy spread and angular-dependent distribution of initial protons are removed at the image point

Summary

INTRODUCTION

The concept of laser acceleration was first invented by Tajima and Dawson [1] in 1979, and was soon extended from accelerating electrons using gas targets to accelerating ions using solid targets. To implement the application of the laser accelerated protons, massive efforts have to be made to solve the broad energy spread, the large divergence angle, the poor reproducibility and flexibility, which are necessary conditions to raise “laser acceleration” to “laser accelerator.” To grapple with these problems of laser-driven proton beams, at first step, permanent magnet quadrupole lenses [25,26,27], solenoid magnets [28,29,30] and laser-triggered microlenses [31] are demonstrated as the focusing components. The proton energy demonstrated here is still far from meeting the requirements of some applications, such as cancer therapy, realizing precise manipulation of the monoenergetic proton beams with RAMI is still an important step, which lays the foundation for subsequent experiments, such as precise biological dose deposition, space irradiation environment simulation, measurement of energy stopping in warm dense matter, detection device calibration and measurement of proton beam parameters

EXPERIMENT SETUP

Generation of monoenergetic proton beam

Adjustment of the beam line

Findings

SUMMARY