Quasi-monoenergetic proton beams by laser-plasma X-rays

D Delle Side,V Nassisi,L Velardi,J Krása

doi:10.1088/1742-6596/508/1/012003

Abstract

We report the details of a technique for the production of proton beams with very low energy spread exploiting the short soft X-rays obtained by laser ablation. These beams have been generated by the dissociation and ionization of an hydrogen buffer gas induced by the laser-plasma X-rays and then accelerated by means of an electrostatic accelerator. Their properties have been analyzed through the time-of-flight method applying different accelerating voltages. The resulting energetic spread ranges between 6 and 11%, as a function of the applied voltage. Such a system could be extremely useful for producing quasi-monoenergetic proton beams.

Highlights

Laser induced plasmas (LIPs) revealed over the years as a prolific field, both for scientific and applicative purposes
The corresponding voltage had to be raised to 5 kV on T to observe the appearance of an additional fast peak on the currents recorded through Faraday cup (FC), when the H2 was fluxed in accelerating chamber (AC)
Increasing the applied voltage resulted in the occurrence of fast and sharp protons signals when a background hydrogen is present, together with a slower population of protons coming from the target, as shown in figure 3

Summary

Introduction

Laser induced plasmas (LIPs) revealed over the years as a prolific field, both for scientific and applicative purposes. Since the early days of lasers, researchers all over the world investigated the effect of focusing high power radiation onto solid targets in high vacuum, obtaining as a result high-density plasmas. In these experiments, plasmas expanding rapidly along the normal to the target surface were known to originate the emission of energetic ions since the early 1960’s[1]. One of the main problems that researchers have to consider when planning the use of a LIS is the broad energy distribution of the ejecta, when used as injectors for particle accelerators In this case, ad hoc systems [8] should be used to reduce the energy spread of the ion beams

Objectives

Methods

Results

Conclusion