High energy proton beam from a laser irradiated thin-foil target and its possible applications

Abstract

In this paper, we present the motivation and future prospects of the laser-driven proton generation and its application to the medical accelerators. Then we present the experimental results of the high energy proton beam produced by a Ta 3 µm target irradiated with a 3 × 10 18 W cm −2 , ∼70 fs pulse laser. The measured proton spectra can be divided into three parts; lowenergy, high-energy, and cut-off. We propose the possible acceleration mechanism which describes our data, and the resultant problems which we should solve to reach our objectives. Vertical axis, µmHorizontal axis, µm 150

A Novel Technique for Monitoring the Reproducibility of Laser Tape-Target Interactions Using an X-ray Pinhole Camera

“…When the distance from the beam waist is equal to the X R , the beam radius is 2 times larger than the radius at the beam waist, and the cross-sectional area of the beam is twice that at the focus. The maximum energy of the laser-driven protons is proportional to (I Laser ) 0.5¿1 , where is the laser intensity 22) . The laser intensity at the X R is half the laser intensity at the focus position.…”

“…The tape target, made of polyimide, can be moved perpendicular to the target surface using a linear translation stage with a motorized actuator. The proton energy was measured using the time-of‰ight energy analyzer described in our previous paper [22][23] .…”