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

Abstract

For accurately controlling relativistic laser-plasma interactions to achieve repetitive proton generation, it is necessary to measure and control the laser irradiation conditions, such as laser parameters and target shooting accuracy, as well as to measure proton parameters for each laser shot. The displacement of the tape target, which is used in an ultra-short Ti: sapphire laser system to generate high-energy protons, is measured by capturing X-ray images of the laser plasma for each laser shot using an X-ray pinhole camera. This method allows the displacement of the target to be measured with a precision of 10 mm. The precision is high enough for present-day laser focusing systems with an F-number of 3.6 ( f＝179 mm). Thus, the proposed technique contributes to accurate control of repetitive laser-driven proton generation.