Improved stability of a compact vacuum-free laser-plasma X-ray source

L Martín,D Cortina-Gil,C Ruiz,J Benlliure,J Peñas

doi:10.1017/hpl.2020.15

Abstract

We report the development of a stable high-average power X-ray source generated by the interaction of ultrashort laser pulses (35 fs, 1 mJ, 1 kHz) with a solid target in air. The achieved source stability, which is essential for the applications foreseen for these laser-driven plasma accelerators, is due to the combination of precise positioning of the target on focus and the development of a fast rotating target system able to ensure the refreshment of the material at every shot while minimizing positioning errors with respect to the focal spot. This vacuum-free laser-plasma X-ray source provides an average dose rate of 1.5 Sv/h at 30 cm and a repeatability better than 93% during more than 36 min of continuous operation per target.

Highlights

X-rays are a very important tool for scientific research in physics, chemistry or biology
We report on the development of a compact vacuum-free laser-plasma X-ray source based on rotating thick targets, which ensures stability, long operation periods and simplicity in terms of design and operation, for its use in different applications
The flux deviation for the 24 different measurements amounts to 6.6%, indicating that the repeatability of this X-ray source is better than 93%

Summary

Introduction

X-rays are a very important tool for scientific research in physics, chemistry or biology They have become essential for a wide variety of societal applications, from nondestructive inspection for security or industry to medical imaging and treatment. For solid targets and intensities larger than 1016 W/cm, electrons can be heated through a series of mechanisms such as resonant absorption[6], vacuum heating[7] depending on the plasma gradient length[8] or j × B at higher intensities[9] These electrons can produce hard X-rays through bremsstrahlung[10] or specific Kα emission. We report on the development of a compact vacuum-free laser-plasma X-ray source based on rotating thick targets, which ensures stability, long operation periods and simplicity in terms of design and operation, for its use in different applications

Table-top X-ray source

Target positioning system

Focusing diagnostics

Results

Conclusions