Method for improving quality of proton beam in interaction of laser and target

Abstract

The invention relates to a method for improving the quality of a proton beam in the interaction of laser and a target. The method comprises the following steps: 1, pre-pulse laser being positively incident on the front surface of a metal target, and heating an irradiated area into plasma; 2, performing pre-pulse laser irradiation, the forward laser I21 being used as a main pulse, emitting forwardly on the front surface of the ionized metal target; 3, irradiating reverse laser I22 from a target back to the back surface of the target in the direction opposite to the forward laser I21; wherein the incident time of the reverse laser light falls behind the incident time of the forward laser light by delta t from the back of the target to the back surface of the target, the value range of deltat is 4-10 fs, the intensity I22 of the reverse laser light I22 being equal to a I21, and the value range of a being 0.1-0.6; when the reverse laser meets the condition that a is equal to 0.2, and whendelta t is equal to 8fs, forward expansion of hot electrons on the back of the target can be inhibited by the prime power of the reverse laser, so that the electron cloud set is distributed at a specific position near the surface of the back of the target, the strength of a sheath electric field on the back of the target is improved to be optimal, the energy of protons is improved to be optimal,and the divergence angle of the protons is reduced.

Description

technical field [0001] The invention belongs to the technical field of laser acceleration, and in particular relates to a method for improving the quality of a proton beam in the interaction between a laser and a target. Background technique [0002] The high-energy proton beam obtained by the interaction between laser and target can be applied in many fields, such as isotope production, tumor treatment, inertial confinement nuclear fusion, etc. The quality of proton beams produced in current experiments is not high, and there are shortcomings such as low energy and large divergence angles, which limit the application of laser accelerated protons. The acceleration mechanism of laser-accelerated protons is generally explained by the target normal sheath acceleration mechanism (Target Normal Sheath Acceleration, TNSA for short). In this mechanism, the thin foil target is ionized after laser pre-pulse irradiation to form a plasma, and the electrons in the plasma move forward u...

AI Technical Summary

Problems solved by technology

However, the thickness of the target used in laser acceleration is generally at the micron or nanometer level, and it is very difficult to process such a thin target into a suitable shape

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