FLASH-therapy suitable single-pulse proton generation using TiH2 under nanosecond laser irradiation

Area of Science:

• Plasma Physics
• Materials Science

Background:

• Titanium hydride (TiH2) is a material with potential applications in laser-driven ion sources.
• Understanding proton emission characteristics is crucial for developing advanced radiation therapies.

Purpose of the Study:

• To investigate proton emission from TiH2 targets irradiated by a Nd:YAG laser.
• To evaluate the potential of TiH2-based sources for ultra-high-dose-rate applications like FLASH-therapy.

Main Methods:

• Irradiation of TiH2 targets in vacuum using a 6-ns, 1064-nm Nd:YAG laser.
• Time-of-flight measurements using a Faraday cup and electrostatic ion analyzer to detect proton emission.
• Systematic scans of laser pulse energy and repeated shots (up to 1000).

Main Results:

• Distinct proton peaks were observed at high pulse energies, with yields around 10^9 protons per shot.
• Integrated proton number remained constant over 1000 shots, despite decreasing peak amplitude.
• Plasma expansion characteristics suggest surface ablation and bulk hydrogen replenishment.

Conclusions:

• TiH2-based laser ion sources demonstrate sustained proton output suitable for high-repetition-rate applications.
• The observed characteristics support TiH2 as a practical candidate for FLASH-therapy research and injector development.
• Direct plasma injection scaling indicates high peak currents and short pulse durations, meeting ultra-high-dose-rate criteria.