Design and characterization of a desk-top laser plasma X-ray source for radiobiology studies

Abstract

A compact desk-top laser-produced plasma source of soft X-rays for radiobiologyy research is presented. The source is based on a double-stream gas pufff target and delivers nanosecond pulses of sooft X-rays in the “water window” spectral range at a fluence of about 4.223×103 photon/µm2 per pulse on a sample pllaced inside the vacuum source chamber and about 2.60×102 photon/µm22 per pulse on a wet sample located outside the chamber in the He-environment. The source has been used to irradiate pBR322 plasmid DNA both in vacuum and the He-environment conditions. Single and double strand breaks were quantified by gel electrophoresis. The nuumber of strand breaks increased with increasing dose of the “water winddow” soft X-rays. The strand breaks of plasmid solution irradiated in helium condition may be associated with damage from water free radicals.