Target considerations for inner-shell photo-ionized X-ray lasing
The authors present target design for the inner-shell photo- ionization (ISPI) x- ray laser scheme and discuss the requirements for the ionizing x-ray source in rise time and flux. An investigation of the rapid rise time of x-ray emission from targets heated by an ultra-short pulse (USP) high-intensity optical laser was conducted for use as the x-ray source for ISPI x-ray lasing. Modeling using the hydrodynamic/atomic kinetics code LASNEX of a 45 fs USP driving laser with energy of order I J incident on a structured Au target composed of vertical rods with diameter of 500 {angstrom} predicts sufficient x rays to produce a gain-length product of order 10 in C at 45 {angstrom}. Collisional ionization to the lower lasing level limits the duration of lasing giving a x-ray laser pulse duration of order 60 fs FWHM. Results of x- ray rise times from instantaneously heated Au rod targets show little benefit in using optical pulse widths less than 15 fs. However calculations for a constant energy source varying the pulse width show significant increased gain for decreasing pulse widths down to approximately 15 fs. However, for a constant 2048 intensity source we see a decrease in gain for shorter pulse widths.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 461390
- Report Number(s):
- UCRL-JC--123798; CONF-9606137--5; ON: DE97051378
- Country of Publication:
- United States
- Language:
- English
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