FOXLA · Focusing of the optimised X-ray laser at PALS: the first step towards laboratory astrophysics
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2005-03-01 → 2006-02-28
- EU contribution
- €40,000
- Participants
- 1
- Scheme
- ERG
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Results in brief
Final Activity Report Summary - FOXLA (Focusing of the optimised X-ray laser at PALS: the first step towards laboratory astrophysics)
The main goal of this project was to explore the feasibility of focusing the multi-millijoule, deeply saturated soft X-ray laser at 21.2 nm. Precise optomechanic focusing system consisting of a spherical mirror at nearly normal incidence has been designed and fabricated. The system represents good compromise between simplicity, throughput, and acceptable optical aberrations, providing a reduced image of the X-ray laser source. The first focusing experiment with this optical tool was conducted at the Prague Asterix Laser System (PALS) using currently the most powerful Ne-like zinc soft X-ray laser. Focal spots were directly observed by imaging the fluorescence induced by the X-ray laser on a Tb:doped phosphor screen. We have successfully focused the X-ray laser beam with the size of 5.6 mm x 8.4 mm down to 40 microns x 60 microns elliptical spot. The actual spot size was determined predominantly by the geometrical demagnification of the emitting X-ray source and astigmatism. The available peak intensity and fluence represent the highest value reported to date at 21 nm, suitable for new applications in nanostructuring of solids, radiobiology and laboratory astrophysics. Material ablation at such a short wavelength was observed for the first time. Using the same focusing system we performed a joint experiment at LULI laser facility (France) with a low-energy transient X-ray laser at 13.9 nm. The smallest focal spot had an average diameter of 20 microns and a homogeneous profile which makes it suitable e.g. for experiments on irradiation of biological samples where smooth, large zone and moderate fluence are both required. To measure emission spectra of plasmas created by the interaction of an X-ray laser with a thin foil target, we have designed and fabricated a high-resolution keV crystal spectrometer.
Data: CORDIS, © European Union
Project objective
The main goal of this project is the achievement of a few-micron focal spot of the optimised, deeply saturated soft X-ray laser at 21.2 nm developed at PALS. The extremely high brightness makes this laser a perfect candidate for experimental studies of las er-matter interaction in the soft X-ray spectral region. Under optimum conditions it provides up to 10 mJ of energy in a narrowly collimated beam with high spatial quality. Assuming a focal spot of at most 10 micrometers, irradiances of at least 5 x 10^12 W/cm^2 may be generated with the 21.2 nm radiation on the target, resulting in conversion of solid matter to a highly ionized plasma relevant to stellar objects and warm dense matter. First, appropriate focusing optics for the X-ray laser at 21.2 nm will b e designed with the help of ray tracing simulation code, then fabricated, coated, and tested. The X-ray laser focal spot will be characterized by means of near-field imaging of the fluorescence induced by the X-ray laser beam on YAG:Ce crystal. The quality of focusing will be evaluated and optimised. Finally, a target consisting of thin foil of aluminum or zirconium will be placed in the focus and emission X-ray spectra from plasma generated by the X-ray laser will be recorded. The success in focusing of X-ray laser will give rise to a completely new and unexplored field in physics - laboratory astrophysics.
Original text from CORDIS.
Participants
- FYZIKÁLNÍ ÚSTAV AV ¿R · PRAGUE 8CoordinatorCountry levelCzechia
Links
Data: CORDIS, © European Union