keV x-ray spectroscopy of plasmas produced by the intense picosecond irradiation of a gas of xenon clusters

Abstract

We have studied the characteristics of x-ray emission in the 12-16Å range from plasmas produced by the irradiation of a target of Xe clusters with picosecond laser pulses at intensities near 10 17 W cm −2 . These plasmas exhibit strong emission from Ni-like through to Mn-like Xe. We find that the strength and character of the x-ray spectra are very similar when either 1053 or 526 nm laser pulses are used to heat the clusters.

Influence of Xe and Kr impurities on x-ray yield from debris-free plasma x-ray sources with an Ar supersonic gas jet irradiated by femtosecond near-infrared-wavelength laser pulses

“…In the hard x-ray region above 9 keV, the yield was much higher for contrast K=10 5 than for contrast K=10 7 . This result pointed to the fact that by changing the time delay we can find a regime when harder x-ray emission (> 9 keV) from XeKrAr jets is more intense for lower laser pulse contrast K=10 5 than for higher contrast K=10 7 .…”

“…For time delay 1000 μs, yields for contrast K=10 5 were several percent higher than for K=10 7 in the softer spectral region (>1.4 keV), and close or lower in the harder x-ray region (>3.5 keV), except near 9 keV where it was 40 % lower. On the other hand, the comparison of yields from XeKrArI jets with shorter time delay (830 μs) for shot #1600 (K=10 5 ) and shot #1588 (K=10 7 ) has shown that yields for laser pulse contrast K=10 5 were several percent lower or similar to those for K=10 7 in the softer spectral region (>1.4 keV, > 2.4 keV) and were similar or a little higher in the harder x-ray region (> 3.5keV). In the hard x-ray region above 9 keV, the yield was much higher for contrast K=10 5 than for contrast K=10 7 .…”

“…On the other hand, the comparison of yields from XeKrArI jets with shorter time delay (830 μs) for shot #1600 (K=10 5 ) and shot #1588 (K=10 7 ) has shown that yields for laser pulse contrast K=10 5 were several percent lower or similar to those for K=10 7 in the softer spectral region (>1.4 keV, > 2.4 keV) and were similar or a little higher in the harder x-ray region (> 3.5keV). In the hard x-ray region above 9 keV, the yield was much higher for contrast K=10 5 than for contrast K=10 7 . This result pointed to the fact that by changing the time delay we can find a regime when harder x-ray emission (> 9 keV) from XeKrAr jets is more intense for lower laser pulse contrast K=10 5 than for higher contrast K=10 7 .…”

“…In many experiments it was demonstrated that when pure Ar [4,5], Kr [6], Xe [7,8], or a Kr/Ar [9] mixture, irradiated by fs laser pulses with wavelength near 1 μm, the gas/cluster jets become efficient x-ray sources. In this work we show that Xe/Kr/Ar mixture jets generate more powerful x-ray bursts and in a broader spectral range.…”

Interaction of intense laser pulses with atomic clusters: Measurements of ion emission, simulations and applications

“…This continues to be an active area of research. One area of controversy is the scaling of the X-ray signal with the laser wavelength, with some groups claiming a very strong scaling, favouring shorter wavelength lasers such as KrF lasers at 248 nm [66], while others finding evidence of a much weaker scaling [67,79]. However, no systematic study has been carried out over a wide range of wavelengths ensuring identical focusing conditions and using exactly the same cluster source.…”