11. |
- Korn, G., et al.
(author)
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Ultrashort 1-kHz laser plasma hard x-ray source
- 2002
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In: Optics Letters. - 0146-9592 .- 1539-4794. ; 27:10, s. 866-868
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Journal article (peer-reviewed)abstract
- We achieved a continuous, stable, ultrashort pulse hard x-ray point source by focusing 1.8-W, 1-kHz, 50-fs laser pulses onto a novel, 30-mum-diameter, high-velocity, liquid-metal gallium jet. This target geometry avoids most of the debris problems of solid targets and provides nearly 4pi illumination. Photon fluxes of 5 X 10(8) photons/s are generated in a two-component spectrum consisting of a broad continuum from 4 to 14 keV and strong K-alpha and K-beta emission lines at 9.25 and 10.26 keV. This source will find wide use in time-resolved x-ray diffraction studies and other applications.
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12. |
- Thoss, A., et al.
(author)
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Kilohertz sources of hard x rays and fast ions with femtosecond laser plasmas
- 2003
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In: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 20:1, s. 224-228
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Journal article (peer-reviewed)abstract
- We demonstrate a new, stable, kilohertz femtosecond laser plasma source of hard-x-ray continuum and K-alpha emission that uses a microscopic liquid jet target that is continuous and debris free. Plasmas produced by ultrashort (50-fs) intense laser pulses from a fine (10-30-mum diameter) liquid Ga jet emit bright 9.3- and 10.3-keV K-alpha and K-beta lines superimposed on a multikilovolt bremmstrahlung continuum. Kilohertz femtosecond x-ray sources will find many applications in time-resolved x-ray diffraction and microscopy studies. As high-intensity lasers become more compact and operate at increasingly high repetition-rates, they require a target configuration that is both repeatable from shot to shot and debris free. Our target provides a pristine, unperturbed filament surface at rates >100 kHz. A number of liquid metal targets are considered. We show the hard-x-ray spectrum described above. The source was generated by a 50-fs-duration, 1-kHz, 2-W, high-intensity Ti:sapphire laser. Using the same technology, we also generate forward-going sub-mega-electron-volt (sub-MeV) protons from a 10-mum liquid water target at 1-kHz repetition rates. Kilohertz sources of high-energy ions will find many applications in time-resolved particle interaction studies and will lead to efficient generation of short-lived isotopes for use in nuclear medicine and other applications. The protons were detected with CR-39 track detectors in both the forward and the backward directions up to energies of similar to500 keV. As the intensity of compact high-repetition-rate lasers sources increases, we can expect improvements in the energy, conversion efficiency, and directionality to occur. The effect of these developments is discussed. As compact, high-repetition-rate femtosecond laser technology reaches focused intensities of similar to10(19) W/cm(2), many new applications of high-repetition-rate hard-x-ray and MeV ion sources will become practical.
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