| 1. |
- Svanberg, Sune, et al.
(författare)
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Applications of terawatt lasers
- 1994
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Ingår i: LASER SPECTROSCOPY - XITH INTERNATIONAL CONFERENCE. - : AIP. - 1551-7616 .- 0094-243X. - 1563962624 ; :290, s. 264-269
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Konferensbidrag (refereegranskat)
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| 2. |
- Albert, F, et al.
(författare)
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Laser produced X-ray source in the 10-60 keV range at 1 kHz. Modified irradiation schemes in order to reach medical imaging quality
- 2001
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Ingår i: Journal de Physique IV. - : EDP Sciences. - 1155-4339. ; 11:PR2, s. 429-432
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Tidskriftsartikel (refereegranskat)abstract
- By tightly focusing ultra-short pulses from a Ti:sapphire terawatt laser onto a high-Z metallic target, hard x-ray pulses of short duration are produced. In most of our previous work concerning x-rays, a 150 mJ laser pulse with a 110 A duration has been used. Using mostly tin and tantalum targets, hard x-rays in the 10-60 keV range have been produced and used in differential absorption imaging around the K-alpha absorption edge of a contrast agent and also in imaging employing gated viewing for suppression of scattered radiation. In order to increase the x-ray yield (shortening the acquisition time) an increase in the laser repetition rate is desirable while still staying in the K-alpha energy regime. We have used a I kHz repetition-rate laser delivering 35 fs pulses in order to work towards these goals. We have clear evidence of hard x-ray generation above 30 keV, even for low laser pulse energies. We also studied the effect of a fs prepulse. The medical imaging capability of the source was explored. The use of a prepulse has been optimized in order to improve the image quality as well as the overall x-ray generation yield.
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| 3. |
- An, W. W., et al.
(författare)
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Synthesis and surface characteristics of CeTbO3+delta induced by femtosecond laser irradiation
- 2007
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Ingår i: Applied Surface Science. - : Elsevier BV. - 1873-5584 .- 0169-4332. ; 253:8, s. 3884-3887
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Tidskriftsartikel (refereegranskat)abstract
- This work describes the use of focused, high-intensity light from a Ti: sapphire laser that generates femtosecond pulses to irradiate mixture of CeO2 and Tb4O7 under ambient conditions. The prepared samples were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). XRD and XPS measurement results demonstrated that solid solution CeTbO3+delta with cubic fluorite structure has been synthesized on the irradiated target surface. SEM micrographs showed that the ultra-short laser irradiation resulted in the formation of foamy structure and spherical particles with size varying from about 30 to 200 nm. The formation mechanism has been discussed in detail. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
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| 6. |
- Blagoev, K, et al.
(författare)
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Radiative lifetimes of 6sns S-3(1) and 6snd D-3(1) excited states of HgI
- 2002
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 66:3
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Tidskriftsartikel (refereegranskat)abstract
- Natural radiative lifetimes have been measured along the 6sns S-3(1) (n=7-10) and 6snd D-3(1) (n=6-11) Rydberg series of neutral mercury using time-resolved laser-induced fluorescence spectroscopy in a laser-produced mercury plasma. The states of Hg I investigated in the present work were populated from the ground state by a stepwise excitation process. Relativistic Hartree-Fock calculations, including intravalence interactions and core-polarization effects, have been performed and the theoretical lifetimes have been compared with the measurements.
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| 7. |
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| 8. |
- Borgstrom, S, et al.
(författare)
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Time-resolved x-ray spectroscopy of optical-field-ionized plasmas
- 1995
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Ingår i: Laser and Particle Beams. - 0263-0346. ; 13:4, s. 459-468
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Tidskriftsartikel (refereegranskat)abstract
- The time-dependent soft X-ray emission of helium and nitrogen plasmas generated by optical-field ionization is reported. The experiments were carried out by focusing pulses of the high-power Ti:sapphire laser of the Lund Institute of Technology (lambda = 796 nm, pulse duration 150 fs, pulse energy 150 mJ) to a 50-mu m diameter spot close to a nozzle, using He and N-2 as target gases. The emission on He+, N4+, and N3+ resonance lines was recorded by means of a flat-field grating spectrometer coupled to an X-ray streak camera. A pronounced difference in the temporal shape of the emission of the Lyman-alpha line of hydrogen-like helium and of the 2p-3d resonance lines of lithium-like and beryllium-like nitrogen was observed. The helium line exhibited an initial spike followed by a slow revival of the emission, whereas the nitrogen lines showed a slow decay after a fast initial rise. These observations are explained with the help of simulations.
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| 9. |
- Fill, E, et al.
(författare)
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Xuv Spectra of Optical-field-ionized Plasmas
- 1995
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Ingår i: Physical Review E: covering statistical, nonlinear, biological, and soft matter physics. - 1063-651X. ; 51:6, s. 6016-6027
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Tidskriftsartikel (refereegranskat)
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| 10. |
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