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X-ray processes in high-intensity laser-matter interactions Adams, Frederick P.
Abstract
In laser-matter-interaction studies there is a continued interest in the emission and transport of x-rays in laser-irradiated solids. We have irradiated metal foil targets with 0.532 μm laser light with pulse lengths of 2.4 to 2.6 us at absorbed irradiances of 10¹² to 10¹³ W/cm . Calorimetric measurements of the energy of x-ray emission by the laser-produced plasma on the target frontside indicate that copper is a better emitter than aluminum or molybdenum in an x-ray band ≥ 800 eV. Measurements comparing x-ray transmission through irradiated foil targets with that through identical, unperturbed filters indicate enhanced transmission of x-ray energy through the targets. Temporally-resolved measurements on aluminum targets show that x-ray transmission through the target is strongly time-dependent, with x-ray power transmission through the targets, with the greatest contribution being that resulting from 2D rarefaction of the target after shock breakout. This corroborates earlier observations of delayed x-ray heating of the target rear surface. Enhanced transmission of x-rays through the targets at the moment of shock breakout was also observed, consistent with a shift of the K-shell x-ray absorption edge in the shocked aluminum plasma allowing increased transmission of the aluminum He[sub α] and IC x-ray lines. Other models which may yield similar enhanced x-ray transmission are investigated and rejected on the basis of experimental measurements on layered targets composed of an aluminum substrate and a copper layer as an x-ray source. Similar enhanced x-ray transmission has also been observed in laser-irradiated magnesium targets. The results provide the first experimental evidence of substantial increase in x-ray transport due to a shift of the K-shell photoabsorption edge induced by shock-compression of a dense plasma.
Item Metadata
Title |
X-ray processes in high-intensity laser-matter interactions
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1986
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Description |
In laser-matter-interaction studies there is a continued interest in the emission and transport of x-rays in laser-irradiated solids. We have irradiated metal foil targets with 0.532 μm laser light with pulse lengths of 2.4 to 2.6 us at absorbed irradiances of 10¹² to 10¹³ W/cm . Calorimetric measurements of the energy of x-ray emission by the laser-produced plasma on the target frontside indicate that copper is a better emitter than aluminum or molybdenum in an x-ray band ≥ 800 eV.
Measurements comparing x-ray transmission through irradiated foil targets with that through identical, unperturbed filters indicate enhanced transmission of x-ray energy through the targets. Temporally-resolved measurements on aluminum targets show that x-ray transmission through the target is strongly time-dependent, with x-ray power transmission through the targets, with the greatest contribution being that resulting from 2D rarefaction of the target after shock breakout. This corroborates earlier observations of delayed x-ray heating of the target rear surface.
Enhanced transmission of x-rays through the targets at the moment of shock breakout was also observed, consistent with a shift of the K-shell x-ray absorption edge in the shocked aluminum plasma allowing increased transmission of the aluminum He[sub α] and IC x-ray lines. Other models which may yield similar enhanced x-ray transmission are investigated and rejected on the basis of experimental measurements on layered targets composed of an aluminum substrate and a copper layer as an x-ray source. Similar enhanced x-ray transmission has also been observed in laser-irradiated magnesium targets. The results provide the first experimental evidence of substantial increase in x-ray transport due to a shift of the K-shell photoabsorption edge induced by shock-compression of a dense plasma.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-06-14
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0085285
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.