Z-Pinch Generated X-Rays Demonstrate Indirect-Drive ICF Potential

International Nuclear Information System (INIS)

Bowers, R.L.; Chandler, G.A.; Derzon, M.S.; Hebron, D.E.; Leeper, R.J.; Matzen, M.K.; Mock, R.C.; Nash, T.J.; Olson, R.E.; Peterson, D.L.; Ruggles, L.E.; Sanford, T.W.L.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.

1999-01-01

Hohlraums (measuring 6-mm in diameter by 7-mm in height) have been heated by x-rays from a z-pinch. Over measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from approximately55 to approximately130 eV, and is in agreement with the Planckian relation P-T 4 . The results suggest that indirect-drive ICF studies involving NIF relevant pulse shapes and <2-mm diameter capsules can he studied using this arrangement

Z-Pinch Generated X-Rays Demonstrate Indirect-Drive ICF Potential

Energy Technology Data Exchange (ETDEWEB)

Bowers, R.L.; Chandler, G.A.; Derzon, M.S.; Hebron, D.E.; Leeper, R.J.; Matzen, M.K.; Mock, R.C.; Nash, T.J.; Olson, R.E.; Peterson, D.L.; Ruggles, L.E.; Sanford, T.W.L.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.

1999-06-16

Hohlraums (measuring 6-mm in diameter by 7-mm in height) have been heated by x-rays from a z-pinch. Over measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from {approximately}55 to {approximately}130 eV, and is in agreement with the Planckian relation P-T{sup 4}. The results suggest that indirect-drive ICF studies involving NIF relevant pulse shapes and <2-mm diameter capsules can he studied using this arrangement.

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

International Nuclear Information System (INIS)

Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

1996-01-01

X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤ 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

International Nuclear Information System (INIS)

Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

1997-01-01

X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time endash history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. copyright 1997 American Institute of Physics

Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

Energy Technology Data Exchange (ETDEWEB)

SANFORD,THOMAS W. L.; OLSON,RICHARD E.; MOCK,RAYMOND CECIL; CHANDLER,GORDON A.; LEEPER,RAMON J.; NASH,THOMAS J.; RUGGLES,LAURENCE E.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; PETERSON,D.L.; BOWERS,R.L.; MATUSKA,W.

2000-07-10

A z-pinch radiation source has been developed that generates 60 {+-} 20 KJ of x-rays with a peak power of 13 {+-} 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 {+-} 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 {+-} 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm{sup 3} CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approximately}40% with only a 3--5% decrease in peak temperature, in agreement with measurements.

Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

International Nuclear Information System (INIS)

Sanford, Thomas W.L.; Olson, Richard E.; Mock, Raymond Cecil; Chandler, Gordon A.; Leeper, Ramon J.; Nash, Thomas J.; Ruggles, Laurence E.; Simpson, Walter W.; Struve, Kenneth W.; Peterson, D.L.; Bowers, R.L.; Matuska, W.

2000-01-01

A z-pinch radiation source has been developed that generates 60 ± 20 KJ of x-rays with a peak power of 13 ± 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 ± 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 ± 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm 3 CH 2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ∼40% with only a 3--5% decrease in peak temperature, in agreement with measurements

Z -Pinch-Generated X Rays Demonstrate Potential for Indirect-Drive ICF Experiments

International Nuclear Information System (INIS)

Sanford, T. W. L.; Olson, R. E.; Bowers, R. L.; Chandler, G. A.; Derzon, M. S.; Hebron, D. E.; Leeper, R. J.; Mock, R. C.; Nash, T. J.; Peterson, D. L.

1999-01-01

Hohlraums measuring 6 mm in diameter by 7 mm in height have been heated by x rays from a Z pinch. Over the measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from ∼55 to ∼130 eV , and is in agreement with the Planckian relation T∼P 1/4 . The results suggest that indirect-drive inertial-confinement-fusion experiments involving National Ignition Facility relevant pulse shapes and <2 mm diameter capsules can be studied using this arrangement. (c) 1999 The American Physical Society

Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120--160 eV

Energy Technology Data Exchange (ETDEWEB)

Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L. (and others)

2000-11-01

A Z-pinch radiation source has been developed that generates 60{+-}20 kJ of x rays with a peak power of 13{+-}4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122{+-}6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155{+-}8 eV -- providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh--Taylor instability in the r--z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approx}40% with only a 3%--5% decrease in peak temperature, in agreement with measurements.

Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120--160 eV

International Nuclear Information System (INIS)

Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L.

2000-01-01

A Z-pinch radiation source has been developed that generates 60±20 kJ of x rays with a peak power of 13±4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122±6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155±8 eV -- providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh--Taylor instability in the r--z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH 2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ∼40% with only a 3%--5% decrease in peak temperature, in agreement with measurements

Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120-160 eV

Science.gov (United States)

Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L.; Bowers, R. L.; Matuska, W.

2000-11-01

A Z-pinch radiation source has been developed that generates 60±20 kJ of x rays with a peak power of 13±4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122±6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155±8 eV—providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ˜40% with only a 3%-5% decrease in peak temperature, in agreement with measurements.

Hohlraum Target Alignment from X-ray Detector Images using Starburst Design Patterns

International Nuclear Information System (INIS)

Leach, R.R.; Conder, A.; Edwards, O.; Kroll, J.; Kozioziemski, B.; Mapoles, E.; McGuigan, D.; Wilhelmsen, K.

2010-01-01

National Ignition Facility (NIF) is a high-energy laser facility comprised of 192 laser beams focused with enough power and precision on a hydrogen-filled spherical, cryogenic target to initiate a fusion reaction. The target container, or hohlraum, must be accurately aligned to an x-ray imaging system to allow careful monitoring of the frozen fuel layer in the target. To achieve alignment, x-ray images are acquired through starburst-shaped windows cut into opposite sides of the hohlraum. When the hohlraum is in alignment, the starburst pattern pairs match nearly exactly and allow a clear view of the ice layer formation on the edge of the target capsule. During the alignment process, x-ray image analysis is applied to determine the direction and magnitude of adjustment required. X-ray detector and source are moved in concert during the alignment process. The automated pointing alignment system described here is both accurate and efficient. In this paper, we describe the control and associated image processing that enables automation of the starburst pointing alignment.

Multi-keV x-ray sources from metal-lined cylindrical hohlraums

Energy Technology Data Exchange (ETDEWEB)

Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph. [CEA, DAM, DIF, F-91297 Arpajon (France)

2012-08-15

As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are {approx}6%-8% for titanium, {approx}2% for copper, and {approx}0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

Multi-keV x-ray sources from metal-lined cylindrical hohlraums

International Nuclear Information System (INIS)

Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.

2012-01-01

As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ∼6%-8% for titanium, ∼2% for copper, and ∼0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

Multi-keV x-ray sources from metal-lined cylindrical hohlraums

Science.gov (United States)

Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.

2012-08-01

As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ˜6%-8% for titanium, ˜2% for copper, and ˜0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

Science.gov (United States)

Hall, G. N.; Jones, O. S.; Strozzi, D. J.; Moody, J. D.; Turnbull, D.; Ralph, J.; Michel, P. A.; Hohenberger, M.; Moore, A. S.; Landen, O. L.; Divol, L.; Bradley, D. K.; Hinkel, D. E.; Mackinnon, A. J.; Town, R. P. J.; Meezan, N. B.; Berzak Hopkins, L.; Izumi, N.

2017-05-01

Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Measurements characterized the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρgf between 0.03 mg/cc ("near vacuum") and 1.6 mg/cc. For hohlraums with ρgf up to 0.85 mg/cc, very little stimulated Raman backscatter (SRS) was observed. For higher ρgf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρgf ≥ 0.6 mg/cc once the laser reached peak power. However, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ˜10% higher than the gas filled hohlraums throughout the main pulse.

The physics of radiation driven ICF hohlraums

International Nuclear Information System (INIS)

Rosen, M.D.

1995-01-01

On the Nova Laser at LLNL, we have recently demonstrated many of the key elements required for assuring that the next proposed laser, the National Ignition Facility (NIF) will drive an Inertial Confinement Fusion (ICF) target to ignition. The target uses the recently declassified indirect drive (sometimes referred to as open-quotes radiation driveclose quotes) approach which converts laser light to x-rays inside a gold cylinder, which then acts as an x-ray open-quotes ovenclose quotes (called a hohlraum) to drive the fusion capsule in its center. On Nova we've demonstrated good understanding of the temperatures reached in hohlraums and of the ways to control the uniformity with which the x-rays drive the spherical fusion capsules. In this lecture we briefly review the fundamentals of ICF, and describe the capsule implosion symmetry advantages of the hohlraum approach. We then concentrate on a quantitative understanding of the scaling of radiation drive with hohlraum size and wall material, and with laser pulse length and power. We demonstrate that coupling efficiency of x-ray drive to the capsule increases as we proceed from Nova to the NIF and eventually to a reactor, thus increasing the gain of the system

Tetrahedral hohlraums at omega

International Nuclear Information System (INIS)

Kyrala, G.A.; Goldman, S.R.; Batha, S.H.; Wallace, J.M.; Klare, K.A.; Schappert, G.T.; Oertel, J.; Turner, R.E.

2000-01-01

We have initiated a study of the usefulness of tetrahedrally illuminated spherical hohlraums, using the Omega laser beams, to drive planar shocks in packages that require indirect drive. A first suite of experiments used spherical hohlraums with a 2-μm thick gold wall surrounded by a 100-μm thick epoxy layer and had an internal diameter of 2.8 mm. Four laser entrance holes each of diameter 700 μm, located on the tips of a regular tetrahedron were used. The shock velocities and the shock uniformities were measured using optical shock break out techniques. The hohlraum x-ray radiation spectrum was also measured using a 10-channel x-ray detector. Tentatively, peak temperatures approaching 195 eV were achieved and shock speeds of 60 μm/ns were measured, when the hohlraum was driven by 22 kJ of 3 ω radiation. (authors)

Development of soft x-ray tracer diagnostics for hohlraum experiments

International Nuclear Information System (INIS)

MacFarlane, J.J.; Cohen, D.H.; Wang, P.; Peterson, R.R.; Moses, G.A.

1998-04-01

The purpose of this report is to summarize work performed by the University of Wisconsin during fiscal year 1996 under the NLUF contract DE-FG-96SF21015. This contract involved the development of soft x-ray spectral diagnostics from tracer layers in hohlraum witness plates. This effort was originally intended to be focused on OMEGA experiments, but the experiments were changed to NOVA because initial indirect drive shots had not yet been performed on the OMEGA upgrade. Data were collected in a series of experiments between January 1997 and October 1997. Experiments were delayed somewhat due to bringing up the Hettrick spectrometer on the NOVA target chamber. The tasks related to the planning, carrying out, and modeling of the experiments are outlined in Table 1.1 and detailed in the remainder of this report

A comparative study of x-ray emission from laser spots in laser-heated hohlraums relative to spots on simple disk targets

International Nuclear Information System (INIS)

Ze, F.; Langer, S.H.; Kauffman, R.L.; Kilkenny, J.D.; Landen, O.; Ress, D.; Rosen, M.D.; Suter, L.J.; Wallace, R.J.; Wiedwald, J.D.

1997-01-01

In this paper we report the results of experiments that compare the x-ray emission from a laser spot in a radiation-filled hohlraum to that from a similar laser spot on a simple disk target. The studies were done using the Nova laser facility [J. D. Lindl, Phys. Plasmas 2, 3933 (1995)] in its 0.35 μm wavelength, 1 ns square pulse configuration. Focal spot intensities were 2 endash 3.5x10 15 W/cm 2 . X-ray images measured x-ray conversion in a hohlraum and from an isolated disk simultaneously. A laser spot inside a hohlraum emitted more x rays, after subtracting the background emission from the hohlraum walls, than a spot on a disk. Numerical models suggest the enhanced spot emission inside the hohlraum is due to an increase in lateral transport relative to the disk. Filamentation in the hohlraum will also increase the spot size. The models agree fairly well with the results on spot spreading but do not explain the overall increase in conversion efficiency. copyright 1997 American Institute of Physics

Development of a Z-pinch-driven ICF hohlraum concept on Z

International Nuclear Information System (INIS)

Cuneo, M.E.; Porter, J.L. Jr.; Vesey, R.A.

1999-01-01

Recent development of high power z-pinches (> 150 MW) on the Z driver has permitted the study of high-temperature, radiation-driven hohlraums. Three complementary, Z-pinch source-hohlraum-ICF capsule configurations are being developed to harness the x-ray output of these Z-pinch's. These are the dynamic-hohlraum, static-wall hohlraum, and Z-pinch-driven hohlraum concepts. Each has different potential strengths and concerns. In this paper, the authors report on the first experiments with the Z-pinch-driven hohlraum (ZPDH) concept. A high-yield ICF capsule design for this concept appears feasible, when driven by z-pinches from a 60 MA-class driver. Initial experiments characterize the behavior of the spoke array on Z-pinch performance and x-ray transmission, and the uniformity of radiation flux incident on a foam capsule in the secondary, for a single-sided drive. Measurements of x-ray wall re-emission power and spectrum, radiation temperatures, spoke-plasma location, and drive uniformity will be presented and compared with 0-D energetics, 2-D Lasnex rad-hydro, and 3-D radiosity calculations of energy transport and drive uniformity

Development of a Z-pinch-driven ICF hohlraum concept on Z

Energy Technology Data Exchange (ETDEWEB)

Cuneo, M E; Porter, Jr, J L; Vesey, R A [and others

1999-07-01

Recent development of high power z-pinches (> 150 MW) on the Z driver has permitted the study of high-temperature, radiation-driven hohlraums. Three complementary, Z-pinch source-hohlraum-ICF capsule configurations are being developed to harness the x-ray output of these Z-pinch's. These are the dynamic-hohlraum, static-wall hohlraum, and Z-pinch-driven hohlraum concepts. Each has different potential strengths and concerns. In this paper, the authors report on the first experiments with the Z-pinch-driven hohlraum (ZPDH) concept. A high-yield ICF capsule design for this concept appears feasible, when driven by z-pinches from a 60 MA-class driver. Initial experiments characterize the behavior of the spoke array on Z-pinch performance and x-ray transmission, and the uniformity of radiation flux incident on a foam capsule in the secondary, for a single-sided drive. Measurements of x-ray wall re-emission power and spectrum, radiation temperatures, spoke-plasma location, and drive uniformity will be presented and compared with 0-D energetics, 2-D Lasnex rad-hydro, and 3-D radiosity calculations of energy transport and drive uniformity.

Optimizing implosion yields using rugby-shaped hohlraums

Science.gov (United States)

Park, Hye-Sook; Robey, H.; Amendt, P.; Philippe, F.; Casner, A.; Caillaud, T.; Bourgade, J.-L.; Landoas, O.; Li, C. K.; Petrasso, R.; Seguin, F.; Rosenberg, M.; Glebov, V. Yu.

2009-11-01

We present the first experimental results on optimizing capsule implosion experiments by using rugby-shaped hohlraums [1] on the Omega laser, University of Rochester. This campaign compared D2-filled capsule performance between standard cylindrical Au hohlraums and rugby-shaped hohlraums for demonstrating the energetics advantages of the rugby geometry. Not only did the rugby-shaped hohlraums show nearly 20% more x-ray drive energy over the cylindrical hohlraums, but also the high-performance design of the capsules provided nearly 20 times more DD neutrons than in any previous Omega hohlraum campaigns, thereby enabling use of neutron temporal diagnostics. Comparison with simulations on neutron burn histories, x-ray core imaging, backscattered laser light and radiation temperature are presented. [1] P. Amendt et al., Phys. Plasmas 15, 012702 (2008)

X-ray drive of beryllium capsule implosions at the National Ignition Facility

International Nuclear Information System (INIS)

Wilson, D C; Yi, S A; Simakov, A N; Kline, J L; Kyrala, G A; Olson, R E; Zylstra, A B; Dewald, E L; Tommasini, R; Ralph, J E; Strozzi, D J; Celliers, P M; Schneider, M B; MacPhee, A G; Callahan, D A; Hurricane, O A; Milovich, J L; Hinkel, D E; Rygg, J R; Rinderknecht, H G

2016-01-01

National Ignition Facility experiments with beryllium capsules have followed a path begun with “high-foot” plastic capsule implosions. Three shock timing keyhole targets, one symmetry capsule, a streaked backlit capsule, and a 2D backlit capsule were fielded before the DT layered shot. After backscatter subtraction, laser drive degradation is needed to match observed X-ray drives. VISAR measurements determined drive degradation for the picket, trough, and second pulse. Time dependence of the total Dante flux reflects degradation of the of the third laser pulse. The same drive degradation that matches Dante data for three beryllium shots matches Dante and bangtimes for plastic shots N130501 and N130812. In the picket of both Be and CH hohlraums, calculations over-estimate the x-ray flux > 1.8 keV by ∼100X, while calculating the total flux correctly. In beryllium calculations these X-rays cause an early expansion of the beryllium/fuel interface at ∼3 km/s. VISAR measurements gave only ∼0.3 km/s. The X-ray drive on the Be DT capsule was further degraded by an unplanned decrease of 9% in the total picket flux. This small change caused the fuel adiabat to rise from 1.8 to 2.3. The first NIF beryllium DT implosion achieved 29% of calculated yield, compared to CH capsules with 68% and 21%. (paper)

Radiation drive in laser heated hohlraums

International Nuclear Information System (INIS)

Suter, L.J.; Kauffman, R.L.; Darrow, C.B.

1995-01-01

Nearly 10 years of Nova experiments and analysis have lead to a relatively detailed quantitative and qualitative understanding of radiation drive in laser heated hohlraums. Our most successful quantitative modelling tool is 2D Lasnex numerical simulations. Analysis of the simulations provides us with insight into the details of the hohlraum drive. In particular we find hohlraum radiation conversion efficiency becomes quite high with longer pulses as the accumulated, high Z blow-off plasma begins to radiate. Extensive Nova experiments corroborate our quantitative and qualitative understanding

Hollow wall to stabilize and enhance ignition hohlraums

Science.gov (United States)

Vandenboomgaerde, M.; Grisollet, A.; Bonnefille, M.; Clérouin, J.; Arnault, P.; Desbiens, N.; Videau, L.

2018-01-01

In the context of the indirect-drive scheme of the inertial-confinement fusion, performance of the gas-filled hohlraums at the National Ignition Facility appears to be reduced. Experiments ascertain a limited efficacy of the laser beam propagation and x-ray conversion. One identified issue is the growth of the gold plasma plume (or bubble) which is generated near the ends of the hohlraum by the impact of the laser beams. This bubble impedes the laser propagation towards the equator of the hohlraum. Furthermore, for high foot or low foot laser pulses, the gold-gas interface of the bubble can be unstable. If this instability should grow to mixing, the x-ray conversion could be degraded. A novel hollow-walled hohlraum is designed, which drastically reduces the growth of the gold bubble and stabilizes the gold-gas interface. The hollow walls are built from the combination of a thin gold foil and a gold domed-wall. We theoretically explain how the bubble expansion can be delayed and the gold-gas interface stabilized. This advanced design lets the laser beams reach the waist of the hohlraum. As a result, the x-ray drive on the capsule is enhanced, and more spherical implosions are obtained. Furthermore, this design only requires intermediate gas fill density to be efficient.

Progress of Rugby Hohlraum Experiments on Omega

Science.gov (United States)

Philippe, Franck; Tassin, Veronique; Casner, Alexis; Gauthier, Pascal; Seytor, Patricia; Monteil, Marie-Christine; Park, Hye-Sook; Robey, Harry; Ross, Steven; Amendt, Peter; Girard, Frederic; Villette, Bruno; Reverdin, Charles; Loiseau, Pascal; Caillaud, Tony; Landoas, Olivier; Li, Chi Kang; Petrasso, Richard; Seguin, Fredrick; Rosenberg, Markus

2011-10-01

The rugby hohlraum concept is predicted to enable better coupling and higher gains in the indirect drive approach to ignition. A collaborative experimental program is currently pursued on OMEGA to test this concept in preparation for future megajoule-scale ignition designs. A direct comparison of gas-filled rugby hohlraums with classical cylinders was recently performed, showing a significant (up to ~40%) observed x-ray drive enhancement and neutron yields that are consistently higher in the rugby case. This work extends and confirms our previous findings in empty rugby hohlraums.

Measuring symmetry of implosions in cryogenic Hohlraums at the NIF using gated x-ray detectors (invited).

Science.gov (United States)

Kyrala, G A; Dixit, S; Glenzer, S; Kalantar, D; Bradley, D; Izumi, N; Meezan, N; Landen, O L; Callahan, D; Weber, S V; Holder, J P; Glenn, S; Edwards, M J; Bell, P; Kimbrough, J; Koch, J; Prasad, R; Suter, L; Kline, J L; Kilkenny, J

2010-10-01

Ignition of imploding inertial confinement capsules requires, among other things, controlling the symmetry with high accuracy and fidelity. We have used gated x-ray imaging, with 10 μm and 70 ps resolution, to detect the x-ray emission from the imploded core of symmetry capsules at the National Ignition Facility. The measurements are used to characterize the time dependent symmetry and the x-ray bang time of the implosion from two orthogonal directions. These measurements were one of the primary diagnostics used to tune the parameters of the laser and Hohlraum to vary the symmetry and x-ray bang time of the implosion of cryogenically cooled ignition scale deuterium/helium filled plastic capsules. Here, we will report on the successful measurements performed with up to 1.2 MJ of laser energy in a fully integrated cryogenics gas-filled ignition-scale Hohlraum and capsule illuminated with 192 smoothed laser beams. We will describe the technique, the accuracy of the technique, and the results of the variation in symmetry with tuning parameters, and explain how that set was used to predictably tune the implosion symmetry as the laser energy, the laser cone wavelength separation, and the Hohlraum size were increased to ignition scales. We will also describe how to apply that technique to cryogenically layered tritium-hydrogen-deuterium capsules.

0-d energetics scaling models for Z-pinch-driven hohlraums

International Nuclear Information System (INIS)

CUNEO, MICHAEL E.; VESEY, ROGER A.; HAMMER, J.H.; PORTER, JOHN L.

2000-01-01

Wire array Z-pinches on the Z accelerator provide the most intense laboratory source of soft x-rays in the world. The unique combination of a highly-Planckian radiation source with high x-ray production efficiency (15% wall plug), large x-ray powers and energies ( >150 TW, ge1 MJ in 7 ns), large characteristic hohlraum volumes (0.5 to >10 cm 3 ), and long pulse-lengths (5 to 20 ns) may make Z-pinches a good match to the requirements for driving high-yield scale ICF capsules with adequate radiation symmetry and margin. The Z-pinch driven hohlraum approach of Hammer and Porter [Phys.Plasmas, 6, 2129(1999)] may provide a conservative and robust solution to the requirements for high yield, and is currently being studied on the Z accelerator. This paper describes a multiple region, 0-d hohlraum energetic model for Z-pinch driven hohlraums in four configurations. The authors observe consistency between the models and the measured x-ray powers and hohlraum wall temperatures to within ±20% in flux, for the four configurations

Laser plasma interaction on rugby hohlraum on the Omega Laser Facility: Comparisons between cylinder, rugby, and elliptical hohlraums

Science.gov (United States)

Masson-Laborde, P. E.; Monteil, M. C.; Tassin, V.; Philippe, F.; Gauthier, P.; Casner, A.; Depierreux, S.; Neuville, C.; Villette, B.; Laffite, S.; Seytor, P.; Fremerye, P.; Seka, W.; Teychenné, D.; Debayle, A.; Marion, D.; Loiseau, P.; Casanova, M.

2016-02-01

Gas-filled rugby-shaped hohlraums have demonstrated high performances compared to a classical similar diameter cylinder hohlraum with a nearly 40% increase of x-ray drive, 10% higher measured peak drive temperature, and an increase in neutron production. Experimental comparisons have been done between rugby, cylinder, and elliptical hohlraums. The impact of these geometry differences on the laser plasma instabilities is examined. Using comparisons with hydrodynamic simulations carried out with the code FCI2 and postprocessed by Piranah, we have been able to reproduce the stimulated Raman and Brillouin scattering spectrum of the different beams. Using a methodology based on a statistical analysis for the gain calculations, we show that the behavior of the laser plasma instabilities in rugby hohlraums can be reproduced. The efficiency of laser smoothing techniques to mitigate these instabilities are discussed, and we show that while rugby hohlraums exhibit more laser plasma instabilities than cylinder hohlraum, the latter can be mitigated in the case of an elliptical hohlraum.

Characterizing high energy spectra of NIF ignition Hohlraums using a differentially filtered high energy multipinhole x-ray imager.

Science.gov (United States)

Park, Hye-Sook; Dewald, E D; Glenzer, S; Kalantar, D H; Kilkenny, J D; MacGowan, B J; Maddox, B R; Milovich, J L; Prasad, R R; Remington, B A; Robey, H F; Thomas, C A

2010-10-01

Understanding hot electron distributions generated inside Hohlraums is important to the national ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with target materials. We used an array of 18 pinholes with four independent filter combinations to image entire Hohlraums with a magnification of 0.87× during the Hohlraum energetics campaign on NIF. Comparing our results with Hohlraum simulations indicates that the characteristic 10-40 keV hot electrons are mainly generated from backscattered laser-plasma interactions rather than from Hohlraum hydrodynamics.

X-ray emission from National Ignition Facility indirect drive targets

International Nuclear Information System (INIS)

Anderson, A.T.; Managan, R.A.; Tobin, M.T.; Peterson, P.F.

1996-01-01

We have performed a series of 1-D numerical simulations of the x-ray emission from National Ignition Facility (NIF) targets. Results are presented in terms of total x-ray energy, pulse length, and spectrum. Scaling of x-ray emissions is presented for variations in both target yield and hohlraum thickness. Experiments conducted on the Nova facility provide some validation of the computational tools and methods

Radiation-driven hydrodynamics of long pulse hohlraums on the National Ignition Facility

International Nuclear Information System (INIS)

Dewald, D L; Landen, O L; Suter, L J; Schein, J; Holder, J.; Campbell, K.; Glenzer, S H.; McDonald, J W.; Niemann, C.; Mackinnon, A J.; Schneider, M S.; Haynam, C.; Hinkel, D.; Hammel, B.A.

2005-01-01

The first hohlraum experiments on the National Ignition Facility (NIF) using the first four laser beams have activated the indirect drive experimental capabilities and tested radiation temperature limits imposed by hohlraum plasma filling. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1 ns to 9 ns long square pulses and energies of up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Furthermore, for a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of plasma filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with analytical modeling that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits on full NIF (1.8 MJ) that are significantly greater than required for ignition hohlraums

X-ray flux and X-ray burn through experiments on reduced-scale targets at the Nif and OMEGA lasers

International Nuclear Information System (INIS)

Schneider, M.B.; Hinkel, D.E.; Young, B.K.; Holder, J.P.; Langdon, A.B.; Bower, D.E.; Bruns, H.C.; Campbell, K.M.; Celeste, J.R.; Compton, S.; Costa, R.L.; Dewald, E.L.; Dixit, S.N.; Eckart, M.J.; Eder, D.C.; Edwards, M.J.; Ellis, A.D.; Emig, J.A.; Froula, D.H.; Glebov, V.; Glenzer, S.H.; Hargrove, D.; Haynam, C.A.; Heeter, R.F.; Henesian, M.A.; Holtmeier, G.; James, D.L.; Jancaitis, K.S.; Kalantar, D.H.; Kamperschroer, J.H.; Kauffman, R.L.; Kimbrough, J.; Kirkwood, R.; Koniges, A.E.; Landen, O.L.; Landon, M.; Lee, F.D.; MacGowan, B.J.; Mackinnon, A.J.; Manes, K.R.; Marshall, C.; May, M.J.; McDonald, J.W.; Menapace, J.; Moon, S.J.; Moses, E.I.; Munro, D.H.; Murray, J.R.; Niemann, C.; Piston, K.; Power, G.D.; Rekow, V.; Ruppe, J.A.; Schein, J.; Shepherd, R.; Singh, M.S.; Sorce, C.; Springer, P.T.; Still, C.H.; Suter, L.J.; Tietbohl, G.L.; Turner, R.E.; Van Wonterghem, B.M.; Wallace, R.J.; Warrick, A.; Weber, F.; Wegner, P.J.; Williams, E.A.; Young, P.E.; Baldis, H.A.; Constantin, C.G.; Bahr, R.; Roberts, S.; Seka, W.; Stoeckl, C.; Pellinen, D.; Watts, P.

2006-01-01

An experimental campaign to maximize radiation drive in small-scale hohlraums has been carried out at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (Livermore, USA) and at the OMEGA laser at the Laboratory for Laser Energetics (Rochester, USA). The small-scale hohlraums, laser energy, laser pulse, and diagnostics were similar at both facilities but the geometries were very different. The NIF experiments used on-axis laser beams whereas the OMEGA experiments used 19 beams in three beam cones. In the cases when the lasers coupled well and produced similar radiation drive, images of X-ray burn-through and laser deposition indicate the pattern of plasma filling is very different. The OMEGA targets fill faster than the NIF targets, which helps explain the time behavior of the X-ray fluences. (authors)

X-ray flux and X-ray burn through experiments on reduced-scale targets at the Nif and OMEGA lasers

Energy Technology Data Exchange (ETDEWEB)

Schneider, M.B.; Hinkel, D.E.; Young, B.K.; Holder, J.P.; Langdon, A.B.; Bower, D.E.; Bruns, H.C.; Campbell, K.M.; Celeste, J.R.; Compton, S.; Costa, R.L.; Dewald, E.L.; Dixit, S.N.; Eckart, M.J.; Eder, D.C.; Edwards, M.J.; Ellis, A.D.; Emig, J.A.; Froula, D.H.; Glebov, V.; Glenzer, S.H.; Hargrove, D.; Haynam, C.A.; Heeter, R.F.; Henesian, M.A.; Holtmeier, G.; James, D.L.; Jancaitis, K.S.; Kalantar, D.H.; Kamperschroer, J.H.; Kauffman, R.L.; Kimbrough, J.; Kirkwood, R.; Koniges, A.E.; Landen, O.L.; Landon, M.; Lee, F.D.; MacGowan, B.J.; Mackinnon, A.J.; Manes, K.R.; Marshall, C.; May, M.J.; McDonald, J.W.; Menapace, J.; Moon, S.J.; Moses, E.I.; Munro, D.H.; Murray, J.R.; Niemann, C.; Piston, K.; Power, G.D.; Rekow, V.; Ruppe, J.A.; Schein, J.; Shepherd, R.; Singh, M.S.; Sorce, C.; Springer, P.T.; Still, C.H.; Suter, L.J.; Tietbohl, G.L.; Turner, R.E.; Van Wonterghem, B.M.; Wallace, R.J.; Warrick, A.; Weber, F.; Wegner, P.J.; Williams, E.A.; Young, P.E. [Lawrence Livermore National Lab., Livermore, CA (United States); Baldis, H.A.; Constantin, C.G. [California at Davis Univ., CA (United States); Bahr, R.; Roberts, S.; Seka, W.; Stoeckl, C. [Laboratory for Laser Energetics, Rochester, NY (United States); Pellinen, D.; Watts, P. [Bechtel Nevada Corporation, Livermore, CA (United States)

2006-06-15

An experimental campaign to maximize radiation drive in small-scale hohlraums has been carried out at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (Livermore, USA) and at the OMEGA laser at the Laboratory for Laser Energetics (Rochester, USA). The small-scale hohlraums, laser energy, laser pulse, and diagnostics were similar at both facilities but the geometries were very different. The NIF experiments used on-axis laser beams whereas the OMEGA experiments used 19 beams in three beam cones. In the cases when the lasers coupled well and produced similar radiation drive, images of X-ray burn-through and laser deposition indicate the pattern of plasma filling is very different. The OMEGA targets fill faster than the NIF targets, which helps explain the time behavior of the X-ray fluences. (authors)

Laser plasma interactions in hohlraums

Energy Technology Data Exchange (ETDEWEB)

Kruer, W.L.

1994-10-05

Lasers plasma instabilities are an important constraint in x-ray driven inertial confinement fusion. In hohlraums irradiated with 1.06 {mu}m light on the Shiva laser, plasma instabilities were extremely deleterious, driving the program to the use of shorter wavelength light. Excellent coupling has been achieved in hohlraums driven with 0.35 {mu}m light on the Nova laser. Considerable attention is being given to the scaling of this excellent coupling to the larger hohlraums for an ignition target. Various instability control mechanisms such as large plasma wave damping and laser beam incoherence are discussed, as well as scaling experiments to check the instability levels.

High Performance Capsule Implosions on the Omega Laser Facility with Rugby Hohlraums

Science.gov (United States)

Robey, Harry F.

2009-11-01

Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly-driven capsule implosions [1]. This concept has recently been tested in a series of shots on the OMEGA laser facility at the Laboratory for Laser Energetics at the University of Rochester. In this talk, experimental results are presented comparing the performance of D2-filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. Not only did the rugby hohlraums demonstrate 18% more x-ray drive energy as compared with the cylinders, but the high-performance design of these implosions (both cylinder and rugby) also provided 20X more DD neutrons than any previous indirectly-driven campaign on Omega (and 3X more than ever achieved on Nova implosions driven with nearly twice the laser energy). This increase in performance enables, for the first time, a measurement of the neutron burn history of an indirectly-driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D^3He rather than D2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in excellent agreement. The design techniques employed in this campaign, e.g., smaller NIF-like laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility. [4pt] [1] P. Amendt, C. Cerjan, D. E. Hinkel, J. L. Milovich, H.-S. Park, and H. F. Robey, ``Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement'', Phys. Plasmas 15, 012702 (2008).

Mode-selective symmetry control for indirect-drive inertial confinement fusion hohlraums

International Nuclear Information System (INIS)

Vesey, R. A.; Slutz, S. A.; Herrmann, M. C.; Mehlhorn, T. A.; Campbell, R. B.

2008-01-01

Achieving a high degree of radiation symmetry is a critical feature of target designs for indirect-drive inertial confinement fusion. Typically, the radiation flux incident on the capsule is required to be uniform to 1% or better. It is generally possible to design a hohlraum that provides low values of higher-order asymmetry (Legendre mode P 10 and above) due to geometric averaging effects. Because low-order intrinsic asymmetry (e.g., Legendre modes P 2 and P 4 ) are less strongly reduced by geometric averaging alone, the development of innovative control techniques has been an active area of research in the inertial fusion community over the years. Shields placed inside the hohlraum are one example of a technique that has often been proposed and incorporated into hohlraum target designs. Simple mathematical considerations are presented indicating that radiation shields may be designed to specifically tune lower-order modes (e.g., P 4 ) without deleterious effects on the higher order modes. Two-dimensional view factor and radiation-hydrodynamics simulations confirm these results and support such a path to achieving a highly symmetric x-ray flux. The term ''mode-selective'' is used because these shields, essentially ring structures offset from the capsule, are designed to affect only a specific Legendre mode (or multiple modes) of interest

First Octahedral Spherical Hohlraum Energetics Experiment at the SGIII Laser Facility

Science.gov (United States)

Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xufei; Ren, Guoli; Cao, Hui; Li, Shu; Lan, Ke; Liu, Jie; Li, Yongsheng; Li, Sanwei; Guo, Liang; Liu, Yonggang; Yang, Dong; Jiang, Xiaohua; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Wang, Zhebin; Deng, Keli; Wang, Qiangqiang; Deng, Bo; Wang, Feng; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Gu, Qianqian; He, Zhibing; Du, Kai; Deng, Xuewei; Zhou, Wei; Wang, Liquan; Huang, Xiaoxia; Wang, Yuancheng; Hu, Dongxia; Zheng, Kuixing; Zhu, Qihua; Ding, Yongkun

2018-04-01

The first octahedral spherical hohlraum energetics experiment is accomplished at the SGIII laser facility. For the first time, the 32 laser beams are injected into the octahedral spherical hohlraum through six laser entrance holes. Two techniques are used to diagnose the radiation field of the octahedral spherical hohlraum in order to obtain comprehensive experimental data. The radiation flux streaming out of laser entrance holes is measured by six flat-response x-ray detectors (FXRDs) and four M -band x-ray detectors, which are placed at different locations of the SGIII target chamber. The radiation temperature is derived from the measured flux of FXRD by using the blackbody assumption. The peak radiation temperature inside hohlraum is determined by the shock wave technique. The experimental results show that the octahedral spherical hohlraum radiation temperature is in the range of 170-182 eV with drive laser energies of 71 kJ to 84 kJ. The radiation temperature inside the hohlraum determined by the shock wave technique is about 175 eV at 71 kJ. For the flat-top laser pulse of 3 ns, the conversion efficiency of gas-filled octahedral spherical hohlraum from laser into soft x rays is about 80% according to the two-dimensional numerical simulation.

The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Schneider, M. B., E-mail: schneider5@llnl.gov; MacLaren, S. A.; Widmann, K.; Meezan, N. B.; Hammer, J. H.; Yoxall, B. E.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Dewald, E. L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Hinkel, D. E.; Hsing, W. W.; Kervin, M. L.; Landen, O. L.; Lindl, J. D.; May, M. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

2015-12-15

At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer.

Target design for high fusion yield with the double Z-pinch-driven hohlraum

International Nuclear Information System (INIS)

Vesey, R. A.; Herrmann, M. C.; Lemke, R. W.; Desjarlais, M. P.; Cuneo, M. E.; Stygar, W. A.; Bennett, G. R.; Campbell, R. B.; Christenson, P. J.; Mehlhorn, T. A.; Porter, J. L.; Slutz, S. A.

2007-01-01

A key demonstration on the path to inertial fusion energy is the achievement of high fusion yield (hundreds of MJ) and high target gain. Toward this goal, an indirect-drive high-yield inertial confinement fusion (ICF) target involving two Z-pinch x-ray sources heating a central secondary hohlraum is described by Hammer et al. [Phys. Plasmas 6, 2129 (1999)]. In subsequent research at Sandia National Laboratories, theoretical/computational models have been developed and an extensive series of validation experiments have been performed to study hohlraum energetics, capsule coupling, and capsule implosion symmetry for this system. These models have been used to design a high-yield Z-pinch-driven ICF target that incorporates the latest experience in capsule design, hohlraum symmetry control, and x-ray production by Z pinches. An x-ray energy output of 9 MJ per pinch, suitably pulse-shaped, is sufficient for this concept to drive 0.3-0.5 GJ capsules. For the first time, integrated two-dimensional (2D) hohlraum/capsule radiation-hydrodynamics simulations have demonstrated adequate hohlraum coupling, time-dependent radiation symmetry control, and the successful implosion, ignition, and burn of a high-yield capsule in the double Z-pinch hohlraum. An important new feature of this target design is mode-selective symmetry control: the use of burn-through shields offset from the capsule that selectively tune certain low-order asymmetry modes (P 2 ,P 4 ) without significantly perturbing higher-order modes and without a significant energy penalty. This paper will describe the capsule and hohlraum design that have produced 0.4-0.5 GJ yields in 2D simulations, provide a preliminary estimate of the Z-pinch load and accelerator requirements necessary to drive the system, and suggest future directions for target design work

Gas-filled hohlraum experiments at the National Ignition Facility

International Nuclear Information System (INIS)

Fernandez, Juan C.; Goldman, S.R.; Kline, J.L.; Dodd, E.S.; Gautier, C.; Grim, G.P.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.; Schmidt, D.W.; Workman, J.B.; Braun, D.G.; Dewald, E.L.; Landen, O.L.; Campbell, K.M.; Holder, J.P.; MacKinnon, A.J.; Niemann, C.; Schein, J.

2006-01-01

Experiments done at the National Ignition Facility laser [J. A. Paisner, E. M. Campbell, and W. Hogan, Fusion Technol. 26, 755 (1994)] using gas-filled hohlraums demonstrate a key ignition design feature, i.e., using plasma pressure from a gas fill to tamp the hohlraum-wall expansion for the duration of the laser pulse. Moreover, our understanding of hohlraum energetics and the ability to predict the hohlraum soft-x-ray drive has been validated in ignition-relevant conditions. Finally, the laser reflectivity from stimulated Raman scattering in the fill plasma, a key threat to hohlraum performance, is shown to be suppressed by choosing a design with a sufficiently high ratio of electron temperature to density

Indirect drive ablative Rayleigh-Taylor experiments with rugby hohlraums on OMEGA

International Nuclear Information System (INIS)

Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.-P.; Liberatore, S.; Vandenboomgaerde, M.

2009-01-01

Results of ablative Rayleigh-Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MegaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on-foil flux that is about 50% smaller than laser-entrance-hole measurements. The experimentally inferred flux is used to simulate experimental optical depths obtained from face-on radiographies for an extensive set of initial conditions: front-side single-mode (wavelength λ=35, 50, and 70 μm) and two-mode perturbations (wavelength λ=35 and 70 μm, in phase or in opposite phase). Three-dimensional pattern growth is also compared with the 2D case. Finally the case of the feedthrough mechanism is addressed with rear-side modulated foils.

Indirect drive ablative Rayleigh-Taylor experiments with rugby hohlraums on OMEGA

Science.gov (United States)

Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.-P.; Liberatore, S.; Vandenboomgaerde, M.

2009-09-01

Results of ablative Rayleigh-Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MégaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on-foil flux that is about 50% smaller than laser-entrance-hole measurements. The experimentally inferred flux is used to simulate experimental optical depths obtained from face-on radiographies for an extensive set of initial conditions: front-side single-mode (wavelength λ =35, 50, and 70 μm) and two-mode perturbations (wavelength λ =35 and 70 μm, in phase or in opposite phase). Three-dimensional pattern growth is also compared with the 2D case. Finally the case of the feedthrough mechanism is addressed with rear-side modulated foils.

Characterization of diagnostic hole-closure in Z-pinch driven hohlraums

International Nuclear Information System (INIS)

Baker, K. L.; Porter, J. L.; Ruggles, L. E.; Chandler, G. A.; Deeney, Chris; Vargas, M.; Moats, Ann; Struve, Ken; Torres, J.; McGurn, J. S.

2000-01-01

In this article we investigate the partial closure of diagnostic holes in Z-pinch driven hohlraums. These hohlraums differ from current laser-driven hohlraums in a number of ways such as their larger size, greater x-ray drive energy, and lower temperature. Although the diameter of the diagnostic holes on these Z-pinch driven hohlraums can be much greater than their laser-driven counterparts, 4 mm in diameter or larger, radiation impinges on the wall material surrounding the hole for the duration of the Z pinch, nearly 100 ns. This incident radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and partially obscure this diagnostic hole. This partial obscuration reduces the effective area over which diagnostics view the hohlraum's radiation. This reduction in area can lead to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. In this article we describe the techniques used to characterize the hole-closure in these hohlraums and present the experimental measurements of this process. (c) 2000 American Institute of Physics

Characterization of diagnostic hole-closure in Z-pinch driven hohlraums

Energy Technology Data Exchange (ETDEWEB)

Baker, K. L. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Porter, J. L. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Ruggles, L. E. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Chandler, G. A. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Deeney, Chris [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Vargas, M. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Moats, Ann [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Struve, Ken [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Torres, J. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); McGurn, J. S. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States)] (and others)

2000-02-01

In this article we investigate the partial closure of diagnostic holes in Z-pinch driven hohlraums. These hohlraums differ from current laser-driven hohlraums in a number of ways such as their larger size, greater x-ray drive energy, and lower temperature. Although the diameter of the diagnostic holes on these Z-pinch driven hohlraums can be much greater than their laser-driven counterparts, 4 mm in diameter or larger, radiation impinges on the wall material surrounding the hole for the duration of the Z pinch, nearly 100 ns. This incident radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and partially obscure this diagnostic hole. This partial obscuration reduces the effective area over which diagnostics view the hohlraum's radiation. This reduction in area can lead to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. In this article we describe the techniques used to characterize the hole-closure in these hohlraums and present the experimental measurements of this process. (c) 2000 American Institute of Physics.

Increasing Z-pinch vacuum hohlraum capsule coupling efficiency

International Nuclear Information System (INIS)

Callahan, Debbie; Vesey, Roger Alan; Cochrane, Kyle Robert; Nikroo, A.; Bennett, Guy R.; Schroen, Diana Grace; Ruggles, Laurence E.; Porter, John L.; Streit, Jon; Mehlhorn, Thomas Alan; Cuneo, Michael Edward

2004-01-01

Symmetric capsule implosions in the double-ended vacuum hohlraum (DEH) on Z have demonstrated convergence ratios of 14-21 for 2.15-mm plastic ablator capsules absorbing 5-7 kJ of x-rays, based on backlit images of the compressed ablator remaining at peak convergence (1). Experiments with DD-filled 3.3-mm diameter capsules designed to absorb 14 kJ of x-rays have begun as an integrated test of drive temperature and symmetry, complementary to thin-shell symmetry diagnostic capsules. These capsule implosions are characterized by excellent control of symmetry (< 3% time-integrated), but low hohlraum efficiency (< 2%). Possible methods to increase the capsule absorbed energy in the DEH include mixed-component hohlraums, large diameter foam ablator capsules, transmissive shine shields between the z-pinch and capsule, higher spoke electrode x-ray transmission, a double-sided power feed, and smaller initial radius z-pinch wire arrays. Simulations will explore the potential for each of these modifications to increase the capsule coupling efficiency for near-term experiments on Z and ZR

Images of the laser entrance hole from the static x-ray imager at NIF.

Science.gov (United States)

Schneider, M B; Jones, O S; Meezan, N B; Milovich, J L; Town, R P; Alvarez, S S; Beeler, R G; Bradley, D K; Celeste, J R; Dixit, S N; Edwards, M J; Haugh, M J; Kalantar, D H; Kline, J L; Kyrala, G A; Landen, O L; MacGowan, B J; Michel, P; Moody, J D; Oberhelman, S K; Piston, K W; Pivovaroff, M J; Suter, L J; Teruya, A T; Thomas, C A; Vernon, S P; Warrick, A L; Widmann, K; Wood, R D; Young, B K

2010-10-01

The static x-ray imager at the National Ignition Facility is a pinhole camera using a CCD detector to obtain images of Hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters, combined with the CCD response, allow recording images in the x-ray range of 3-5 keV with 60 μm spatial resolution. The routines used to obtain the apparent size of the backlit LEH and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition Hohlraum) is discussed.

eHXI: a permanently installed, hard x-ray imager for the National Ignition Facility

International Nuclear Information System (INIS)

Döppner, T.; Bachmann, B.; Albert, F.; Bell, P.; Burns, S.; Celeste, J.; Chow, R.; Divol, L.; Dewald, E.L.; Huntington, C.M.; Izumi, N.; LaCaille, G.; Landen, O.L.; Palmer, N.; Park, H.-S.; Thomas, C.A.; Hohenberger, M.

2016-01-01

We have designed and built a multi-pinhole imaging system for high energy x-rays (≥ 50 keV) that is permanently installed in the equatorial plane outside of the target chamber at the National Ignition Facility (NIF). It records absolutely-calibrated, time-integrated x-ray images with the same line-of-sight as the multi-channel, spatially integrating hard x-ray detector FFLEX [McDonald et al., Rev. Sci. Instrum. 75 (2004) 3753], having a side view of indirect-drive inertial confinement fusion (ICF) implosion targets. The equatorial hard x-ray imager (eHXI) has recorded images on the majority of ICF implosion experiments since May 2011. eHXI provides valuable information on hot electron distribution in hohlraum experiments, target alignment, potential hohlraum drive asymmetries and serves as a long term reference for the FFLEX diagnostics.

Gas-filled Rugby hohlraum energetics and implosions experiments on OMEGA

Science.gov (United States)

Casner, Alexis; Philippe, F.; Tassin, V.; Seytor, P.; Monteil, M. C.; Villette, B.; Reverdin, C.

2010-11-01

Recent experiments [1,2] have validated the x-ray drive enhancement provided by rugby-shaped hohlraums over cylinders in the indirect drive (ID) approach to inertial confinement fusion (ICF). This class of hohlraum is the baseline design for the Laser Mégajoule program, is also applicable to the National Ignition Facility and could therefore benefit ID Inertial Fusion Energy studies. We have carried out a serie of energetics and implosions experiments with OMEGA ``scale 1'' rugby hohlraums [1,2]. For empty hohlraums these experiments provide complementary measurements of backscattered light along 42 cone, as well as detailed drive history. In the case of gas-filled rugby hohlraums we have also study implosion performance (symmetry, yield, bangtime, hotspot spectra...) using a high contrast shaped pulse leading to a different implosion regime and for a range of capsule convergence ratios. These results will be compared with FCI2 hydrocodes calculations and future experimental campaigns will be suggested. [4pt] [1] F. Philippe et al., Phys. Rev. Lett. 104, 035004 (2010). [0pt] [2] H. Robey et al., Phys. Plasnas 17, 056313 (2010).

X-ray geometrical smoothing effect in indirect x-ray-drive implosion

International Nuclear Information System (INIS)

Mochizuki, Takayasu; Sakabe, Shuji; Yamanaka, Chiyoe

1983-01-01

X-ray geometrical smoothing effect in indirect X-ray drive pellet implosion for inertial confinement fusion has been numerically analyzed. Attainable X-ray driven ablation pressure has been found to be coupled with X-ray irradiation uniformity. (author)

Lithium ion beam driven hohlraums for PBFA II

International Nuclear Information System (INIS)

Dukart, R.J.

1994-01-01

In our light ion inertial confinement fusion (ICF) program, fusion capsules are driven with an intense x-ray radiation field produced when an intense beam of ions penetrates a radiation case and deposits energy in a foam x-ray conversion region. A first step in the program is to generate and measure these intense fields on the Particle Beam Fusion Accelerator II (PBFA II). Our goal is to generate a 100-eV radiation temperature in lithium ion beam driven hohlraums, the radiation environment which will provide the initial drive temperature for ion beam driven implosion systems designed to achieve high gain. In this paper, we describe the design of such hohlraum targets and their predicted performance on PBFA II as we provide increasing ion beam intensities

Implosion spectroscopy in Rugby hohlraums on OMEGA

Science.gov (United States)

Philippe, Franck; Tassin, Veronique; Bitaud, Laurent; Seytor, Patricia; Reverdin, Charles

2014-10-01

The rugby hohlraum concept has been validated in previous experiments on the OMEGA laser facility. This new hohlraum type can now be used as a well-characterized experimental platform to study indirect drive implosion, at higher radiation temperatures than would be feasible at this scale with classical cylindrical hohlraums. Recent experiments have focused on the late stages of implosion and hotspot behavior. The capsules included both a thin buried Titanium tracer layer, 0-3 microns from the inner surface, Argon dopant in the deuterium gas fuel and Germanium doped CH shells, providing a variety of spectral signatures of the plasma conditions in different parts of the target. X-ray spectroscopy and imaging were used to study compression, Rayleigh-Taylor instabilities growth at the inner surface and mix between the shell and gas.

Hohlraum drive and implosion experiments on Nova. Revision 1

International Nuclear Information System (INIS)

Kilkenny, J.D.; Suter, L.J.; Cable, M.D.

1994-01-01

Experiments on Nova have demonstrated hohlraum radiation temperatures up to 300 eV and in lower temperature experiments reproducible time integrated symmetry to 1--2%. Detailed 2-D LASNEX simulations satisfactorily reproduce Nova's drive and symmetry scaling data bases. Hohlraums has been used for implosion experiments achieving convergence ratios (initial capsule radius/final fuel radius) up to 24 with high density glass surrounding a hot gas fill

Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR

International Nuclear Information System (INIS)

Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

2007-01-01

We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays

High performance capsule implosions on the OMEGA Laser facility with rugby hohlraums

International Nuclear Information System (INIS)

Robey, H. F.; Amendt, P.; Park, H.-S.; Town, R. P. J.; Milovich, J. L.; Doeppner, T.; Hinkel, D. E.; Wallace, R.; Sorce, C.; Strozzi, D. J.; Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Liberatore, S.; Monteil, M.-C.; Seguin, F.; Rosenberg, M.; Li, C. K.; Petrasso, R.

2010-01-01

Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly driven capsule implosions. This concept has recently been tested in a series of shots on the OMEGA laser facility [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)]. In this paper, experimental results are presented comparing the performance of D 2 -filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. The rugby hohlraums demonstrated 18% more x-ray drive energy as compared with the cylinders, and the high-performance design of these implosions (both cylinder and rugby) also provided ≅20x more deuterium (DD) neutrons than any previous indirectly driven campaign on OMEGA and ≅3x more than ever achieved on NOVA [E. M. Campbell, Laser Part. Beams 9, 209 (1991)] implosions driven with nearly twice the laser energy. This increase in performance enables, for the first time, a measurement of the neutron burn history and imaging of the neutron core shapes in an indirectly driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D 3 He rather than D 2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in very good agreement. The design techniques employed in this campaign, e.g., smaller laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility [J. D. Lindl, P. Amendt, R. L. Berger et al., Phys. Plasmas 11, 339 (2004)].

Progress in hohlraum physics for the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Moody, J. D., E-mail: moody4@llnl.gov; Callahan, D. A.; Hinkel, D. E.; Amendt, P. A.; Baker, K. L.; Bradley, D.; Celliers, P. M.; Dewald, E. L.; Divol, L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Jones, O.; Haan, S. W.; Ho, D.; Hopkins, L. B.; Izumi, N.; Kalantar, D.; Kauffman, R. L.; Kilkenny, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); and others

2014-05-15

Advances in hohlraums for inertial confinement fusion at the National Ignition Facility (NIF) were made this past year in hohlraum efficiency, dynamic shape control, and hot electron and x-ray preheat control. Recent experiments are exploring hohlraum behavior over a large landscape of parameters by changing the hohlraum shape, gas-fill, and laser pulse. Radiation hydrodynamic modeling, which uses measured backscatter, shows that gas-filled hohlraums utilize between 60% and 75% of the laser power to match the measured bang-time, whereas near-vacuum hohlraums utilize 98%. Experiments seem to be pointing to deficiencies in the hohlraum (instead of capsule) modeling to explain most of the inefficiency in gas-filled targets. Experiments have begun quantifying the Cross Beam Energy Transfer (CBET) rate at several points in time for hohlraum experiments that utilize CBET for implosion symmetry. These measurements will allow better control of the dynamic implosion symmetry for these targets. New techniques are being developed to measure the hot electron energy and energy spectra generated at both early and late time. Rugby hohlraums offer a target which requires little to no CBET and may be less vulnerable to undesirable dynamic symmetry “swings.” A method for detecting the effect of the energetic electrons on the fuel offers a direct measure of the hot electron effects as well as a means to test energetic electron mitigation methods. At higher hohlraum radiation temperatures (including near vacuum hohlraums), the increased hard x-rays (1.8–4 keV) may pose an x-ray preheat problem. Future experiments will explore controlling these x-rays with advanced wall materials.

Symmetry control using beam phasing in ∼0.2 NIF scale high temperature Hohlraum experiment on OMEGA

International Nuclear Information System (INIS)

Delamater, Norman D.; Wilson, Goug C.; Kyrala, George A.; Seifter, Achim; Hoffman, N.M.; Dodd, E.; Glebov, V.

2009-01-01

Results are shown from recent experiments at the Omega laser facility, using 40 Omega beams driving the hohlraum with 3 cones from each side and up to 19.5 kJ of laser energy. Beam phasing is achieved by decreasing the energy separately in each of the three cones, by 3 kJ, for a total drive energy of 16.5kJ. This results in a more asymmetric drive, which will vary the shape of the imploded symmetry capsule core from round to oblate or prolate in a systematic and controlled manner. These results would be the first demonstration of beam phasing for implosions in such 'high temperature' (275 eV) hohlraums at Omega. Dante measurements confirmed the predicted peak drive temperatures of 275 eV. Implosion core time dependent x-ray images were obtained from framing camera data which show the expected change in symmetry due to beam phasing and which also agree well with post processed hydro code calculations. Time resolved hard x-ray data has been obtained and it was found that the hard x-rays are correlated mainly with the low angle 21 o degree cone.

Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

Energy Technology Data Exchange (ETDEWEB)

Philippe, F.; Villette, B. [CEA, DAM, DIF, F-91297 Arpajon (France); Michel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Giraldez, E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; and others

2014-07-15

A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

Science.gov (United States)

Philippe, F.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Villette, B.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; Michel, P.; Frenje, J.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Glebov, V.; Sorce, C.; Stoeckl, C.; Nikroo, A.; Giraldez, E.

2014-07-01

A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

International Nuclear Information System (INIS)

Philippe, F.; Villette, B.; Michel, P.; Petrasso, R.; Stoeckl, C.; Giraldez, E.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.

2014-01-01

A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results

Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

Energy Technology Data Exchange (ETDEWEB)

Philippe, F. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Tassin, V. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Depierreux, S. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Gauthier, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Masson-Laborde, P. E. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Monteil, M. C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Seytor, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Villette, B. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Lasinski, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Amendt, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Doeppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wallace, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Michel, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Gatu-Johnson, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Li, C. K. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Petrasso, R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Glebov, V. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Sorce, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Stoeckl, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Nikroo, A. [General Atomics, San Diego, CA (United States); Giraldez, E. [General Atomics, San Diego, CA (United States)

2014-07-25

A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

Computational modeling of z-pinch-driven hohlraum experiments on Z

International Nuclear Information System (INIS)

Vesey, R.A.; Porter, J.L. Jr.; Cuneo, M.E.

1999-01-01

The high-yield inertial confinement fusion concept based on a double-ended z-pinch driven hohlraum tolerates the degree of spatial inhomogeneity present in z-pinch plasma radiation sources by utilizing a relatively large hohlraum wall surface to provide spatial smoothing of the radiation delivered to the fusion capsule. The z-pinch radiation sources are separated from the capsule by radial spoke arrays. Key physics issues for this concept are the behavior of the spoke array (effect on the z-pinch performance, x-ray transmission) and the uniformity of the radiation flux incident on the surface of the capsule. Experiments are underway on the Z accelerator at Sandia National laboratories to gain understanding of these issues in a single-sided drive geometry. These experiments seek to measure the radiation coupling among the z-pinch, source hohlraum, and secondary hohlraum, as well as the uniformity of the radiation flux striking a foam witness ball diagnostic positioned in the secondary hohlraum. This paper will present the results of computational modeling of various aspects of these experiments

Hohlraum Radiation Drive Measurements on the Omega Laser

International Nuclear Information System (INIS)

Decker, C.; Turner, R.E.; Landen, O.L.; Suter, L.J.; Amendt, P.; Kornblum, H.N.; Hammel, B.A.; Murphy, T.J.; Wallace, J.; Delamater, N.D.; Gobby, P.; Hauer, A.A.; Magelssen, G.R.; Oertel, J.A.; Knauer, J.; Marshall, F.J.; Bradley, D.; Seka, W.; Soures, J.M.

1997-01-01

Time-resolved drive measurements with thin-walled hohlraum targets on Omega [J.M.Soures et al., Phys.Plasmas 3, 2108 (1996)] are presented and compared with two-dimensional hydrodynamical simulations. For the first time, radiation fluxes are measured through the laser entrance hole instead of through a diagnostic side hole. We find improved agreement between time dependent experiments and simulations using this new technique. In addition, the drive history obtained in this manner correlates well with the drive onto the capsule at target center. copyright 1997 The American Physical Society

X-ray system with coupled source drive and detector drive

International Nuclear Information System (INIS)

1976-01-01

An electronic coupling replacing the (more expensive) mechanical coupling which controls the speed of two sets of two electric motors, one driving an X-ray source and the other an X-ray detector, is described. Source and detector are kept rotating in parallel planes with a fairly constant velocity ratio. The drives are controlled by an electronic system comprising a comparator circuit comparing the position-indicative signals, a process control circuit and an inverter switch. The control system regulates the speed of the electric motors. The signal processing is described

The LMJ project - status of our knowledge in hohlraum energetics physics: production and control of the radiation flux; Projet laser megajoule - les etudes et activites dans le domaine de la physique de la cavite (hohlraum): production et controle du flux radiatif

Energy Technology Data Exchange (ETDEWEB)

Dattolo, E

2001-09-01

CEA-DAM in France is working on Inertial controlled Fusion (ICF) since the beginning of nineties. In an indirect drive scheme, the laser light is converted in X-ray in a hohlraum made with an high-Z material. Part of this radiation flux is absorbed by a micro-balloon filled with DT, placed in the center of the hohlraum, and generates its implosion, ignition and burn. This paper gives the status of our knowledge and studies for production and control of the radiation flux in the hohlraum, in the perspective of the Laser MegaJoule (LMJ). (authors)

The LMJ project - status of our knowledge in hohlraum energetics physics: production and control of the radiation flux

International Nuclear Information System (INIS)

Dattolo, E.

2001-09-01

CEA-DAM in France is working on Inertial controlled Fusion (ICF) since the beginning of nineties. In an indirect drive scheme, the laser light is converted in X-ray in a hohlraum made with an high-Z material. Part of this radiation flux is absorbed by a micro-balloon filled with DT, placed in the center of the hohlraum, and generates its implosion, ignition and burn. This paper gives the status of our knowledge and studies for production and control of the radiation flux in the hohlraum, in the perspective of the Laser MegaJoule (LMJ). (authors)

High performance capsule implosions driven by the Z-pinch dynamic hohlraum

Energy Technology Data Exchange (ETDEWEB)

Rochau, G A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Bailey, J E [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Chandler, G A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Cooper, G [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Dunham, G S [K-tech Corporation, 10800 Gibson S E, Albuquerque, NM 87123 (United States); Lake, P W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Leeper, R J [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Lemke, R W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Mehlhorn, T A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Nikroo, A [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Peterson, K J [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Ruiz, C L [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Schroen, D G [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Slutz, S A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Steinman, D [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Stygar, W A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Varnum, W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States)

2007-12-15

The Z-pinch dynamic hohlraum (ZPDH) is a high-power x-ray source that has been used in a variety of high energy-density experiments including inertial confinement fusion (ICF) studies. The system consists of a tungsten wire-array Z pinch that implodes onto a low-density CH{sub 2} foam converter launching a radiating shock that heats the hohlraum to radiation temperatures >200 eV. Through time-gated pinhole camera measurements, the mean shock speed is measured from 28 experiments to be 326 {+-} 4 {mu}m ns{sup -1} with a shot-to-shot standard deviation of 7%. Broad-band x-ray measurements indicate that the shot-to-shot reproducibility in the power emission and pulse-shape of the source shock is <15% and {approx}5%, respectively. Calculations have shown that an ICF capsule placed at the center of the foam in the ZPDH can absorb >40 kJ of x-ray energy, within a factor of 4 of the energy believed sufficient for ICF ignition. The capsule types imploded by the ZPDH have evolved over four years culminating in a design that produces record indirect-drive DD thermonuclear neutron yields of up to 3.5E11.

Three-dimensional modeling of capsule implosions in OMEGA tetrahedral hohlraums

International Nuclear Information System (INIS)

Schnittman, J. D.; Craxton, R. S.

2000-01-01

Tetrahedral hohlraums have been proposed as a means for achieving the highly uniform implosions needed for ignition with inertial confinement fusion (ICF) [J. D. Schnittman and R. S. Craxton, Phys. Plasmas 3, 3786 (1996)]. Recent experiments on the OMEGA laser system have achieved good drive uniformity consistent with theoretical predictions [J. M. Wallace et al., Phys. Rev. Lett. 82, 3807 (1999)]. To better understand these experiments and future investigations of high-convergence ICF implosions, the three-dimensional (3-D) view-factor code BUTTERCUP has been expanded to model the time-dependent radiation transport in the hohlraum and the hydrodynamic implosion of the capsule. Additionally, a 3-D postprocessor has been written to simulate x-ray images of the imploded core. Despite BUTTERCUP's relative simplicity, its predictions for radiation drive temperatures, fusion yields, and core deformation show close agreement with experiment. (c) 2000 American Institute of Physics

Pulsed power driven hohlraum research at Sandia National Laboratories

International Nuclear Information System (INIS)

Leeper, R.J.; Alberts, T.E.; Allshouse, G.A.

1996-01-01

Three pulsed power driven hohlraum concepts are being investigated at Sandia for application to inertial fusion research. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. Research on these hohlraum systems will continue on Sandia's PBFA II-Z facility

Measurements of the growth rate of the short wavelength Rayleigh-Taylor instability of foam foil packages driven by a soft x-ray pulse

International Nuclear Information System (INIS)

Willi, O.; Pasley, J.; Iwase, A.; Nazarov, W.; Rose, S.J.

2000-01-01

The Rayleigh-Taylor instability was studied in the short wavelength regime using single mode targets that were driven by hohlraum radiation allowing the Takabe-Morse roll-over due to ablative stabilisation to be investigated. A temporally shaped soft x-ray drive was generated by focusing one of the PHEBUS laser beams into a gold hohlraum with a maximum radiation temperature of about 120 eV. Thin plastic foils with sinusoidal modulations with wavelengths between 12 and 50 μm, and a perturbation amplitude of about 10% of the wavelength, were used. A low density 50 mg/cc tri-acrylate foam 150 μm in length facing the hohlraum was attached to the modulated foam target. The targets were radiographed face-on at an x-ray energy of about 1.3 keV with a spatial resolution of about 5 μm using a Wolter-like x-ray microscope coupled to an x-ray streak camera with a temporal resolution of 50 ps. The acceleration was obtained from side-on radiography. 2-D hydrodynamic code simulations have been carried out to compare the experimental results with the simulations. (authors)

Measurement of preheat in aluminium target in indirect drive using the SGIII prototype facilities

International Nuclear Information System (INIS)

Zhang, C; Zheng, J; Wang, Z B; Liu, H; Peng, X S; Wang, F; Ding, Y K

2016-01-01

The velocity interferometer system for any reflector (VISAR) is used to demonstrate preheat effect in aluminium in indirect drive. The rear surface motion prior to shock front was observed and compared with a multi-group calculation. By properly adjusting the hard x-ray portion of the radiation source, the calculated rear surface motion fits well with the experimental results, which gives us confidence to predict the preheated temperature of the sample by hard x-rays. Further, the effect of hohlraum geometry is compared and discussed experimentally. The result suggests gas-filled hohlraum or hohlraum with low Z substrates should be considered to further reduce preheating. (paper)

Proton Radiography of Spontaneous Fields, Plasma Flows and Dynamics in X-Ray Driven Inertial-Confinement Fusion Implosions

Science.gov (United States)

Li, C. K.; Seguin, F. H.; Frenje, J. A.; Rosenberg, M.; Zylstra, A. B.; Rinderknecht, H. G.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Town, R. P. J.; Betti, R.; Knauer, J. P.; Meyerhofer, D. D.; Back, C. A.; Kilkenny, J. D.; Nikroo, A.

2010-11-01

Backlighting of x-ray-driven implosions in empty hohlraums with mono-energetic protons on the OMEGA laser facility has allowed a number of important phenomena to be observed. Several critical parameters were determined, including plasma flow, three types of spontaneous electric fields and megaGauss magnetic fields. These results provide insight into important issues in indirect-drive ICF. Even though the cavity is effectively a Faraday cage, the strong, local fields inside the hohlraum can affect laser-plasma instabilities, electron distributions and implosion symmetry. They are of fundamental scientific importance for a range of new experiments at the frontiers of high-energy-density physics. Future experiments designed to characterize the field formation and evolution in low-Z gas fill hohlraums will be discussed.

Pulsed power driven hohlraum research at Sandia National Laboratories

Energy Technology Data Exchange (ETDEWEB)

Leeper, R J; Alberts, T E; Allshouse, G A [Sandia Labs., Albuquerque, NM (United States); and others

1997-12-31

Three pulsed power driven hohlraum concepts are being investigated at Sandia National Laboratories. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. The paper is an overview of the experiments that have been conducted on these hohlraum systems and discusses several new and novel hohlraum characterization diagnostics that have been developed for this work. These diagnostics include an active shock breakout measurement of hohlraum temperature and a new transmission grating spectrograph for detailed thermal radiation spectral measurements. (author). 3 figs., 6 refs.

Pulsed power driven hohlraum research at Sandia National Laboratories

International Nuclear Information System (INIS)

Leeper, R.J.; Alberts, T.E.; Allshouse, G.A.

1996-01-01

Three pulsed power driven hohlraum concepts are being investigated at Sandia National Laboratories. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. The paper is an overview of the experiments that have been conducted on these hohlraum systems and discusses several new and novel hohlraum characterization diagnostics that have been developed for this work. These diagnostics include an active shock breakout measurement of hohlraum temperature and a new transmission grating spectrograph for detailed thermal radiation spectral measurements. (author). 3 figs., 6 refs

Scaling laws for specialized hohlraums

International Nuclear Information System (INIS)

Rosen, M.D.

1993-01-01

The author presents scaling laws for the behavior of hohlraums that are somewhat more complex than a simple sphere or cylinder. In particular the author considers hohlraums that are in what has become known as a open-quotes primaryclose quotes open-quotes secondaryclose quotes configuration, namely geometries in which the laser is absorbed in a primary region of a hohlraum, and only radiation energy is transported to a secondary part of the hohlraum that is shielded from seeing the laser light directly. Such hohlraums have been in use of late for doing LTE opacity experiments on a sample in the secondary and in recently proposed open-quotes shimmedclose quotes hohlraums that use gold disks on axis to block a capsule's view of the cold laser entrance hole. The temperature/drive of the secondary, derived herein, scales somewhat differently than the drive in simple hohlraums

High Foot Implosion Experiments in Rugby Hohlraums

Science.gov (United States)

Ralph, Joseph; Leidinger, J.-P.; Callahan, D.; Kaiser, P.; Morice, O.; Marion, D.; Moody, J. D.; Ross, J. S.; Amendt, P.; Kritcher, A. L.; Milovich, J. L.; Strozzi, D.; Hinkel, D.; Michel, P.; Berzak Hopkins, L.; Pak, A.; Dewald, E. L.; Divol, L.; Khan, S.; Rygg, R.; Hurricane, O.; Lawrence Livermore National Lab Team; CEA/DAM Team

2015-11-01

The rugby hohlraum design is aimed at providing uniform x-ray drive on the capsule while minimizing the need for crossed beam energy transfer (CBET). As part of a series of experiments at the NIF using rugby hohlraums, design improvements in dual axis shock tuning experiments produced some of the most symmetric shocks measured on implosion experiments at the NIF. Additionally, tuning of the in-flight shell and hot spot shape have demonstrated that capsules can be tuned between oblate and prolate with measured velocities of nearly 340 km/s. However, these experimental measurements were accompanied by high levels of Stimulated Raman Scattering (SRS) that may result from the long inner beam path length, reamplification of the inner SRS by the outers, significant (CBET) or a combination of these. All rugby shots results were achieved with lower levels of hot electrons that can preheat the DT fuel layer for increased adiabat and reduced areal density. Detailed results from these experiments and those planned throughout the summer will be presented and compared with results obtained from cylindrical hohlraums. This work performed under the auspices of U.S. Department of Energy by Lawrence Livermore National Lab under Contract DE-AC52-07NA27344.

Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

Energy Technology Data Exchange (ETDEWEB)

Clark, D. S.; Weber, C. R.; Smalyuk, V. A.; Robey, H. F.; Kritcher, A. L.; Milovich, J. L.; Salmonson, J. D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

2016-07-15

Current indirect drive implosion experiments on the National Ignition Facility (NIF) [Moses et al., Phys. Plasmas 16, 041006 (2009)] are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or “shimmed,” so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.

Dynamic hohlraum and ICF pellet implosion experiments on Z

International Nuclear Information System (INIS)

Nash, T.J.; Derzon, M.S.; Chandler, G.A.

1999-01-01

By stabilizing an imploding z-pinch on Z (20 MA, 100 ns) with a solid current return can and a nested wire array the authors have achieved dynamic hohlraum radiation temperatures over 200 eV at a diameter of approximately 1 mm. The pinch configuration yielding this temperature is a nested tungsten wire array of 240 and 120 wires at 4 and 2 cm diameters weighing 2 and 1 mg, 1 cm long, imploding onto a 5 mm diameter, 14 mg/cc cylindrical CH foam, weighing 3 mg. They have used a single 4 cm diameter tungsten wire array to drive a 1.6 mm diameter ICF capsule mounted in a 6 mg/cc foam inside a 3 mg copper annulus at 5 mm diameter, and measured x-ray emissions indicative of the pellet implosion. Mounting the pellet in foam may have caused the hohlraum to become equator-hot. They will present results from upcoming pellet experiments in which the pellet is mounted by thread and driven by a larger diameter, 6 or 7 mm, copper annulus to improve radiation drive symmetry. They will also discuss designs for tapered foam annular targets that distort a cylindrical pinch into a quasi-sphere that will wrap around an ICF pellet to further improve drive symmetry

First laser-plasma interaction and hohlraum experiments on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; Holder, J; McDonald, J W; Niemann, C; Mackinnon, A J; Hammel, B A [Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94550 (United States)

2005-12-15

Recently the first laser-plasma interaction and hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive inertial confinement fusion designs. The effects of laser beam smoothing by spectral dispersion and polarization smoothing on the intense (2 x 10{sup 15} W cm{sup -2}) beam propagation in gas-filled tubes has been studied at up to 7 mm plasma scales as found in indirect drive gas filled ignition hohlraum designs. These experiments have shown the expected full propagation without filamentation and beam break up when using full laser smoothing. In addition, vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the Nova and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment using in analytical models and radiation hydrodynamics calculations with the code LASNEX has been proven in these studies. The comparison of these results with modelling will be discussed.

Status Update: Modeling Energy Balance in NIF Hohlraums

Energy Technology Data Exchange (ETDEWEB)

Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-07-22

We have developed a standardized methodology to model hohlraum drive in NIF experiments. We compare simulation results to experiments by 1) comparing hohlraum xray fluxes and 2) comparing capsule metrics, such as bang times. Long-pulse, high gas-fill hohlraums require a 20-28% reduction in simulated drive and inclusion of ~15% backscatter to match experiment through (1) and (2). Short-pulse, low fill or near-vacuum hohlraums require a 10% reduction in simulated drive to match experiment through (2); no reduction through (1). Ongoing work focuses on physical model modifications to improve these matches.

Simulation of the hohlraum for a laser facility of Megajoule scale

Energy Technology Data Exchange (ETDEWEB)

Chizhkov, M N; Kozmanov, M Y U; Lebedev, S N; Lykov, V A; Rykovanova, V V; Seleznev, V N; Selezneva, K I; Stryakhnina, O V; Shestakov, A A; Vronskiy, A V, E-mail: M.N.Chizhkov@VNIITF.r [Russian Federal Nuclear Center - VNIITF Vasilieva str. 13, Snezhinsk, Chelyabinsk reg., 456770 (Russian Federation)

2010-08-01

2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

Simulation of the hohlraum for a laser facility of Megajoule scale

International Nuclear Information System (INIS)

Chizhkov, M N; Kozmanov, M Y U; Lebedev, S N; Lykov, V A; Rykovanova, V V; Seleznev, V N; Selezneva, K I; Stryakhnina, O V; Shestakov, A A; Vronskiy, A V

2010-01-01

2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

LDRD Final Report: Advanced Hohlraum Concepts

Energy Technology Data Exchange (ETDEWEB)

Jones, Ogden S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-11-08

Indirect drive inertial confinement fusion (ICF) experiments to date have mostly used cylindrical, laser-heated, gas-filled hohlraums to produce the radiation drive needed to symmetrically implode DT-filled fusion capsules. These hohlraums have generally been unable to produce a symmetric radiation drive through the end of the desired drive pulse, and are plagued with complications due to laser-plasma interactions (LPI) that have made it difficult to predict their performance. In this project we developed several alternate hohlraum concepts. These new hohlraums utilize different hohlraum geometries, radiation shields, and foam materials in an attempt to improve performance relative to cylindrical hohlraums. Each alternate design was optimized using radiation hydrodynamic (RH) design codes to implode a reference DT capsule with a high-density carbon (HDC) ablator. The laser power and energy required to produce the desired time-dependent radiation drive, and the resulting time-dependent radiation symmetry for each new concept were compared to the results for a reference cylindrical hohlraum. Since several of the new designs needed extra laser entrance holes (LEHs), techniques to keep small LEHs open longer, including high-Z foam liners and low-Z wires at the LEH axis, were investigated numerically. Supporting experiments and target fabrication efforts were also done as part of this project. On the Janus laser facility plastic tubes open at one end (halfraums) and filled with SiO₂ or Ta₂O₅ foam were heated with a single 2w laser. Laser propagation and backscatter were measured. Generally the measured propagation was slower than calculated, and the measured laser backscatter was less than calculated. A comparable, scaled up experiment was designed for the NIF facility and four targets were built. Since low density gold foam was identified as a desirable material for lining the LEH and the hohlraum wall, a technique was developed to

Comparison of high-density carbon implosions in unlined uranium versus gold hohlraums

Science.gov (United States)

Dewald, Eduard; Meezan, Nathan; Tommasini, Riccardo; Khan, Shahab; MacKinnon, Andrew; Berzak Hopkins, Laura; Divol, Laurent; Lepape, Sebastien; Moore, Alastair; Schneider, Marilyn; Pak, Arthur; Nikroo, Abbas; Landen, Otto

2016-10-01

In Inertial Confinement Fusion (ICF) implosions, laser energy is converted to x-ray radiation in hohlraums with High-Z walls. At radiation temperatures near 300 eV relevant for ICF experiments, the radiative losses in heating the wall are lower for U than for Au hohlraums. Furthermore, the intensity of the ``M-band'' x-rays with photon energies h ν >1.8 keV is lower for uranium, allowing for reduced capsule dopant concentrations employed to minimize inner ablator preheat and hence keep favorable fuel/ablator interface Atwood numbers. This in turn improves the ablator rocket efficiency and reduces the risk of polluting the hot-spot with emissive dopant material. The first uranium vacuum hohlraum experiments on the National Ignition Facility (NIF) with undoped high-density carbon (HDC, or diamond) capsules have demonstrated 30% lower ``M-band'' intensity relative to Au, resulting in lower inflight ablator thickness due to reduced preheat. In addition, fusion neutron yields are 2x higher in U than in Au hohlraums for D2-gas filled capsule implosions at ICF relevant velocities of 380 +/-20 km/s. These results have led the NIF ICF implosions to routinely employ U hohlraums. Prepared by LLNL under Contract DE-AC52-07NA27344.

pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

Science.gov (United States)

Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

2015-11-01

We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

Electromagnetic radiations from laser interaction with gas-filled Hohlraum

Science.gov (United States)

Yang, Ming; Yang, Yongmei; Li, Tingshuai; Yi, Tao; Wang, Chuanke; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun

2018-01-01

The emission of intensive electromagnetic pulse (EMP) due to laser-target interactions at the ShenGuang-III laser facility has been evaluated by probes. EMP signals measured using the small discone antennas demonstrated two variation trends including a bilateral oscillation wave and a unilateral oscillation wave. The new trend of unilateral oscillation could be attributed to the hohlraum structure and low-Z gas in the hohlraum. The EMP waveform showed multiple peaks when the gas-filled hohlraum was shot by the high-power laser. Comparing the EMP signals with the verification of stimulated Raman scattering energy and hard x-ray energy spectrum, we found that the intensity of EMP signals decreased with the increase of the hohlraum size. The current results are expected to offer preliminary information to study physical processes on laser injecting gas-filled hohlraums in the National Ignition Facility implementation.

Heating of low-density CHO-foam layers by means of soft X-rays

Energy Technology Data Exchange (ETDEWEB)

Rosmej, O.N., E-mail: o.rosmej@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 164291 Darmstadt (Germany); Bagnoud, V.; Eisenbarth, U. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 164291 Darmstadt (Germany); Vatulin, V.; Zhidkov, N.; Suslov, N.; Kunin, A.; Pinegin, A. [All Russian Scientific Research Institute of Experimental Physics, RFNC-VNIIEF, Mira St. 37, Sarov (Russian Federation); Schaefer, D.; Nisius, Th.; Wilhein, Th. [RheinAhrCampus Remagen, Institute for X-optics, Suedallee 2, 53424 Remagen (Germany); Rienecker, T.; Wiechula, J.; Jacoby, J. [Goethe University, Frankfurt am Main (Germany); Zhao, Y. [Institute of Modern Physics, CAS, Nanchang Road 509, 730000 Lanzhou (China); Vergunova, G.; Borisenko, N. [Lebedev Physical Institute, Leninskii Prospekt, 65 Moscow (Russian Federation); Orlov, N. [Joint Institute for High Temperatures RAS, Institute for High Energy Density, Izhorskaya. 13, building 2, 125412 Moscow (Russian Federation)

2011-10-11

Interaction of soft X-ray thermal radiation with polymer foam layers has been studied experimentally. Indirectly heated CHO-foams were used to create a plasma target for applications in combined heavy ion beam-laser experiments that are aimed at investigation of the heavy ion energy loss in ionized matter. In this work, we report experimental results on heating of low Z foams by means of the Planckian radiation generated in gold hohlraums. The experimental goal was to study the hohlraum radiation field, duration of the soft X-ray pulse, the conversion efficiency of the laser energy into soft X-rays, measurements of the absorption properties of foam layers and parameters of the foam targets heated by the Plankian radiation.

Heating of low-density CHO-foam layers by means of soft X-rays

International Nuclear Information System (INIS)

Rosmej, O.N.; Bagnoud, V.; Eisenbarth, U.; Vatulin, V.; Zhidkov, N.; Suslov, N.; Kunin, A.; Pinegin, A.; Schaefer, D.; Nisius, Th.; Wilhein, Th.; Rienecker, T.; Wiechula, J.; Jacoby, J.; Zhao, Y.; Vergunova, G.; Borisenko, N.; Orlov, N.

2011-01-01

Interaction of soft X-ray thermal radiation with polymer foam layers has been studied experimentally. Indirectly heated CHO-foams were used to create a plasma target for applications in combined heavy ion beam-laser experiments that are aimed at investigation of the heavy ion energy loss in ionized matter. In this work, we report experimental results on heating of low Z foams by means of the Planckian radiation generated in gold hohlraums. The experimental goal was to study the hohlraum radiation field, duration of the soft X-ray pulse, the conversion efficiency of the laser energy into soft X-rays, measurements of the absorption properties of foam layers and parameters of the foam targets heated by the Plankian radiation.

Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic.

Science.gov (United States)

Swadling, G F; Ross, J S; Datte, P; Moody, J; Divol, L; Jones, O; Landen, O

2016-11-01

An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm -2 . This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 10 19 cm -2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

Science.gov (United States)

Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

2016-10-01

A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum.

Indirect-drive noncryogenic double-shell ignition targets for the National Ignition Facility: Design and analysis

International Nuclear Information System (INIS)

Amendt, Peter; Colvin, J.D.; Tipton, R.E.; Hinkel, D.E.; Edwards, M.J.; Landen, O.L.; Ramshaw, J.D.; Suter, L.J.; Varnum, W.S.; Watt, R.G.

2002-01-01

Analysis and design of indirect-drive National Ignition Facility double-shell targets with hohlraum temperatures of 200 eV and 250 eV are presented. The analysis of these targets includes the assessment of two-dimensional radiation asymmetry and nonlinear mix. Two-dimensional integrated hohlraum simulations indicate that the x-ray illumination can be adjusted to provide adequate symmetry control in hohlraums specially designed to have high laser-coupling efficiency [Suter et al., Phys. Plasmas 7, 2092 (2000)]. These simulations also reveal the need to diagnose and control localized 10-15 keV x-ray emission from the high-Z hohlraum wall because of strong absorption by the high-Z inner shell. Preliminary estimates of the degree of laser backscatter from an assortment of laser-plasma interactions suggest comparatively benign hohlraum conditions. The application of a variety of nonlinear mix models and phenomenological tools, including buoyancy-drag models, multimode simulations and fall-line optimization, indicates a possibility of achieving ignition, i.e., fusion yields greater than 1 MJ. Planned experiments on the Omega laser will test current understanding of high-energy radiation flux asymmetry and mix-induced yield degradation in double-shell targets

Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

Energy Technology Data Exchange (ETDEWEB)

Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2016-11-15

An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause “blanking” (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm{sup −2}. This is significantly above the expected threshold for the onset of “blanking” effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate “blanking.” Estimates suggest that an areal density of 10{sup 19} cm{sup −2} Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

New compact hohlraum configuration research at the 1.7 MA Z-pinch generator

Energy Technology Data Exchange (ETDEWEB)

Kantsyrev, V. L., E-mail: victor@unr.edu; Shrestha, I. K.; Esaulov, A. A.; Safronova, A. S.; Shlyaptseva, V. V.; Osborne, G. C.; Astanovitsky, A. L.; Weller, M. E.; Stafford, A.; Schultz, K. A.; Cooper, M. C. [Physics Department, University of Nevada, Reno, NV 89557 (United States); Chuvatin, A. S. [Laboratorie de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau (France); Rudakov, L. I. [Icarus Research Inc., P.O. Box 30780, Bethesda, MD 20824-0780 (United States); Velikovich, A. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Cuneo, M. E.; Jones, B.; Vesey, R. A. [Sandia National Laboratories, Albuquerque, NM 87110 (United States)

2014-12-15

A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources – planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubled the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed.

Improved Understanding of Implosion Symmetry through New Experimental Techniques Connecting Hohlraum Dynamics with Laser Beam Deposition

Science.gov (United States)

Ralph, Joseph; Salmonson, Jay; Dewald, Eduard; Bachmann, Benjamin; Edwards, John; Graziani, Frank; Hurricane, Omar; Landen, Otto; Ma, Tammy; Masse, Laurent; MacLaren, Stephen; Meezan, Nathan; Moody, John; Parrilla, Nicholas; Pino, Jesse; Sacks, Ryan; Tipton, Robert

2017-10-01

Understanding what affects implosion symmetry has been a challenge for scientists designing indirect drive inertial confinement fusion experiments on the National Ignition Facility (NIF). New experimental techniques and data analysis have been employed aimed at improving our understanding of the relationship between hohlraum dynamics and implosion symmetry. Thin wall imaging data allows for time-resolved imaging of 10 keV Au l-band x-rays providing for the first time on the NIF, a spatially resolved measurement of laser deposition with time. In the work described here, we combine measurements from the thin wall imaging with time resolved views of the interior of the hohlraum. The measurements presented are compared to hydrodynamic simulations as well as simplified physics models. The goal of this work is to form a physical picture that better explains the relationship of the hohlraum dynamics and capsule ablator on laser beam propagation and implosion symmetry. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

Reducing the effects of X-ray pre-heat in double shell NIF capsules by over-coating the high Z shell

Science.gov (United States)

Wilson, Douglas; Milovich, J. L.; Daughton, W. S.; Loomis, E. N.; Sauppe, J. P.; Dodd, E. S.; Merritt, E. C.; Montgomery, D. S.; Renner, D. B.; Haines, B. M.; Cardenas, T.; Desjardins, T.; Palaniyappan, S.; Batha, S. H.

2017-10-01

Hohlraum generated X-rays will penetrate the ablator of a double shell capsule and be absorbed in the outer surface of the inner capsule. The ablative pressure this generates drives a shock into the central fuel, and a reflected shock that reaches the inner high-Z shell surface before the main shock even enters the fuel. With a beryllium over-coat preheat X-rays deposit just inside the beryllium/high z interface. The beryllium tamps the preheat expansion, eliminating ablation, and dramatically reducing pressure. The slow shock or pressure wave it generates is then overtaken by the main shock, avoiding an early shock in the fuel and increasing capsule yield.

First Laser-Plasma Interaction and Hohlraum Experiments on NIF

International Nuclear Information System (INIS)

Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; McDonald, J W; Niemann, C; Mackinnon, A J

2005-01-01

Recently the first hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive Inertial Confinement Fusion (ICF) designs. The effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled pipes has been studied at plasma scales as found in indirect drive gas filled ignition hohlraum designs. The long scale gas-filled target experiments have shown propagation over 7 mm of dense plasma without filamentation and beam break up when using full laser smoothing. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment in analytical models and in LASNEX calculations has been proven for the first time. The comparison of these results with modeling will be discussed

Demonstration of high coupling efficiency to Al capsule in rugby hohlraum on NIF

Science.gov (United States)

Ping, Y.; Smalyuk, V.; Amendt, P.; Bennett, D.; Chen, H.; Dewald, E.; Goyon, C.; Graziani, F.; Johnson, S.; Khan, S.; Landen, O.; Nikroo, A.; Pino, J.; Ralph, J.; Seugling, R.; Strozzi, D.; Tipton, R.; Tommasini, R.; Wang, M.; Loomis, E.; Merritt, E.; Montgomery, D.

2017-10-01

A new design of the double-shell approach predicts a high coupling efficiency from the hohlraum to the capsule, with 700 kJ in the capsule instead of 200kJ in the conventional low-Z single-shell scheme, improving prospects of double-shell performance. A recent experiment on NIF has evaluated a first step toward this goal of energy coupling using 0.7x subscale Al capsule, Au rugby hohlraum and 1MJ drive. A shell velocity of 150 μm/ns was measured, DANTE peak temperature of 255 eV was measured, and shell kinetic energy of 36 kJ was inferred using a rocket model, all close to predictions and consistent with 330kJ of total energy coupled to the capsule. Data analysis and more results from subsequent experiments will be presented. In the next step, an additional 2x increase of total coupled energy up to 700 kJ is projected for full-scale 2-MJ drive in U Rugby hohlraum. This work was performed under DOE contract DE-AC52-07NA27344.

Comprehensive diagnostic set for intense lithium ion hohlraum experiments on PBFA II

International Nuclear Information System (INIS)

Leeper, R.J.; Bailey, J.E.; Carlson, A.L.

1994-01-01

A review of the comprehensive diagnostic package developed at Sandia National Laboratories for intense lithium ion hohlraum target experiments on PBFA II will be presented. This package contains an extensive suite of x-ray spectral and imaging diagnostics that enable measurements of target radiation smoothing, hydro-motion, and temperature. The x-ray diagnostics include time-integrated and time-resolved pinhole cameras, energy-resolved 1-D streaked imaging diagnostics that enable measurements of target radiation smoothing, hydro-motion, and temperature. The x-ray diagnostics include time-integrated and time-resolved pinhole cameras, energy-resolved 1-D streaked imaging diagnostics, time-integrated and time-resolved grazing incidence spectrographs, a transmission grating spectrography, an elliptical crystal spectrograph, a bolometer array, an eleven element x-ray diode (XRD) array, and an eleven element PIN diode detector array. A hohlraum temperature measurement technique under development is a shock breakout diagnostic that measures the radiation pressure at the hohlraum wall. The incident Li beam symmetry and an estimate of incident Li beam power density are measured from ion beam-induced characteristic x-ray line and neutron emissions. An attempt to measure the Li beam intensity directly on target used Rutherford scattered ions into an ion movie camera and a magnetic spectrograph. The philosophy used in designing all the diagnostics in the set has emphasized redundant and independent measurements of fundamental physical quantities relevant to the performance of the target. Details of each diagnostic, its integration, data reduction procedures, and recent PBFA-II data will be discussed

Plasma instability control toward high fluence, high energy x-ray continuum source

Science.gov (United States)

Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

2017-10-01

X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

ICF ignition capsule neutron, gamma ray, and high energy x-ray images

Science.gov (United States)

Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

2003-03-01

Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

International Nuclear Information System (INIS)

Zou, Shiyang; Song, Peng; Pei, Wenbing; Guo, Liang

2013-01-01

Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux can be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses

Hohlraum manufacture for inertial confinement fusion

International Nuclear Information System (INIS)

Foreman, L.R.; Gobby, P.; Bartos, J.

1994-01-01

Hohlraums are an integral part of indirect drive targets for Inertial Confinement Fusion (ICF) research. Hohlraums are made by an electroforming process that combines elements of micromachining and coating technology. The authors describe how these target element are made and extension of the method that allow fabrication of other, more complex target components

X-ray apparatus

International Nuclear Information System (INIS)

Sell, L.J.

1981-01-01

A diagnostic x-ray device, readily convertible between conventional radiographic and tomographic operating modes, is described. An improved drive system interconnects and drives the x-ray source and the imaging device through coordinated movements for tomography

A 1-D Study of the Ignition Space for Magnetic Indirect (X-ray) Drive Targets

Energy Technology Data Exchange (ETDEWEB)

Cobble, James Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sinars, Daniel Brian [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-06-02

The ICF program today is investigating three approaches to achieving multi-MJ fusion yields and ignition: (1) laser indirect (x-ray) drive on the National Ignition Facility (NIF), (2) laser direct drive (primarily on the Omega laser facility at the University of Rochester), and (3) magnetic direct drive on the Z pulsed power facility. In this white paper we briefly consider a fourth approach, magnetic indirect drive, in which pulsedpower- driven x-ray sources are used in place of laser driven sources. We first look at some of the x-ray sources studied on Z prior to 2007 before the pulsed power ICF program shifted to magnetic direct drive. We then show results from a series of 1D Helios calculations of double-shell capsules that suggest that these sources, scaled to higher temperatures, could be a promising path to achieving multi-MJ fusion yields and ignition. We advocate here that more detailed design calculations with widely accepted 2D/3D ICF codes should be conducted for a better assessment of the prospects.

Hybrid indirect-drive/direct-drive target for inertial confinement fusion

Energy Technology Data Exchange (ETDEWEB)

Perkins, Lindsay John

2018-02-27

A hybrid indirect-drive/direct drive for inertial confinement fusion utilizing laser beams from a first direction and laser beams from a second direction including a central fusion fuel component; a first portion of a shell surrounding said central fusion fuel component, said first portion of a shell having a first thickness; a second portion of a shell surrounding said fusion fuel component, said second portion of a shell having a second thickness that is greater than said thickness of said first portion of a shell; and a hohlraum containing at least a portion of said fusion fuel component and at least a portion of said first portion of a shell; wherein said hohlraum is in a position relative to said first laser beam and to receive said first laser beam and produce X-rays that are directed to said first portion of a shell and said fusion fuel component; and wherein said fusion fuel component and said second portion of a shell are in a position relative to said second laser beam such that said second portion of a shell and said fusion fuel component receive said second laser beam.

Numerical simulations of radiation hydrodynamics and modeling of high temperature hohlraum cavities

International Nuclear Information System (INIS)

Gupta, N.K.; Godwal, B.K.

2003-10-01

A summary of our efforts towards the validation of radiation hydrodynamics and opacity models are presented. Effects of various parameters on the radiation temperature inside an inertial confinement fusion (ICF) hohlraum, the effects of non-local thermodynamic equilibrium conditions on emission and absorption, and the hydrodynamics of aluminium and gold foils driven by radiation are studied. LTE and non-LTE predictions for emitted radiation are compared with the experimental results and it is seen that non-LTE simulations show a marked improvement over LTE results. It is shown that the mixing of two high Z materials can lead to an enhancement in the Rosseland mean. An experimental study of soft x-ray emission from laser-irradiated Au-Cu mix-Z targets confirmed these predictions. It is seen that only multi group non-LTE radiation transport is able to explain experimentally observed features in the conversion efficiency of laser light to x-rays. One group radiation transport under predicts the radiation temperature. It is shown that erroneous results can be obtained if the space mesh in the hohlraum wall is not fine enough. Hydrodynamics of a wedge shaped aluminium foil driven by the hohlraum radiation is also presented and results are compared with NOVA laser experiments. Laser driven shock wave EOS and gold hohlraum experiments carried out at CAT are analyzed and they confirmed our theoretical estimates. (author)

Generation and Beaming of Early Hot Electrons onto the Capsule in Laser-Driven Ignition Hohlraums

Science.gov (United States)

Dewald, E. L.; Hartemann, F.; Michel, P.; Milovich, J.; Hohenberger, M.; Pak, A.; Landen, O. L.; Divol, L.; Robey, H. F.; Hurricane, O. A.; Döppner, T.; Albert, F.; Bachmann, B.; Meezan, N. B.; MacKinnon, A. J.; Callahan, D.; Edwards, M. J.

2016-02-01

In hohlraums for inertial confinement fusion (ICF) implosions on the National Ignition Facility, suprathermal hot electrons, generated by laser plasma instabilities early in the laser pulse ("picket") while blowing down the laser entrance hole (LEH) windows, can preheat the capsule fuel. Hard x-ray imaging of a Bi capsule surrogate and of the hohlraum emissions, in conjunction with the measurement of time-resolved bremsstrahlung spectra, allows us to uncover for the first time the directionality of these hot electrons and infer the capsule preheat. Data and Monte Carlo calculations indicate that for most experiments the hot electrons are emitted nearly isotropically from the LEH. However, we have found cases where a significant fraction of the generated electrons are emitted in a collimated beam directly towards the capsule poles, where their local energy deposition is up to 10 × higher than the average preheat value and acceptable levels for ICF implosions. The observed "beaming" is consistent with a recently unveiled multibeam stimulated Raman scattering model [P. Michel et al., Phys. Rev. Lett. 115, 055003 (2015)], where laser beams in a cone drive a common plasma wave on axis. Finally, we demonstrate that we can control the amount of generated hot electrons by changing the laser pulse shape and hohlraum plasma.

Predicting the Equilibrium Deuterium-Tritium Fuel Layer Thickness Profile in an Indirect-Drive Hohlraum Capsule

International Nuclear Information System (INIS)

Sanchez, Jorge J.; Giedt, Warren H.

2004-01-01

A numerical procedure for calculating the equilibrium thickness distribution of a thin layer of deuterium and tritium on the inner surface of an indirect drive target sphere (∼2.0 mm in diameter) is described. Starting with an assumed uniform thickness layer and with specified thermal boundary conditions, the temperature distribution throughout the capsule and hohlraum (including natural convection in the hohlraum gas) is calculated. Results are used to make a first estimate of the final non-uniform thickness distribution of the layer. This thickness distribution is then used to make a second calculation of the temperature distribution with the same boundary conditions. Legendre polynomial coefficients are evaluated for the two temperature distributions and the two thickness profiles. Final equilibrium Legendre coefficients are determined by linear extrapolation. From these coefficients, the equilibrium layer thickness can be computed

Development of X-ray tracer diagnostics for radiatively-driven ablator experiments

International Nuclear Information System (INIS)

MacFarlane, J.J.; Cohen, D.H.; Wang, P.; Moses, G.A.; Peterson, R.R.; Jaanimagi, P.A.; Langen, O.L.; Olson, R.E.; Murphy, T.J.; Magelssen, G.R.; Delamater, N.D.

1999-01-01

This report covers fiscal year 1998 of our ongoing project to develop tracer X-ray spectroscopic diagnostics for hohlraum environments. This effort focused on an experimental campaign carried out at OMEGA on 25--27 August 1998. This phase of the project heavily emphasized experimental design, diagnostic development, and target fabrication, as well as building up numerical models for the experiments. The spectral diagnostic under development involves using two thin (few 1000 Angstroem) mid-Z tracers in two witness plates mounted on the side of a hohlraum with the tracers' K a absorption features seen against an X-ray backlighter. The absorption data are used to sample the time-dependent, localized properties of each witness plate as a radiation wave ablates it. The experiments represented the first application of this diagnostic, in this case to side-by-side doped and undoped plastic to investigate the effects of capsule ablator dopants

Prolate-Spheroid ('Rugby-Shaped') Hohlraum for Inertial Confinement Fusion

International Nuclear Information System (INIS)

Vandenboomgaerde, M.; Bastian, J.; Casner, A.; Galmiche, D.; Jadaud, J.-P.; Laffite, S.; Liberatore, S.; Malinie, G.; Philippe, F.

2007-01-01

A novel rugby-ball shaped hohlraum is designed in the context of the indirect-drive scheme of inertial-confinement fusion (ICF). Experiments were performed on the OMEGA laser and are the first use of rugby hohlraums for ICF studies. Analysis of experimental data shows that the hohlraum energetics is well understood. We show that the rugby-ball shape exhibits advantages over cylinder, in terms of temperature and of symmetry control of the capsule implosion. Simulations indicate that rugby hohlraum driven targets may be candidates for ignition in a context of early Laser MegaJoule experiments with reduced laser energy

Development of the re-emit technique for ICF foot symmetry tuning for indirect drive ignition on NIF

Science.gov (United States)

Dewald, Eduard; Milovich, Jose; Edwards, John; Thomas, Cliff; Kalantar, Dan; Meeker, Don; Jones, Ogden

2007-11-01

Tuning of the the symmetry of the hohlraum radiation drive for the first 2 ns of the ICF pulse on NIF will be assessed by the re-emit technique [1] which measures the instantaneous x-ray drive asymmetry based on soft x-ray imaging of the re-emission of a high-Z sphere surrogate capsule. We will discuss the design of re-emit foot symmetry tuning measurements planned on NIF and their surrogacy for ignition experiments, including assessing the residual radiation asymmetry of the patches required for soft x-ray imaging. We will present the tuning strategy and expected accuracies based on calculations, analytical estimates and first results from scaled experiments performed at the Omega laser facility. [1] N. Delamater, G. Magelssen, A. Hauer, Phys. Rev. E 53, 5241 (1996.)

Rayleigh-Taylor instabilities in indirect laser drive with rugby-shaped hohlraums

International Nuclear Information System (INIS)

Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.P.; Richard, A.; Liberatore, S.; Vandenboomgaerde, M.

2009-01-01

The mastering of the development of hydrodynamic instabilities like Rayleigh-Taylor instabilities is an important milestone on the way to perform efficient laser implosions. The complexity of these instabilities implies an experimental validation of the theoretical models and their computer simulations. An experimental platform involving the Omega laser has allowed us to perform indirect drive with rugby-shaped hohlraums. The experiments have validated the growth of 2- and 3-dimensional initial defects as predicted by theory. We have shown that the 3-dimensional defect saturates for an higher amplitude than the 2-dimensional one does. The experiments have been made by using a plastic shell doped with Germanium (CH:Ge). (A.C.)

Impeding hohlraum plasma stagnation in inertial-confinement fusion.

Science.gov (United States)

Li, C K; Séguin, F H; Frenje, J A; Rosenberg, M J; Rinderknecht, H G; Zylstra, A B; Petrasso, R D; Amendt, P A; Landen, O L; Mackinnon, A J; Town, R P J; Wilks, S C; Betti, R; Meyerhofer, D D; Soures, J M; Hund, J; Kilkenny, J D; Nikroo, A

2012-01-13

This Letter reports the first time-gated proton radiography of the spatial structure and temporal evolution of how the fill gas compresses the wall blowoff, inhibits plasma jet formation, and impedes plasma stagnation in the hohlraum interior. The potential roles of spontaneously generated electric and magnetic fields in the hohlraum dynamics and capsule implosion are discussed. It is shown that interpenetration of the two materials could result from the classical Rayleigh-Taylor instability occurring as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blowoff. This experiment showed new observations of the effects of the fill gas on x-ray driven implosions, and an improved understanding of these results could impact the ongoing ignition experiments at the National Ignition Facility.

High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

Science.gov (United States)

Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

2018-02-01

The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.

Development and characterization of a Z-pinch-driven hohlraum high-yield inertial confinement fusion target concept

International Nuclear Information System (INIS)

Cuneo, Michael E.; Vesey, Roger A.; Porter, John L. Jr.; Chandler, Gordon A.; Fehl, David L.; Gilliland, Terrance L.; Hanson, David L.; McGurn, John S.; Reynolds, Paul G.; Ruggles, Laurence E.; Seamen, Hans; Spielman, Rick B.; Struve, Ken W.; Stygar, William A.; Simpson, Walter W.; Torres, Jose A.; Wenger, David F.; Hammer, James H.; Rambo, Peter W.; Peterson, Darrell L.

2001-01-01

Initial experiments to study the Z-pinch-driven hohlraum high-yield inertial confinement fusion (ICF) concept of Hammer, Tabak, and Porter [Hammer et al., Phys. Plasmas 6, 2129 (1999)] are described. The relationship between measured pinch power, hohlraum temperature, and secondary hohlraum coupling ('hohlraum energetics') is well understood from zero-dimensional semianalytic, and two-dimensional view factor and radiation magnetohydrodynamics models. These experiments have shown the highest x-ray powers coupled to any Z-pinch-driven secondary hohlraum (26±5 TW), indicating the concept could scale to fusion yields of >200 MJ. A novel, single-sided power feed, double-pinch driven secondary that meets the pinch simultaneity requirements for polar radiation symmetry has also been developed. This source will permit investigation of the pinch power balance and hohlraum geometry requirements for ICF relevant secondary radiation symmetry, leading to a capsule implosion capability on the Z accelerator [Spielman et al., Phys. Plasmas 5, 2105 (1998)

PBFA II lithium beam characterization from inner-shell x-ray images

International Nuclear Information System (INIS)

Moats, A.R.; Derzon, M.S.; Chandler, G.A.; Dukart, R.J.; Haill, T.A.

1994-01-01

The Particle Beam Fusion Accelerator (PBFA II) is not driving targets with ICF-relevant lithium ion beams. During the most recent lithium beam target series, time-integrated x-ray pinhole cameras viewed the ion-induced inner-shell x-ray fluorescence from the central gold cone target and a titanium-coated strip. Ion beam profiles at a nominal 10 mm radius and fixed azimuthal direction were obtained from images of the Ti K α , fluorescence of a Ti-coated Al diagnostic wire. The gold cone gave us beam profiles at a nominal 3 mm radius and at all azimuthal angles from the Au L α fluorescence. From these profiles, we obtained the ion beam vertical focus position, full-width-at-half-maximum, and the degree of azimuthal uniformity for the lithium target shots. For these initial results, beam steering problems were evident. Azimuthal uniformity was measured from the ion beam footprint on the outer Au case (predominantly Au L α ) of the hohlraum target and were found to be in the same range (up to 30%) as for previous proton beam target series. We then present plans for Li beam diagnostics for an upcoming target experimental series

Panoramic dental X-ray machine X-motion drive

International Nuclear Information System (INIS)

Cushman, R.H.; Flynn, J.J.

1980-01-01

A panoramic dental x-ray machine is described which provides continuous and discontinuous radiographic images of the dental arch area of a patient. The systems for moving the chair and the column which carries the x-ray source and camera are specified. (U.K.)

Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

Science.gov (United States)

Casner, A.; Jalinaud, T.; Galmiche, D.

2016-03-01

Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2.

Foot-pulse radiation drive necessary for ICF ignition capsule demonstrated on Z generator

International Nuclear Information System (INIS)

Sanford, T.W.L.; Olson, R.E.; Chandler, G.A.

1999-01-01

Implosion and ignition of an indirectly-driven ICF capsule operating near a Fermi-degenerate isentrope requires initial Planckian-radiation-drive temperatures of 70-to-90 eV to be present for a duration of 10-to-15 ns prior to the main drive pulse. Such capsules are being designed for high pulsed-power generators. This foot-pulse drive capability has been recently demonstrated in a NIF-sized (φ = 6-mm 1 = 7-mm), gold hohlraum, using a one-sided static-wall hohlraum geometry on the Z generator. The general arrangement utilized nested tungsten-wire arrays of radii (mass) 20 mm (2 mg) and 10 mm (1 mg) that had an axial length of approximately 10 mm. The arrays were driven by a peak current of approximately 21 MA and were made to implode on a 2-microm-thick Cu annulus (mass = 4.5 mg), which had a radius of 4 mm and was filled with a low-density CH foam, all centered about the z-axis. The gold hohlraum was mounted on axis and above the Cu/foam target. A 2.9-mm-radius axial hole between the top of the target and hohlraum permitted the x-rays generated from the implosion to enter the hohlraum. The radiation within the hohlraum was monitored by viewing the hohlraum through a 3-mm diameter hole on the lateral side of the hohlraum with a suite of diagnostics.The radiation entering the hohlraum was estimated by an additional suite of on-axis diagnostics, in a limited number of separate shots, when the hohlraum was not present. Additionally, the radiation generated outside the Cu annulus was monitored, for all shots, through a 3-mm diameter aperture located on the outside of the current return can. In the full paper, the characteristics of the radiation measured from these diagnostic sets, including the Planckian temperature of the hohlraum and radiation images, will be discussed as a function of the incident wire-array geometry (single vs nested array and array mass), target length (10, or 20 mm), annulus material (Cu, Au, or nothing), and CH-foam-fill density (10, 6, 2

Novel spherical hohlraum with cylindrical laser entrance holes and shields

Energy Technology Data Exchange (ETDEWEB)

Lan, Ke [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zheng, Wudi [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2014-09-15

Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums.

Novel spherical hohlraum with cylindrical laser entrance holes and shields

International Nuclear Information System (INIS)

Lan, Ke; Zheng, Wudi

2014-01-01

Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums

Measurement of anisotropic soft X-ray emission during radio-frequency current drive in the JFT-2M tokamak

International Nuclear Information System (INIS)

Kawashima, Hisato; Matoba, Tohru; Hoshino, Katsumichi; Kawakami, Tomohide; Yamamoto, Takumi; Hasegawa, Mitsuru; Fuchs, Gerhard; Uesugi, Yoshihiko.

1994-01-01

A new vertical soft X-ray pulse height analyzer (PHA) system and a tangential PHA system were used to measure the anisotropy of soft X-ray emission during lower-hybrid current drive (LHCD) and also during current drive by the combination of LHCD and electron cyclotron resonance heating (ECRH) in the JFT-2M tokamak. The strong soft X-ray emission was measured in the parallel forward direction during LHCD. When ECRH was applied during LHCD, the perpendicular emission was enhanced. The high-energy electron velocity distribution was evaluated by comparing the measured and calculated X-ray spectra. The distribution form was consistent with the theoretical prediction based on the electron Landau damping of lower-hybrid waves and the electron cyclotron damping of electron cyclotron waves for reasonable energy ranges. (author)

Cylindrical target Li-beam-driven hohlraum experiments

International Nuclear Information System (INIS)

Derzon, M.S.; Aubert, J.; Chandler, G.A.

1998-06-01

The authors performed a series of experiments on the Particle Beam Fusion Accelerator II (PBFA II) in May, 1994, and obtained a brightness temperature of 61 ± 2 eV for an ion-beam heated hohlraum. The hohlraum was a 4-mm-diameter, right-circular cylinder with a 1.5-mm-thick gold wall, a low-density CH foam fill, and a 1.5- or 3-mm-diameter diagnostic aperture in the top. The nominal parameters of the radially-incident PBFA II Li ion beam were 9 MeV peak energy (∼10 MeV at the gas cell) at the target at a peak power of 2.5 ± 0.3 TW/cm 2 and a 15 ns pulse width. Azimuthal variations in intensity of a factor of 3, with respect to the mean, were observed. Nonuniformities in thermal x-ray emission across the area of the diagnostic hole were also observed. Time-dependent hole-closure velocities were measured: the time-averaged velocity of ∼2 cm/micros is in good agreement with sound speed estimates. Unfolded x-ray spectra and brightness temperatures as a function of time are reported and compared to simulations. Hole closure corrections are discussed with comparisons between XRD and bolometer measurements. Temperature scaling with power on target is also presented

Use of d-3He proton spectroscopy as a diagnostic of shell rho r in capsule implosion experiments with approximately 0.2 NIF scale high temperature Hohlraums at Omega.

Science.gov (United States)

Delamater, N D; Wilson, D C; Kyrala, G A; Seifter, A; Hoffman, N M; Dodd, E; Singleton, R; Glebov, V; Stoeckl, C; Li, C K; Petrasso, R; Frenje, J

2008-10-01

We present the calculations and preliminary results from experiments on the Omega laser facility using d-(3)He filled plastic capsule implosions in gold Hohlraums. These experiments aim to develop a technique to measure shell rho r and capsule unablated mass with proton spectroscopy and will be applied to future National Ignition Facility (NIF) experiments with ignition scale capsules. The Omega Hohlraums are 1900 microm length x 1200 microm diameter and have a 70% laser entrance hole. This is approximately a 0.2 NIF scale ignition Hohlraum and reaches temperatures of 265-275 eV similar to those during the peak of the NIF drive. These capsules can be used as a diagnostic of shell rho r, since the d-(3)He gas fill produces 14.7 MeV protons in the implosion, which escape through the shell and produce a proton spectrum that depends on the integrated rho r of the remaining shell mass. The neutron yield, proton yield, and spectra change with capsule shell thickness as the unablated mass or remaining capsule rho r changes. Proton stopping models are used to infer shell unablated mass and shell rho r from the proton spectra measured with different filter thicknesses. The experiment is well modeled with respect to Hohlraum energetics, neutron yields, and x-ray imploded core image size, but there are discrepancies between the observed and simulated proton spectra.

Applications and results of X-ray spectroscopy in implosion experiments on the National Ignition Facility

Science.gov (United States)

Epstein, R.; Regan, S. P.; Hammel, B. A.; Suter, L. J.; Scott, H. A.; Barrios, M. A.; Bradley, D. K.; Callahan, D. A.; Cerjan, C.; Collins, G. W.; Dixit, S. N.; Döppner, T.; Edwards, M. J.; Farley, D. R.; Fournier, K. B.; Glenn, S.; Glenzer, S. H.; Golovkin, I. E.; Hamza, A.; Hicks, D. G.; Izumi, N.; Jones, O. S.; Key, M. H.; Kilkenny, J. D.; Kline, J. L.; Kyrala, G. A.; Landen, O. L.; Ma, T.; MacFarlane, J. J.; Mackinnon, A. J.; Mancini, R. C.; McCrory, R. L.; Meyerhofer, D. D.; Meezan, N. B.; Nikroo, A.; Park, H.-S.; Patel, P. K.; Ralph, J. E.; Remington, B. A.; Sangster, T. C.; Smalyuk, V. A.; Springer, P. T.; Town, R. P. J.; Tucker, J. L.

2017-03-01

Current inertial confinement fusion experiments on the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)] are attempting to demonstrate thermonuclear ignition using x-ray drive by imploding spherical targets containing hydrogen-isotope fuel in the form of a thin cryogenic layer surrounding a central volume of fuel vapor [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. The fuel is contained within a plastic ablator layer with small concentrations of one or more mid-Z elements, e.g., Ge or Cu. The capsule implodes, driven by intense x-ray emission from the inner surface of a hohlraum enclosure irradiated by the NIF laser, and fusion reactions occur in the central hot spot near the time of peak compression. Ignition will occur if the hot spot within the compressed fuel layer attains a high-enough areal density to retain enough of the reaction product energy to reach nuclear reaction temperatures within the inertial hydrodynamic disassembly time of the fuel mass [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. The primary purpose of the ablator dopants is to shield the ablator surface adjacent to the DT ice from heating by the hohlraum x-ray drive [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Simulations predicted that these dopants would produce characteristic K-shell emission if ablator material mixed into the hot spot [B. A. Hammel et al., High Energy Density Phys. 6, 171 (2010)]. In NIF ignition experiments, emission and absorption features from these dopants appear in x-ray spectra measured with the hot-spot x-ray spectrometer in Supersnout II [S. P. Regan et al., "Hot-Spot X-Ray Spectrometer for the National Ignition Facility," to be submitted to Review of Scientific Instruments]. These include K-shell emission lines from the hot spot (driven primarily by inner-shell collisional ionization and dielectronic recombination) and photoionization edges, fluorescence, and absorption lines caused by the absorption of the

Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

Energy Technology Data Exchange (ETDEWEB)

Amendt, Peter, E-mail: amendt1@llnl.gov; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2014-11-15

Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and –resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold–helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to

Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

International Nuclear Information System (INIS)

Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David

2014-01-01

Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and –resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold–helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to

Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

Science.gov (United States)

Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David

2014-11-01

Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and -resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold-helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to hindered

Obtaining absolute spatial flux measurements with a time-resolved pinhole camera

International Nuclear Information System (INIS)

Baker, K.L.; Porter, J.L.; Ruggles, L.E.; Fehl, D.L.; Chandler, G.A.; Vargas, M.; Mix, L.P.; Simpson, W.W.; Deeney, C.; Chrien, R.E.; Idzorek, G.C.

1999-01-01

A technique is described to determine the spatial x-ray flux emitted from a hohlraum wall and subsequently transmitted through a diagnostic hole. This technique uses x-ray diodes, bolometers, and a time-resolved pinhole camera to determine the spatial flux of x rays emitted through a hohlraum close-quote s diagnostic hole. The primary motivation for this analysis was the relatively long duration, nearly 100 ns, of the x-ray drive present in z-pinch driven hohlraums. This radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and results in a partial obscuration that reduces the effective area over which diagnostics view the radiation. The effective change in area leads to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. An analysis similar to the one described below is then necessary to understand the radiation environment present in x-ray driven hohlraums when these diagnostics are used and hole closure is important. copyright 1999 American Institute of Physics

Indirect drive targets for fusion power

Energy Technology Data Exchange (ETDEWEB)

Amendt, Peter A.; Miles, Robin R.

2016-10-11

A hohlraum for an inertial confinement fusion power plant is disclosed. The hohlraum includes a generally cylindrical exterior surface, and an interior rugby ball-shaped surface. Windows over laser entrance holes at each end of the hohlraum enclose inert gas. Infrared reflectors on opposite sides of the central point reflect fusion chamber heat away from the capsule. P2 shields disposed on the infrared reflectors help assure an enhanced and more uniform x-ray bath for the fusion fuel capsule.

The physics basis for ignition using indirect-drive targets on the National Ignition Facility

International Nuclear Information System (INIS)

Lindl, John D.; Amendt, Peter; Berger, Richard L.; Glendinning, S. Gail; Glenzer, Siegfried H.; Haan, Steven W.; Kauffman, Robert L.; Landen, Otto L.; Suter, Laurence J.

2004-01-01

The 1990 National Academy of Science final report of its review of the Inertial Confinement Fusion Program recommended completion of a series of target physics objectives on the 10-beam Nova laser at the Lawrence Livermore National Laboratory as the highest-priority prerequisite for proceeding with construction of an ignition-scale laser facility, now called the National Ignition Facility (NIF). These objectives were chosen to demonstrate that there was sufficient understanding of the physics of ignition targets that the laser requirements for laboratory ignition could be accurately specified. This research on Nova, as well as additional research on the Omega laser at the University of Rochester, is the subject of this review. The objectives of the U.S. indirect-drive target physics program have been to experimentally demonstrate and predictively model hohlraum characteristics, as well as capsule performance in targets that have been scaled in key physics variables from NIF targets. To address the hohlraum and hydrodynamic constraints on indirect-drive ignition, the target physics program was divided into the Hohlraum and Laser-Plasma Physics (HLP) program and the Hydrodynamically Equivalent Physics (HEP) program. The HLP program addresses laser-plasma coupling, x-ray generation and transport, and the development of energy-efficient hohlraums that provide the appropriate spectral, temporal, and spatial x-ray drive. The HEP experiments address the issues of hydrodynamic instability and mix, as well as the effects of flux asymmetry on capsules that are scaled as closely as possible to ignition capsules (hydrodynamic equivalence). The HEP program also addresses other capsule physics issues associated with ignition, such as energy gain and energy loss to the fuel during implosion in the absence of alpha-particle deposition. The results from the Nova and Omega experiments approach the NIF requirements for most of the important ignition capsule parameters, including

Wire array z-pinch insights for high X-ray power generation

International Nuclear Information System (INIS)

Sanford, T.W.L.; Marder, B.M.; Desjarlais, M.P.

1998-01-01

The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn and Z. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X-ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays

Wire array z-pinch insights for high X-ray power generation

Energy Technology Data Exchange (ETDEWEB)

Sanford, T.W.L.; Marder, B.M.; Desjarlais, M.P. [and others

1998-12-31

The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn and Z. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X-ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

Wire array z-pinch insights for high x-ray power generation

Energy Technology Data Exchange (ETDEWEB)

Sanford, T.W.L.; Mock, R.C.; Marder, B.M. [and others

1997-12-31

The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn and Z. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X-ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

Wire array z-pinch insights for high x-ray power generation

Energy Technology Data Exchange (ETDEWEB)

Sanford, T.W.L.; Mock, R.C.; Nash, T.J. [and others

1998-08-01

The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X=ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

Wire array z-pinch insights for high x-ray power generation

International Nuclear Information System (INIS)

Sanford, T.W.L.; Mock, R.C.; Marder, B.M.

1998-08-01

The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn and Z. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X=ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays

Hohlraum modeling for opacity experiments on the National Ignition Facility

Science.gov (United States)

Dodd, E. S.; DeVolder, B. G.; Martin, M. E.; Krasheninnikova, N. S.; Tregillis, I. L.; Perry, T. S.; Heeter, R. F.; Opachich, Y. P.; Moore, A. S.; Kline, J. L.; Johns, H. M.; Liedahl, D. A.; Cardenas, T.; Olson, R. E.; Wilde, B. H.; Urbatsch, T. J.

2018-06-01

This paper discusses the modeling of experiments that measure iron opacity in local thermodynamic equilibrium (LTE) using laser-driven hohlraums at the National Ignition Facility (NIF). A previous set of experiments fielded at Sandia's Z facility [Bailey et al., Nature 517, 56 (2015)] have shown up to factors of two discrepancies between the theory and experiment, casting doubt on the validity of the opacity models. The purpose of the new experiments is to make corroborating measurements at the same densities and temperatures, with the initial measurements made at a temperature of 160 eV and an electron density of 0.7 × 1022 cm-3. The X-ray hot spots of a laser-driven hohlraum are not in LTE, and the iron must be shielded from a direct line-of-sight to obtain the data [Perry et al., Phys. Rev. B 54, 5617 (1996)]. This shielding is provided either with the internal structure (e.g., baffles) or external wall shapes that divide the hohlraum into a laser-heated portion and an LTE portion. In contrast, most inertial confinement fusion hohlraums are simple cylinders lacking complex gold walls, and the design codes are not typically applied to targets like those for the opacity experiments. We will discuss the initial basis for the modeling using LASNEX, and the subsequent modeling of five different hohlraum geometries that have been fielded on the NIF to date. This includes a comparison of calculated and measured radiation temperatures.

Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

International Nuclear Information System (INIS)

Casner, A.; Jalinaud, T.; Galmiche, D.

2016-01-01

Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2. (paper)

Demonstration of Enhanced Radiation Drive in Hohlraums Made from a Mixture of High-Z Wall Materials

International Nuclear Information System (INIS)

Schein, Jochen; Jones, Ogden; Rosen, Mordecai; Dewald, Eduard; Glenzer, Siegfried; Gunther, Janelle; Hammel, Bruce; Landen, Otto; Suter, Laurence; Wallace, Russell

2007-01-01

We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature compared to a pure Au hohlraum that is in agreement with predictions and is ascribable to reduced wall losses. The data suggest that a National Ignition Facility ignition hohlraum made of a U:Au:Dy cocktail should have ∼17% reduction in wall losses compared to a similar gold hohlraum

2D simulations of hohlraum targets for laser-plasma experiments and ion stopping measurement in hot plasmas

Energy Technology Data Exchange (ETDEWEB)

Basko, M.M. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Maruhn, J.; Tauschwitz, Anna [Frankfurt Univ. (Germany); Novikov, V.G.; Grushin, A.S. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

2011-12-15

An attractive way to create uniform plasma states at high temperatures and densities is by using hohlraums - cavities with heavy-metal walls that are either directly or indirectly heated by intense laser pulses to x-ray temperatures of tens and hundreds electron volts. A sample material, whose plasma state is to be studied, can be placed inside such a hohlraum (usually in the form of a low-density foam) and uniformly heated to a high temperature. In this case a high-Z hohlraum enclosure serves a double purpose: it prevents the hot plasma from rapid disassembly due to hydrodynamic expansion and, at the same time, suppresses its rapid radiative cooling by providing high diffusive resistivity for X-rays. Of course, both the inertial and the thermal confinement of high-temperature plasmas can be achieved only for a limited period of time - on the order of nanoseconds for millimeter-scale hohlraums. Some time ago such hohlraum targets were proposed for measurements of the stopping power of hot dense plasmas for fast ions at GSI (Darmstadt). Theoretical modeling of hohlraum targets has always been a challenging task for computational physics because it should combine multidimensional hydrodynamic simulations with the solution of the spectral transfer equation for thermal radiation. In this work we report on our latest progress in this direction, namely, we present the results of 2D (two-dimensional) simulations with a newly developed radiation-hydrodynamics code RALEF-2D of two types of the hohlraum targets proposed for experiments on the PHELIX laser at GSI. The first configuration is a simple spherical hohlraum with gold walls and empty interior, which has two holes - one for laser beam entrance, and the other for diagnostics. The hohlraums of this type have already been used in several experimental sessions with the NHELIX and PHELIX lasers at GSI. The second type is a two-chamber cylindrical hohlraum with a characteristic {omega}-shaped cross-section of the enclosure

High convergence, indirect drive inertial confinement fusion experiments at Nova

International Nuclear Information System (INIS)

Lerche, R.A.; Cable, M.D.; Hatchett, S.P.; Caird, J.A.; Kilkenny, J.D.; Kornblum, H.N.; Lane, S.M.; Laumann, C.; Murphy, T.J.; Murray, J.; Nelson, M.B.; Phillion, D.W.; Powell, H.; Ress, D.

1996-01-01

High convergence, indirect drive implosion experiments have been done at the Nova Laser Facility. The targets were deuterium and deuterium/tritium filled, glass microballoons driven symmetrically by x rays produced in a surrounding uranium hohlraum. Implosions achieved convergence ratios of 24:1 with fuel densities of 19 g/cm 3 ; this is equivalent to the range required for the hot spot of ignition scale capsules. The implosions used a shaped drive and were well characterized by a variety of laser and target measurements. The primary measurement was the fuel density using the secondary neutron technique (neutrons from the reaction 2 H( 3 H,n) 4 He in initially pure deuterium fuel). Laser measurements include power, energy and pointing. Simultaneous measurement of neutron yield, fusion reaction rate, and x-ray images provide additional information about the implosion process. Computer models are in good agreement with measurement results. copyright 1996 American Institute of Physics

Analytic Models of High-Temperature Hohlraums

International Nuclear Information System (INIS)

Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

2000-01-01

A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P s = (A s +(1minusα W )A W +A H )σT R 4 + (4Vσ/c)(dT R r /dt) where P S is the total power radiated by the source, A s is the source area, A W is the area of the cavity wall excluding the source and holes in the wall, A H is the area of the holes, σ is the Stefan-Boltzmann constant, T R is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo α W triple b ond (T W /T R ) 4 where T W is the brightness temperature of area A W . The net power radiated by the source P N = P S -A S σT R 4 , which suggests that for laser-driven hohlraums the conversion efficiency η CE be defined as P N /P LASER . The characteristic time required to change T R 4 in response to a change in P N is 4V/C((lminusα W )A W +A H ). Using this model, T R , α W , and η CE can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P N = {(1minusα W )A W +A H +((1minusα C )(A S +A W α W )A C /A T = )}σT RC 4 where α C is the capsule albedo, A C is the capsule area, A T triple b ond (A S +A W +A H ), and T RC is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented

Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Moore, A. S., E-mail: alastair.moore@physics.org; Graham, P.; Comley, A. J.; Foster, J. [Directorate Science and Technology, AWE Aldermaston, Reading RG7 4PR (United Kingdom); Cooper, A. B. R.; Schneider, M. B.; MacLaren, S.; Lu, K.; Seugling, R.; Satcher, J.; Klingmann, J.; Marrs, R.; May, M.; Widmann, K.; Glendinning, G.; Castor, J.; Sain, J.; Baker, K.; Hsing, W. W.; Young, B. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

2014-06-15

Experiments that characterize and develop a high energy-density half-hohlraum platform for use in benchmarking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic diffusive Marshak wave, which propagates into a high atomic number Ta{sub 2}O{sub 5} aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range of x-ray measurements that absolutely quantify the energetics and radiation partition inside the target.

Experimental results and modeling of a dynamic hohlraum on SATURN

International Nuclear Information System (INIS)

Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J.; Matuska, W.; Peterson, D.L.; MacFarlane, J.J.; Ryutov, D.D.

1998-06-01

Experiments were performed at SATURN, a high current z-pinch, to explore the feasibility of creating a hohlraum by imploding a tungsten wire array onto a low-density foam. Emission measurements in the 200--280 eV energy band were consistent with a 110--135 eV Planckian before the target shock heated, or stagnated, on-axis. Peak pinch radiation temperatures of nominally 160 eV were obtained. Measured early time x-ray emission histories and temperature estimates agree well with modeled performance in the 200--280 eV band using a 2D radiation magneto-hydrodynamics code. However, significant differences are observed in comparisons of the x-ray images and 2D simulations

Rugby and elliptical-shaped hohlraums experiments on the OMEGA laser facility

Science.gov (United States)

Tassin, Veronique; Monteil, Marie-Christine; Depierreux, Sylvie; Masson-Laborde, Paul-Edouard; Philippe, Franck; Seytor, Patricia; Fremerye, Pascale; Villette, Bruno

2017-10-01

We are pursuing on the OMEGA laser facility indirect drive implosions experiments in gas-filled rugby-shaped hohlraums in preparation for implosion plateforms on LMJ. The question of the precise wall shape of rugby hohlraum has been addressed as part of future megajoule-scale ignition designs. Calculations show that elliptical-shaped holhraum is more efficient than spherical-shaped hohlraum. There is less wall hydrodynamics and less absorption for the inner cone, provided a better control of time-dependent symmetry swings. In this context, we have conducted a series of experiments on the OMEGA laser facility. The goal of these experiments was therefore to characterize energetics with a complete set of laser-plasma interaction measurements and capsule implosion in gas-filled elliptical-shaped hohlraum with comparison with spherical-shaped hohlraum. Experiments results are discussed and compared to FCI2 radiation hydrodynamics simulations.

Progress of LMJ-relevant implosions experiments on OMEGA

Directory of Open Access Journals (Sweden)

Casner A.

2013-11-01

Full Text Available In preparation of the first ignition attempts on the Laser Mégajoule (LMJ, an experimental program is being pursued on OMEGA to investigate LMJ-relevant hohlraums. First, radiation temperature levels close to 300 eV were recently achieved in reduced-scale hohlraums with modest backscatter losses. Regarding the baseline target design for fusion experiments on LMJ, an extensive experimental database has also been collected for scaled implosions experiments in both empty and gas-filled rugby-shaped hohlraums. We acquired a full picture of hohlraum energetics and implosion dynamics. Not only did the rugby hohlraums show significantly higher x-ray drive energy over the cylindrical hohlraums, but symmetry control by power balance was demonstrated, as well as high-performance D2 implosions enabling the use of a complete suite of neutrons diagnostics. Charged particle diagnostics provide complementary insights into the physics of these x-ray driven implosions. An overview of these results demonstrates our ability to control the key parameters driving the implosion, lending more confidence in extrapolations to ignition-scale targets.

Numerical investigation on target implosions driven by radiation ablation and shock compression in dynamic hohlraums

Energy Technology Data Exchange (ETDEWEB)

Xiao, Delong; Sun, Shunkai; Zhao, Yingkui; Ding, Ning; Wu, Jiming; Dai, Zihuan; Yin, Li; Zhang, Yang; Xue, Chuang [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2015-05-15

In a dynamic hohlraum driven inertial confinement fusion (ICF) configuration, the target may experience two different kinds of implosions. One is driven by hohlraum radiation ablation, which is approximately symmetric at the equator and poles. The second is caused by the radiating shock produced in Z-pinch dynamic hohlraums, only taking place at the equator. To gain a symmetrical target implosion driven by radiation ablation and avoid asymmetric shock compression is a crucial issue in driving ICF using dynamic hohlraums. It is known that when the target is heated by hohlraum radiation, the ablated plasma will expand outward. The pressure in the shocked converter plasma qualitatively varies linearly with the material temperature. However, the ablation pressure in the ablated plasma varies with 3.5 power of the hohlraum radiation temperature. Therefore, as the hohlraum temperature increases, the ablation pressure will eventually exceed the shock pressure, and the expansion of the ablated plasma will obviously weaken the shock propagation and decrease its velocity after propagating into the ablator plasma. Consequently, longer time duration is provided for the symmetrical target implosion driven by radiation ablation. In this paper these processes are numerically investigated by changing drive currents or varying load parameters. The simulation results show that a critical hohlraum radiation temperature is needed to provide a high enough ablation pressure to decelerate the shock, thus providing long enough time duration for the symmetric fuel compression driven by radiation ablation.

The x-ray laser as a tool for imaging plasmas

International Nuclear Information System (INIS)

Libby, S.B.; Da Silva, L.B.; Barbee, T.W. Jr.

1995-07-01

The x-ray laser is now being used at LLNL as a tool for measuring the behaviors of hot dense plasmas. In particular, we have used the 155 Angstrom yttrium laser to study transient plasmas by both radiography and moire deflectrometry. These techniques have been used to probe long scale length plasmas at electron densities exceeding 10 22 cm -3 . Recent advances in multilayer technology have made it possible to directly image ion densities in directly driven thin foils to an accuracy of 1--2 μm. In addition, we have constructed an x-ray laser Mach-Zehnder interferometer using multilayer beam-splitters. This interferometer yields direct 2D projections of electron densities in plasmas with micron spatial resolution. In addition, this interferometer can be used to measure spectral line shapes to high accuracy. Among the subject plasmas under study are laser irradiated planar targets, gold hohlraums, and x-ray lasers themselves

Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on NIF

Science.gov (United States)

Callahan, Debra

2017-10-01

Over the past two years, we have been exploring low gasfill hohlraums (He fill at 0.3-0.6 mg/cc) as an alternate to the high gasfill hohlraums used in NIC and the High Foot campaigns (He fill at 1-1.6 mg/cc). These low fill hohlraums have significantly reduced laser-plasma instabilities and increased coupling to the target as compared to the high fill hohlraums and take us to a new region of parameter space where the hohlraum is limited by hydrodynamic motion of the hohlraum wall rather than by laser plasma interactions. The outer cone laser beams interacting with the hohlraum wall produce a ``bubble'' of low density, high Z material that moves toward the center of the hohlraum. This gold or depleted uranium bubble eventually intercepts the inner cone beams and prevents the inner cone beams from reaching the waist of the hohlraum-where they are needed to get a symmetric implosion. Thus, the speed of the bubble expansion sets the allowable pulse duration in a given size hohlraum. Data and simulations suggest that the bubble is launched by the early part of the laser pulse (``picket'') and the gold/gas interfaces moves nearly linearly in time toward the axis of the hohlraum. The velocity of the bubble is related to the square root of the energy in the picket of the pulse - thus the picket energy and pulse duration set the allowable hohlraum size and case-to-capsule ratio. In this talk, will discuss a data based model to describe the bubble motion and apply this model to a broad set of data from a variety of ablators (CH, HDC, Be), pulse durations (6-14 ns), case-to-capsule ratios (rhohl/rcap of 3-4.2), hohlraum sizes (5.4-6.7 mm diameter), and hohlraum gasfill densities (0.3-0.6 mg/cc). We will discuss how this model can help guide future designs and how improvements in the hohlraum (foam liners, hohlraum shape) can open up new parts of parameter space. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National

The near vacuum hohlraum campaign at the NIF: A new approach

Science.gov (United States)

Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Mackinnon, A. J.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G.; Haan, S.; Izumi, N.; Hatarik, R.; Sterne, P.; Celliers, P.; Ralph, J.; Rygg, R.; Strozzi, D.; Kilkenny, J.; Rosenberg, M.; Rinderknecht, H.; Sio, H.; Gatu-Johnson, M.; Frenje, J.; Petrasso, R.; Zylstra, A.; Town, R.; Hurricane, O.; Nikroo, A.; Edwards, M. J.

2016-05-01

The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

The near vacuum hohlraum campaign at the NIF: A new approach

Energy Technology Data Exchange (ETDEWEB)

Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

2016-05-15

The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

Absolute Hugoniot measurements from a spherically convergent shock using x-ray radiography

Science.gov (United States)

Swift, Damian C.; Kritcher, Andrea L.; Hawreliak, James A.; Lazicki, Amy; MacPhee, Andrew; Bachmann, Benjamin; Döppner, Tilo; Nilsen, Joseph; Collins, Gilbert W.; Glenzer, Siegfried; Rothman, Stephen D.; Kraus, Dominik; Falcone, Roger W.

2018-05-01

The canonical high pressure equation of state measurement is to induce a shock wave in the sample material and measure two mechanical properties of the shocked material or shock wave. For accurate measurements, the experiment is normally designed to generate a planar shock which is as steady as possible in space and time, and a single state is measured. A converging shock strengthens as it propagates, so a range of shock pressures is induced in a single experiment. However, equation of state measurements must then account for spatial and temporal gradients. We have used x-ray radiography of spherically converging shocks to determine states along the shock Hugoniot. The radius-time history of the shock, and thus its speed, was measured by radiographing the position of the shock front as a function of time using an x-ray streak camera. The density profile of the shock was then inferred from the x-ray transmission at each instant of time. Simultaneous measurement of the density at the shock front and the shock speed determines an absolute mechanical Hugoniot state. The density profile was reconstructed using the known, unshocked density which strongly constrains the density jump at the shock front. The radiographic configuration and streak camera behavior were treated in detail to reduce systematic errors. Measurements were performed on the Omega and National Ignition Facility lasers, using a hohlraum to induce a spatially uniform drive over the outside of a solid, spherical sample and a laser-heated thermal plasma as an x-ray source for radiography. Absolute shock Hugoniot measurements were demonstrated for carbon-containing samples of different composition and initial density, up to temperatures at which K-shell ionization reduced the opacity behind the shock. Here we present the experimental method using measurements of polystyrene as an example.

Radiation symmetry control for inertial confinement fusion capsule implosions in double Z-pinch hohlraums on Z

International Nuclear Information System (INIS)

Vesey, Roger A.; Cuneo, Michael E.; Porter, John L. Jr.; Adams, Richard G.; Aragon, Rafael A.; Rambo, Patrick K.; Ruggles, Laurence E.; Simpson, Walter W.; Smith, Ian C.; Bennett, Guy R.

2003-01-01

The double Z-pinch hohlraum high-yield concept [Hammer et al., Phys. Plasmas 6, 2129 (1999)] utilizes two 63-MA Z pinches to heat separate primary hohlraums at either end of a secondary hohlraum containing the cryogenic fusion capsule. Recent experiments on the Z accelerator [Spielman et al., Phys. Plasmas 5, 2105 (1998)] at Sandia National Laboratories have developed an advanced single-sided power feed, double Z-pinch load to study radiation symmetry and pinch power balance using implosion capsules [Cuneo et al., Phys. Rev. Lett. 88, 215004 (2002)]. Point-projection x-ray imaging with the Z-Beamlet Laser mapped the trajectory and distortion of 2-mm diameter plastic ablator capsules. Using the backlit capsule distortion as a symmetry diagnostic, the ability to predictably tune symmetry at the 2 Legendre mode asymmetry coefficient over a range of ±6% (±2% considering points nearest the optimum) was achieved by varying the length of the cylindrical secondary hohlraum containing the capsule, in agreement with viewfactor and radiation-hydrodynamics simulations

Data Analysis of the Gated-LEH X-Ray Imaging Diagnostic at the NIF

Science.gov (United States)

Thibodeau, Matthew; Chen, Hui

2017-10-01

The Gated Laser Entrance Hole (G-LEH) x-ray imaging diagnostic in use at the NIF offers a desirable combination of spatial and temporal resolution. By looking inside of NIF hohlraums with time resolution, G-LEH measures target features including LEH size and capsule size. A framework is presented for automated and systematic analysis of G-LEH images that measures several physical parameters of interest and their evolution over time. The results from these analyses enable comparisons with hohlraum models and allow model validation of LEH closure velocity and the extent of capsule blow-off. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

2-D simulation of hohlraum targets for HIDIF: gold vs. beryllium converters

International Nuclear Information System (INIS)

Honrubia, J.J.; Meyer-ter-Vehn, J.

2000-01-01

Two cylindrical hohlraum targets for heavy-ion-fusion are compared from the point of view of total ion-energy required to ignite a specified capsule. Target a, a simple bare gold cylindrical cavity behaves much more efficiently than Target b, the former one internally cladded with solid beryllium where convenient, to ensure ion energy conversion to X-rays mainly in this cladding. A discussion of the problem is provided. (authors)

Proton imaging of hohlraum plasma stagnation in inertial-confinement-fusion experiments

International Nuclear Information System (INIS)

Li, C.K.; Séguin, F.H.; Frenje, J.A.; Sinenian, N.; Rosenberg, M.J.; Manuel, M.J.-E; Rinderknecht, H.G.; Zylstra, A.B.; Petrasso, R.D.; Amendt, P.A.; Landen, O.L.; Mackinnon, A.J.; Town, R.P.J.; Wilks, S.C.; Betti, R.; Meyerhofer, D.D.; Soures, J.M.; Hund, J.; Kilkenny, J.D.; Nikroo, A.

2013-01-01

Proton radiography of the spatial structure and temporal evolution of plasma blowing off from a hohlraum wall reveals how the fill gas compresses the wall blow-off, inhibits plasma jet formation and impedes plasma stagnation in the hohlraum interior. The roles of spontaneously generated electric and magnetic fields in hohlraum dynamics and capsule implosions are demonstrated. The heat flux is shown to rapidly convect the magnetic field due to the Nernst effect, which is shown to be ∼10 times faster than convection by the plasma fluid from expanded wall blow-off (v N ∼ 10v). This leads to inhibition of heat transfer from the gas region in the laser beam paths to the surrounding cold gas, resulting in a local plasma temperature increase. The experiments show that interpenetration of the two materials (gas and wall) occurs due to the classical Rayleigh–Taylor instability as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blow-off. This experiment provides physics insight into the effects of fill gas on x-ray-driven implosions, and would impact the ongoing ignition experiments at the National Ignition Facility. (paper)

Indirect-drive ablative Rayleigh-Taylor growth experiments on the Shenguang-II laser facility

Energy Technology Data Exchange (ETDEWEB)

Wu, J. F.; Fan, Z. F.; Zheng, W. D.; Wang, M.; Pei, W. B.; Zhu, S. P.; Zhang, W. Y. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Miao, W. Y.; Yuan, Y. T.; Cao, Z. R.; Deng, B.; Jiang, S. E.; Liu, S. Y.; Ding, Y. K. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, L. F.; Ye, W. H., E-mail: ye-wenhua@iapcm.ac.cn; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2014-04-15

In this research, a series of single-mode, indirect-drive, ablative Rayleigh-Taylor (RT) instability experiments performed on the Shenguang-II laser facility [X. T. He and W. Y. Zhang, Eur. Phys. J. D 44, 227 (2007)] using planar target is reported. The simulation results from the one-dimensional hydrocode for the planar foil trajectory experiment indicate that the energy flux at the hohlraum wall is obviously less than that at the laser entrance hole. Furthermore, the non-Planckian spectra of x-ray source can strikingly affect the dynamics of the foil flight and the perturbation growth. Clear images recorded by an x-ray framing camera for the RT growth initiated by small- and large-amplitude perturbations are obtained. The observed onset of harmonic generation and transition from linear to nonlinear growth regime is well predicted by two-dimensional hydrocode simulations.

Lithium beam characterization of cylindrical PBFA II hohlraum experiments

International Nuclear Information System (INIS)

Moats, A.R.; Derzon, M.S.; Chandler, G.A.; Haill, T.A.; Johnson, D.J.; Leeper, R.J.; Ruiz, C.L.; Wenger, D.F.

1995-01-01

Sandia National Laboratories is actively engaged in exploring indirect-drive inertial confinement fusion on the Particle Beam Fusion Accelerator (PBFA II) with pulsed-power accelerated lithium ions as the driver. Experiments utilizing cylindrical hohlraum targets were conducted in 1994. Using the incoming ion beam-induced line radiation from titanium wires surrounding these hohlraums, beam profiles during these experiments have been measured and characterized. These data, their comparison/cross-correlation with particle-based beam diagnostics, and an analysis of the beam parameters that most significantly influence target temperature are presented

Design for LTE EOS and opacity experiments using supersonic radiation waves

Science.gov (United States)

Tierney, T. E.; Peterson, R. R.; Tierney, H. E.

2007-11-01

Opacity and EOS at 100-200 eV are important physical parameters in ICF experiments. We describe an experiment design that uses the supersonic propagation of hohlraum radiation in foams to isochorically heat samples. Laser and Z-pinch experiments frequently use 150 to 220-eV quasi-blackbody emission from hohlraums to drive physics experiments. A foam target encapsulated in a gold-wall cylinder is placed next to the hohlraum. The low density and opacity foam captures some hohlraum emission and generates a supersonically-propagating radiation wave. The material heated by the wave is cooler towards the high-albedo gold wall. Modeling and past measurements show that core regions of the foam have small thermal gradients. We place a small, thin sample (e.g., Al, Si, or Fe) in the thermally-uniform region. X-ray emission of tracers and the sample as well as quasi-continuum x-ray absorption will be measured using time-resolved x-ray spectroscopy. The foam's EOS can be measured to ±5% by blast waves with a well characterized drive. This experiment could use the OMEGA, Z-Beamlet, and/or ZR facilities to explore temperature-dependent conditions.

Wall-shaped hohlraum influence on symmetry and energetics in gas-filled hohlraums

Science.gov (United States)

Tassin, Veronique; Philippe, Franck; Laffite, Stephane; Videau, Laurent; Monteil, Marie-Christine; Villette, Bruno; Stemmler, Philippe; Bednarczyk, Sophie; Peche, Emilie; Reneaume, Benoit; Thessieux, Christian

2008-11-01

On the way to the LMJ completion, achieving ignition with 40 quads in a 2-cone configuration will be attempted as a first step. Theoretical investigation of a rugby-shaped hohlraum shows energetics optimization and a better symmetry control compared to a cylindrical hohlraum [1]. We recently conducted experiments on the Omega laser facility with 3 different wall-shaped methane-filled hohlraum configurations. We present here the experimental results. Energetics benefits are shown for reduced wall area hohlraums. The wall-shaped hohlraum influence on time-dependent radiation symmetry is also discussed. For the 3 gas-filled hohlraums configurations, we compare the foamball early-time radiographs, the D2Ar-filled capsule time-integrated images and the core self-emission images. [1] M. Vandenboomgaerde, Phys. Rev. Lett., 99, 065004 (2007).

First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole

Directory of Open Access Journals (Sweden)

Wenyi Huo

2016-01-01

Full Text Available The octahedral spherical hohlraums have natural superiority in maintaining high radiation symmetry during the entire capsule implosion process in indirect drive inertial confinement fusion. While, in contrast to the cylindrical hohlraums, the narrow space between the laser beams and the spherical hohlraum wall is usually commented. In this Letter, we address this crucial issue and report our experimental work conducted on the SGIII-prototype laser facility which unambiguously demonstrates that a simple design of cylindrical laser entrance hole (LEH can dramatically improve the laser propagation inside the spherical hohlraums. In addition, the laser beam deflection in the hohlraum is observed for the first time in the experiments. Our 2-dimensional simulation results also verify qualitatively the advantages of the spherical hohlraums with cylindrical LEHs. Our results imply the prospect of adopting the cylindrical LEHs in future spherical ignition hohlraum design.

An iterative method for unfolding time-resolved soft x-ray spectra of laser plasmas

International Nuclear Information System (INIS)

Tang Yongjian; Shen Kexi; Xu Hepin

1991-01-01

Dante-recorded temporal waveforms have been unfolded by using Fast Fourier transformation (FFT) and the inverted convolution theorem of Fourier analysis. The conversion of the signals to time-dependent soft x-ray spectra is accomplished on the IBM-PC/XT-286 microcomputer system with the code DTSP including SAND II reported by W.N.Mcelory et al.. An amplitude-limited iterative and periodic smoothing technique has been developed in the code DTSP. Time-resolved soft x-ray spectra with sixteen time-cell, and time-dependent radiation, [T R (t)], have been obtained for hohlraum targets irradiated with laser beams (λ = 1.06 μm) on LF-12 in 1989

Diagnosing x-ray power and energy of tungsten wire array z-pinch with a flat spectral response x-ray diode

International Nuclear Information System (INIS)

Wang, Kun-lun; Ren, Xiao-dong; Huang, Xian-bin; Zhang, Si-qun; Zhou, Shao-tong; Dan, Jia-kun; Li, Jing; Xu, Qiang; Ouyang, Kai; Cai, Hong-chun; Wei, Bing; Ji, Ce; Feng, Shu-ping; Wang, Meng; Xie, Wei-ping; Deng, Jian-jun

2015-01-01

Fast z-pinch is a very efficient way of converting electromagnetic energy to radiation. With an 8-10 MA current on primary test stand facility, about 1 MJ electromagnetic energy is delivered to vacuum chamber, which heats z-pinch plasma to radiate soft x-ray. To develop a pulsed high power x-ray source, we studied the applicability of diagnosing x-ray power from tungsten wire array z-pinch with a flat spectral response x-ray diode (FSR-XRD). The detector was originally developed to diagnose radiation of a hohlraum in SG-III prototype laser facility. It utilized a gold cathode XRD and a specially configured compound gold filter to yield a nearly flat spectral response in photon energy range of 0.1-4 keV. In practice, it was critical to avoid surface contamination of gold cathode. It is illustrated that an exposure of an XRD to multiple shots caused a significant change of response. Thus, in diagnosing x-ray power and energy, we used each XRD in only one shot after calibration. In a shot serial, output of FSR-XRD was compared with output of a nickel bolometer. In these shots, the outputs agreed with each other within their uncertainties which were about 12% for FSR-XRD and about 15% for bolometer. Moreover, the ratios between the FSR-XRD and the bolometer among different shots were explored. In 8 shots, the standard deviation of the ratio was 6%. It is comparable to XRD response change of 7%

High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

International Nuclear Information System (INIS)

Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

2015-01-01

A recent low gas-fill density (0.6 mg/cc 4 He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4 He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth

High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

Science.gov (United States)

Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

2015-04-01

A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

Energy Technology Data Exchange (ETDEWEB)

Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2015-04-15

A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

Progress in octahedral spherical hohlraum study

Directory of Open Access Journals (Sweden)

Ke Lan

2016-01-01

Full Text Available In this paper, we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study. From our theoretical study, the octahedral spherical hohlraums with 6 Laser Entrance Holes (LEHs of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7. In addition, the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology. We studied the laser arrangement and constraints of the octahedral spherical hohlraums, and gave a design on the laser arrangement for ignition octahedral hohlraums. As a result, the injection angle of laser beams of 50°–60° was proposed as the optimum candidate range for the octahedral spherical hohlraums. We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields, in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport. We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums, the rugby hohlraums and the cylindrical hohlraums, and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive. Up till to now, we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG laser facilities, including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums, spherical hohlraum energetics on the SGIII prototype laser facility, and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.

Radiation drive with a composite laser pulse shape

International Nuclear Information System (INIS)

Cobble, James A.; Tubbs, David L.; Hoffman, Nelson M.; Swift, Damian C.; Tierney, Thomas

2004-01-01

The objective is to develop a 6-ns Hohlraum environment on Omega for Be anisotropy studies. In particular, they are seeking an environment for Be isotropy studies with enough growth times to assess the suitability of Be for NIF ignition capsules. In 20 shots to date, we have: (1) synchronized 2 laser pulse shapes at Omega to obtain a smooth halfraum drive for ∼6 ns; (2) characterized the drive with Dante (∼180 eV peak); (3) obtained high quality VISAR data (using a mirror); (4) measured ejected Be sample velocity; (5) made the first estimates of Au migration to the axis of the vacuum halfraum; and (6) collected the first face-on x-ray images of sinusoidally perturbed Be samples. The immediate objective is to qualify a target for the Be studies. To that end, we hope: (1) to explore alternate foot drives; (2) optimize the radiography; and (3) to field and characterize gas-filled targets within the next 6 months.

Z-pinch driven inertial confinement fusion target physics research at Sandia National Laboratories

International Nuclear Information System (INIS)

Leeper, R.J.; Alberts, T.E.; Asay, J.R.

2001-01-01

Three hohlraum concepts are being pursued at Sandia National Laboratories (SNL) to investigate the possibility of using pulsed power driven magnetic implosions (z-pinches) to drive high gain targets capable of yields in the range of 200-1000 MJ. This research is being conducted on SNL's Z facility that is capable of driving peak currents of 20 MA in z-pinch loads producing implosion velocities as high as 7.5x10 7 cm/s, x-ray energies approaching 2 MJ, and x-ray powers exceeding 200 TW. This paper will discuss each of these hohlraum concepts and will overview the experiments that have been conducted on these systems to date. (author)

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

Science.gov (United States)

Döppner, T; Callahan, D A; Hurricane, O A; Hinkel, D E; Ma, T; Park, H-S; Berzak Hopkins, L F; Casey, D T; Celliers, P; Dewald, E L; Dittrich, T R; Haan, S W; Kritcher, A L; MacPhee, A; Le Pape, S; Pak, A; Patel, P K; Springer, P T; Salmonson, J D; Tommasini, R; Benedetti, L R; Bond, E; Bradley, D K; Caggiano, J; Church, J; Dixit, S; Edgell, D; Edwards, M J; Fittinghoff, D N; Frenje, J; Gatu Johnson, M; Grim, G; Hatarik, R; Havre, M; Herrmann, H; Izumi, N; Khan, S F; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Merrill, F E; Moody, J; Moore, A S; Nikroo, A; Ralph, J E; Remington, B A; Robey, H F; Sayre, D; Schneider, M; Streckert, H; Town, R; Turnbull, D; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

2015-07-31

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

3D Simulations of the ``Keyhole'' Hohlraum for Shock Timing on NIF

Science.gov (United States)

Robey, H. F.; Marinak, M. M.; Munro, D. H.; Jones, O. S.

2007-11-01

Ignition implosions planned for the National Ignition Facility (NIF) require a pulse shape with a carefully designed series of steps, which launch a series of shocks through the ablator and DT fuel. The relative timing of these shocks must be tuned to better than +/- 100ps to maintain the DT fuel on a sufficiently low adiabat. To meet these requirements, pre-ignition tuning experiments using a modified hohlraum geometry are being planned. This modified geometry, known as the ``keyhole'' hohlraum, adds a re-entrant gold cone, which passes through the hohlraum and capsule walls, to provide an optical line-of-sight to directly measure the shocks as they break out of the ablator. In order to assess the surrogacy of this modified geometry, 3D simulations using HYDRA [1] have been performed. The drive conditions and the resulting effect on shock timing in the keyhole hohlraum will be compared with the corresponding results for the standard ignition hohlraum. [1] M.M. Marinak, et al., Phys. Plasmas 8, 2275 (2001).

Platform development of x-ray absorption-based temperature measurements above 100-eV on the OMEGA laser

Science.gov (United States)

Workman, Jonathan; Keiter, P.; Tierney, T.; Tierney, H.; Belle, K.; Magelssen, G.; Peterson, R.; Fryer, C.; Comley, A.; Taylor, M.

2007-11-01

Experiments were performed on the OMEGA laser system at the University of Rochester to measure radiation temperature in hohlraum-heated foams. Using x-ray absorption spectroscopy in the 3-6-keV x-ray range allows temperature determination in the range of 50-200-eV. Uranium, bismuth and gold M-shell x-ray emission were used as broadband backlighters. Backlighter absorption through heated chlorinated foam and scandium tracers were used to determine temperatures. The development of this technique in the temperature range of 100-200-eV will be used for platform development of future NIF experiments. We will present time-integrated and time-resolved measurements of x-ray emission from the backlighter materials as well as absorption measurements trough the heated tracer materials. We will also present future directions in the development of this platform.

Laser-Plasma Interactions in Drive Campaign targets on the National Ignition Facility

International Nuclear Information System (INIS)

Hinkel, D E; Callahan, D A; Moody, J D; Amendt, P A; Lasinski, B F; MacGowan, B J; Meeker, D; Michel, P A; Ralph, J; Rosen, M D; Ross, J S; Schneider, M B; Storm, E; Strozzi, D J; Williams, E A

2016-01-01

The Drive campaign [D A Callahan et al., this conference] on the National Ignition Facility (NIF) laser [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, R. Al-Ayat, Phys. Plasmas 16, 041006 (2009)] has the focused goal of understanding and optimizing the hohlraum for ignition. Both the temperature and symmetry of the radiation drive depend on laser and hohlraum characteristics. The drive temperature depends on the coupling of laser energy to the hohlraum, and the symmetry of the drive depends on beam-to-beam interactions that result in energy transfer [P. A. Michel, S. H. Glenzer, L. Divol, et al, Phys. Plasmas 17, 056305 (2010).] within the hohlraum. To this end, hohlraums are being fielded where shape (rugby vs. cylindrical hohlraums), gas fill composition (neopentane at room temperature vs. cryogenic helium), and gas fill density (increase of ∼ 150%) are independently changed. Cylindrical hohlraums with higher gas fill density show improved inner beam propagation, as should rugby hohlraums, because of the larger radius over the capsule (7 mm vs. 5.75 mm in a cylindrical hohlraum). Energy coupling improves in room temperature neopentane targets, as well as in hohlraums at higher gas fill density. In addition cross-beam energy transfer is being addressed directly by using targets that mock up one end of a hohlraum, but allow observation of the laser beam uniformity after energy transfer. Ideas such as splitting quads into “doublets” by re-pointing the right and left half of quads are also being pursued. LPI results of the Drive campaign will be summarized, and analyses of future directions presented. (paper)

Numerical simulations of inertial confinement fusion hohlraum with LARED-integration code

International Nuclear Information System (INIS)

Li Jinghong; Li Shuanggui; Zhai Chuanlei

2011-01-01

In the target design of the Inertial Confinement Fusion (ICF) program, it is common practice to apply radiation hydrodynamics code to study the key physical processes happened in ICF process, such as hohlraum physics, radiation drive symmetry, capsule implosion physics in the radiation-drive approach of ICF. Recently, many efforts have been done to develop our 2D integrated simulation capability of laser fusion with a variety of optional physical models and numerical methods. In order to effectively integrate the existing codes and to facilitate the development of new codes, we are developing an object-oriented structured-mesh parallel code-supporting infrastructure, called JASMIN. Based on two-dimensional three-temperature hohlraum physics code LARED-H and two-dimensional multi-group radiative transfer code LARED-R, we develop a new generation two-dimensional laser fusion code under the JASMIN infrastructure, which enable us to simulate the whole process of laser fusion from the laser beams' entrance into the hohlraum to the end of implosion. In this paper, we will give a brief description of our new-generation two-dimensional laser fusion code, named LARED-Integration, especially in its physical models, and present some simulation results of holhraum. (author)

Symmetry control in subscale near-vacuum hohlraums

Science.gov (United States)

Turnbull, D.; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; Meezan, N.; Landen, O. L.; Ho, D. D.; Mackinnon, A.; Zylstra, A. B.; Rinderknecht, H. G.; Sio, H.; Petrasso, R. D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E. L.; Callahan, D. A.; Hurricane, O.; Hsing, W. W.; Edwards, M. J.

2016-05-01

Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.

Symmetry control in subscale near-vacuum hohlraums

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D., E-mail: turnbull2@llnl.gov; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; Meezan, N.; Landen, O. L.; Ho, D. D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E. L.; Callahan, D. A.; Hurricane, O.; Hsing, W. W.; Edwards, M. J. [National Ignition Facility, LLNL, Livermore, California 94550 (United States); Mackinnon, A. [National Ignition Facility, LLNL, Livermore, California 94550 (United States); Linac Coherent Light Source, SLAC, Menlo Park, California 94025 (United States); Zylstra, A. B. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rinderknecht, H. G. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); National Ignition Facility, LLNL, Livermore, California 94550 (United States); Sio, H.; Petrasso, R. D. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States)

2016-05-15

Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.

Soft x-ray power diagnostic improvements at the Omega Laser Facility

International Nuclear Information System (INIS)

Sorce, C.; Schein, J.; Weber, F.; Widmann, K.; Campbell, K.; Dewald, E.; Turner, R.; Landen, O.; Jacoby, K.; Torres, P.; Pellinen, D.

2006-01-01

Soft x-ray power diagnostics are essential for evaluating high temperature laser plasma experiments. The Dante soft x-ray spectrometer, a core diagnostic for radiation flux and temperature measurements of Hohlraums, installed on the Omega Laser Facility at the Laboratory for Laser Energetics has recently undergone a series of upgrades. Work performed at Brookhaven National Laboratory for the development of the National Ignition Facility (NIF) Dante spectrometer enables the Omega Dante to offer a total of 18 absolutely calibrated channels in the energy range from 50 eV to 20 keV. This feature provides Dante with the capability to measure higher, NIF relevant, radiation temperatures with increased accuracy including a differentiation of higher energy radiation such as the Au M and L bands. Diagnostic monitoring using experimental data from directly driven Au spherical shots is discussed

Mitigation of stimulated Raman scattering in hohlraum plasmas

International Nuclear Information System (INIS)

Kline, J L; Montgomery, D S; Rose, H A; Goldman, S R; Froula, D H; Ross, J S; Stevenson, R M; Lushnikov, P M

2008-01-01

One aspect of recent research to control Stimulated Raman Scattering (SRS) in hohlraum plasmas is the investigation of risk mitigation strategies for indirect drive inertial confinement fusion. Experimental tests of these strategies, based on prior theoretical and experimental knowledge of SRS, are performed in hohlraum experiments. In the last year, two strategies have been investigated. The first is the use of high Z dopants to reduce SRS backscatter. Forward stimulated Brillouin scattering (FSBS) could lead to beam spray reducing SRS. Since FSBS depends on the electron temperature and thermal effects depend strongly on Z 2 , a small amount of a high Z dopant, 1-2%, can have a large effect. Experiments have been conducted at the Omega laser to test this theory by varying the amount of Xe dopant in neo-pentane gas filled hohlraums. The experimental measurements do show a decrease in SRS backscatter as Xe dopant is added. However, there are still uncertainties regarding the responsible mechanism since increases inverse-Bremsstrahlung absorption of the SRS light may play a role. The second strategy investigated is using high kλ D plasmas to reduce SRS backscatter. Experiments conducted at the Omega laser facility in hohlraum plasmas determined the critical onset intensity for a range of kλ D . A scaling of the critical onset intensity as a function of kλ D has been determined

Radial profiles of hard X-ray emission during steady state current drive in the TRIAM-1M tokamak

International Nuclear Information System (INIS)

Nakamura, Y.; Takabatake, Y.; Jotaki, E.; Moriyama, S.; Nagao, A.; Nakamura, K.; Hiraki, N.; Itoh, S.

1990-01-01

The hard X-ray emission from the TRIAM-1M tokamak plasma during steady state lower hybrid current drive with a discharge duration of a few minutes was measured with sodium iodide scintillation spectrometers. The radial profiles of the X-ray emission were also measured and indicate that, in the low density regime (n e =(1-3)x10 12 cm -3 ), the current carrying high energy electrons are mainly in the inner region of the plasma column and their radial profile remains unchanged during current drive. On the other hand, high density discharges (n e =(3-6)x10 12 cm -3 ) are always accompanied by an abrupt drop of the plasma current, and the X-ray emission profile changes from peaked to broad. This change can be attributed to the conditions of wave accessibility. As the electron density increases, the accessibility of the plasma to lower hybrid waves with low values of the parallel wave number n parallel is significantly reduced and high energy electrons resonating with the waves are produced at the plasma periphery. Interaction of these electrons with the limiters causes an increase of the electron density in this region; waves with low n parallel then become completely excluded from the inner part of the plasma column. This interpretation is supported by measurements of the density profile and impurity radiation, and has been confirmed in an investigation of discharges with additional gas puffing. (author). 17 refs, 21 figs

A final report to the Laboratory Directed Research and Development committee on Project 93-ERP-075: ''X-ray laser propagation and coherence: Diagnosing fast-evolving, high-density laser plasmas using X-ray lasers''

International Nuclear Information System (INIS)

Wan, A.S.; Cauble, R.; Da Silva, L.B.; Libby, S.B.; Moreno, J.C.

1996-02-01

This report summarizes the major accomplishments of this three-year Laboratory Directed Research and Development (LDRD) Exploratory Research Project (ERP) entitled ''X-ray Laser Propagation and Coherence: Diagnosing Fast-evolving, High-density Laser Plasmas Using X-ray Lasers,'' tracking code 93-ERP-075. The most significant accomplishment of this project is the demonstration of a new laser plasma diagnostic: a soft x-ray Mach-Zehnder interferometer using a neonlike yttrium x-ray laser at 155 angstrom as the probe source. Detailed comparisons of absolute two-dimensional electron density profiles obtained from soft x-ray laser interferograms and profiles obtained from radiation hydrodynamics codes, such as LASNEX, will allow us to validate and benchmark complex numerical models used to study the physics of laser-plasma interactions. Thus the development of soft x-ray interferometry technique provides a mechanism to probe the deficiencies of the numerical models and is an important tool for, the high-energy density physics and science-based stockpile stewardship programs. The authors have used the soft x-ray interferometer to study a number of high-density, fast evolving, laser-produced plasmas, such as the dynamics of exploding foils and colliding plasmas. They are pursuing the application of the soft x-ray interferometer to study ICF-relevant plasmas, such as capsules and hohlraums, on the Nova 10-beam facility. They have also studied the development of enhanced-coherence, shorter-pulse-duration, and high-brightness x-ray lasers. The utilization of improved x-ray laser sources can ultimately enable them to obtain three-dimensional holographic images of laser-produced plasmas

Suppression of Stimulated Brillouin Scattering in multiple-ion species inertial confinement fusion Hohlraum Plasmas

International Nuclear Information System (INIS)

Neumayer, P

2007-01-01

A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO 2 and C 3 H 8 varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ of 351-nm light, thus increasing progressively Landau damping by an order of magnitude at constant electron density and temperature. A delayed 351-nm interaction beam, spatially smoothed to produce a 200-(micro)m laser spot at best focus, has propagated along the axis of the hohlraum. The backscattered light, both into the lens and outside, the transmitted light through the hohlraum plasma and the radiation temperature of the hohlraum has been measured. For ignition relevant laser intensities (3-9 10 14 Wcm -2 ), we find that the SBS reflectivity scales as predicted with Landau damping from >30% to <1%. Simultaneously, the hohlraum radiation

Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

Science.gov (United States)

Amendt, Peter

2006-10-01

The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) [1] targets as a complementary path to the baseline cryogenic single-shell approach [2]. Benefits of DS targets include room-temperature deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances [3], and loose shock timing requirements. On the other hand, DS ignition presents several challenges, including room-temperature containment of high-pressure DT (790 atm) in the inner shell; strict concentricity requirements on the two shells; development of nanoporous, low-density, metallic foams for structural support of the inner shell and hydrodynamic instability mitigation; and effective control of perturbation growth on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition target designs using vacuum hohlraums is described, offering the potential for low levels of laser backscatter from stimulated Raman and Brillouin processes. In addition, vacuum hohlraums have the operational advantages of room temperature fielding and fabrication simplicity, as well as benefiting from extensive benchmarking on the Nova and Omega laser facilities. As an alternative to standard cylindrical hohlraums, a rugby-shaped geometry is also introduced that may provide energetics and symmetry tuning benefits for more robust DS designs with yields exceeding 10 MJ for 2 MJ of 3w laser energy. The recent progress in hohlraum designs and required advanced materials development are scheduled to culminate in a prototype demonstration of a NIF-scale ignition-ready DS in 2007. [1] P. Amendt et al., PoP 9, 2221 (2002). [2] J.D. Lindl et al., PoP 11, 339 (2004). [3] M.N. Chizhkov et al., Laser Part. Beams 23, 261 (2005). In collaboration with C. Cerjan, A. Hamza, J. Milovich and H. Robey.

Dynamic Characterizations of an 8-frame, Half-Strip, High-speed X-ray Microchannel Plate Imager

International Nuclear Information System (INIS)

Ken Moy; Ming Wu; Craig Kruschwitz; Aric Tibbits; Matt Griffin; Greg Rochau

2008-01-01

High-speed microchannel plate (MCP)-based imagers are critical detectors for x-ray diagnostics employed on Z-experiments at Sandia National Laboratories (SNL) to measure time-resolved x-ray spectra and to image dynamic hohlraums. A multiframe design using eight half strips in one imager permits recordings of radiation events in discrete temporal snapshots to yield a time-evolved movie. We present data using various facilities to characterize the performance of this design. These characterization studies include DC and pulsed-voltage biased measurements in both saturated and linear operational regimes using an intense, short-pulsed UV laser. Electrical probe measurements taken to characterize the shape of the HV pulse propagating across the strips help to corroborate the spatial gain dependence

Electron density measurement of a colliding plasma using soft x-ray laser interferometry

International Nuclear Information System (INIS)

Wan, A.S.; Back, C.A.; Barbee, T.W.Jr.; Cauble, R.; Celliers, P.; DaSilva, L.B.; Glenzer, S.; Moreno, J.C.; Rambo, P.W.; Stone, G.F.; Trebes, J.E.; Weber, F.

1996-05-01

The understanding of the collision and subsequent interaction of counter-streaming high-density plasmas is important for the design of indirectly-driven inertial confinement fusion (ICF) hohlraums. We have employed a soft x-ray Mach-Zehnder interferometer, using a Ne- like Y x-ray laser at 155 angstrom as the probe source, to study interpenetration and stagnation of two colliding plasmas. We observed a peaked density profile at the symmetry axis with a wide stagnation region with width of order 100 μm. We compare the measured density profile with density profiles calculated by the radiation hydrodynamic code LASNEX and a multi-specie fluid code which allows for interpenetration. The measured density profile falls in between the calculated profiles using collisionless and fluid approximations. By using different target materials and irradiation configurations, we can vary the collisionality of the plasma. We hope to use the soft x-ray laser interferometry as a mechanism to validate and benchmark our numerical codes used for the design and analysis of high-energy- density physics experiments

Lasers, extreme UV and soft X-ray

Energy Technology Data Exchange (ETDEWEB)

Nilsen, Joseph [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-09-20

Three decades ago, large ICF lasers that occupied entire buildings were used as the energy sources to drive the first X-ray lasers. Today X-ray lasers are tabletop, spatially coherent, high-repetition rate lasers that enable many of the standard optical techniques such as interferometry to be extended to the soft X-ray regime between wavelengths of 10 and 50 nm. Over the last decade X-ray laser performance has been improved by the use of the grazing incidence geometry, diode-pumped solid-state lasers, and seeding techniques. The dominant X-ray laser schemes are the monopole collisional excitation lasers either driven by chirped pulse amplification (CPA) laser systems or capillary discharge. The CPA systems drive lasing in neon-like or nickel-like ions, typically in the 10 – 30 nm range, while the capillary system works best for neon-like argon at 46.9 nm. Most researchers use nickel-like ion lasers near 14 nm because they are well matched to the Mo:Si multilayer mirrors that have peak reflectivity near 13 nm and are used in many applications. As a result, the last decade has seen the birth of the X-ray free electron laser (XFEL) that can reach wavelengths down to 0.15 nm and the inner-shell Ne laser at 1.46 nm.

Characteristics of a molybdenum X-pinch X-ray source as a probe source for X-ray diffraction studies

International Nuclear Information System (INIS)

Zucchini, F.; Chauvin, C.; Combes, P.; Sol, D.; Loyen, A.; Roques, B.; Grunenwald, J.; Bland, S. N.

2015-01-01

X-ray emission from a molybdenum X-pinch has been investigated as a potential probe for the high pressure states made in dynamic compression experiments. Studies were performed on a novel 300 kA, 400 ns generator which coupled the load directly to a low inductance capacitor and switch combination. The X-pinch load consisted of 4 crossed molybdenum wires of 13 μm diameter, crossed at an angle of 62°. The load height was 10 mm. An initial x-ray burst generated at the wire crossing point, radiated in the soft x-ray range (hυ < 10 keV). This was followed, 2–5 ns later, by at least one harder x-ray burst (hυ > 10 keV) whose power ranged from 1 to 7 MW. Time integrated spectral measurements showed that the harder bursts were dominated by K-alpha emission; though, a lower level, wide band continuum up to at least 30 keV was also present. Initial tests demonstrated that the source was capable of driving Laue diffraction experiments, probing uncompressed samples of LiF and aluminium

Mass-ablation-rate measurements in direct-drive cryogenic implosions using x-ray self-emission images

Energy Technology Data Exchange (ETDEWEB)

Davis, A. K., E-mail: adavi@lle.rochester.edu; Michel, D. T.; Hu, S. X.; Craxton, R. S.; Epstein, R.; Goncharov, V. N.; Igumenshchev, I. V.; Sangster, T. C.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

2014-11-15

A technique to measure the mass ablation rate in direct-drive inertial confinement fusion implosions using a pinhole x-ray framing camera is presented. In target designs consisting of two layers of different materials, two x-ray self-emission peaks from the coronal plasma were measured once the laser burned through the higher-Z outer layer. The location of the inner peak is related to the position of the ablation front and the location of the outer peak corresponds to the position of the interface of the two layers in the plasma. The emergence of the second peak was used to measure the burnthrough time of the outer layer, giving the average mass ablation rate of the material and instantaneous mass remaining. By varying the thickness of the outer layer, the mass ablation rate can be obtained as a function of time. Simulations were used to validate the methods and verify that the measurement techniques are not sensitive to perturbation growth at the ablation surface.

Observation of hydrodynamic processes of radiation-ablated plasma in a small hole

Energy Technology Data Exchange (ETDEWEB)

Li, Hang; Kuang, Longyu; Jiang, Shaoen, E-mail: jiangshn@vip.sina.com; Ding, Yongkun, E-mail: ding-yk@vip.sina.com [CAS Key Laboratory of Basic Plasma Physics and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900 (China); Song, Tianming; Yang, Jiamin, E-mail: yjm70018@sina.cn; Zhu, Tuo; Lin, Zhiwei; Zheng, Jianhua; Zhang, Haiying; Yu, Ruizhen; Liu, Shenye [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900 (China); Hu, Guangyue; Zhao, Bin; Zheng, Jian [CAS Key Laboratory of Basic Plasma Physics and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2015-07-15

In the hohlraum used in laser indirect-drive inertial confinement fusion experiments, hydrodynamic processes of radiation-ablated high-Z plasma have a great effect on laser injection efficiency, radiation uniformity, and diagnosis of hohlraum radiation field from diagnostic windows (DW). To study plasma filling in the DWs, a laser-irradiated Ti disk was used to generate 2–5 keV narrow energy band X-ray as the intense backlighter source, and laser-produced X-ray in a hohlraum with low-Z foam tamper was used to heat a small hole surrounded by gold wall with 150 μm in diameter and 100 μm deep. The hydrodynamic movement of the gold plasma in the small hole was measured by an X-ray framing camera and the results are analyzed. Quantitative measurement of the plasma areal density distribution and evolution in the small hole can be used to assess the effect of plasma filling on the diagnosis from the DWs.

X-ray ablation measurements and modeling for ICF applications

International Nuclear Information System (INIS)

Anderson, A.T.

1996-09-01

X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. Experiments have been conducted at the Nova laser on the effects of relevant x-ray fluences on various materials. The response was diagnosed using post-shot examinations of the surfaces with scanning electron microscope and atomic force microscope instruments. Judgments were made about the dominant removal mechanisms for each material. Measurements of removal depths were made to provide data for the modeling. The finite difference ablation code developed here (ABLATOR) combines the thermomechanical response of materials to x-rays with models of various removal mechanisms. The former aspect refers to energy deposition in such small characteristic depths (∼ micron) that thermal conduction and hydrodynamic motion are significant effects on the nanosecond time scale. The material removal models use the resulting time histories of temperature and pressure-profiles, along with ancillary local conditions, to predict rates of surface vaporization and the onset of conditions that would lead to spallation

Polarization-dependent force driving the Eg mode in bismuth under optical excitation: comparison of first-principles theory with ultra-fast x-ray experiments

Science.gov (United States)

Fahy, Stephen; Murray, Eamonn

2015-03-01

Using first principles electronic structure methods, we calculate the induced force on the Eg (zone centre transverse optical) phonon mode in bismuth immediately after absorption of a ultrafast pulse of polarized light. To compare the results with recent ultra-fast, time-resolved x-ray diffraction experiments, we include the decay of the force due to carrier scattering, as measured in optical Raman scattering experiments, and simulate the optical absorption process, depth-dependent atomic driving forces, and x-ray diffraction in the experimental geometry. We find excellent agreement between the theoretical predictions and the observed oscillations of the x-ray diffraction signal, indicating that first-principles theory of optical absorption is well suited to the calculation of initial atomic driving forces in photo-excited materials following ultrafast excitation. This work is supported by Science Foundation Ireland (Grant No. 12/IA/1601) and EU Commission under the Marie Curie Incoming International Fellowships (Grant No. PIIF-GA-2012-329695).

X-ray image subtracting system

International Nuclear Information System (INIS)

Wesbey, W.H.; Keyes, G.S.; Georges, J.-P.J.

1982-01-01

An X-ray image subtracting system for making low contrast structures in the images more conspicuous is described. An X-ray source projects successive high and low energy X-ray beam pulses through a body and the resultant X-ray images are converted to optical images. Two image pick-up devices such as TV cameras that have synchronously operated shutters receive the alternate images and convert them to corresponding analog video signals. In some embodiments, the analog signals are converted to a matrix of digital pixel signals that are variously processed and subtracted and converted to signals for driving a TV monitor display and analog storage devices. In other embodiments the signals are processed and subtracted in analog form for display. The high and low energy pulses can follow each other immediately so good registration between subtracted images is obtainable even though the anatomy is in motion. The energy levels of the X-ray pulses are chosen to maximize the difference in attenuation between the anatomical structure which is to be subtracted out and that which remains. (author)

Relationship between symmetry and laser pulse shape in low-fill hohlraums at the National Ignition Facility

Science.gov (United States)

MacLaren, Steve; Zylstra, A. B.; Yi, A.; Kline, J. L.; Kyrala, G. A.; Kot, L. B.; Loomis, E. N.; Perry, T. S.; Shah, R. C.; Masse, L. P.; Ralph, J. E.; Khan, S. F.

2017-10-01

Typically in indirect-drive inertial confinement fusion (ICF) hohlraums cryogenic helium gas fill is used to impede the motion of the hohlraum wall plasma as it is driven by the laser pulse. A fill of 1 mg/cc He has been used to significantly suppress wall motion in ICF hohlraums at the National Ignition Facility (NIF); however, this level of fill also causes laser-plasma instabilities (LPI) which result in hot electrons, time-dependent symmetry swings and reduction in drive due to increased backscatter. There are currently no adequate models for these phenomena in codes used to simulate integrated ICF experiments. A better compromise is a fill in the range of 0.3 0.6 mg/cc, which has been shown to provide some reduction in wall motion without incurring significant LPI effects. The wall motion in these low-fill hohlraums and the resulting effect on symmetry due to absorption of the inner cone beams by the outer cone plasma can be simulated with some degree of accuracy with the hydrodynamics and inverse Bremsstrahlung models in ICF codes. We describe a series of beryllium capsule implosions in 0.3 mg/cc He fill hohlraums that illustrate the effect of pulse shape on implosion symmetry in the ``low-fill'' regime. In particular, we find the shape of the beginning or ``foot'' of the pulse has significant leverage over the final symmetry of the stagnated implosion. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

Conceptual design of initial opacity experiments on the national ignition facility

Science.gov (United States)

Heeter, R. F.; Bailey, J. E.; Craxton, R. S.; Devolder, B. G.; Dodd, E. S.; Garcia, E. M.; Huffman, E. J.; Iglesias, C. A.; King, J. A.; Kline, J. L.; Liedahl, D. A.; McKenty, P. W.; Opachich, Y. P.; Rochau, G. A.; Ross, P. W.; Schneider, M. B.; Sherrill, M. E.; Wilson, B. G.; Zhang, R.; Perry, T. S.

2017-02-01

Accurate models of X-ray absorption and re-emission in partly stripped ions are necessary to calculate the structure of stars, the performance of hohlraums for inertial confinement fusion and many other systems in high-energy-density plasma physics. Despite theoretical progress, a persistent discrepancy exists with recent experiments at the Sandia Z facility studying iron in conditions characteristic of the solar radiative-convective transition region. The increased iron opacity measured at Z could help resolve a longstanding issue with the standard solar model, but requires a radical departure for opacity theory. To replicate the Z measurements, an opacity experiment has been designed for the National Facility (NIF). The design uses established techniques scaled to NIF. A laser-heated hohlraum will produce X-ray-heated uniform iron plasmas in local thermodynamic equilibrium (LTE) at temperatures eV and electron densities 21~\\text{cm}-3$ . The iron will be probed using continuum X-rays emitted in a ps, diameter source from a 2 mm diameter polystyrene (CH) capsule implosion. In this design, of the NIF beams deliver 500 kJ to the mm diameter hohlraum, and the remaining directly drive the CH capsule with 200 kJ. Calculations indicate this capsule backlighter should outshine the iron sample, delivering a point-projection transmission opacity measurement to a time-integrated X-ray spectrometer viewing down the hohlraum axis. Preliminary experiments to develop the backlighter and hohlraum are underway, informing simulated measurements to guide the final design.

Early time implosion symmetry from two-axis shock-timing measurements on indirect drive NIF experiments

Energy Technology Data Exchange (ETDEWEB)

Moody, J. D., E-mail: moody4@llnl.gov; Robey, H. F.; Celliers, P. M.; Munro, D. H.; Barker, D. A.; Baker, K. L.; Döppner, T.; Hash, N. L.; Berzak Hopkins, L.; LaFortune, K.; Landen, O. L.; LePape, S.; MacGowan, B. J.; Ralph, J. E.; Ross, J. S.; Widmayer, C. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Nikroo, A.; Giraldez, E. [General Atomics, San Diego, California 92186-5608 (United States); Boehly, T. [Laboratory for Laser Energetics, Rochester, New York 14623-1299 (United States)

2014-09-15

An innovative technique has been developed and used to measure the shock propagation speed along two orthogonal axes in an inertial confinement fusion indirect drive implosion target. This development builds on an existing target and diagnostic platform for measuring the shock propagation along a single axis. A 0.4 mm square aluminum mirror is installed in the ablator capsule which adds a second orthogonal view of the x-ray-driven shock speeds. The new technique adds capability for symmetry control along two directions of the shocks launched in the ablator by the laser-generated hohlraum x-ray flux. Laser power adjustments in four different azimuthal cones based on the results of this measurement can reduce time-dependent symmetry swings during the implosion. Analysis of a large data set provides experimental sensitivities of the shock parameters to the overall laser delivery and in some cases shows the effects of laser asymmetries on the pole and equator shock measurements.

Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

International Nuclear Information System (INIS)

Amendt, Peter; Cerjan, C.; Hamza, A.; Hinkel, D. E.; Milovich, J. L.; Robey, H. F.

2007-01-01

The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (≅4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT (≅790 atm) in the inner shell, strict concentricity requirements on the two shells ( 2 nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010

Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

Science.gov (United States)

Li, Yongsheng; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang; Ding, Yongkun; Lan, Ke; Ye, Wenhua; Zhang, Weiyan

2016-07-01

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting "tent." Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

Energy Technology Data Exchange (ETDEWEB)

Li, Yongsheng [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Graduate School, China Academy of Engineering Physics, Beijing 100088 (China); Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Lan, Ke; Ye, Wenhua, E-mail: ye-wenhua@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zhang, Weiyan [China Academy of Engineering Physics, Mianyang 621900 (China)

2016-07-15

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

International Nuclear Information System (INIS)

Li, Yongsheng; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang; Ding, Yongkun; Lan, Ke; Ye, Wenhua; Zhang, Weiyan

2016-01-01

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

High-temperature dynamic hohlraums on the pulsed power driver Z

International Nuclear Information System (INIS)

Nash, T.J.; Derzon, M.S.; Chandler, G.A.; Leeper, R.; Fehl, D.; Lash, J.; Ruiz, C.; Cooper, G.; Seaman, J.F.; McGurn, J.; Lazier, S.; Torres, J.; Jobe, D.; Gilliland, T.; Hurst, M.; Mock, R.; Ryan, P.; Nielsen, D.; Armijo, J.; McKenney, J.; Hawn, R.; Hebron, D.; MacFarlane, J.J.; Petersen, D.; Bowers, R.; Matuska, W.; Ryutov, D.D.

1999-01-01

In the concept of the dynamic hohlraum an imploding Z pinch is optically thick to its own radiation. Radiation may be trapped inside the pinch to give a radiation temperature inside the pinch greater than that outside the pinch. The radiation is typically produced by colliding an outer Z-pinch liner onto an inner liner. The collision generates a strongly radiating shock, and the radiation is trapped by the outer liner. As the implosion continues after the collision, the radiation temperature may continue to increase due to ongoing PdV (pressure times change in volume) work done by the implosion. In principal, the radiation temperature may increase to the point at which the outer liner burns through, becomes optically thin, and no longer traps the radiation. One application of the dynamic hohlraum is to drive an ICF (inertial confinement fusion) pellet with the trapped radiation field. Members of the dynamic hohlraum team at Sandia National Labs have used the pulsed power driver Z (20 MA, 100 ns) to create a dynamic hohlraum with temperature linearly ramping from 100 to 180 eV over 5 ns. On this shot zp214 a nested tungsten wire array of 4 and 2 cm diam with masses of 2 and 1 mg imploded onto a 2.5 mg plastic annulus at 5 mm diam. The current return can on this shot was slotted. It is likely the radiation temperature may be increased to over 200 eV by stabilizing the pinch with a solid current return can. A current return can with nine slots imprints nine filaments onto the imploding pinch. This degrades the optical trapping and the quality of the liner collision. A 1.6 mm diam capsule situated inside this dynamic hohlraum of zp214 would see 15 kJ of radiation impinging on its surface before the pinch itself collapses to a 1.6 mm diam. Dynamic hohlraum shots including pellets were scheduled to take place on Z in September of 1998. copyright 1999 American Institute of Physics

High Temperature Dynamic Hohlraums on the Pulsed Power Driver Z

International Nuclear Information System (INIS)

Armijo, J.; Chandler, G.A.; Cooper, G.; Derzon, M.S.; Fehl, D.; Gilliland, T.; Hawn, R.; Hebron, D.; Hurst, M.; Jobe, D.; Lash, J.; Lazier, S.; Leeper, R.; McGurn, J.; McKenney, J.; Mock, R.; Nash, T.J.; Nielsen, D.; Ruiz, C.; Ryan, P.; Seaman, J.F.; Torres, J.

1999-01-01

In the concept of the dynamic hohlraum an imploding z-pinch is optically thick to its own radiation. Radiation may be trapped inside the pinch to give a radiation temperature inside the pinch greater than that outside the pinch. The radiation is typically produced by colliding an outer Z-pinch liner onto an inner liner. The collision generates a strongly radiating shock, and the radiation is trapped by the outer liner. As the implosion continues after the collision the radiation temperature may continue to increase due to ongoing PdV (pressure times change in volume) work done by the implosion. In principal the radiation temperature may increase to the point at which the outer liner burns through, becomes optically thin, and no longer traps the radiation. One application of the dynamic hohlraum is to drive an ICF (inertial confinement fusion) pellet with the trapped radiation field. Members of the dynamic hohlraum team at Sandia National Labs have used the pulsed power driver Z (20 LMA, 100 ns) to create a dynamic hohlraum with temperature linearly ramping from 100 to 180 eV over 5 ns. On this shot zp214 a nested tungsten wire array of 4 and 2 cm diameters with masses of 2 and 1 mg imploded onto a 2.5 mg plastic annulus at 5 mm diameter. The current return can on this shot was slotted. It is likely the radiation temperature may be increased to over 200 CV by stabilizing the pinch with a solid current return can. A current return can with 9 slots imprints 9 filaments onto the imploding pinch. This degrades the optical trapping and the quality of the liner collision. A 1.6 mm diameter capsule situated inside this dynamic hohlraum of zp214 would see 15 kJ of radiation impinging on its surface before the pinch itself collapses to a 1.6 mm diameter. Dynamic hohlraum shots including pellets are scheduled to take place on Z in September of 1998

Hohlraum glint and laser pre-pulse detector for NIF experiments using velocity interferometer system for any reflector.

Science.gov (United States)

Moody, J D; Clancy, T J; Frieders, G; Celliers, P M; Ralph, J; Turnbull, D P

2014-11-01

Laser pre-pulse and early-time laser reflection from the hohlraum wall onto the capsule (termed "glint") can cause capsule imprint and unwanted early-time shocks on indirect drive implosion experiments. In a minor modification to the existing velocity interferometer system for any reflector diagnostic on NIF a fast-response vacuum photodiode was added to detect this light. The measurements show evidence of laser pre-pulse and possible light reflection off the hohlraum wall and onto the capsule.

Detailed spectral simulations in support of PBFA-Z dynamic hohlraum Z-pinch experiments

International Nuclear Information System (INIS)

MacFarlane, J.J.; Wang, P.; Derzon, M.S.; Haill, A.; Nash, T.J.; Peterson, D.L.

1997-01-01

In PBFA-Z dynamic hohlraum Z-pinch experiments, 16--18 MA of current is delivered to a load comprises of a tungsten wire array surrounding a low-density cylindrical CH foam. The magnetic field accelerates the W plasma radially inward at velocities ∼ 40--60 cm/micros. The W plasma impacts into the foam, generating a high T R radiation field which diffuses into the foam. The authors are investigating several types of spectral diagnostics which can be used to characterize the time-dependent conditions in the foam. In addition, they are examining the potential ramifications of axial jetting on the interpretation of axial x-ray diagnostics. In the analysis, results from 2-D radiation-magnetohydrodynamics simulations are post-processed using a hybrid spectral analysis code in which low-Z material is treated using a detailed collisional-radiative atomic model, while high-Z material is modeled using LTE UTA (unresolved transition array) opacities. They will present results from recent simulations and discuss ramifications for x-ray diagnostics

Hard X-ray intensity reduction during lower hybrid current drive experiments

International Nuclear Information System (INIS)

Mlynar, J.; Stoeckel, J.; Magula, P.

1993-01-01

A strong hard X-ray intensity reduction during a standard LHCD at the CASTOR tokamak was studied. From discussion it followed that the magnetic fluctuations level decrease is likely to be responsible for this effect beside the loop voltage decrease. To verify this idea, the connection between the magnetic fluctuation level and the hard X-ray intensity was studied in a nonstandard LHCD regime with a zero loop voltage reduction. These measurements strongly supported the concept that magnetic fluctuations level substantially influences the runaway electrons cross-field transport. Though, more data and a good code for modelling the anomalous transport and hard X-rays production would be of high value. Similar measurements especially for higher RF power should be carried out soon. Besides, the reduction of hard X-rays was observed in the experiments with edge plasma polarization lately; therefore, the magnetic fluctuations level in these experiments should be studied soon. (author) 6 figs., 6 refs

The I-Raum: A new shaped hohlraum for improved inner beam propagation in indirectly-driven ICF implosions on the National Ignition Facility

Science.gov (United States)

Robey, H. F.; Berzak Hopkins, L.; Milovich, J. L.; Meezan, N. B.

2018-01-01

Recent work in indirectly-driven inertial confinement fusion implosions on the National Ignition Facility has indicated that late-time propagation of the inner cones of laser beams (23° and 30°) is impeded by the growth of a "bubble" of hohlraum wall material (Au or depleted uranium), which is initiated by and is located at the location where the higher-intensity outer beams (44° and 50°) hit the hohlraum wall. The absorption of the inner cone beams by this "bubble" reduces the laser energy reaching the hohlraum equator at late time driving an oblate or pancaked implosion, which limits implosion performance. In this article, we present the design of a new shaped hohlraum designed specifically to reduce the impact of this bubble by adding a recessed pocket at the location where the outer cones hit the hohlraum wall. This recessed pocket displaces the bubble radially outward, reducing the inward penetration of the bubble at all times throughout the implosion and increasing the time for inner beam propagation by approximately 1 ns. This increased laser propagation time allows one to drive a larger capsule, which absorbs more energy and is predicted to improve implosion performance. The new design is based on a recent National Ignition Facility shot, N170601, which produced a record neutron yield. The expansion rate and absorption of laser energy by the bubble is quantified for both cylindrical and shaped hohlraums, and the predicted performance is compared.

A review of laser–plasma interaction physics of indirect-drive fusion

International Nuclear Information System (INIS)

Kirkwood, R K; Moody, J D; Dewald, E; Glenzer, S; Divol, L; Michel, P; Hinkel, D; Berger, R; Williams, E; Milovich, J; MacGowan, B; Landen, O; Rosen, M; Lindl, J; Kline, J; Yin, L; Rose, H

2013-01-01

The National Ignition Facility (NIF) has been designed, constructed and has recently begun operation to investigate the ignition of nuclear fusion with a laser with up to 1.8 MJ of energy per pulse. The concept for fusion ignition on the NIF, as first proposed in 1990, was based on an indirectly driven spherical capsule of fuel in a high-Z hohlraum cavity filled with low-Z gas (Lindl et al 2004 Phys. Plasmas 11 339). The incident laser energy is converted to x-rays with keV energy on the hohlraums interior wall. The x-rays then impinge on the surface of the capsule, imploding it and producing the fuel conditions needed for ignition. It was recognized at the inception that this approach would potentially be susceptible to scattering of the incident light by the plasma created in the gas and the ablated material in the hohlraum interior. Prior to initial NIF operations, expectations for laser–plasma interaction (LPI) in ignition-scale experiments were based on experimentally benchmarked simulations and models of the plasma effects that had been carried out as part of the original proposal for NIF and expanded during the 13-year design and construction period. The studies developed the understanding of the stimulated Brillouin scatter, stimulated Raman scatter and filamentation that can be driven by the intense beams. These processes produce scatter primarily in both the forward and backward direction, and by both individual beams and collective interaction of multiple beams. Processes such as hot electron production and plasma formation and transport were also studied. The understanding of the processes so developed was the basis for the design and planning of the recent experiments in the ignition campaign at NIF, and not only indicated that the plasma instabilities could be controlled to maximize coupling, but predicted that, for the first time, they would be beneficial in controlling drive symmetry. The understanding is also now a critical component in the

Femtosecond profiling of shaped x-ray pulses

Science.gov (United States)

Hoffmann, M. C.; Grguraš, I.; Behrens, C.; Bostedt, C.; Bozek, J.; Bromberger, H.; Coffee, R.; Costello, J. T.; DiMauro, L. F.; Ding, Y.; Doumy, G.; Helml, W.; Ilchen, M.; Kienberger, R.; Lee, S.; Maier, A. R.; Mazza, T.; Meyer, M.; Messerschmidt, M.; Schorb, S.; Schweinberger, W.; Zhang, K.; Cavalieri, A. L.

2018-03-01

Arbitrary manipulation of the temporal and spectral properties of x-ray pulses at free-electron lasers would revolutionize many experimental applications. At the Linac Coherent Light Source at Stanford National Accelerator Laboratory, the momentum phase-space of the free-electron laser driving electron bunch can be tuned to emit a pair of x-ray pulses with independently variable photon energy and femtosecond delay. However, while accelerator parameters can easily be adjusted to tune the electron bunch phase-space, the final impact of these actuators on the x-ray pulse cannot be predicted with sufficient precision. Furthermore, shot-to-shot instabilities that distort the pulse shape unpredictably cannot be fully suppressed. Therefore, the ability to directly characterize the x-rays is essential to ensure precise and consistent control. In this work, we have generated x-ray pulse pairs via electron bunch shaping and characterized them on a single-shot basis with femtosecond resolution through time-resolved photoelectron streaking spectroscopy. This achievement completes an important step toward future x-ray pulse shaping techniques.

A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

International Nuclear Information System (INIS)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu; Zhang, Baohan; Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming

2016-01-01

During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

Energy Technology Data Exchange (ETDEWEB)

Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu, E-mail: yqgu@caep.cn; Zhang, Baohan [Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); and others

2016-06-15

During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on the National Ignition Facility Laser

Science.gov (United States)

Callahan, D. A.; Hurricane, O. A.; Ralph, J. E.; Thomas, C. A.; Baker, K. L.; Benedetti, L. R.; Berzak Hopkins, L. F.; Casey, D. T.; Chapman, T.; Czajka, C. E.; Dewald, E. L.; Divol, L.; Döppner, T.; Hinkel, D. E.; Hohenberger, M.; Jarrott, L. C.; Khan, S. F.; Kritcher, A. L.; Landen, O. L.; LePape, S.; MacLaren, S. A.; Masse, L. P.; Meezan, N. B.; Pak, A. E.; Salmonson, J. D.; Woods, D. T.; Izumi, N.; Ma, T.; Mariscal, D. A.; Nagel, S. R.; Kline, J. L.; Kyrala, G. A.; Loomis, E. N.; Yi, S. A.; Zylstra, A. B.; Batha, S. H.

2018-05-01

We present a data-based model for low mode asymmetry in low gas-fill hohlraum experiments on the National Ignition Facility {NIF [Moses et al., Fusion Sci. Technol. 69, 1 (2016)]} laser. This model is based on the hypothesis that the asymmetry in these low fill hohlraums is dominated by the hydrodynamics of the expanding, low density, high-Z (gold or uranium) "bubble," which occurs where the intense outer cone laser beams hit the high-Z hohlraum wall. We developed a simple model which states that the implosion symmetry becomes more oblate as the high-Z bubble size becomes large compared to the hohlraum radius or the capsule size becomes large compared to the hohlraum radius. This simple model captures the trends that we see in data that span much of the parameter space of interest for NIF ignition experiments. We are now using this model as a constraint on new designs for experiments on the NIF.

Experimental room temperature hohlraum performance study on the National Ignition Facility

Science.gov (United States)

Ralph, J. E.; Strozzi, D.; Ma, T.; Moody, J. D.; Hinkel, D. E.; Callahan, D. A.; MacGowan, B. J.; Michel, P.; Kline, J. L.; Glenzer, S. H.; Albert, F.; Benedetti, L. R.; Divol, L.; MacKinnon, A. J.; Pak, A.; Rygg, J. R.; Schneider, M. B.; Town, R. P. J.; Widmann, K.; Hsing, W.; Edwards, M. J.

2016-12-01

Room temperature or "warm" (273 K) indirect drive hohlraum experiments have been conducted on the National Ignition Facility with laser energies up to 1.26 MJ and compared to similar cryogenic or "cryo" (˜20 K) experiments. Warm experiments use neopentane (C5H12) as the low pressure hohlraum fill gas instead of helium, and propane (C3H8) to replace the cryogenic DT or DHe3 capsule fill. The increased average Z of the hohlraum fill leads to increased inverse bremsstrahlung absorption and an overall hotter hohlraum plasma in simulations. The cross beam energy transfer (CBET) from outer laser beams (pointed toward the laser entrance hole) to inner beams (pointed at the equator) was inferred indirectly from measurements of Stimulated Raman Scattering (SRS). These experiments show that a similar hot spot self-emission shape can be produced with less CBET in warm hohlraums. The measured inner cone SRS reflectivity (as a fraction of incident power neglecting CBET) is ˜2.5 × less in warm than cryo shots with similar hot spot shapes, due to a less need for CBET. The measured outer-beam stimulated the Brillouin scattering power that was higher in the warm shots, leading to a ceiling on power to avoid the optics damage. These measurements also show that the CBET induced by the flow where the beams cross can be effectively mitigated by a 1.5 Å wavelength shift between the inner and outer beams. A smaller scale direct comparison indicates that warm shots give a more prolate implosion than cryo shots with the same wavelength shift and pulse shape. Finally, the peak radiation temperature was found to be between 5 and 7 eV higher in the warm than the corresponding cryo experiments after accounting for differences in backscatter.

Laser plasma interaction in rugby-shaped hohlraums

Science.gov (United States)

Masson-Laborde, P.-E.; Philippe, F.; Tassin, V.; Monteil, M.-C.; Gauthier, P.; Casner, A.; Depierreux, S.; Seytor, P.; Teychenne, D.; Loiseau, P.; Freymerie, P.

2014-10-01

Rugby shaped-hohlraum has proven to give high performance compared to a classical similar-diameter cylinder hohlraum. Due to this performance, this hohlraum has been chosen as baseline ignition target for the Laser MegaJoule (LMJ). Many experiments have therefore been performed during the last years on the Omega laser facility in order to study in details the rugby hohlraum. In this talk, we will discuss the interpretation of these experiments from the point of view of the laser plasma instability problem. Experimental comparisons have been done between rugby, cylinder and elliptical shape rugby hohlraums and we will discuss how the geometry differences will affect the evolution of laser plasma instabilities (LPI). The efficiency of laser smoothing techniques on these instabilities will also be discussed as well as gas filling effect. The experimental results will be compared with FCI2 hydroradiative calculations and linear postprocessing with Piranah. Experimental Raman and Brillouin spectrum, from which we can infer the location of the parametric instabilities, will be compared to simulated ones, and will give the possibility to compare LPI between the different hohlraum geometries.

Performance of high-density-carbon (HDC) ablator implosion experiments on the National Ignition Facility (NIF)

Science.gov (United States)

MacKinnon, Andy

2013-10-01

A series of experiments on the National Ignition Facility (NIF) have been performed to measure high-density carbon (HDC) ablator performance for indirect drive inertial confinement fusion (ICF). HDC is a very promising ablator material; being 3x denser than plastic, it absorbs more hohlraum x-rays, leading to higher implosion efficiency. For the HDC experiments the NIF laser generated shaped laser pulses with peak power up to 410 TW and total energy of 1.3 MJ. Pulse shapes were designed to drive 2, 3 or 4 shocks in cryogenic layered implosions. The 2-shock pulse, with a designed fuel adiabat of ~3 is 6-7ns in duration, allowing use of near vacuum hohlraums, which greatly increases the coupling efficiency due to low backscatter losses. Excellent results were obtained for 2,3 and 4 shock pulses. In particular a deuterium-tritium gas filled HDC capsule driven by a 4-shock pulse in a gas-filled hohlraum produced a neutron yield of 1.6 × 1015, a record for a non-cryogenically layered capsule driven by a gas-filled hohlraum. The first 2-shock experiment used a vacuum hohlraum to drive a DD gas filled HDC capsule with a 6.5 ns, laser pulse. This hohlraum was 40% more efficient than the gas-filled counterpart used for 3 and 4 shock experiments, producing near 1D performance at 11 x convergence ratio, peak radiation temperature of 317 eV, 98% laser-hohlraum coupling, and DD neutron yield of 2.2e13, a record for a laser driven DD implosion. The HDC campaigns will be presented, including options for pushing towards the alpha dominated regime. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Hard X-ray studies on the Castor tokamak

International Nuclear Information System (INIS)

Mlynar, J.

1990-04-01

The electron runaway processes in tokamaks are discussed with regard to hard X radiation measurements. The origin and confinement of runaway electrons, their bremsstrahlung spectra and the influence of lower hybrid current drive on the distribution of high-energy electrons are analyzed for the case of the Castor tokamak. The hard X-ray spectrometer designed for the Castor tokamak is also described and preliminary qualitative results of hard X-ray measurements are presented. The first series of integral measurements made it possible to map the azimuthal dependence of the hard X radiation

Progress in symmetric ICF capsule implosions and wire-array z-pinch source physics for double z-pinch driven hohlraums

International Nuclear Information System (INIS)

Bliss, David Emery; Vesey, Roger Alan; Rambo, Patrick K.; Lebedev, Sergey V.; Hanson, David L.; Nash, Thomas J.; Yu, Edmund P.; Matzen, Maurice Keith; Afeyan, Bedros B.; Smith, Ian Craig; Stygar, William A.; Porter, John Larry Jr.; Cuneo, Michael Edward; Bennett, Guy R.; Campbell, Robert B.; Sinars, Daniel Brian; Chittenden, Jeremy Paul; Waisman, Eduardo Mario; Mehlhorn, Thomas Alan

2005-01-01

Over the last several years, rapid progress has been made evaluating the double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is irradiated from two sides by z-pinches to produce low odd-mode radiation asymmetry. This double-pinch source is driven from a single electrical power feed (Cuneo et al 2002 Phys. Rev. Lett. 88 215004) on the 20 MA Z accelerator. The double z-pinch has imploded ICF capsules with even-mode radiation symmetry of 3.1 ± 1.4% and to high capsule radial convergence ratios of 14-21 (Bennett et al 2002 Phys. Rev. Lett. 89 245002; Bennett et al 2003 Phys. Plasmas 10 3717; Vesey et al 2003 Phys. Plasmas 10 1854). Advances in wire-array physics at 20 MA are improving our understanding of z-pinch power scaling with increasing drive current. Techniques for shaping the z-pinch radiation pulse necessary for low adiabat capsule compression have also been demonstrated.

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

Science.gov (United States)

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

2015-11-17

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

Z-pinch driven hohlraums design for the 100 nanoseconds current time scale

International Nuclear Information System (INIS)

Hamann, F.

2003-12-01

This work estimates Z-pinch driven hohlraums capabilities to obtain high temperatures (>200 eV). Simple models are proposed to calculate the performances offered by currents of 5 to 100 MA in 100 ns. The one dimensional physics of the Z-pinch at the length scale of its thickness and the hydrodynamics instabilities are studied. Then the enhancement of hohlraums performances with double nested Z-pinches or the use of an axial magnetic field is analysed. Z-pinch direct drive approach for inertial confinement fusion is finally considered. All the presented results are based on theoretical and 2D numerical approach and on the analysis of experimental results which were obtained on the american 'Z' generator. Annexes recall radiation MHD equations and check their validity for Z-pinch implosion. (author)

The Hard X-ray Sky: Recent Observational Progress

International Nuclear Information System (INIS)

Gehrels, Neil; Cannizzo, John K.

2009-01-01

The last fifty years have witnessed the birth, development, and maturation to full potential of hard X-ray astrophysics. The primary force driving the history of the field has been the development of space-based instrumentation optimized for getting the maximum science out of observations of high-energy photons from astrophysical sources. Hard X-ray telescopes are leading research in areas such as galactic diffuse emission, galactic transients, and active galactic nuclei.

10th International Conference on X-Ray Lasers

CERN Document Server

Nickles, P.V; X-Ray Lasers 2006

2007-01-01

The search for table-top and repetitive pump schemes during the last decade has been the driving force behind the spectacular advances demonstrated during the 10th International Conference on X-Ray Lasers, organized in 2006 in Berlin. Since 1986, international experts have gathered every two years at this established conference to discuss the progress in theory, experiment and application of plasma-based soft X-ray lasers. Traditionally, the conference sessions devoted to complementary and alternative sources of short wavelength radiation, such as high harmonics, XFEL or incoherent X-rays are organized so as to emphasize the role of X-ray laser research in relation to the other short wavelength sources. Grazing incidence pumping (GRIP) and seeding with high harmonics were the dominant topics of the conference. High repetition rate and portable X-ray lasers were reported to have been applied in metrology and photochemistry for the first time. The proceedings of this series of conferences constitute a comprehen...

Usefulness of a Rugby-shaped hohlraum in a Laser M'egaJoule (LMJ) 40-quad configuration

Science.gov (United States)

Malinie, G.; Vandenboomgaerde, M.; Bastian, J.; Galmiche, D.; Laffite, S.; Liberatore, S.

2007-11-01

The LMJ setup will consist of 60 quads in a 3-cone configuration, at angles 33.2^o, 49^o and 59.5^o. First ignition attempts in indirect drive are planned to be made on the way to the completion of the full facility, with only 40 quads in a 2-cone configuration, at angles 33.2^o and 49^o. By analytic considerations, we show that in a 40-quad configuration, the angular location of the hohlraum outer irradiating ring, as seen from the capsule, must be closer to the laser entrance hole than with the full LMJ. The use of a Rugby-shaped hohlraum instead of a cylinder therefore allows to keep a correct symmetry while reducing the wall surface, which improves the global energetic efficiency of the target. Simplified 2D numerical simulations of Rugby hohlraums are presented, achieving a yield of about 30 MJ with our 1.215 mm-radius, CH-uniform-ablator capsule. These results suggests this kind of hohlraum might be an interesting candidate for 40-quad ignition experiments. Work on optimizing the present design and refining the numerical simulations is currently pursued.

The hydrodynamic and radiative properties of low-density foams heated by x-rays

Czech Academy of Sciences Publication Activity Database

Rosmej, O. N.; Suslov, N.; Martsovenko, D.; Vergunova, G.; Borisenko, N.; Orlov, N.; Rienecker, T.; Klír, Daniel; Řezáč, Karel; Orekhov, A.; Borisenko, L.; Krouský, Eduard; Pfeifer, Miroslav; Dudžák, Roman; Maeder, R.; Schaechinger, M.; Schoenlein, A.; Zaehter, S.; Jacoby, J.; Limpouch, J.; Ullschmied, Jiří; Zhidkov, N.

2015-01-01

Roč. 57, č. 9 (2015), č. článku 094001. ISSN 0741-3335 R&D Projects: GA MŠk(CZ) LG13029; GA MŠk LM2010014 Grant - others:FP7(XE) 284464 Program:FP7 Institutional support: RVO:61389021 Keywords : hohlraum * low density polymer aerogel * opacity * Planckian radiation * plasma * x-rays Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015 http://iopscience.iop.org/article/10.1088/0741-3335/57/9/094001;jsessionid=E4079D2364DFCC5CA64FBF3B9F73D180.c2.iopscience.cld.iop.org

X-ray filter for x-ray powder diffraction

Science.gov (United States)

Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.; Dooryhee, Eric; Ghose, Sanjit

2018-01-23

Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and walls defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.

X-ray fluorescence imaging with polycapillary X-ray optics

International Nuclear Information System (INIS)

Yonehara, Tasuku; Yamaguchi, Makoto; Tsuji, Kouichi

2010-01-01

X-ray fluorescence spectrometry imaging is a powerful tool to provide information about the chemical composition and elemental distribution of a specimen. X-ray fluorescence spectrometry images were conventionally obtained by using a μ-X-ray fluorescence spectrometry spectrometer, which requires scanning a sample. Faster X-ray fluorescence spectrometry imaging would be achieved by eliminating the process of sample scanning. Thus, we developed an X-ray fluorescence spectrometry imaging instrument without sample scanning by using polycapillary X-ray optics, which had energy filter characteristics caused by the energy dependence of the total reflection phenomenon. In the present paper, we show that two independent straight polycapillary X-ray optics could be used as an energy filter of X-rays for X-ray fluorescence. Only low energy X-rays were detected when the angle between the two optical axes was increased slightly. Energy-selective X-ray fluorescence spectrometry images with projection mode were taken by using an X-ray CCD camera equipped with two polycapillary optics. It was shown that Fe Kα (6.40 keV) and Cu Kα (8.04 keV) could be discriminated for Fe and Cu foils.

High-density carbon ablator experiments on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

MacKinnon, A. J., E-mail: mackinnon2@llnl.gov; Meezan, N. B.; Ross, J. S.; Le Pape, S.; Berzak Hopkins, L.; Divol, L.; Ho, D.; Milovich, J.; Pak, A.; Ralph, J.; Döppner, T.; Patel, P. K.; Thomas, C.; Tommasini, R.; Haan, S.; MacPhee, A. G.; McNaney, J.; Caggiano, J.; Hatarik, R.; Bionta, R. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

2014-05-15

High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2× higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 ± 20 km/s with no observed ablator mixing into the hot spot.

Picosecond Soft-X-ray studies of Dense Plasma Regimes Progress Report (April 1, 2006 - March 31, 2007)

International Nuclear Information System (INIS)

Rocca, Jorge; Marconi, Mario; Shlyaptsev, Vyacheslav; Dunn, James; Moon, Stephen; Nilsen, Joseph

2007-01-01

The goal of this project is to investigate and characterize high-density converging plasma configurations using new soft x-ray laser based interferometric techniques. The results are used to verify and validate multi-dimensional hydrodynamic codes in plasma regimes which densities and size exceed those that can be probed with optical laser beams. The dynamics of converging plasmas created by laser irradiation of half-hohlraum cylindrical cavities targets was probed using a compact 46.9 nm soft x-ray laser. The results were used for comparison with extensive simulations conducted with the multi-dimensional hydrodynamic code HYDRA. As part of this study we have also investigated plasma regimes in which the index of refraction of the plasmas can not be defined solely based on the contribution of free electron, as is usually assumed for multiply ionized plasmas. Our results demonstrate the existence of plasma regimes in which the contribution of bound electrons from ions dominates the refractive index at soft x-ray wavelengths. We are also working in extending plasma interferometry to the sub 10 nm wavelength range. In the process we are advancing soft x-ray laser plasma diagnostics techniques to allow the measurement of large-scale, high-density plasmas with picosecond temporal resolution and micrometer spatial resolution, laying the foundations for future advanced diagnostics at high energy density DOE facilities. Dense plasma diagnostics, soft x-ray laser interferometry, converging plasmas

The Athena X-ray Integral Field Unit (X-IFU)

Science.gov (United States)

Barret, Didier; Trong, Thein Lam; Den Herder, Jan-Willem; Piro, Luigi; Barcons, Xavier; Huovelin, Juhani; Kelley, Richard; Mas-Hesse, J. Miquel; Mitsuda, Kazuhisa; Paltani, Stephane;

Analysis of hohlraum energetics of the SG series and the NIF experiments with energy balance model

Directory of Open Access Journals (Sweden)

Guoli Ren

2017-01-01

Full Text Available The basic energy balance model is applied to analyze the hohlraum energetics data from the Shenguang (SG series laser facilities and the National Ignition Facility (NIF experiments published in the past few years. The analysis shows that the overall hohlraum energetics data are in agreement with the energy balance model within 20% deviation. The 20% deviation might be caused by the diversity in hohlraum parameters, such as material, laser pulse, gas filling density, etc. In addition, the NIF's ignition target designs and our ignition target designs given by simulations are also in accordance with the energy balance model. This work confirms the value of the energy balance model for ignition target design and experimental data assessment, and demonstrates that the NIF energy is enough to achieve ignition if a 1D spherical radiation drive could be created, meanwhile both the laser plasma instabilities and hydrodynamic instabilities could be suppressed.

X-ray photoelectron microscope with a compact x-ray source generated by line-focused laser irradiation

International Nuclear Information System (INIS)

Yamaguchi, N.; Okamoto, Y.; Hara, T.; Takahashi, Z.; Nishimura, Y.; Sakata, A.; Watanabe, K.; Azuma, H.

2004-01-01

Full text: A laboratory-sized microscopic system of x-ray photoelectrons has been developing using a compact x-ray source produced by line-focused laser irradiation. The system is a scanning type photoelectron microscope where x-ray beam is micro-focused via a Schwartzschild optics. A compact laser-plasma x-ray source has been developed with a YAG laser system, a line-focus lens system, a tape-target driving system and a debris prevention system, that was operated at repetition rate of 10 Hz or 50 Hz. X-rays were delivered along line plasma whose length was 0.6 to 11 mm with higher intensity than that from a point-focused source. Because the transition line of Al V (13.1 nm) was prominent in the soft x-ray spectrum when the Al tape target irradiated at the lower power density of 10 11 W/cm 2 , the 13.1 nm x-ray was used as an excitation source. The Schwartzschild optics was set on the beamline at a distance about 1 m from the source, which was coated with Mo/Si multilayers for 13.1 nm x-ray. The designed demagnification is 224 that was confirmed in the previous experiment. Therefore, an x-ray micro spot of sub-micron size can be formed on a sample surface when the source size is less than about 0.2 mm. Samples were set on a two-axis high-precision piezo stage mounted to a four-axis manipulator. The electron energy analyzer was a spherical capacitor analyzer with mean diameter of 279.4 mm. The electron detector was a microchannel plate (MCP) with a phosphor screen and the optical image of electrons on the exit plane of the analyzer was taken and recorded by using an ultra low dark noise CCD camera, that was suited for detection of vast photoelectrons excited by x-ray pulse of ns-order duration. We performed spatial resolution test measurements by using a GaAs wafer coated with photo-resist that formed a stripe pattern. The spatial resolution less than 3 micron has been obtained from the variation of As 3d electron intensity along the position of the GaAs sample

X-ray lithography for micro and nanotechnology at RRCAT

International Nuclear Information System (INIS)

Shukla, Rahul; Dhamgaye, V.P.; Jain, V.K.; Lodha, G.S.

2013-01-01

At Indus-2 Soft and Deep X-ray Lithography beamline (BL-07) is functional and is capable of developing various high aspect ratio and high resolution structures at micro and nano scale. These micro and nano structures can be made to work as a mechanism, sensor, actuator and transducer for varieties of applications and serve as basic building blocks for the development of X-ray and IR optics, LASERs, lab-on-a-chip, micromanipulators and nanotechnology. To achieve these goals we have started developing high aspect ratio comb-drives, electrostatic micromotors, micro fluidic channels, X-ray optics and novel transducers for RF applications by Deep X-ray Lithography (DXRL). Comb-drive is one of most studied electrostatic device in MEMS (Micro Electro-Mechanical Systems). It can be used as a sensor, actuator, resonator, energy harvester and filter. Analysis and simulation shows that the comb actuator of aspect ratio 16 (air gap 50 μm) will produce nearly 1.25 μm displacement when DC voltage of 100 V is applied. For fabrication, first time in India, Polyimide X-ray mask is realized and exposure and development is done at BL-7 at RRCAT. The displacement increases as gap between comb finger decreases. Further refinement is in progress to get higher output from high aspect ratio (∼ 80) comb actuators (i.e. 1 μm at 5V). The other important design parameters like resonance frequency, capacitance will also be discussed. (author)

Single photon energy dispersive x-ray diffraction

International Nuclear Information System (INIS)

Higginbotham, Andrew; Patel, Shamim; Ciricosta, Orlando; Suggit, Matthew J.; Wark, Justin S.; Hawreliak, James A.; Collins, Gilbert W.; Coppari, Federica; Eggert, Jon H.; Tang, Henry

2014-01-01

With the pressure range accessible to laser driven compression experiments on solid material rising rapidly, new challenges in the diagnosis of samples in harsh laser environments are emerging. When driving to TPa pressures (conditions highly relevant to planetary interiors), traditional x-ray diffraction techniques are plagued by increased sources of background and noise, as well as a potential reduction in signal. In this paper we present a new diffraction diagnostic designed to record x-ray diffraction in low signal-to-noise environments. By utilising single photon counting techniques we demonstrate the ability to record diffraction patterns on nanosecond timescales, and subsequently separate, photon-by-photon, signal from background. In doing this, we mitigate many of the issues surrounding the use of high intensity lasers to drive samples to extremes of pressure, allowing for structural information to be obtained in a regime which is currently largely unexplored

Single photon energy dispersive x-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Higginbotham, Andrew; Patel, Shamim; Ciricosta, Orlando; Suggit, Matthew J.; Wark, Justin S. [Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Hawreliak, James A.; Collins, Gilbert W.; Coppari, Federica; Eggert, Jon H. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Tang, Henry [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, California 94720 (United States)

2014-03-15

With the pressure range accessible to laser driven compression experiments on solid material rising rapidly, new challenges in the diagnosis of samples in harsh laser environments are emerging. When driving to TPa pressures (conditions highly relevant to planetary interiors), traditional x-ray diffraction techniques are plagued by increased sources of background and noise, as well as a potential reduction in signal. In this paper we present a new diffraction diagnostic designed to record x-ray diffraction in low signal-to-noise environments. By utilising single photon counting techniques we demonstrate the ability to record diffraction patterns on nanosecond timescales, and subsequently separate, photon-by-photon, signal from background. In doing this, we mitigate many of the issues surrounding the use of high intensity lasers to drive samples to extremes of pressure, allowing for structural information to be obtained in a regime which is currently largely unexplored.

An X-ray and infrared survey of the Lynds 1228 cloud core

Energy Technology Data Exchange (ETDEWEB)

Skinner, Stephen L. [CASA, University of Colorado, Boulder, CO 80309-0389 (United States); Rebull, Luisa [Spitzer Science Center/Caltech, M/S 220-6, 1200 East California Blvd., Pasadena, CA 91125 (United States); Güdel, Manuel, E-mail: stephen.skinner@colorado.edu, E-mail: rebull@ipac.caltech.edu, E-mail: manuel.guedel@univie.ac.at [Department of Astrophysics, University of Vienna, Türkenschanzstr. 17, A-1180 Vienna (Austria)

2014-04-01

The nearby Lynds 1228 (L1228) dark cloud at a distance of ∼200 pc is known to harbor several young stars including the driving sources of the giant HH 199 and HH 200 Herbig-Haro (HH) outflows. L1228 has previously been studied at optical, infrared, and radio wavelengths but not in X-rays. We present results of a sensitive 37 ks Chandra ACIS-I X-ray observation of the L1228 core region. Chandra detected 60 X-ray sources, most of which are faint (<40 counts) and non-variable. Infrared counterparts were identified for 53 of the 60 X-ray sources using archival data from the Two Micron All-Sky Survey, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer. Object classes were assigned using mid-IR colors for those objects with complete photometry, most of which were found to have colors consistent with extragalactic background sources. Seven young stellar object candidates were identified including the class I protostar HH 200-IRS which was detected as a faint hard X-ray source. No X-ray emission was detected from the luminous protostar HH 199-IRS. We summarize the X-ray and infrared properties of the detected sources and provide IR spectral energy distribution modeling of high-interest objects including the protostars driving the HH outflows.

X-Ray Absorption with Transmission X-Ray Microscopes

NARCIS (Netherlands)

de Groot, F.M.F.

2016-01-01

In this section we focus on the use of transmission X-ray microscopy (TXM) to measure the XAS spectra. In the last decade a range of soft X-ray and hard X-ray TXM microscopes have been developed, allowing the measurement of XAS spectra with 10–100 nm resolution. In the hard X-ray range the TXM

Inner-shell photo-ionized X-ray laser schemes for low-Z elements

International Nuclear Information System (INIS)

Moon, S.J.; Strobel, G.L.

1994-01-01

Gain calculations for inner-shell photo-ionized lasing in C at 45 angstrom are performed. An incident x-ray source represented by a 150 eV blackbody with a rise time of 50 fsec gives a gain of order 10 cm -1 . The x-ray source and thus the driving optical laser requirements are significantly reduced as compared to what is needed for Ne at 15 angstrom. The authors expect that existing ultra-short pulse lasers can produce the required x-ray source and thus produce a table-top x-ray laser at 45 angstrom

Krypton K-shell X-ray spectra recorded by the HENEX spectrometer

Energy Technology Data Exchange (ETDEWEB)

Seely, J.F. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)]. E-mail: john.seely@nrl.navy.mil; Back, C.A. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Constantin, C. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Hudson, L.T. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Szabo, C.I. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Henins, A. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Holland, G.E. [SFA Inc., 9315 Largo Drive West Suite 200, Largo MD 20774 (United States); Atkin, R. [Tiger Innovations, L.L.C., 3610 Vacation Lane, Arlington VA 22207 (United States); Marlin, L. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)

2006-05-15

High-resolution X-ray spectra were recorded by the High-Energy Electronic X-ray (HENEX) spectrometer from a variety of targets irradiated by the Omega laser at the Laboratory for Laser Energetics. The HENEX spectrometer utilizes four reflection crystals covering the 1-20keV energy range and one quartz(10-11) transmission crystal (Laue geometry) covering the 11-40keV range. The time-integrated spectral images were recorded on five CMOS X-ray detectors. In the spectra recorded from krypton-filled gasbag and hohlraum targets, the helium-like K-shell transitions n=1-2, 1-3, and 1-4 appeared in the 13-17keV energy range. A number of additional spectral features were observed at energies lower than the helium-like n=1-3 and n=1-4 transitions. Based on computational simulations of the spectra using the FLYCHK/FLYSPEC codes, which included opacity effects, these additional features are identified to be inner-shell transitions from the Li-like through N-like krypton charge states. The comparisons of the calculated and observed spectra indicate that these transitions are characteristic of the plasma conditions immediately after the laser pulse when the krypton density is 2x10{sup 18}cm{sup -3} and the electron temperature is in the range 2.8-3.2keV. These spectral features represent a new diagnostic for the charge state distribution, the density and electron temperature, and the plasma opacity. Laboratory experiments indicate that it is feasible to record K-shell spectra from gold and higher Z targets in the >60keV energy range using a Ge(220) transmission crystal.

Recent developments in X-ray imaging detectors

CERN Document Server

Moy, J P

2000-01-01

The replacement of the radiographic film in medical imaging has been the driving force in X-ray imaging developments. It requires a approx 40 cm wide detector to cover all examinations, an equivalent noise level of 1-5 X-ray quanta per pixel, and spatial resolution in the range 100-150 mu m. The need for entirely electronic imaging equipments has fostered the development of many X-ray detectors, most of them based on an array of amorphous silicon pixels, which is the only technology capable to achieve such large areas. Essentially, two concepts have been implemented: - intermediate conversion of X-rays to light by a scintillator, detected by an array of light sensitive pixels, comprising a photodiode and a switching device, either a TFT or a diode. - conversion into electron-hole pairs in a photoconductor, collected by an array of electrodes and switches. In both cases, charge amplifiers read the generated charges line by line. Scintillator and photoconductor-based systems are now close to production. They ac...

Hard X-Ray PHA System on the HT-7 Tokamak

International Nuclear Information System (INIS)

Lin Shiyao; Shi Yuejiang; Wan Baonian; Chen Zhongyong; Hu Liqun

2006-01-01

A new hard X-ray pulse-height analysis (PHA) system has been established on HT-7 tokamak for long pulse steady-state operation. This PHA system consists of hard X-ray diagnostics and multi-channel analysers (MCA). The hard X-ray diagnostics consists of a vertical X-ray detector array (CdTe) and a horizontal X-ray detector array (NaI). The hard X-ray diagnostics can provide the profile of power deposition and the distribution function of fast electron during radio frequency (RF) current drive. The MCA system is the electronic part of the PHA system, which has been modularized and linked to PC through LAN. Each module of MCA can connect with 8 X-ray detectors. The embedded Ethernet adapter in the MCA module makes the data communication between PC and MCA very convenient. A computer can control several modules of MCA through certain software and a hub. The RAM in MCA can store 1024 or more spectra for each detector and therefore the PHA system can be applied in the long pulse discharge of several minutes

X-ray energy selected imaging with Medipix II

International Nuclear Information System (INIS)

Ludwig, J.; Zwerger, A.; Benz, K.-W.; Fiederle, M.; Braml, H.; Fauler, A.; Konrath, J.-P.

2004-01-01

Two different X-ray tube accelerating voltages (60 and 70 kV) are used for diagnosis of front teeth and molars. Different energy ranges are necessary as function of tooth thickness to obtain similar contrast for imaging. This technique drives the costs for the X-ray tube up and allows for just two optimized settings. Energy range selection for the detection of the penetrating X-rays would overcome these severe setbacks. The single photon counting chip MEDIPIX2 http://www.cern.ch/medipix exhibits exactly this feature. First simulations and measurements have been carried out using a dental X-ray source. As a demonstrator a real tooth has been used with different cavities and filling materials. Simulations showed in general larger improvements as compared to measurements regarding SNR and contrast: A beneficial factor of 4% wrt SNR and 25% for contrast, measurements showed factors of 2.5 and up to 10%, respectively

X-ray energy selected imaging with Medipix II

Science.gov (United States)

Ludwig, J.; Zwerger, A.; Benz, K.-W.; Fiederle, M.; Braml, H.; Fauler, A.; Konrath, J.-P.

2004-09-01

Two different X-ray tube accelerating voltages (60 and 70kV) are used for diagnosis of front teeth and molars. Different energy ranges are necessary as function of tooth thickness to obtain similar contrast for imaging. This technique drives the costs for the X-ray tube up and allows for just two optimized settings. Energy range selection for the detection of the penetrating X-rays would overcome these severe setbacks. The single photon counting chip MEDIPIX2 http://www.cern.ch/medipix exhibits exactly this feature.First simulations and measurements have been carried out using a dental X-ray source. As a demonstrator a real tooth has been used with different cavities and filling materials. Simulations showed in general larger improvements as compared to measurements regarding SNR and contrast: A beneficial factor of 4% wrt SNR and 25% for contrast, measurements showed factors of 2.5 and up to 10%, respectively.

Recent experimental results on ICF target implosions by Z-pinch radiation sources and their relevance to ICF ignition studies

International Nuclear Information System (INIS)

Mehlhorn, T A; Bailey, J E; Bennett, G; Chandler, G A; Cooper, G; Cuneo, M E; Golovkin, I; Hanson, D L; Leeper, R J; MacFarlane, J J; Mancini, R C; Matzen, M K; Nash, T J; Olson, C L; Porter, J L; Ruiz, C L; Schroen, D G; Slutz, S A; Varnum, W; Vesey, R A

2003-01-01

Inertial confinement fusion capsule implosions absorbing up to 35 kJ of x-rays from a ∼220 eV dynamic hohlraum on the Z accelerator at Sandia National Laboratories have produced thermonuclear D-D neutron yields of (2.6±1.3) x 10 10 . Argon spectra confirm a hot fuel with T e ∼ 1 keV and n e ∼ (1-2) x 10 23 cm -3 . Higher performance implosions will require radiation symmetry control improvements. Capsule implosions in a ∼70 eV double-Z-pinch-driven secondary hohlraum have been radiographed by 6.7 keV x-rays produced by the Z-beamlet laser (ZBL), demonstrating a drive symmetry of about 3% and control of P 2 radiation asymmetries to ±2%. Hemispherical capsule implosions have also been radiographed in Z in preparation for future experiments in fast ignition physics. Z-pinch-driven inertial fusion energy concepts are being developed. The refurbished Z machine (ZR) will begin providing scaling information on capsule and Z-pinch in 2006. The addition of a short pulse capability to ZBL will enable research into fast ignition physics in the combination of ZR and ZBL-petawatt. ZR could provide a test bed to study NIF-relevant double-shell ignition concepts using dynamic hohlraums and advanced symmetry control techniques in the double-pinch hohlraum backlit by ZBL

Recent experimental results on ICF target implosions by Z-pinch radiation sources and their relevance to ICF ignition studies

International Nuclear Information System (INIS)

Bailey, James E.; Chandler, Gordon Andrew; Vesey, Roger Alan; Hanson, David Lester; Olson, Craig Lee; Nash, Thomas J.; Matzen, Maurice Keith; Ruiz, Carlos L.; Porter, John Larry Jr.; Cuneo, Michael Edward; Varnum, William S.; Bennett, Guy R.; Cooper, Gary Wayne; Schroen, Diana Grace; Slutz, Stephen A.; MacFarlane, Joseph John; Leeper, Ramon Joe; Golovkin, I.E.; Mehlhorn, Thomas Alan; Mancini, Roberto Claudio

2003-01-01

Inertial confinement fusion capsule implosions absorbing up to 35 kJ of x-rays from a ∼220 eV dynamic hohlraum on the Z accelerator at Sandia National Laboratories have produced thermonuclear D-D neutron yields of (2.6 ± 1.3) x 10 10 . Argon spectra confirm a hot fuel with Te ∼ 1 keV and n e ∼ (1-2) x 10 23 cm -3 . Higher performance implosions will require radiation symmetry control improvements. Capsule implosions in a ∼70 eV double-Z-pinch-driven secondary hohlraum have been radiographed by 6.7 keV x-rays produced by the Z-beamlet laser (ZBL), demonstrating a drive symmetry of about 3% and control of P 2 radiation asymmetries to ±2%. Hemispherical capsule implosions have also been radiographed in Z in preparation for future experiments in fast ignition physics. Z-pinch-driven inertial fusion energy concepts are being developed. The refurbished Z machine (ZR) will begin providing scaling information on capsule and Z-pinch in 2006. The addition of a short pulse capability to ZBL will enable research into fast ignition physics in the combination of ZR and ZBL-petawatt. ZR could provide a test bed to study NIF-relevant double-shell ignition concepts using dynamic hohlraums and advanced symmetry control techniques in the double-pinch hohlraum backlit by ZBL.

X-Rays from NGC 3256: High-Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X-Ray Background

International Nuclear Information System (INIS)

Moran, Edward C.; Lehnert, Matthew D.; Helfand, David J.

1999-01-01

The infrared-luminous galaxy NGC 3256 is a classic example of a merger-induced nuclear starburst system. We find here that it is the most X-ray-luminous star-forming galaxy yet detected (L 0.5-10keV =1.6x10 42 ergs s-1). Long-slit optical spectroscopy and a deep, high-resolution ROSAT X-ray image show that the starburst is driving a ''superwind'' which accounts for ∼20% of the observed soft X-ray emission. Analysis of X-ray spectral data from ASCA indicates this gas has a characteristic temperature of kT≅0.3 keV. Our model for the broadband X-ray emission of NGC 3256 contains two additional components: a warm thermal plasma (kT≅0.8 keV) associated with the central starburst, and a hard power-law component with an energy index of α X ≅0.7. We discuss the energy budget for the two thermal plasmas and find that the input of mechanical energy from the starburst is more than sufficient to sustain the observed level of emission. We also examine possible origins for the power-law component, concluding that neither a buried AGN nor the expected population of high-mass X-ray binaries can account for this emission. Inverse Compton scattering, involving the galaxy's copious flux of infrared photons and the relativistic electrons produced by supernovae, is likely to make a substantial contribution to the hard X-ray flux. Such a model is consistent with the observed radio and IR fluxes and the radio and X-ray spectral indices. We explore the role of X-ray-luminous starbursts in the production of the cosmic X-ray background radiation. The number counts and spectral index distribution of the faint radio source population, thought to be dominated by star-forming galaxies, suggest that a significant fraction of the hard X-ray background could arise from starbursts at moderate redshift. (c) (c) 1999. The American Astronomical Society

Hohlraum energetics scaling to 520 TW on the National Ignition Facilitya)

Science.gov (United States)

Kline, J. L.; Callahan, D. A.; Glenzer, S. H.; Meezan, N. B.; Moody, J. D.; Hinkel, D. E.; Jones, O. S.; MacKinnon, A. J.; Bennedetti, R.; Berger, R. L.; Bradley, D.; Dewald, E. L.; Bass, I.; Bennett, C.; Bowers, M.; Brunton, G.; Bude, J.; Burkhart, S.; Condor, A.; Di Nicola, J. M.; Di Nicola, P.; Dixit, S. N.; Doeppner, T.; Dzenitis, E. G.; Erbert, G.; Folta, J.; Grim, G.; Glenn, S.; Hamza, A.; Haan, S. W.; Heebner, J.; Henesian, M.; Hermann, M.; Hicks, D. G.; Hsing, W. W.; Izumi, N.; Jancaitis, K.; Jones, O. S.; Kalantar, D.; Khan, S. F.; Kirkwood, R.; Kyrala, G. A.; LaFortune, K.; Landen, O. L.; Lagin, L.; Larson, D.; Pape, S. Le; Ma, T.; MacPhee, A. G.; Michel, P. A.; Miller, P.; Montincelli, M.; Moore, A. S.; Nikroo, A.; Nostrand, M.; Olson, R. E.; Pak, A.; Park, H. S.; Patel, J. P.; Pelz, L.; Ralph, J.; Regan, S. P.; Robey, H. F.; Rosen, M. D.; Ross, J. S.; Schneider, M. B.; Shaw, M.; Smalyuk, V. A.; Strozzi, D. J.; Suratwala, T.; Suter, L. J.; Tommasini, R.; Town, R. P. J.; Van Wonterghem, B.; Wegner, P.; Widmann, K.; Widmayer, C.; Wilkens, H.; Williams, E. A.; Edwards, M. J.; Remington, B. A.; MacGowan, B. J.; Kilkenny, J. D.; Lindl, J. D.; Atherton, L. J.; Batha, S. H.; Moses, E.

2013-05-01

Indirect drive experiments have now been carried out with laser powers and energies up to 520 TW and 1.9 MJ. These experiments show that the energy coupling to the target is nearly constant at 84% ± 3% over a wide range of laser parameters from 350 to 520 TW and 1.2 to 1.9 MJ. Experiments at 520 TW with depleted uranium hohlraums achieve radiation temperatures of ˜330 ± 4 eV, enough to drive capsules 20 μm thicker than the ignition point design to velocities near the ignition goal of 370 km/s. A series of three symcap implosion experiments with nearly identical target, laser, and diagnostics configurations show the symmetry and drive are reproducible at the level of ±8.5% absolute and ±2% relative, respectively.

Rayleigh-Taylor instabilities in indirect laser drive with rugby-shaped hohlraums; Experiences d'instabilites Rayleigh-Taylor en attaque indirecte avec des cavites rugby

Energy Technology Data Exchange (ETDEWEB)

Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.P.; Richard, A.; Liberatore, S.; Vandenboomgaerde, M. [CEA Bruyeres-le-Chatel, 91 (France)

2009-07-01

The mastering of the development of hydrodynamic instabilities like Rayleigh-Taylor instabilities is an important milestone on the way to perform efficient laser implosions. The complexity of these instabilities implies an experimental validation of the theoretical models and their computer simulations. An experimental platform involving the Omega laser has allowed us to perform indirect drive with rugby-shaped hohlraums. The experiments have validated the growth of 2- and 3-dimensional initial defects as predicted by theory. We have shown that the 3-dimensional defect saturates for an higher amplitude than the 2-dimensional one does. The experiments have been made by using a plastic shell doped with Germanium (CH:Ge). (A.C.)

Progress toward a soft X-ray FEL

International Nuclear Information System (INIS)

Pellegrini, C.

1988-01-01

We review the FEL physics and obtain scaling laws for the extension of its operation to the soft X-ray region. We also discuss the properties of an electron beam needed to drive such an FEL, and the present state of the art for the beam production. (orig.)

X-ray astronomy

International Nuclear Information System (INIS)

Giacconi, R.; Gursky, H.

1974-01-01

This text contains ten chapters and three appendices. Following an introduction, chapters two through five deal with observational techniques, mechanisms for the production of x rays in a cosmic setting, the x-ray sky and solar x-ray emission. Chapters six through ten include compact x-ray sources, supernova remnants, the interstellar medium, extragalactic x-ray sources and the cosmic x-ray background. Interactions of x rays with matter, units and conversion factors and a catalog of x-ray sources comprise the three appendices. (U.S.)

A triboelectric closed loop band system for the generation of x-rays

Science.gov (United States)

Van Cleve, E.; Lucas, B.; Ganlieli, Z.; Wong, E. W.; Cortes, P.; Mehta, N.; Cuadra, D.; Fong, J.; Hansen, S.; Kotowski, A.; Camara, C. G.

2015-08-01

X-ray have been commercially produced using the same basic design since their discovery by Wilhelm Roentgen in 1895, for which he was awarded the first Nobel prize in physics. This technology requires high voltage elements, ultra high vacuum tubes, and high voltage electronics. The vacuum and high voltage drive up the price of x-ray technology and in order to bring down the cost, a brand new way to produce x-rays is needed. In 2008 Carlos Camara, Juan Escobar, Jonathan R. Hird, and Seth Putterman1 discovered that by pealing scotch tape in a vacuum you could create enough x-rays to take an x-ray radiograph of a finger. This lead to the formation of Tribogenics and the development of the rod and band x-ray architecture.

The Athena X-ray Integral Field Unit

Science.gov (United States)

Barret, D.

2017-10-01

The Athena X-ray Integral Field Unit (X-IFU) is a high-resolution X-ray spectrometer, providing 2.5 eV spectral resolution, over a 5' (equivalent diameter) field of view, and count rate capabilities up to 1 Crab in the 0.2-12 keV range. Approaching the end of its feasibility study (scheduled around the end of 2017), I will briefly recall the scientific objectives of Athena driving the X-IFU specifications and will describe its current baseline configuration and the expected performances. I will outline the on-going technology developments that will enable the X-IFU. The X-IFU will be developed by an international consortium led by France (IRAP/CNES), the Netherlands (SRON), Italy (IAPS), with ESA member state contributions from Belgium, Finland, Germany, Poland, Spain and Switzerland, and international partner contributions from Japan and the United States. This talk is given on behalf of the X-IFU Consortium.

High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

NARCIS (Netherlands)

Groot, F.M.F. de

2000-01-01

In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

The wire array Z-pinch: an efficient x-ray source for ICF and a new ion heating mechanism

Science.gov (United States)

Haines, M. G.

2008-10-01

The Z-pinch provides an efficient x-ray source for driving a hohlraum for inertial confinement fusion. The basic physics of wire-array implosions is reviewed. It can be understood in several sequential stages. Firstly, the wires heat and form a surrounding vapour which ionizes, causing the current to transfer to this lower resistance. The J×B global force leads to ejection of this plasma towards the axis to form a precursor plasma. The wire cores continue to ablate due to the heat flux from the Joule-heated nearby plasma. The cooling of this plasma by the wire-cores leads to a low magnetic Reynolds number so that the precursor plasma carries little or no current. When gaps appear in the liquid/vapour cores the plasma temperature and Reynolds number rise and this plasma accelerates in towards the axis carrying the current. This is the main implosion, and it sweeps up earlier ablated plasma, which acts to reduce Rayleigh-Taylor growth. At stagnation, the ion kinetic energy is thermalized and equipartition heats the electrons, which then radiate in a 5 ns pulse. In some conditions the energy radiated by soft x-rays exceeds the ion kinetic energy by a factor of 3 or 4. A theory has been developed to explain this in which fine-scale, fast growing m= 0 MHD instabilities grow to saturation, viscous dissipation of which leads to ion heating, followed by equipartition. World record ion temperatures of 2-3 billion Kelvin were predicted, and measured at Sandia National Laboratory. Lastly, progress in capsule implosions and in application to inertial fusion energy is reported.

Flash X-ray

International Nuclear Information System (INIS)

Sato, Eiichi

2003-01-01

Generation of quasi-monochromatic X-ray by production of weakly ionized line plasma (flash X-ray), high-speed imaging by the X-ray and high-contrast imaging by the characteristic X-ray absorption are described. The equipment for the X-ray is consisted from the high-voltage power supply and condenser, turbo molecular pump, and plasma X-ray tube. The tube has a long linear anticathode to produce the line plasma and flash X-ray at 20 kA current at maximum. X-ray spectrum is measured by the imaging plate equipped in the computed radiography system after diffracted by a LiF single crystal bender. Cu anticathode generates sharp peaks of K X-ray series. The tissue images are presented for vertebra, rabbit ear and heart, and dog heart by X-ray fluoroscopy with Ce anticathode. Generation of K-orbit characteristic X-ray with extremely low bremsstrahung is to be attempted for medical use. (N.I.)

Development and characterization of femtosecond laser driven soft x-ray lasers

International Nuclear Information System (INIS)

Bettaibi, I.

2005-06-01

Coherent soft x-ray sources have an important potential for scientific, medical and industrial applications. The development of high intensity laser systems allowed the realization of new coherent and fast soft x-ray sources like high order harmonic generation and soft x-ray lasers. These sources are compact, cheaper than traditional sources such as synchrotrons, and are thus interesting. This thesis presents the study of a new soft x-ray laser pumped by a femto-second laser beam working at 10 Hz. The circularly polarized ultra intense laser is longitudinally focused in a cell filled with xenon or krypton, to obtain the amplification of two lasing lines at 41.8 nm and 32.8 nm in Pd-like xenon and Ni-like krypton respectively. We carry out an experimental and numerical study of the source to understand the importance of different parameters such as the laser intensity and polarization, the gas pressure and the cell length. We have also spatially and temporally characterized the soft x-ray laser beam. To compensate the refraction of the driving laser we have investigated guiding techniques consisting in creating a plasma channel by electric discharge or using the multiple reflections of the driving laser on the internal walls of the dielectric tubes of sapphire or glass. A spectacular improvement of the source performances has been observed in both cases. Finally, we present a preliminary study on a different x-ray scheme: the inner shell photo pumping of neutral atoms. We have developed an optical system, which should create the appropriate conditions for the realisation of short wavelength x-ray amplifier. (author)

Development of online cable eccentricity detection system based on X-ray CCD

International Nuclear Information System (INIS)

Chen Jianzhen; Li Bin; Wei Kaixia; Guo Lanying; Qu Guopu

2008-01-01

An improved technology of online cable eccentricity detection, based on X-ray CCD, greatly improves the measuring precision and the responding speed. The theory of eccentricity measuring based on X-ray CCD, and the structure of an apparatus are described. The apparatus is composed of scanning drive subsystem, X-ray generation components, data acquiring subsystem and high performance computer system. The measuring results are also presented. The features of this cable eccentricity detection technology are compared with the features of other technologies. (authors)

Micro controller application as x-ray machine's high voltage controller

International Nuclear Information System (INIS)

Wiranto Budi Santoso; Beny Syawaludin

2010-01-01

The micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive the stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-B051 compiler. The test results show that the stepper motor could rotate according to an input value. (author)

X-Ray

Science.gov (United States)

... enema. What you can expect During the X-ray X-rays are performed at doctors' offices, dentists' offices, ... as those using a contrast medium. Your child's X-ray Restraints or other techniques may be used to ...

Progress Toward Ignition on the National Ignition Facility

International Nuclear Information System (INIS)

Kauffman, R.L.

2011-01-01

The principal approach to ignition on the National Ignition Facility (NIF) is indirect drive. A schematic of an ignition target is shown in Figure 1. The laser beams are focused through laser entrance holes at each end of a high-Z cylindrical case, or hohlraum. The lasers irradiate the hohlraum walls producing x-rays that ablate and compress the fuel capsule in the center of the hohlraum. The hohlraum is made of Au, U, or other high-Z material. For ignition targets, the hohlraum is ∼0.5 cm diameter by ∼1 cm in length. The hohlraum absorbs the incident laser energy producing x-rays for symmetrically imploding the capsule. The fuel capsule is a ∼2-mm-diameter spherical shell of CH, Be, or C filled with DT fuel. The DT fuel is in the form of a cryogenic layer on the inside of the capsule. X-rays ablate the outside of the capsule, producing a spherical implosion. The imploding shell stagnates in the center, igniting the DT fuel. NIC has overseen installation of all of the hardware for performing ignition experiments, including commissioning of approximately 50 diagnostic systems in NIF. The diagnostics measure scattered optical light, x-rays from the hohlraum over the energy range from 100 eV to 500 keV, and x-rays, neutrons, and charged particles from the implosion. An example of a diagnostic is the Magnetic Recoil Spectrometer (MRS) built by a collaboration of scientists from MIT, UR-LLE, and LLNL shown in Figure 2. MRS measures the neutron spectrum from the implosion, providing information on the neutron yield and areal density that are metrics of the quality of the implosion. Experiments on NIF extend ICF research to unexplored regimes in target physics. NIF can produce more than 50 times the laser energy and more than 20 times the power of any previous ICF facility. Ignition scale hohlraum targets are three to four times larger than targets used at smaller facilities, and the ignition drive pulses are two to five times longer. The larger targets and longer

Synchrotron x-ray microbeam characteristics for x-ray fluorescence analysis

International Nuclear Information System (INIS)

Iida, Atsuo; Noma, Takashi

1995-01-01

X-ray fluorescence analysis using a synchrotron x-ray microprobe has become an indispensable technique for non-destructive micro-analysis. One of the most important parameters that characterize the x-ray microbeam system for x-ray fluorescence analysis is the beam size. For practical analysis, however, the photon flux, the energy resolution and the available energy range are also crucial. Three types of x-ray microbeam systems, including monochromatic and continuum excitation systems, were compared with reference to the sensitivity, the minimum detection limit and the applicability to various types of x-ray spectroscopic analysis. 16 refs., 5 figs

X-ray sky

International Nuclear Information System (INIS)

Gruen, M.; Koubsky, P.

1977-01-01

The history is described of the discoveries of X-ray sources in the sky. The individual X-ray detectors are described in more detail, i.e., gas counters, scintillation detectors, semiconductor detectors, and the principles of X-ray spectrometry and of radiation collimation aimed at increased resolution are discussed. Currently, over 200 celestial X-ray sources are known. Some were identified as nebulae, in some pulsations were found or the source was identified as a binary star. X-ray bursts of novae were also observed. The X-ray radiation is briefly mentioned of spherical star clusters and of extragalactic X-ray sources. (Oy)

Measurements of direct drive laser imprint in thin foils by radiography using an x-ray laser backlighter

International Nuclear Information System (INIS)

Kalantar, D.H.; Key, M.H.; Da Silva, L.B.; Glendinning, S.G.; Remington, B.A.; Rothenberg, J.E.; Weber, F.; Weber, S.V.; Wolfrum, E.; Kim, N.S.; Neely, D.; Zhang, J.; Wark, J.S.; Demir, A.; Lin, J.; Smith, R.; Tallents, G.J.; Lewis, C.L.; MacPhee, A.; Warwick, J.; Knauer, J.P.

1997-01-01

In direct drive inertial confinement fusion, the residual speckle pattern remaining after beam smoothing plays an important role in the seeding of instabilities at the ablation front. An x-ray laser is used as an extreme ultraviolet backlighter to characterize the imprinted modulation in thin foils for smoothing by random phase plate and by spectral dispersion for both 0.35 and 0.53 μm irradiation, and by induced spatial incoherence for 0.53 μm irradiation. Measurements of the imprinted modulation due to a single optical mode generated by two beam interference, and modification of the imprint with a superposed smooth irradiation to study time dependence of the imprinting process are demonstrated. copyright 1997 American Institute of Physics

X-ray astronomy

International Nuclear Information System (INIS)

Culhane, J.L.; Sanford, P.W.

1981-01-01

X-ray astronomy has been established as a powerful means of observing matter in its most extreme form. The energy liberated by sources discovered in our Galaxy has confirmed that collapsed stars of great density, and with intense gravitational fields, can be studied by making observations in the X-ray part of the electromagnetic spectrum. The astronomical objects which emit detectable X-rays include our own Sun and extend to quasars at the edge of the Universe. This book describes the history, techniques and results obtained in the first twenty-five years of exploration. Space rockets and satellites are essential for carrying the instruments above the Earth's atmosphere where it becomes possible to view the X-rays from stars and nebulae. The subject is covered in chapters, entitled: the birth of X-ray astronomy; the nature of X-radiation; X-rays from the Sun; solar-flare X-rays; X-rays from beyond the solar system; supernovae and their remnants; X-rays from binary stars; white dwarfs and neutron stars; black holes; X-rays from galaxies and quasars; clusters of galaxies; the observatories of the future. (author)

Stimulated X-Ray Emission Spectroscopy in Transition Metal Complexes

Science.gov (United States)

Kroll, Thomas; Weninger, Clemens; Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Mercadier, Laurent; Majety, Vinay P.; Marinelli, Agostino; Lutman, Alberto; Guetg, Marc W.; Decker, Franz-Josef; Boutet, Sébastien; Aquila, Andy; Koglin, Jason; Koralek, Jake; DePonte, Daniel P.; Kern, Jan; Fuller, Franklin D.; Pastor, Ernest; Fransson, Thomas; Zhang, Yu; Yano, Junko; Yachandra, Vittal K.; Rohringer, Nina; Bergmann, Uwe

2018-03-01

We report the observation and analysis of the gain curve of amplified K α x-ray emission from solutions of Mn(II) and Mn(VII) complexes using an x-ray free electron laser to create the 1 s core-hole population inversion. We find spectra at amplification levels extending over 4 orders of magnitude until saturation. We observe bandwidths below the Mn 1 s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ˜1.7 eV FWHM is constant over 3 orders of magnitude, pointing to the buildup of transform limited pulses of ˜1 fs duration. Driving the amplification into saturation leads to broadening and a shift of the line. Importantly, the chemical sensitivity of the stimulated x-ray emission to the Mn oxidation state is preserved at power densities of ˜1020 W /cm2 for the incoming x-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) x-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear x-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis, and materials science.

Skull x-ray

Science.gov (United States)

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

Neck x-ray

Science.gov (United States)

X-ray - neck; Cervical spine x-ray; Lateral neck x-ray ... There is low radiation exposure. X-rays are monitored so that the lowest amount of radiation is used to produce the image. Pregnant women and ...

X-ray filter for chest X-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

A description is given of an X-ray filter comprised of a sheet of radiation absorbing material with an opening corresponding to the spine and central portion of the heart. The upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter. This filter will permit an acceptable density level of x-ray exposure for the lungs while allowing a higher level of x-ray exposure for the mediastinum areas of the body. (author)

Kinetic modeling of Nernst effect in magnetized hohlraums.

Science.gov (United States)

Joglekar, A S; Ridgers, C P; Kingham, R J; Thomas, A G R

2016-04-01

We present nanosecond time-scale Vlasov-Fokker-Planck-Maxwell modeling of magnetized plasma transport and dynamics in a hohlraum with an applied external magnetic field, under conditions similar to recent experiments. Self-consistent modeling of the kinetic electron momentum equation allows for a complete treatment of the heat flow equation and Ohm's law, including Nernst advection of magnetic fields. In addition to showing the prevalence of nonlocal behavior, we demonstrate that effects such as anomalous heat flow are induced by inverse bremsstrahlung heating. We show magnetic field amplification up to a factor of 3 from Nernst compression into the hohlraum wall. The magnetic field is also expelled towards the hohlraum axis due to Nernst advection faster than frozen-in flux would suggest. Nonlocality contributes to the heat flow towards the hohlraum axis and results in an augmented Nernst advection mechanism that is included self-consistently through kinetic modeling.

X-ray optics and X-ray microscopes: new challenges

International Nuclear Information System (INIS)

Susini, J.

2004-01-01

Soon after the discovery of X-rays in 1895 by W. Roentgen, it became rapidly clear that the methods traditionally used in the visible light regime, namely refraction, diffraction and reflection were difficult to apply for X-ray optics. The physical origins of these difficulties are closely linked to the very nature of interaction of X-rays with matter. The small deviation δ of the refractive index of condensed matter from unity makes it difficult to extend refraction-based optics from the optical spectral region to the X-ray region because the refraction angle is proportional to δ. Similarly it is very challenging to extend diffraction-based focusing techniques to X-rays because the diffraction angle scales inversely with wavelength. Finally, the use of reflection-based optics is also limited by the very small critical angle for total reflection. All those fundamental limitations prevented for almost one century, the development of X-ray microscopy whereas electron microscopy became a standard tool. In the past twenty years, interests for X-ray microscopy revived, mainly because of several major advances in X-ray sources and X-ray optics. X-ray microscopy techniques are now emerging as powerful and complementary tools for submicron investigations. Soft X-ray microscopes offer traditionally the possibility to form direct images of thick hydrated biological material in near-native environment, at a spatial resolution well beyond that achievable with visible light microscopy. Natural contrast is available in the soft X-ray region, in the so-called ''water-window'', due to the presence of absorption edges of the major constituents (C,N,O). Recent advances in manufacturing techniques have enlarged the accessible energy range of micro-focussing optics and offer new applications in a broad range of disciplines. X-ray microscopy in the 1 - 30 keV energy range is better suited for fluorescence to map trace elements, tomography for 3D imaging and micro-diffraction. The

X-ray filter for chest x-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

Filter for use in medical x-ray apparatus to permit higher intensity x-ray exposure in the heart and mediastinum area while maintaining a normal level of x-ray exposure in other areas of the body, particlarly in the lung area. The filter comprises a sheet of radiation absorbing material having an opening therein, said opening corresponding to the spine and central portion of the heart. Accordingly, the upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter

Bump evolution driven by the x-ray ablation Richtmyer-Meshkov effect in plastic inertial confinement fusion Ablators

Directory of Open Access Journals (Sweden)

Loomis Eric

2013-11-01

Full Text Available Growth of hydrodynamic instabilities at the interfaces of inertial confinement fusion capsules (ICF due to ablator and fuel non-uniformities are a primary concern for the ICF program. Recently, observed jetting and parasitic mix into the fuel were attributed to isolated defects on the outer surface of the capsule. Strategies for mitigation of these defects exist, however, they require reduced uncertainties in Equation of State (EOS models prior to invoking them. In light of this, we have begun a campaign to measure the growth of isolated defects (bumps due to x-ray ablation Richtmyer-Meshkov in plastic ablators to validate these models. Experiments used hohlraums with radiation temperatures near 70 eV driven by 15 beams from the Omega laser (Laboratory for Laser Energetics, University of Rochester, NY, which sent a ∼1.25Mbar shock into a planar CH target placed over one laser entrance hole. Targets consisted of 2-D arrays of quasi-gaussian bumps (10 microns tall, 34 microns FWHM deposited on the surface facing into the hohlraum. On-axis radiography with a saran (Cl Heα − 2.76keV backlighter was used to measure bump evolution prior to shock breakout. Shock speed measurements were also performed to determine target conditions. Simulations using the LEOS 5310 and SESAME 7592 models required the simulated laser power be turned down to 80 and 88%, respectively to match observed shock speeds. Both LEOS 5310 and SESAME 7592 simulations agreed with measured bump areal densities out to 6 ns where ablative RM oscillations were observed in previous laser-driven experiments, but did not occur in the x-ray driven case. The QEOS model, conversely, over predicted shock speeds and under predicted areal density in the bump.

Different X-ray spectral evolution for black hole X-ray binaries in dual tracks of radio-X-ray correlation

International Nuclear Information System (INIS)

Cao, Xiao-Feng; Wu, Qingwen; Dong, Ai-Jun

2014-01-01

Recently, an 'outlier' track of radio-X-ray correlation was found, which is much steeper than the former universal correlation, where dual tracks were speculated to be triggered by different accretion processes. In this work, we test this issue by exploring hard X-ray spectral evolution in four black-hole X-ray binaries with multiple, quasi-simultaneous radio and X-ray observations. First, we find that hard X-ray photon indices, Γ, are negatively and positively correlated with X-ray fluxes when the X-ray flux, F 3-9 keV , is below and above a critical flux, F X, crit , which are consistent with predictions of the advection-dominated accretion flow and the disk-corona model, respectively. Second, and most importantly, we find that the radio-X-ray correlations are also clearly different when the X-ray fluxes are higher and lower than the critical flux as defined by X-ray spectral evolution. The data points with F 3-9 keV ≳ F X, crit have a steeper radio-X-ray correlation (F X ∝F R b and b ∼ 1.1-1.4), which roughly forms the ''outlier'' track. However, the data points with anti-correlation of Γ – F 3-9 keV either stay in the universal track with b ∼ 0.61 or stay in the transition track (from the universal to 'outlier' tracks or vice versa). Therefore, our results support that the universal and ''outlier'' tracks of radio-X-ray correlations are regulated by radiatively inefficient and radiatively efficient accretion model, respectively.

A rugby-shaped cavity for the LMJ

International Nuclear Information System (INIS)

Vandenboomgaerde, M.; Bastian, J.; Casner, A.; Galmiche, D.; Jadaud, J.P.; Lafitte, S.; Liberatore, S.; Malinie, G.; Philippe, F.

2008-01-01

Numerical studies show that a rugby-shaped hohlraum for indirect drive laser ignition has some advantages: it allows a better symmetry for the X-ray irradiation of the central target and it required less laser power. Rugby-shaped cavities have been tested successfully at the Omega facility. The energetic advantage is all the more important as the cavity is bigger. Simulations have shown that a rugby-shaped hohlraum plus adequate materials for the intern wall plus an optimization of the central target could open the way to an ignition with only 160 laser beams at the LMJ (Megajoule Laser) facility. (A.C.)

A rugby-shaped cavity for the LMJ; Une cavite en forme de ballon de rugby pour le LMJ

Energy Technology Data Exchange (ETDEWEB)

Vandenboomgaerde, M.; Bastian, J.; Casner, A.; Galmiche, D.; Jadaud, J.P.; Lafitte, S.; Liberatore, S.; Malinie, G.; Philippe, F. [CEA Bruyeres-le-Chatel, 91 (France)

2008-07-01

Numerical studies show that a rugby-shaped hohlraum for indirect drive laser ignition has some advantages: it allows a better symmetry for the X-ray irradiation of the central target and it required less laser power. Rugby-shaped cavities have been tested successfully at the Omega facility. The energetic advantage is all the more important as the cavity is bigger. Simulations have shown that a rugby-shaped hohlraum plus adequate materials for the intern wall plus an optimization of the central target could open the way to an ignition with only 160 laser beams at the LMJ (Megajoule Laser) facility. (A.C.)

Comparison of x-ray output of inverter-type x-ray equipment

International Nuclear Information System (INIS)

Asano, Hiroshi; Miyake, Hiroyuki; Yamamoto, Keiichi

2000-01-01

The x-ray output of 54 inverter-type x-ray apparatuses used at 18 institutions was investigated. The reproducibility and linearity of x-ray output and variations among the x-ray equipment were evaluated using the same fluorescence meter. In addition, the x-ray apparatuses were re-measured using the same non-invasive instrument to check for variations in tube voltage, tube current, and irradiation time. The non-invasive instrument was calibrated by simultaneously obtaining measurements with an invasive instrument, employing the tube voltage and current used for the invasive instrument, and the difference was calculated. Reproducibility of x-ray output was satisfactory for all x-ray apparatuses. The coefficient of variation was 0.04 or less for irradiation times of 5 ms or longer. In 84.3% of all x-ray equipment, variation in the linearity of x-ray output was 15% or less for an irradiation time of 5 ms. However, for all the apparatuses, the figure was 50% when irradiation time was the shortest (1 to 3 ms). Variation in x-ray output increased as irradiation time decreased. Variation in x-ray output ranged between 1.8 and 2.5 compared with the maximum and minimum values, excluding those obtained at the shortest irradiation time. The relative standard deviation ranged from ±15.5% to ±21.0%. The largest variation in x-ray output was confirmed in regions irradiated for the shortest time, with smaller variations observed for longer irradiation times. The major factor responsible for variation in x-ray output in regions irradiated for 10 ms or longer, which is a relatively long irradiation time, was variation in tube current. Variation in tube current was slightly greater than 30% at maximum, with an average value of 7% compared with the preset tube current. Variations in x-ray output in regions irradiated for the shortest time were due to photographic effects related to the rise and fall times of the tube voltage waveform. Accordingly, in order to obtain constant x-ray

High performance capsule implosions on the OMEGA Laser facility with rugby hohlraumsa)

Science.gov (United States)

Robey, H. F.; Amendt, P.; Park, H.-S.; Town, R. P. J.; Milovich, J. L.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Sorce, C.; Strozzi, D. J.; Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Liberatore, S.; Monteil, M.-C.; Séguin, F.; Rosenberg, M.; Li, C. K.; Petrasso, R.; Glebov, V.; Stoeckl, C.; Nikroo, A.; Giraldez, E.

2010-05-01

Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly driven capsule implosions. This concept has recently been tested in a series of shots on the OMEGA laser facility [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)]. In this paper, experimental results are presented comparing the performance of D2-filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. The rugby hohlraums demonstrated 18% more x-ray drive energy as compared with the cylinders, and the high-performance design of these implosions (both cylinder and rugby) also provided ≈20× more deuterium (DD) neutrons than any previous indirectly driven campaign on OMEGA and ≈3× more than ever achieved on NOVA [E. M. Campbell, Laser Part. Beams 9, 209 (1991)] implosions driven with nearly twice the laser energy. This increase in performance enables, for the first time, a measurement of the neutron burn history and imaging of the neutron core shapes in an indirectly driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D H3e rather than D2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in very good agreement. The design techniques employed in this campaign, e.g., smaller laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility [J. D. Lindl, P. Amendt, R. L. Berger et al., Phys. Plasmas 11, 339 (2004)].

Chest X-Ray

Medline Plus

Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

Laser-plasma interactions and implosion symmetry in rugby hohlraums

Science.gov (United States)

Michel, Pierre; Berger, R. L.; Lasinski, B. F.; Ross, J. S.; Divol, L.; Williams, E. A.; Meeker, D.; Langdon, B. A.; Park, H.; Amendt, P.

2011-10-01

Cross-beam energy transfer is studied in the context of ``rugby''-hohlraum experiments at the Omega laser facility in FY11, in preparation for future NIF experiments. The transfer acts in opposite direction between rugby and cylinder hohlraums due to the different beam pointing geometries and flow patterns. Its interaction with backscatter is also different as both happen in similar regions inside rugby hohlraums. We will analyze the effects of non-linearities and temporal beam smoothing on energy transfer using the code pF3d. Calculations will be compared to experiments at Omega; analysis of future rugby hohlraum experiments on NIF will also be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Wide field X-ray telescopes: Detecting X-ray transients/afterglows related to gamma ray bursts

International Nuclear Information System (INIS)

Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul; Rezek, Tomas

1999-01-01

The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited field of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70ies but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster eye type are presented and discussed. Optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

X-ray bursts observed with JEM-X

DEFF Research Database (Denmark)

Brandt, Søren Kristian; Chenevez, Jérôme; Lund, Niels

2006-01-01

We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found.......We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found....

Tokamak physics studies using x-ray diagnostic methods

International Nuclear Information System (INIS)

Hill, K.W.; Bitter, M.; von Goeler, S.

1987-03-01

X-ray diagnostic measurements have been used in a number of experiments to improve our understanding of important tokamak physics issues. The impurity content in TFTR plasmas, its sources and control have been clarified through soft x-ray pulse-height analysis (PHA) measurements. The dependence of intrinsic impurity concentrations and Z/sub eff/ on electron density, plasma current, limiter material and conditioning, and neutral-beam power have shown that the limiter is an important source of metal impurities. Neoclassical-like impurity peaking following hydrogen pellet injection into Alcator C and a strong effect of impurities on sawtooth behavior were demonstrated by x-ray imaging (XIS) measurements. Rapid inward motion of impurities and continuation of m = 1 activity following an internal disruption were demonstrated with XIS measurements on PLT using injected aluminum to enhance the signals. Ion temperatures up to 12 keV and a toroidal plasma rotation velocity up to 6 x 10 5 m/s have been measured by an x-ray crystal spectrometer (XCS) with up to 13 MW of 85-keV neutral-beam injection in TFTR. Precise wavelengths and relative intensities of x-ray lines in several helium-like ions and neon-like ions of silver have been measured in TFTR and PLT by the XCS. The data help to identify the important excitation processes predicted in atomic physics. Wavelengths of n = 3 to 2 silver lines of interest for x-ray lasers were measured, and precise instrument calibration techniques were developed. Electron thermal conductivity and sawtooth dynamics have been studied through XIS measurements on TFTR of heat-pulse propagation and compound sawteeth. A non-Maxwellian electron distribution function has been measured, and evidence of the Parail-Pogutse instability identified by hard x-ray PHA measurements on PLT during lower-hybrid current-drive experiments

X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

Directory of Open Access Journals (Sweden)

Kumiko Morihana

2014-12-01

Full Text Available We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE. We extracted 2,002 X-ray point sources in the Chandra Bulge Field (l =0°.113, b = 1°.424 down to ~10-14.8 ergscm-2s-1 in 2-8 keV band with the longest observation (900 ks of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard, B (soft and broad spectrum, and C (soft and peaked spectrum. In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907.

Science.gov (United States)

Israel, Gian Luca; Belfiore, Andrea; Stella, Luigi; Esposito, Paolo; Casella, Piergiorgio; De Luca, Andrea; Marelli, Martino; Papitto, Alessandro; Perri, Matteo; Puccetti, Simonetta; Castillo, Guillermo A Rodríguez; Salvetti, David; Tiengo, Andrea; Zampieri, Luca; D'Agostino, Daniele; Greiner, Jochen; Haberl, Frank; Novara, Giovanni; Salvaterra, Ruben; Turolla, Roberto; Watson, Mike; Wilms, Joern; Wolter, Anna

2017-02-24

Ultraluminous x-ray sources (ULXs) in nearby galaxies shine brighter than any x-ray source in our Galaxy. ULXs are usually modeled as stellar-mass black holes (BHs) accreting at very high rates or intermediate-mass BHs. We present observations showing that NGC 5907 ULX is instead an x-ray accreting neutron star (NS) with a spin period evolving from 1.43 seconds in 2003 to 1.13 seconds in 2014. It has an isotropic peak luminosity of [Formula: see text]1000 times the Eddington limit for a NS at 17.1 megaparsec. Standard accretion models fail to explain its luminosity, even assuming beamed emission, but a strong multipolar magnetic field can describe its properties. These findings suggest that other extreme ULXs (x-ray luminosity [Formula: see text] 10 41 erg second[Formula: see text]) might harbor NSs. Copyright © 2017, American Association for the Advancement of Science.

X-ray heating of laboratory photoionized plasmas at Z

Science.gov (United States)

Mancini, R.; Lockard, T.; Mayes, D.; Loisel, G.; Bailey, J.; Rochau, G.; Abdallah, J.; Fontes, C.; Liedahl, D.; Golovkin, I.

2017-10-01

In separate experiments performed at the Z facility of Sandia National Laboratories two different samples were employed to produce and characterize photoionized plasmas. One was a gas cell filled with neon, and the other was a thin silicon layer coated with plastic. Both samples were driven by the broadband x-ray flux produced at the collapse of a wire array z-pinch implosion. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the charge state distribution, and the electron temperature was extracted from a Li-like ion level population ratio. To interpret the temperature measurement, we performed Boltzmann kinetics and radiation-hydrodynamic simulations. We found that non-equilibrium atomic physics and the coupling of the radiation flux to the level population kinetics play a critical role in modeling the x-ray heating of photoionized plasmas. In spite of being driven by similar x-ray drives, differences of ionization and charged state distributions in the neon and silicon plasmas are reflected in the plasma heating and observed temperatures. DOE OFES Grant DE-SC0014451 and ZFSP.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small dose ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

Bone X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Abdomen X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a very small ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

Measurements of direct drive laser imprint in thin foils by XUV radiography using an X-ray laser backlighter

International Nuclear Information System (INIS)

Kalantar, D.H.; Key, M.H.; DaSilva, L.B.

1996-11-01

In direct drive inertial confinement fusion, the residual speckle pattern remaining after beam smoothing plays an important role in the seeding of instabilities at the ablation front. We have used an x-ray laser as an XUV backlighter to characterize the imprinted modulation in thin foils for smoothing by random phase plate and spectral dispersion at both 0.35 pm and 0.53 pm irradiation, and induced spatial incoherence at 0.53 pm irradiation. We also demonstrate measurements of the modulation due to a single mode optical imprint generated by a narrow slit interference pattern, and modification of the imprint with a superposed smooth irradiation to study time dependence of the imprinting process. 8 refs., 10 figs

CRL X-ray tube

International Nuclear Information System (INIS)

Kolchevsky, N.N.; Petrov, P.V.

2015-01-01

A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed. (authors)

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Novel X-ray telescopes for wide-field X-ray monitoring

International Nuclear Information System (INIS)

Hudec, R.; Inneman, A.; Pina, L.; Sveda, L.

2005-01-01

We report on fully innovative very wide-field of view X-ray telescopes with high sensitivity as well as large field of view. The prototypes are very promising, allowing the proposals for space projects with very wide-field Lobster-eye X-ray optics to be considered. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study and to understand various astrophysical objects such as AGN, SNe, Gamma-ray bursts (GRBs), X-ray flashes (XRFs), galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc. The Lobster optics based X-ray All Sky Monitor is capable to detect around 20 GRBs and 8 XRFs yearly and this will surely significantly contribute to the related science

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Perfect-crystal x-ray optics to treat x-ray coherence

International Nuclear Information System (INIS)

Yamazaki, Hiroshi; Ishikawa, Tetsuya

2007-01-01

X-ray diffraction of perfect crystals, which serve as x-ray monochromator and collimator, modifies coherence properties of x-ray beams. From the time-dependent Takagi-Taupin equations that x-ray wavefields obey in crystals, the reflected wavefield is formulated as an integral transform of a general incident wavefield with temporal and spatial inhomogeneity. A reformulation of rocking-curve profiles from the field solution of the Takagi-Taupin equations allows experimental evaluation of the mutual coherence function of x-ray beam. The rigorous relationship of the coherence functions between before and after reflection clarifies how the coherence is transferred by a crystal. These results will be beneficial to developers of beamline optics for the next generation synchrotron sources. (author)

X-ray emission lines from photoionized plasmas

International Nuclear Information System (INIS)

Liedahl, D.A.

1992-11-01

Plasma emission codes have become a standard tool for the analysis of spectroscopic data from cosmic X-ray sources. However, the assumption of collisional equilibrium, typically invoked in these codes, renders them inapplicable to many important astrophysical situations, particularly those involving X-ray photoionized nebulae, which are likely to exist in the circumsource environments of compact X-ray sources. X-ray line production in a photoionized plasma is primarily the result of radiative cascades following recombination. Through the development of atomic models of several highly-charged ions, this work extends the range of applicability of discrete spectral models to plasmas dominated by recombination. Assuming that ambient plasma conditions lie in the temperature range 10 5 --10 6 K and the density range 10 11 --10 16 cm -3 , X-ray line spectra are calculated over the wavelength range 5--45 angstrom using the HULLAC atomic physics package. Most of the work focuses on the Fe L-shell ions. Line ratios of the form (3s-2p)/(3d-2p) are shown to characterize the principal mode of line excitation, thereby providing a simple signature of photoionization. At electron densities exceeding 10 12 cm -3 , metastable state populations in the ground configurations approach their LTE value, resulting in the enrichment of the Fe L-shell recombination spectrum and a set of density-sensitive X-ray line ratios. Radiative recombination continua and emission lines produced selectively by Δn = 0 dielectronic recombination are shown to provide two classes of temperature diagnostics. Because of the extreme overionization, the recombination continua are expected to be narrow (ΔE/E much-lt 1), with ΔE = kT. Dielectronic recombination selectively drives radiative transitions that originate on states with vacancies in the 2s subshell, states that are inaccessible under pure RR population kinetics

X-ray scattering in X-ray fluorescence spectra with X-ray tube excitation - Modelling, experiment, and Monte-Carlo simulation

International Nuclear Information System (INIS)

Hodoroaba, V.-D.; Radtke, M.; Vincze, L.; Rackwitz, V.; Reuter, D.

2010-01-01

X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The knowledge of the X-ray spectrometer efficiency, but also of the spectrometer response functions makes it possible to define a physical spectral background of XRF spectra. Background subtraction relying on purely mathematical procedures is state-of-the-art. The results produced by the analytical model are at least as reliable as those obtained by Monte-Carlo simulations, even without considering the very challenging contribution of multiple scattering. Special attention has been paid to Compton broadening. Relevant applications of the implementation of the analytical model presented in this paper are the prediction of the limits of detection for particular cases or the determination of the transmission of X-ray polycapillary lenses.

X-Ray Scattering Applications Using Pulsed X-Ray Sources

Energy Technology Data Exchange (ETDEWEB)

Larson, B.C.

1999-05-23

Pulsed x-ray sources have been used in transient structural phenomena investigations for over fifty years; however, until the advent of synchrotrons sources and the development of table-top picosecond lasers, general access to ligh temporal resolution x-ray diffraction was relatively limited. Advances in diffraction techniques, sample excitation schemes, and detector systems, in addition to IncEased access to pulsed sources, have ld tO what is now a diverse and growing array of pulsed-source measurement applications. A survey of time-resolved investigations using pulsed x-ray sources is presented and research opportunities using both present and planned pulsed x-ray sources are discussed.

X-ray diagnostic installation for X-ray tomographic images

International Nuclear Information System (INIS)

Haendle, J.; Sklebitz, H.

1984-01-01

An exemplary embodiment includes at least one x-ray tube for the generation of an x-ray beam, a patient support, an image detector, and a control generator-connected with the x-ray tube and the image detector-for the purpose of moving the x-ray beam, and in opposition thereto, the image field of the image detector. There is connected to the control generator a layer height computer which calculates the enlargement from the geometric data for the tomogram. The image detector has a circuit-connected with the layer height computer-for the purpose of fading-in a marking for the dimensions in the layer plane

X-ray emission spectroscopy. X-ray fluorescence

International Nuclear Information System (INIS)

Despujols, J.

1992-01-01

Principles of X-ray emission spectrometry are first recalled, then wave-length dispersive and energy dispersive X-ray fluorescence spectrometer are described. They are essentially designed for qualitative and quantitative analysis of elements (Z>10). Sample preparation, calibration, corrections, interferences, accuracy are reviewed. Examples of use in different industries are given. (71 refs.)

Providing x-rays

International Nuclear Information System (INIS)

Mallozzi, P.J.; Epstein, H.M.

1985-01-01

This invention provides an apparatus for providing x-rays to an object that may be in an ordinary environment such as air at approximately atmospheric pressure. The apparatus comprises: means (typically a laser beam) for directing energy onto a target to produce x-rays of a selected spectrum and intensity at the target; a fluid-tight enclosure around the target; means for maintaining the pressure in the first enclosure substantially below atmospheric pressure; a fluid-tight second enclosure adjoining the first enclosure, the common wall portion having an opening large enough to permit x-rays to pass through but small enough to allow the pressure reducing means to evacuate gas from the first enclosure at least as fast as it enters through the opening; the second enclosure filled with a gas that is highly transparent to x-rays; the wall of the second enclosure to which the x-rays travel having a portion that is highly transparent to x-rays (usually a beryllium or plastic foil), so that the object to which the x-rays are to be provided may be located outside the second enclosure and adjacent thereto and thus receive the x-rays substantially unimpeded by air or other intervening matter. The apparatus is particularly suited to obtaining EXAFS (extended x-ray fine structure spectroscopy) data on a material

The Prompt-afterglow Connection in Gamma-ray Bursts: a Comprehensive Statistical Analysis of Swift X-ray Light-curves

Science.gov (United States)

Margutti, R.; Zaninoni, E.; Bernardini, M. G.; Chincarini, G.; Pasotti, F.; Guidorzi, C.; Angelini, Lorella; Burrows, D. N.; Capalbi, M.; Evans, P. A.;

Electron temperature measurements inside the ablating plasma of gas-filled hohlraums at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brown, G. V.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Regan, S. P. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Jaquez, J.; Huang, H. [General Atomics, San Diego, California 92121 (United States); Hansen, S. B. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

2016-05-15

The first measurement of the electron temperature (T{sub e}) inside a National Ignition Facility hohlraum is obtained using temporally resolved K-shell X-ray spectroscopy of a mid-Z tracer dot. Both isoelectronic- and interstage-line ratios are used to calculate the local T{sub e} via the collisional–radiative atomic physics code SCRAM [Hansen et al., High Energy Density Phys 3, 109 (2007)]. The trajectory of the mid-Z dot as it is ablated from the capsule surface and moves toward the laser entrance hole (LEH) is measured using side-on x-ray imaging, characterizing the plasma flow of the ablating capsule. Data show that the measured dot location is farther away from the LEH in comparison to the radiation-hydrodynamics simulation prediction using HYDRA [Marinak et al., Phys. Plasmas 3, 2070 (1996)]. To account for this discrepancy, the predicted simulation T{sub e} is evaluated at the measured dot trajectory. The peak T{sub e}, measured to be 4.2 keV ± 0.2 keV, is ∼0.5 keV hotter than the simulation prediction.

High speed hydraulic scanner for deep x-ray lithography

International Nuclear Information System (INIS)

Milne, J.C.; Johnson, E.D.

1997-07-01

From their research and development in hard x-ray lithography, the authors have found that the conventional leadscrew driven scanner stages do not provide adequate scan speed or travel. These considerations have led the authors to develop a scanning system based on a long stroke hydraulic drive with 635 mm of travel and closed loop feedback to position the stage to better than 100 micrometers. The control of the device is through a PC with a custom LabView interface coupled to simple x-ray beam diagnostics. This configuration allows one to set a variety of scan parameters, including target dose, scan range, scan rates, and dose rate. Results from the prototype system at beamline X-27B are described as well as progress on a production version for the X-14B beamline

High speed hydraulic scanner for deep x-ray lithography

Energy Technology Data Exchange (ETDEWEB)

Milne, J.C.; Johnson, E.D.

1997-07-01

From their research and development in hard x-ray lithography, the authors have found that the conventional leadscrew driven scanner stages do not provide adequate scan speed or travel. These considerations have led the authors to develop a scanning system based on a long stroke hydraulic drive with 635 mm of travel and closed loop feedback to position the stage to better than 100 micrometers. The control of the device is through a PC with a custom LabView interface coupled to simple x-ray beam diagnostics. This configuration allows one to set a variety of scan parameters, including target dose, scan range, scan rates, and dose rate. Results from the prototype system at beamline X-27B are described as well as progress on a production version for the X-14B beamline.

X-ray detector for a panoramic X-ray unit

Energy Technology Data Exchange (ETDEWEB)

Cowell, D; Ensslin, F H

1976-01-15

The discovery deals with an X-ray detector suitable for the controlling of panoramic X-ray systems. It consists of a fluorescent image screen and a semiconductor photo cell. The output signal of the detector is proportional to the intensity of the X-radiation and the response time is large enough to follow the change of amplitude of the contours of the modulated X radiation. The detector with band-pass filter regulates, via a control system, the moving rate of the X-ray source and of the film opposite it in dependence of the intensity, so that a uniform exposure is ensured.

X-ray imaging with compound refractive lens and microfocus X-ray tube

OpenAIRE

Pina, Ladislav; Dudchik, Yury; Jelinek, Vaclav; Sveda, Libor; Marsik, Jiri; Horvath, Martin; Petr, Ondrej

2008-01-01

Compound refractive lenses (CRL), consisting of a lot number in-line concave microlenses made of low-Z material were studied. Lenses with focal length 109 mm and 41 mm for 8-keV X-rays, microfocus X-ray tube and X-ray CCD camera were used in experiments. Obtained images show intensity distribution of magnified microfocus X-ray source focal spot. Within the experiments, one lens was also used as an objective lens of the X-ray microscope, where the copper anode X-ray microfocus tube served as a...

Abdominal x-ray

Science.gov (United States)

Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

X-ray spectroscopy and X-ray crystallography of metalloenzymes at XFELs

International Nuclear Information System (INIS)

Yano, Junko

2016-01-01

The ultra-bright femtosecond X-ray pulses provided by X-ray Free Electron Lasers (XFELs) open capabilities for studying the structure and dynamics of a wide variety of biological and inorganic systems beyond what is possible at synchrotron sources. Although the structure and chemistry at the catalytic sites have been studied intensively in both biological and inorganic systems, a full understanding of the atomic-scale chemistry requires new approaches beyond the steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure at ambient conditions, while overcoming X-ray damage to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by using the intense and ultra-short femtosecond X-ray pulses from an XFEL, where sample is probed before it is damaged. We have developed methodology for simultaneously collecting crystallography data and X-ray emission spectra, using an energy dispersive spectrometer at ambient conditions. In addition, we have developed a way to collect metal L-edge data of dilute samples using soft X-rays at XFELs. The advantages and challenges of these methods will be described in this review. (author)

A microcontroller application as X-ray machine's high voltage controller

International Nuclear Information System (INIS)

Wiranto Budi Santoso; Beny Syawaludin

2010-01-01

A micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x-ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive a stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-8051 compiler. The test results show that the stepper motor could rotate according to an input value (author)

Direct observation of ultrafast atomic motion using time-resolved X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Shymanovich, U.

2007-11-13

This thesis is dedicated to the study of the atomic motion in laser irradiated solids on a picosecond to subpicosecond time-scale using the time-resolved X-ray diffraction technique. In the second chapter, the laser system, the laser-plasma based X-ray source and the experimental setup for optical pump / X-ray probe measurements were presented. Chapter 3 is devoted to the characterization and comparison of different types of X-ray optics. Chapter 4 presented the time-resolved X-ray diffraction experiments performed for this thesis. The first two sections of this chapter discuss the measurements of initially unexpected strain-induced transient changes of the integrated reflectivity of the X-ray probe beam. The elimination of the strain-induced transient changes of the integrated reflectivity represented an important prerequisite to perform the study of lattice heating in Germanium after femtosecond optical excitation by measuring the transient Debye-Waller effect. The third section describes the investigations of acoustic waves upon ultrafast optical excitation and discusses the two different pressure contributions driving them: the thermal and the electronic ones. (orig.)

Direct observation of ultrafast atomic motion using time-resolved X-ray diffraction

International Nuclear Information System (INIS)

Shymanovich, U.

2007-01-01

This thesis is dedicated to the study of the atomic motion in laser irradiated solids on a picosecond to subpicosecond time-scale using the time-resolved X-ray diffraction technique. In the second chapter, the laser system, the laser-plasma based X-ray source and the experimental setup for optical pump / X-ray probe measurements were presented. Chapter 3 is devoted to the characterization and comparison of different types of X-ray optics. Chapter 4 presented the time-resolved X-ray diffraction experiments performed for this thesis. The first two sections of this chapter discuss the measurements of initially unexpected strain-induced transient changes of the integrated reflectivity of the X-ray probe beam. The elimination of the strain-induced transient changes of the integrated reflectivity represented an important prerequisite to perform the study of lattice heating in Germanium after femtosecond optical excitation by measuring the transient Debye-Waller effect. The third section describes the investigations of acoustic waves upon ultrafast optical excitation and discusses the two different pressure contributions driving them: the thermal and the electronic ones. (orig.)

Chest X-Ray

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Full Text Available ... talk with you about chest radiography also known as chest x-rays. Chest x-rays are the ... treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray ...

Modern X-ray spectroscopy 3. X-ray fluorescence holography

International Nuclear Information System (INIS)

Hayashi, Kouichi

2008-01-01

X-ray fluorescence holography (XFH) provides three dimensional atomic images around specified elements. The XFH uses atoms as a wave source or monitor of interference field within a crystal sample, and therefore it can record both intensity and phase of scattered X-rays. Its current performance makes it possible to apply to ultra thin film, impurity and quasicrystal. In this article, I show the theory including solutions for twin image problem, advanced measuring system, data processing for reconstruction of the atomic images and for obtaining accurate atomic positions, applications using resonant X-ray scattering and X-ray excited optical luminescence, and an example of XFH result on the local structure around copper in silicon steal. (author)

X-ray holography: X-ray interactions and their effects

International Nuclear Information System (INIS)

London, R.A.; Trebes, J.E.; Rosen, M.D.

1988-01-01

The authors summarize a theoretical study of the interactions of x-rays with a biological sample during the creation of a hologram. The choice of an optimal wavelength for x-ray holography is discussed, based on a description of scattering by objects within an aqueous environment. The problem of the motion resulting from the absorption of x-rays during a short exposure is described. The possibility of using very short exposures in order to capture the image before motion can compromise the resolution is explored. The impact of these calculation on the question of the feasibility of using an x-ray laser for holography of biological structures is discussed. 12 refs., 2 figs

Monte Carlo Methods in ICF

Science.gov (United States)

Zimmerman, George B.

Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ions and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved 50X in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burn and burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials.

Monte Carlo methods in ICF

International Nuclear Information System (INIS)

Zimmerman, George B.

1997-01-01

Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ions and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved 50X in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burn and burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials

Development of confocal micro X-ray fluorescence instrument using two X-ray beams

International Nuclear Information System (INIS)

Tsuji, Kouichi; Nakano, Kazuhiko; Ding Xunliang

2007-01-01

A new confocal micro X-ray fluorescence instrument was developed. This instrument has two independent micro X-ray tubes with Mo targets. A full polycapillary X-ray lens was attached to each X-ray tube. Another half polycapillary lens was attached to a silicon drift X-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The effects of the excitation of two X-ray beams were investigated. The instrument enabled highly sensitive three-dimensional X-ray fluorescence analysis. We confirmed that the X-ray fluorescence intensity from the sample increased by applying the two independent X-ray tubes in confocal configuration. Elemental depth profiling of black wheat was demonstrated with the result that each element in the surface coat of a wheat grain showed unique distribution

Modern X-ray difraction. X-ray diffractometry for material scientists, physicists, and chemicists

International Nuclear Information System (INIS)

Spiess, L.; Schwarzer, R.; Behnken, H.; Teichert, G.

2005-01-01

The book yields a comprehensive survey over the applications of X-ray diffraction in fields like material techniques, metallurgy, electrotechniques, machine engineering, as well as micro- and nanotechniques. The necessary fundamental knowledge on X-ray diffraction are mediated foundedly and illustratively. Thereby new techniques and evaluation procedures are presented as well as well known methods. The content: Production and properties of X radiation, diffraction of X radiation, hardware for X-ray diffraction, methods of X-ray diffraction, lattice-constant determination, phase analysis, X-ray profile analysis, crystal structure analysis, X-ray radiographic stress analysis, X-ray radiographic texture analysis, crystal orientation determination, pecularities at thin films, small angle scattering

X-Ray Exam: Pelvis

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Pelvis KidsHealth / For Parents / X-Ray Exam: ... Ray Exam: Hip Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

Design of the nickel-like tin x-ray laser at 12.0 nm

International Nuclear Information System (INIS)

Yan Fei; Zhang Jie; Lu Xin; Zhong, Jia Y.

2005-01-01

The effects of the drive laser intensity, pulse duration, and pulse configuration on the performance of the Ni-like Sn x-ray laser at 12.0 nm (4d→4p, J=0→1) are investigated with use of a one-dimensional hydrodynamic code coupled with an atomic physics code. High gain operation is predicted for the optimized drive pulse configuration. The effects of refraction and saturation on the propagation of the x-ray laser in the plasma medium are also investigated by use of a two-dimensional ray-tracing code. The results show that the refraction plays an important role. The saturated output with an effective gain product length of 17.88 can be obtained for an ∼0.40-cm-long plasma column by use of optimized parameters

X-ray scattering measurements from thin-foil x-ray mirrors

DEFF Research Database (Denmark)

Christensen, Finn Erland; BYRNAK, BP; Hornstrup, Allan

1992-01-01

Thin foil X-ray mirrors are to be used as the reflecting elements in the telescopes of the X-ray satellites Spectrum-X-Gamma (SRG) and ASTRO-D. High resolution X-ray scattering measurements from the Au coated and dip-lacquered Al foils are presented. These were obtained from SRG mirrors positioned...... in a test quadrant of the telescope structure and from ASTRO-D foils held in a simple fixture. The X-ray data is compared with laser data and other surface structure data such as STM, atomic force microscopy (AFM), TEM, and electron micrography. The data obtained at Cu K-alpha(1), (8.05 keV) from all...

X-ray examination apparatus

NARCIS (Netherlands)

2000-01-01

The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an

Characterization of nova plasmas using an x-ray spectrometer with temporal and spatial resolution

International Nuclear Information System (INIS)

Back, C.A.; Kauffman, R.L.; Bell, P.; Kilkenny, J.D.

1994-05-01

Spectroscopic diagnostics have great potential to obtain high temperature measurements of plasmas created in ICF targets. The plasmas may be over 1 mm in size and therefore, one of the first steps in making accurate spectroscopic measurements has been to improve the resolution of the instrument. A spectrograph is now available for Nova experiments which takes advantage of gated technology by coupling a Bragg crystal to a microchannel plate that can record data over a 250 ps time frame. The crystal disperses the x-rays, while slits add the ability to image the plasmas in the perpendicular direction. The characteristics of this diagnostic, TSPEC, will be evaluated for laser-produced plasmas. Recent data will be presented from colliding plasmas and large-scale hohlraums which indicate that imaging can greatly enhance the ability to diagnose these plasmas

Development of x-ray laminography under an x-ray microscopic condition

International Nuclear Information System (INIS)

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Yagi, Naoto

2011-01-01

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatial resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.

Chest X-Ray

Medline Plus

Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

Element-resolved x-ray ferrimagnetic and ferromagnetic resonance spectroscopy

International Nuclear Information System (INIS)

Boero, G; Mouaziz, S; Rusponi, S; Bencok, P; Nolting, F; Stepanow, S; Gambardella, P

2008-01-01

We report on the measurement of element-specific magnetic resonance spectra at gigahertz frequencies using x-ray magnetic circular dichroism (XMCD). We investigate the ferrimagnetic precession of Gd and Fe ions in Gd-substituted yttrium iron garnet, showing that the resonant field and linewidth of Gd precisely coincide with Fe up to the nonlinear regime of parametric excitations. The opposite sign of the Gd x-ray magnetic resonance signal with respect to Fe is consistent with dynamic antiferromagnetic alignment of the two ionic species. Further, we investigate a bilayer metal film, Ni 80 Fe 20 (5 nm)/Ni(50 nm), where the coupled resonance modes of Ni and Ni 80 Fe 20 are separately resolved, revealing shifts in the resonance fields of individual layers but no mutual driving effects. Energy-dependent dynamic XMCD measurements are introduced, combining x-ray absorption and magnetic resonance spectroscopies

Microfocussing of synchrotron X-rays using X-ray refractive lens

Indian Academy of Sciences (India)

X-ray lenses are fabricated in polymethyl methacrylate using deep X-ray lithography beamline of Indus-2. The focussing performance of these lenses is evaluated using Indus-2 and Diamond Light Source Ltd. The process steps for the fabrication of X-ray lenses and microfocussing at 10 keV at moderate and low emittance ...

Reproducibility of hohlraum-driven implosion symmetry on the National Ignition Facility

Directory of Open Access Journals (Sweden)

Kyrala G.A.

2013-11-01

Full Text Available Indirectly driven Symcap capsules are used at the NIF to obtain information about ignition capsule implosion performance, in particular shape. Symcaps replace the cryogenic fuel layer with an equivalent ablator mass and can be similarly diagnosed. Symcaps are good symmetry surrogates to an ignition capsule after the peak of the drive, radiation-hydrodynamics simulations predict that doping of the symcaps vary the behavior of the implosion. We compare the equatorial shapes of a symcap doped with Si or Ge, as well as examine the reproducibility of the shape measurement using two symcaps with the same hohlraum and laser conditions.

X-ray detector array

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

The object of the invention (an ionization chamber X-ray detector array for use with high speed computerised tomographic imaging apparatus) is to reduce the time required to produce a tomographic image. The detector array described determines the distribution of X-ray intensities in one or more flat, coplanar X-ray beams. It comprises three flat anode sheets parallel to the X-ray beam, a plurality of rod-like cathodes between the anodes, a detector gas between the electrodes and a means for applying a potential between the electrodes. Each of the X-ray sources is collimated to give a narrow, planar section of X-ray photons. Sets of X-ray sources in the array are pulsed simultaneously to obtain X-ray transmission data for tomographic image reconstruction. (U.K.)

Observation of cosmic hard x-ray by L-3H-9 rocket

International Nuclear Information System (INIS)

Hayakawa, Sachio; Makino, Fumiyoshi; Matsui, Yutaka; Fukada, Yutaka.

1978-01-01

It has been considered that the isotropic constituents of cosmic hard X-ray have their origins outside the galactic system. As the spectra are uncertain, the generation mechanism of X-ray has not been clearly known yet. It was attempted to make more reliable observation by shutter method and the technique removing charged particles, using the L-3H-8 rocket. The equipment consists of NaI scintillation counter, a front counter, a Xenon counter, a UV sensor, a collimator, a shutter and a shutter-driving device. The L-3H-9 rocket was launched on August 16, 1977, and reached height of 310 km in about 300 seconds. Then the observation was started, but it was not able to observe the isotropic constituents of hard X-ray which were aimed at, as the shutter didn't work normally. It is expected to make another observation with the K-9M-64 rocket in August, 1978, after investigating the action of the shutter and employing and improved driving device. (Kobatake, H.)

Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

Directory of Open Access Journals (Sweden)

L. Miaja-Avila

2015-03-01

Full Text Available We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ∼106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

Velocity-Resolved [Ne III] from X-Ray Irradiated Sz 102 Microjets

Science.gov (United States)

Liu, C.-F.; Shang, H.; Walter, F. M.; Herczeg, G. J.

2014-03-01

Neon emission lines are good indicators of high-excitation regions close to a young stellar system because of their high ionization potentials and large critical densities. We have discovered [Ne III] .3869 emission from the microjet of low-mass young star Sz 102. Spectroastrometric analysis of the two-dimensional [Ne III] spectral image obtained from the archival high-dispersion (R - 33,000) Very Large Telescope/UVES spectra suggests that the emission consists of two velocity components spatially separated by ~ 0.''3. The stronger redshifted component is centered at ~ +21 km s-1 with a line width of ~ 140 km s-1, and the weaker blueshifted component at ~ -90 km s-1 with a larger line width of ~ 190 km s-1. Both components have large line widths that extend across the systemic velocity, suggesting their origin from diverging streamlines of a wide-angle wind. Optical line ratio diagnostics indicate that Sz 102 drives a pair of hot (T . 2 ◊ 104 K) and ionized (ne . 2 ◊ 104 cm-3) jets. The blueshifted jet has on average ~ 50% higher temperature and electron density. We suggest that the jet is ionized by an embedded hard X-ray source close to the driving region. Freezing-in of the ionization state is consistent with the flow speed and the Ne2+ recombination timescales. We postulate that these X-rays originate from hard coronae or stellar flares; the hard (keV) X-ray photons ionize neon in the inner wind, while the soft X-rays are mostly absorbed by the accretion funnel. These postulates await validation from high-sensitivity X-ray and subarcsecond resolution optical observations.

X-ray instrumentation in astronomy

International Nuclear Information System (INIS)

Cuhlane, J.L.

1985-01-01

This book presents the proceedings of a conference devoted to x-ray instrumentation in astronomy. Special sections are: AXAF X-Ray Optical Systems; Specialized X-Ray Systems; X-Ray Optical Systems I; X-Ray Optical Systems II; Gas Filled X-Ray Detectors II; The NASA Advanced X-Ray Astrophysics Facility; X-Ray and EUV Spectrometers; Microchannel Plates; and Solid State Detectors

Systems analysis and engineering of the X-1 Advanced Radiation Source

International Nuclear Information System (INIS)

Rochau, G.E.; Hands, J.A.; Raglin, P.S.; Ramirez, J.J.

1998-01-01

The X-1 Advanced Radiation Source, which will produce ∼ 16 MJ in x-rays, represents the next step in providing US Department of Energy's Stockpile Stewardship program with the high-energy, large volume, laboratory x-ray sources needed for the Radiation Effects Science and Simulation (RES), Inertial Confinement Fusion (ICF), and Weapon Physics (WP) Programs. Advances in fast pulsed power technology and in z-pinch hohlraums on Sandia National Laboratories' Z Accelerator in 1997 provide sufficient basis for pursuing the development of X-1. This paper will introduce the X-1 Advanced Radiation Source Facility Project, describe the systems analysis and engineering approach being used, and identify critical technology areas being researched

Panoramic Dental X-Ray

Science.gov (United States)

... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

Chest X-Ray

Medline Plus

Full Text Available ... I’d like to talk with you about chest radiography also known as chest x-rays. Chest x-rays are the most ... far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! ...

Miniature x-ray point source for alignment and calibration of x-ray optics

International Nuclear Information System (INIS)

Price, R.H.; Boyle, M.J.; Glaros, S.S.

1977-01-01

A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

Advances in X-Ray Simulator Technology

Science.gov (United States)

1995-07-01

d’Etudes de Gramat ; I. Vitkovitsky, Logicon RDA INTRODUCTION DNA’s future x-ray simulators are based upon inductive energy storage, a technology which...switch. SYRINX, a proposed design to be built by the Centre d’Etudes de Gramat (CEG) in France would employ a modular approach, possibly with a...called SYRINX, would be built at the Centred’ Etudes de Gramat (CEG). It would employ a modular.long conduction time current source to drive a PRS

Subluminous X-ray binaries

NARCIS (Netherlands)

Armas Padilla, M.

2013-01-01

The discovery of the first X-ray binary, Scorpius X-1, by Giacconi et al. (1962), marked the birth of X-ray astronomy. Following that discovery, many additional X-ray sources where found with the first generation of X-ray rockets and observatories (e.g., UHURU and Einstein). The short-timescale

X-Ray Exam: Forearm

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Forearm KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

X-Ray Exam: Foot

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Foot KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

X-Ray Exam: Wrist

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Wrist KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

Thoracic spine x-ray

Science.gov (United States)

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

X-Ray Exam: Finger

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español X-Ray Exam: Finger KidsHealth / For Parents / X-Ray Exam: ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

Soft x-ray lasers

International Nuclear Information System (INIS)

Matthews, D.L.; Rosen, M.D.

1988-01-01

One of the elusive dreams of laser physicists has been the development of an x-ray laser. After 25 years of waiting, the x-ray laser has at last entered the scientific scene, although those now in operation are still laboratory prototypes. They produce soft x rays down to about five nanometers. X-ray lasers retain the usual characteristics of their optical counterparts: a very tight beam, spatial and temporal coherence, and extreme brightness. Present x-ray lasers are nearly 100 times brighter that the next most powerful x-ray source in the world: the electron synchrotron. Although Lawrence Livermore National Laboratory (LLNL) is widely known for its hard-x-ray laser program which has potential applications in the Strategic Defense Initiative, the soft x-ray lasers have no direct military applications. These lasers, and the scientific tools that result from their development, may one day have a place in the design and diagnosis of both laser fusion and hard x-ray lasers. The soft x-ray lasers now in operation at the LLNL have shown great promise but are still in the primitive state. Once x-ray lasers become reliable, efficient, and economical, they will have several important applications. Chief among them might be the creation of holograms of microscopic biological structures too small to be investigated with visible light. 5 figs

CHANDRA X-RAY DETECTION OF THE ENIGMATIC FIELD STAR BP Psc

International Nuclear Information System (INIS)

Kastner, Joel H.; Montez, Rodolfo; Rodriguez, David; Zuckerman, B.; Perrin, Marshall D.; Grosso, Nicolas; Forveille, Thierry; Graham, James R.

2010-01-01

BP Psc is a remarkable emission-line field star that is orbited by a dusty disk and drives a parsec-scale system of jets. We report the detection by the Chandra X-ray Observatory of a weak X-ray point source coincident with the centroids of optical/IR and submillimeter continuum emission at BP Psc. As the star's photosphere is obscured throughout the visible and near-infrared, the Chandra X-ray source likely represents the first detection of BP Psc itself. The X-rays most likely originate with magnetic activity at BP Psc and hence can be attributed either to a stellar corona or to star-disk interactions. The log of the ratio of X-ray to bolometric luminosity, log(L X /L bol ), lies in the range -5.8 to -4.2. This is smaller than log(L X /L bol ) ratios typical of low-mass, pre-main sequence stars, but is well within the log(L X /L bol ) range observed for rapidly rotating (FK Com-type) G giant stars. Hence, the Chandra results favor an exotic model wherein the disk/jet system of BP Psc is the result of its very recently engulfing a companion star or a giant planet, as the primary star ascended the giant branch.

Comparison of X-ray source concepts for radiographic purposes at OMEGA

International Nuclear Information System (INIS)

Jacquet, L.; Primout, M.; Villette, B.; Girard, F.; Oudot, G.

2013-01-01

As multi-keV X-ray sources, seven targets including thick and thin foils, metal-lined halfraums and a foil combined with a plastic cylinder, have been shot on Omega in September 2011. Titanium was used as X-ray emitting material for all the sources. Using experimental data and FCI 2 simulation results, we have, for each source type, characterized the emission lobes and determined the spatial directions of maximum multi-keV energy. These results demonstrate the benefit of using a laser drive with a prepulse for both thick and thin foils. The favorable effect of a confinement cylinder for the X-ray emitted from front side by a thin foil has also been experimentally found but is not yet confirmed by the simulations. The temporal waveforms of the X-ray power obtained from the different sources as well as the emission spots at the times of maximum emission are also compared. (authors)

Frequency filter of seed x-ray by use of x-ray laser medium. Toward the generation of the temporally coherent x-ray laser

International Nuclear Information System (INIS)

Hasegawa, Noboru; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kouta; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; Kato, Yoshiaki; Renzhong, Tai

2009-01-01

We evaluate the characteristics of a higher-order harmonics light as a seed X-ray amplified through a laser-produced X-ray amplifier. The narrow spectral bandwidth of the X-ray amplifier works as the frequency filter of the seed X-ray, resulting in that only the temporally coherent X-ray is amplified. Experimental investigation using the 29th-order harmonic light of the Ti:sapphire laser at a wavelength of 26.9 nm together with a neon-like manganese X-ray laser medium shows evident spectral narrowing of the seed X-ray and amplification without serious diffraction effects on the propagation of the amplified X-ray beam. This implies that the present combination is potential to realize temporally coherent X-ray lasers, with an expected duration of approximately 400 fs. (author)

Joint European x-ray monitor (JEM-X): x-ray monitor for ESA's

DEFF Research Database (Denmark)

Schnopper, H.W.; Budtz-Joergensen, C.; Westergaard, Niels Jørgen Stenfeldt

1996-01-01

JEM-X will extend the energy range of the gamma ray instruments on ESA's INTEGRAL mission (SPI, IBIS) to include the x-ray band. JEM-X will provide images with arcminute angular resolution in the 2 - 60 keV band. The baseline photon detection system consists of two identical, high pressure, imagi...

Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

International Nuclear Information System (INIS)

Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

1998-01-01

The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

Convergent ablation measurements of plastic ablators in gas-filled rugby hohlraums on OMEGA

Science.gov (United States)

Casner, A.; Jalinaud, T.; Masse, L.; Galmiche, D.

2015-10-01

Indirect-drive implosions experiments were conducted on the Omega Laser Facility to test the performance of uniformly doped plastic ablators for Inertial Confinement Fusion. The first convergent ablation measurements in gas-filled rugby hohlraums are reported. Ignition relevant limb velocities in the range from 150 to 300 μm .n s-1 have been reached by varying the laser drive energy and the initial capsule aspect ratio. The measured capsule trajectory and implosion velocity are in good agreement with 2D integrated simulations and a zero-dimensional modeling of the implosions. We demonstrate experimentally the scaling law for the maximum implosion velocity predicted by the improved rocket model [Y. Saillard, Nucl. Fusion 46, 1017 (2006)] in the high-ablation regime case.

X rays and condensed matter

International Nuclear Information System (INIS)

Daillant, J.

1997-01-01

After a historical review of the discovery and study of X rays, the various interaction processes between X rays and matter are described: Thomson scattering, Compton scattering, X-photon absorption through photoelectric effect, and magnetic scattering. X ray sources such as the European Synchrotron Radiation Facility (ESRF) are described. The various X-ray applications are presented: imagery such as X tomography, X microscopy, phase contrast; X-ray photoelectron spectroscopy and X-ray absorption spectroscopy; X-ray scattering and diffraction techniques

Improvement of density resolution in short-pulse hard x-ray radiographic imaging using detector stacks

Energy Technology Data Exchange (ETDEWEB)

Borm, B.; Gärtner, F.; Khaghani, D. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Johann Wolfgang Goethe-Universität, Frankfurt am Main (Germany); Neumayer, P. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)

2016-09-15

We demonstrate that stacking several imaging plates (IPs) constitutes an easy method to increase hard x-ray detection efficiency. Used to record x-ray radiographic images produced by an intense-laser driven hard x-ray backlighter source, the IP stacks resulted in a significant improvement of the radiograph density resolution. We attribute this to the higher quantum efficiency of the combined detectors, leading to a reduced photon noise. Electron-photon transport simulations of the interaction processes in the detector reproduce the observed contrast improvement. Increasing the detection efficiency to enhance radiographic imaging capabilities is equally effective as increasing the x-ray source yield, e.g., by a larger drive laser energy.

Electron beam requirements for soft x-ray/XUV free-electron lasers

International Nuclear Information System (INIS)

Goldstein, J.C.

1987-01-01

A discussion of the electron beam quality (peak current, energy spread, and transverse emittance) required to drive short wavelength free-electron lasers in the XUV (10-100 nm) and soft x-ray (<10 nm) optical wavelength ranges is presented

Generation of plasma X-ray sources via high repetition rate femtosecond laser pulses

Science.gov (United States)

Baguckis, Artūras; Plukis, Artūras; Reklaitis, Jonas; Remeikis, Vidmantas; Giniūnas, Linas; Vengris, Mikas

2017-12-01

In this study, we present the development and characterization of Cu plasma X-ray source driven by 20 W average power high repetition rate femtosecond laser in ambient atmosphere environment. The peak Cu- Kα photon flux of 2.3 × 109 photons/s into full solid angle is demonstrated (with a process conversion efficiency of 10-7), using pulses with peak intensity of 4.65 × 1014 W/cm2. Such Cu- Kα flux is significantly larger than others found in comparable experiments, performed in air environment. The effects of resonance plasma absorption process, when optimized, are shown to increase measured flux by the factor of 2-3. The relationship between X-ray photon flux and plasma-driving pulse repetition rate is quasi-linear, suggesting that fluxes could further be increased to 1010 photons/s using even higher average powers of driving radiation. These results suggest that to fully utilize the potential of high repetition rate laser sources, novel target material delivery systems (for example, jet-based ones) are required. On the other hand, this study demonstrates that high energy lasers currently used for plasma X-ray sources can be conveniently and efficiently replaced by high average power and repetition rate laser radiation, as a way to increase the brightness of the generated X-rays.

Extending the methodology of X-ray crystallography to allow X-ray microscopy without X-ray optics

International Nuclear Information System (INIS)

Miao Jianwei; Kirz, Janos; Sayre, David; Charalambous, Pambos

2000-01-01

We demonstrate that the soft X-ray diffraction pattern from a micron-size noncrystalline specimen can be recorded and inverted to form a high-resolution image. The phase problem is overcome by oversampling the diffraction pattern. The image is obtained using an iterative algorithm. The technique provides a method for X-ray microscopy requiring no high-resolution X-ray optical elements or detectors. In the present work, a resolution of approximately 60 nm was obtained, but we believe that considerably higher resolution can be achieved

Dental X-ray apparatus

International Nuclear Information System (INIS)

Weiss, M.E.

1980-01-01

Intra-oral dental X-ray apparatus for panoramic radiography is described in detail. It comprises a tubular target carrier supporting at its distal end a target with an inclined forward face. Image definition is improved by positioning in the path of the X-rays a window of X-ray transmitting ceramic material, e.g. 90% oxide of Be, or Al, 7% Si0 2 . The target carrier forms a probe which can be positioned in the patient's mouth. X-rays are directed forwardly and laterally of the target to an X-ray film positioned externally. The probe is provided with a detachable sleeve having V-form arms of X-ray opaque material which serve to depress the tongue out of the radiation path and also shield the roof of the mouth and other regions of the head from the X-ray pattern. A cylindrical lead shield defines the X-ray beam angle. (author)

X-ray diagnostics for TFTR

International Nuclear Information System (INIS)

von Goeler, S.; Hill, K.W.; Bitter, M.

1982-12-01

A short description of the x-ray diagnostic preparation for the TFTR tokamak is given. The x-ray equipment consists of the limiter x-ray monitoring system, the soft x-ray pulse-height-analysis-system, the soft x-ray imaging system and the x-ray crystal spectrometer. Particular attention is given to the radiation protection of the x-ray systems from the neutron environment

Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Milovich, J. L., E-mail: milovich1@llnl.gov; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2016-03-15

Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or “picket”) period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P{sub 2}), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the “Rev5” CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions

Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

International Nuclear Information System (INIS)

Milovich, J. L.; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J.

2016-01-01

Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or “picket”) period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P_2), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the “Rev5” CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using

Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

Science.gov (United States)

Milovich, J. L.; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J.

2016-03-01

Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or "picket") period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P2), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the "Rev5" CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using different

X-ray beam generator

International Nuclear Information System (INIS)

Koller, T.J.; Randmer, J.A.

1977-01-01

A method of minimizing the preferential angular absorption of the divergent beam from an X-ray generator is described. The generator consists of an X-ray shielded housing with an X-ray transmissive window symmetrically placed in radial alignment with a focal spot area on a sloped target surface of an X-ray tube in the housing. The X-ray tube may be of the stationary anode type or of the rotating anode type. (U.K.)

Monte Carlo Methods in ICF (LIRPP Vol. 13)

Science.gov (United States)

Zimmerman, George B.

2016-10-01

Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ions and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved SOX in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burn and burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... ray examination. X-rays usually have no side effects in the typical diagnostic range for this exam. ... x-rays. A Word About Minimizing Radiation Exposure Special care is taken during x-ray examinations to ...

Semiconductor X-ray detectors

CERN Document Server

Lowe, Barrie Glyn

2014-01-01

Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

Backscatter spectra measurements of the two beams on the same cone on Shenguang-III laser facility

Science.gov (United States)

Zha, Weiyi; Yang, Dong; Xu, Tao; Liu, Yonggang; Wang, Feng; Peng, Xiaoshi; Li, Yulong; Wei, Huiyue; Liu, Xiangming; Mei, Yu; Yan, Yadong; He, Junhua; Li, Zhichao; Li, Sanwei; Jiang, Xiaohua; Guo, Liang; Xie, Xufei; Pan, Kaiqiang; Liu, Shenye; Jiang, Shaoen; Zhang, Baohan; Ding, Yongkun

2018-01-01

In laser driven hohlraums, laser beams on the same incident cone may have different beam and plasma conditions, causing beam-to-beam backscatter difference and subsequent azimuthal variations in the x-ray drive on the capsule. To elucidate the large variation of backscatter proportion from beam to beam in some gas-filled hohlraum shots on Shenguang-III, two 28.5° beams have been measured with the Stimulated Raman Scattering (SRS) time-resolved spectra. A bifurcated fiber is used to sample two beams and then coupled to a spectrometer and streak camera combination to reduce the cost. The SRS spectra, characterized by a broad wavelength, were further corrected considering the temporal distortion and intensity modulation caused by components along the light path. This measurement will improve the understanding of the beam propagation inside the hohlraum and related laser plasma instabilities.

X-ray apparatus

International Nuclear Information System (INIS)

Grady, J.K.

1985-01-01

X-ray apparatus is described which has a shutter between the X-ray source and the patient. The shutter controls the level of radiation to which the patient is exposed instead of merely discontinuing the electric power supplied to the source. When the shutter is opened a radiation sensor senses the level of X-radiation. When a preset quantity of X-radiation has been measured an exposure control closes the shutter. Instead of using the radiation sensor, the integrated power supplied to the anode of the X-ray source may be measured. (author)

Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

Science.gov (United States)

Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

2015-03-10

A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

Studies on radiation symmetrization in heavy-ion driven hohlraum targets

International Nuclear Information System (INIS)

Temporal, M.; Atzeni, S.

1993-01-01

Radiation symmetrization within spherical, ellipsoidal and cylindral hohlraum targets for heavy ion inertial confinement fusion (ICF) is studied by means of a 3-D numerical, static model, in which realistic assumptions are made concerning the geometry of the system and, particularly, of the radiation converters. Among the systems so far studied, only spherical hohlraums with six converters achieve the illumination symmetry of the fusion capsule considered necessary for ICF applications. A parametric study of cylindrical hohlraums enlightens the effect of several parameter changes, and suggests directions for further studies, aiming at the design of two-converter targets

Unusual Black Hole Binary LMC X-3: A Transient High-Mass X-Ray Binary That Is Almost Always On?

Science.gov (United States)

Torpin, Trevor J.; Boyd, Patricia T.; Smale, Alan P.; Valencic, Lynne A.

2017-01-01

We have analyzed a rich, multimission, multiwavelength data set from the black hole X-ray binary (BHXB) LMC X-3, covering a new anomalous low state (ALS), during which the source flux falls to an unprecedentedly low and barely detectable level, and a more normal low state. Simultaneous X-ray and UV/optical monitoring data from Swift are combined with pointed observations from the Rossi X-ray Timing Explorer (RXTE) and X-ray Multi- Mirror Mission (XMM-Newton) and light curves from the Monitor of All-Sky X-ray Image (MAXI) instrument to compare the source characteristics during the ALS with those seen during the normal low state. An XMM-Newton spectrum obtained during the ALS can be modeled using an absorbed power law with Gamma = 1.41‚+/- 0.65 and a luminosity of 7.97 x 10(exp 33) erg/s (0.6-5 keV). The Swift X-ray and UV light curves indicate an X-ray lag of approx. 8 days as LMC X-3 abruptly exits the ALS, suggesting that changes in the mass accretion rate from the donor drive the X-ray lag. The normal low state displays an asymmetric profile in which the exit occurs more quickly than the entry, with minimum X-ray flux a factor of approx. 4300 brighter than during the ALS. The UV brightness of LMC X-3 in the ALS is also fainter and less variable than during normal low states. The existence of repeated ALSs in LMC X-3, as well as a comparison with other BHXBs, implies that it is very close to the transient/persistent X-ray source dividing line. We conclude that LMC X-3 is a transient source that is almost always "on."

Optical and X-ray studies of Compact X-ray Binaries in NGC 5904

Science.gov (United States)

Bhalotia, Vanshree; Beck-Winchatz, Bernhard

2018-06-01

Due to their high stellar densities, globular cluster systems trigger various dynamical interactions, such as the formation of compact X-ray binaries. Stellar collisional frequencies have been correlated to the number of X-ray sources detected in various clusters and we hope to measure this correlation for NGC 5904. Optical fluxes of sources from archival HST images of NGC 5904 have been measured using a DOLPHOT PSF photometry in the UV, optical and near-infrared. We developed a data analysis pipeline to process the fluxes of tens of thousands of objects using awk, python and DOLPHOT. We plot color magnitude diagrams in different photometric bands in order to identify outliers that could be X-ray binaries, since they do not evolve the same way as singular stars. Aligning previously measured astrometric data for X-ray sources in NGC 5904 from Chandra with archival astrometric data from HST will filter out the outlier objects that are not X-ray producing, and provide a sample of compact binary systems that are responsible for X-ray emission in NGC 5904. Furthermore, previously measured X-ray fluxes of NGC 5904 from Chandra have also been used to measure the X-ray to optical flux ratio and identify the types of compact X-ray binaries responsible for the X-ray emissions in NGC 5904. We gratefully acknowledge the support from the Illinois Space Grant Consortium.

CCD-based X-ray detectors for X-ray diffraction studies

International Nuclear Information System (INIS)

Ito, K.; Amemiya, Y.

1999-01-01

CCD-based X-ray detectors are getting to be used for X-ray diffraction studies especially in the studies where real time (automated) measurements and time-resolved measurements are required. Principles and designs of two typical types of CCD-based detectors are described; one is ths system in which x-ray image intensifiers are coupled to maximize the detective quantum efficiency for time-resolved measurements, and the other is the system in which tapered optical fibers are coupled for the reduction of the image into the CCD, which is optimized for automated measurements for protein crystallography. These CCD-based X-ray detectors have an image distortion and non-uniformity of response to be corrected by software. Correction schemes which we have developed are also described. (author)

Simulation of transmitted X-rays in a polycapillary X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Peng, Shiqi [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Liu, Zhiguo, E-mail: liuzhiguo512@126.com [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi; Wang, Kai; Yi, Longtao; Yang, Kui; Chen, Man; Wang, Jinbang [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-09-21

The geometrical description of capillary systems adjusted for the controlled guiding of X-rays and the basic theory of the transmission of X-rays are presented. A method of numerical calculation, based on Ray-Tracing theory, is developed to simulate the transmission efficiency of an X-ray parallel lens and the shape and size of the light spot gain from it. The simulation results for two half-lenses are in good agreement with the experimental results.

Microfocussing of synchrotron X-rays using X-ray refractive lens developed at Indus-2 deep X-ray lithography beamline

International Nuclear Information System (INIS)

Dhamgaye, V.P.; Tiwari, M.K.; Lodha, G.S.; Sawhney, K.J.S.

2014-01-01

X-ray lenses are fabricated in polymethyl methacrylate using deep X-ray lithography beamline of Indus-2. The focussing performance of these lenses is evaluated using Indus-2 and Diamond Light Source Ltd. The process steps for the fabrication of X-ray lenses and microfocussing at 10 keV at moderate and low emittance sources are compared. (author)

X pinch a point x-ray source

International Nuclear Information System (INIS)

Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

1993-01-01

X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

Monte Carlo methods in ICF

International Nuclear Information System (INIS)

Zimmerman, G.B.

1997-01-01

Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ions and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved 50X in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burn and burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials. copyright 1997 American Institute of Physics

Chest X-Ray

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Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... d like to talk with you about chest radiography also known as chest x-rays. Chest x- ...

Compact X-ray sources: X-rays from self-reflection

Science.gov (United States)

Mangles, Stuart P. D.

2012-05-01

Laser-based particle acceleration offers a way to reduce the size of hard-X-ray sources. Scientists have now developed a simple scheme that produces a bright flash of hard X-rays by using a single laser pulse both to generate and to scatter an electron beam.

Phase-contrast X-ray imaging using an X-ray interferometer for biological imaging

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi; Koyama, Ichiro [Tokyo Univ., Dept. of Applied Physics, Tokyo (Japan); Takeda, Tohoru; Itai, Yuji [Tsukuba Univ., Inst. of Clinical Medicine, Tsukuba, Ibaraki (Japan); Yoneyama, Akio [Hitachi Ltd., Advanced Research Laboratory, Saitama (Japan)

2002-04-01

The potential of phase-contrast X-ray imaging using an X-ray interferometer is discussed comparing with other phase-contrast X-ray imaging methods, and its principle of contrast generation is presented including the case of phase-contrast X-ray computed tomography. The status of current instrumentation is described and perspectives for practical applications are discussed. (author)

X-ray crystallography

Science.gov (United States)

2001-01-01

X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

Development of X-ray excitable luminescent probes for scanning X-ray microscopy

International Nuclear Information System (INIS)

Moronne, M.M.

1999-01-01

Transmission soft X-ray microscopy is now capable of achieving resolutions that are typically 5 times better than the best-visible light microscopes. With expected improvements in zone plate optics, an additional factor of two may be realized within the next few years. Despite the high resolution now available with X-ray microscopes and the high X-ray contrast provided by biological molecules in the soft X-ray region (λ=2-5 nm), molecular probes for localizing specific biological targets have been lacking. To circumvent this problem, X-ray excitable molecular probes are needed that can target unique biological features. In this paper we report our initial results on the development of lanthanide-based fluorescent probes for biological labeling. Using scanning luminescence X-ray microscopy (SLXM, Jacobsen et al., J. Microscopy 172 (1993) 121-129), we show that lanthanide organo-polychelate complexes are sufficiently bright and radiation resistant to be the basis of a new class of X-ray excitable molecular probes capable of providing at least a fivefold improvement in resolution over visible light microscopy. Lanthanide probes, able to bind 80-100 metal ions per molecule, were found to give strong luminescent signals with X-ray doses exceeding 10 8 Gy, and were used to label actin stress fibers and in vitro preparations of polymerized tubulin. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Projection-type X-ray microscope based on a spherical compound refractive X-ray lens

OpenAIRE

Dudchik, Yu. I.; Gary, C. K.; Park, H.; Pantell, R. H.; Piestrup, M. A.

2007-01-01

New projection- type X-ray microscope with a compound refractive lens as the optical element is presented. The microscope consists of an X-ray source that is 1-2 mm in diameter, compound X-ray lens and X-ray camera that are placed in-line to satisfy the lens formula. The lens forms an image of the X-ray source at camera sensitive plate. An object is placed between the X-ray source and the lens as close as possible to the source, and the camera shows a shadow image of the object. Spatial resol...

X-Ray Lasers 2016

CERN Document Server

Bulanov, Sergei; Daido, Hiroyuki; Kato, Yoshiaki

2018-01-01

These proceedings comprise a selection of invited and contributed papers presented at the 15th International Conference on X-Ray Lasers (ICXRL 2016), held at the Nara Kasugano International Forum, Japan, from May 22 to 27, 2016. This conference was part of an ongoing series dedicated to recent developments in the science and technology of x-ray lasers and other coherent x-ray sources with additional focus on supporting technologies, instrumentation and applications.   The book showcases recent advances in the generation of intense, coherent x-rays, the development of practical devices and their applications across a wide variety of fields. It also discusses emerging topics such as plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generations, as well as other x-ray generation schemes.

The Mapping X-ray Fluorescence Spectrometer (MapX)

Science.gov (United States)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

X-ray Heating and Electron Temperature of Laboratory Photoionized Plasmas

Science.gov (United States)

Mancini, Roberto; Lockard, Tom; Mayes, Daniel C.; Loisel, Guillaume; Bailey, James E.; Rochau, Gregory; Abdallah, J.; Golovkin, I.

2018-06-01

In separate experiments performed at the Z facility of Sandia National Laboratories two different samples were employed to produce and characterize photoionized plasmas. One was a gas cell filled with neon, and the other was a thin silicon layer coated with plastic. Both samples were driven by the broadband x-ray flux produced at the collapse of a wire array z-pinch implosion. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the charge state distribution, and the electron temperature was extracted from a Li-like ion level population ratio. To interpret the temperature measurement, we performed Boltzmann kinetics and radiation-hydrodynamic simulations. We found that non-equilibrium atomic physics and the coupling of the radiation flux to the atomic level population kinetics play a critical role in modeling the x-ray heating of photoionized plasmas. In spite of being driven by similar x-ray drives, differences of ionization and charged state distributions in the neon and silicon plasmas are reflected in the plasma heating and observed electron temperatures.This work was sponsored in part by DOE Office of Science Grant DE-SC0014451, and the Z Facility Fundamental Science Program of SNL.

Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

Energy Technology Data Exchange (ETDEWEB)

Sun, Xuepeng; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Yi, Longtao; Sun, Weiyuan; Li, Fangzuo; Jiang, Bowen [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-12-01

Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300 μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4 μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3 μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

Wavelength dispersive X-ray absorption fine structure imaging by parametric X-ray radiation

International Nuclear Information System (INIS)

Inagaki, Manabu; Sakai, Takeshi; Sato, Isamu; Hayakawa, Yasushi; Nogami, Kyoko; Tanaka, Toshinari; Hayakawa, Ken; Nakao, Keisuke

2008-01-01

The parametric X-ray radiation (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a monochromatic and coherent X-ray source with horizontal wavelength dispersion. The energy definition of the X-rays, which depends on the horizontal size of the incident electron beam on the generator target crystal, has been investigated experimentally by measuring the X-ray absorption near edge structure (XANES) spectra on Cu and CuO associated with conventional X-ray absorption imaging technique. The result demonstrated the controllability of the spectrum resolution of XANES by adjusting of the horizontal electron beam size on the target crystal. The XANES spectra were obtained with energy resolution of several eV at the narrowest case, which is in qualitative agreement with the energy definition of the PXR X-rays evaluated from geometrical consideration. The result also suggested that the wavelength dispersive X-ray absorption fine structure measurement associated with imaging technique is one of the promising applications of PXR. (author)

Compact tunable Compton x-ray source from laser-plasma accelerator and plasma mirror

International Nuclear Information System (INIS)

Tsai, Hai-En; Wang, Xiaoming; Shaw, Joseph M.; Li, Zhengyan; Zgadzaj, Rafal; Henderson, Watson; Downer, M. C.; Arefiev, Alexey V.; Zhang, Xi; Khudik, V.; Shvets, G.

2015-01-01

We present an in-depth experimental-computational study of the parameters necessary to optimize a tunable, quasi-monoenergetic, efficient, low-background Compton backscattering (CBS) x-ray source that is based on the self-aligned combination of a laser-plasma accelerator (LPA) and a plasma mirror (PM). The main findings are (1) an LPA driven in the blowout regime by 30 TW, 30 fs laser pulses produce not only a high-quality, tunable, quasi-monoenergetic electron beam, but also a high-quality, relativistically intense (a 0 ∼ 1) spent drive pulse that remains stable in profile and intensity over the LPA tuning range. (2) A thin plastic film near the gas jet exit retro-reflects the spent drive pulse efficiently into oncoming electrons to produce CBS x-rays without detectable bremsstrahlung background. Meanwhile, anomalous far-field divergence of the retro-reflected light demonstrates relativistic “denting” of the PM. Exploiting these optimized LPA and PM conditions, we demonstrate quasi-monoenergetic (50% FWHM energy spread), tunable (75–200 KeV) CBS x-rays, characteristics previously achieved only on more powerful laser systems by CBS of a split-off, counter-propagating pulse. Moreover, laser-to-x-ray photon conversion efficiency (∼6 × 10 −12 ) exceeds that of any previous LPA-based quasi-monoenergetic Compton source. Particle-in-cell simulations agree well with the measurements

Experimental investigation of bright spots in broadband, gated x-ray images of ignition-scale implosions on the National Ignition Facility

International Nuclear Information System (INIS)

Barrios, M. A.; Suter, L. J.; Glenn, S.; Benedetti, L. R.; Bradley, D. K.; Collins, G. W.; Hammel, B. A.; Izumi, N.; Ma, T.; Scott, H.; Smalyuk, V. A.; Regan, S. P.; Epstein, R.; Kyrala, G. A.

2013-01-01

Bright spots in the hot spot intensity profile of gated x-ray images of ignition-scale implosions at the National Ignition Facility [G. H. Miller et al., Opt. Eng. 443, (2004)] are observed. X-ray images of cryogenically layered deuterium-tritium (DT) and tritium-hydrogen-deuterium (THD) ice capsules, and gas filled plastic shell capsules (Symcap) were recorded along the hohlraum symmetry axis. Heterogeneous mixing of ablator material and fuel into the hot spot (i.e., hot-spot mix) by hydrodynamic instabilities causes the bright spots. Hot-spot mix increases the radiative cooling of the hot spot. Fourier analysis of the x-ray images is used to quantify the evolution of bright spots in both x- and k-space. Bright spot images were azimuthally binned to characterize bright spot location relative to known isolated defects on the capsule surface. A strong correlation is observed between bright spot location and the fill tube for both Symcap and cryogenically layered DT and THD ice targets, indicating the fill tube is a significant seed for the ablation front instability causing hot-spot mix. The fill tube is the predominant seed for Symcaps, while other capsule non-uniformities are dominant seeds for the cryogenically layered DT and THD ice targets. A comparison of the bright spot power observed for Si- and Ge-doped ablator targets shows heterogeneous mix in Symcap targets is mostly material from the doped ablator layer

XAssist: A System for the Automation of X-ray Astrophysics Analysis

Science.gov (United States)

Ptak, A.

2004-08-01

XAssist is a NASA AISR-funded project for the automation of X-ray astrophysics. It is capable of data reprocessing, source detection, and preliminary spatial, temporal and spectral analysis for each source with sufficient counts. The bulk of the system is written in Python, which in turn drives underlying software (CIAO for Chandra data, etc.). Future work will include a GUI (mainly for beginners and status monitoring) and the exposure of at least some functionality as web services. The latter will help XAssist to eventually become part of the VO, making advanced queries possible, such as determining the X-ray fluxes of counterparts to HST or SDSS sources (including the use of unpublished X-ray data), and add the ability of ``on-the-fly'' X-ray processing. Pipelines are running on Chandra and XMM-Newton observations of galaxies to demonstrate XAssist's capabilities, and the results are available online (in real time) at http://www.xassist.org. XAssist itself as well as various associated projects are available for download.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? A ...

Bone X-Ray (Radiography)

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Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

Bone X-Ray (Radiography)

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Full Text Available ... that might interfere with the x-ray images. Women should always inform their physician and x-ray ... Safety page for more information about radiation dose. Women should always inform their physician or x-ray ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... of knee x-rays. A portable x-ray machine is a compact apparatus that can be taken ... of the body being examined, an x-ray machine produces a small burst of radiation that passes ...

Bone X-Ray (Radiography)

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Full Text Available ... drawer under the table holds the x-ray film or image recording plate . Sometimes the x-ray ... extended over the patient while an x-ray film holder or image recording plate is placed beneath ...

Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

Science.gov (United States)

Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

2008-02-01

We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

A diamond detector for inertial confinement fusion X-ray bang-time measurements at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

MacPhee, A G; Brown, C; Burns, S; Celeste, J; Glenzer, S H; Hey, D; Jones, O S; Landen, O; Mackinnon, A J; Meezan, N; Parker, J; Edgell, D; Glebov, V Y; Kilkenny, J; Kimbrough, J

2010-11-09

An instrument has been developed to measure X-ray bang-time for inertial confinement fusion capsules; the time interval between the start of the laser pulse and peak X-ray emission from the fuel core. The instrument comprises chemical vapor deposited polycrystalline diamond photoconductive X-ray detectors with highly ordered pyrolytic graphite X-ray monochromator crystals at the input. Capsule bang-time can be measured in the presence of relatively high thermal and hard X-ray background components due to the selective band pass of the crystals combined with direct and indirect X-ray shielding of the detector elements. A five channel system is being commissioned at the National Ignition Facility at Lawrence Livermore National Laboratory for implosion optimization measurements as part of the National Ignition Campaign. Characteristics of the instrument have been measured demonstrating that X-ray bang-time can be measured with {+-} 30ps precision, characterizing the soft X-ray drive to +/- 1eV or 1.5%.

X-ray holography

International Nuclear Information System (INIS)

Faigel, G.; Tegze, M.; Belakhovsky, M.; Marchesini, S.; Bortel, G.

2003-01-01

In the last decade holographic methods using hard X-rays were developed. They are able to resolve atomic distances, and can give the 3D arrangement of atoms around a selected element. Therefore, hard X-ray holography has potential applications in chemistry, biology and physics. In this article we give a general description of these methods and discuss the developments in the experimental technique. The capabilities of hard X-ray holography are demonstrated by examples

Progress in the applicability of plasma X-ray lasers

Energy Technology Data Exchange (ETDEWEB)

Kuehl, T., E-mail: T.Kuehl@gsi.de; Aurand, B.; Bagnoud, V.; Ecker, B.; Eisenbarth, U. [GSI (Germany); Guilbaud, O. [Universite Paris Sud (France); Fils, J.; Goette, S. [GSI (Germany); Habib, J. [Universite Paris Sud (France); Hochhaus, D.; Javorkova, D. [GSI (Germany); Neumayer, P. [Extreme Matter Institute, EMMI (Germany); Kazamias, S.; Pittman, M.; Ros, D. [Universite Paris Sud (France); Seres, J.; Spielmann, Ch. [Friedrich Schiller-University (Germany); Zielbauer, B.; Zimmer, D. [GSI (Germany)

2010-02-15

Proposed as satellite-based weapons during the 1980s, X-ray lasing was for a long time only achieved with enormous amounts of pump energy in either nuclear explosions or at kilojoule-class laser installations. During the last few years a tremendous development was achieved, most visible in the realisation of the FEL lasers at DESY and SLAC. As important for a wider applicability is the enormous reduction in pump energy for laser pumped plasma X-ray lasers, which now brings such devices into the range of applications for diagnostics and spectroscopy even in smaller laboratories. Main developments were the transient excitation scheme and the optimized pumping concepts. This paper concentrates on developments at the GSI Helmholtzcenter at Darmstadt aiming towards reliable X-ray laser sources in the range from 50 to several 100 eV. The main driving forces for the laser development at GSI are the possible application for the spectroscopy of Li-like ions in the storage ring ESR and the future storage ring NESR at FAIR, and the interest in novel plasma diagnostics.

Progress in the applicability of plasma X-ray lasers

International Nuclear Information System (INIS)

Kuehl, T.; Aurand, B.; Bagnoud, V.; Ecker, B.; Eisenbarth, U.; Guilbaud, O.; Fils, J.; Goette, S.; Habib, J.; Hochhaus, D.; Javorkova, D.; Neumayer, P.; Kazamias, S.; Pittman, M.; Ros, D.; Seres, J.; Spielmann, Ch.; Zielbauer, B.; Zimmer, D.

2010-01-01

Proposed as satellite-based weapons during the 1980s, X-ray lasing was for a long time only achieved with enormous amounts of pump energy in either nuclear explosions or at kilojoule-class laser installations. During the last few years a tremendous development was achieved, most visible in the realisation of the FEL lasers at DESY and SLAC. As important for a wider applicability is the enormous reduction in pump energy for laser pumped plasma X-ray lasers, which now brings such devices into the range of applications for diagnostics and spectroscopy even in smaller laboratories. Main developments were the transient excitation scheme and the optimized pumping concepts. This paper concentrates on developments at the GSI Helmholtzcenter at Darmstadt aiming towards reliable X-ray laser sources in the range from 50 to several 100 eV. The main driving forces for the laser development at GSI are the possible application for the spectroscopy of Li-like ions in the storage ring ESR and the future storage ring NESR at FAIR, and the interest in novel plasma diagnostics.

Ultrashort X-ray pulse science

Energy Technology Data Exchange (ETDEWEB)

Chin, Alan Hap [Univ. of California, Berkeley, CA (US). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

1998-05-01

A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90° Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ~ 300 fs, 30 keV (0.4 Å) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been demonstrated as a

Ultrashort X-ray pulse science

International Nuclear Information System (INIS)

Chin, A.H.; Lawrence Berkeley National Lab., CA

1998-01-01

A variety of phenomena involves atomic motion on the femtosecond time-scale. These phenomena have been studied using ultrashort optical pulses, which indirectly probe atomic positions through changes in optical properties. Because x-rays can more directly probe atomic positions, ultrashort x-ray pulses are better suited for the study of ultrafast structural dynamics. One approach towards generating ultrashort x-ray pulses is by 90 o Thomson scattering between terawatt laser pulses and relativistic electrons. Using this technique, the author generated ∼ 300 fs, 30 keV (0.4 (angstrom)) x-ray pulses. These x-ray pulses are absolutely synchronized with ultrashort laser pulses, allowing femtosecond optical pump/x-ray probe experiments to be performed. Using the right-angle Thomson scattering x-ray source, the author performed time-resolved x-ray diffraction studies of laser-perturbated InSb. These experiments revealed a delayed onset of lattice expansion. This delay is due to the energy relaxation from a dense electron-hole plasma to the lattice. The dense electron-hole plasma first undergoes Auger recombination, which reduces the carrier concentration while maintaining energy content. Longitudinal-optic (LO) phonon emission then couples energy to the lattice. LO phonon decay into acoustic phonons, and acoustic phonon propagation then causes the growth of a thermally expanded layer. Source characterization is instrumental in utilizing ultrashort x-ray pulses in time-resolved x-ray spectroscopies. By measurement of the electron beam diameter at the generation point, the pulse duration of the Thomson scattered x-rays is determined. Analysis of the Thomson scattered x-ray beam properties also provides a novel means of electron bunch characterization. Although the pulse duration is inferred for the Thomson scattering x-ray source, direct measurement is required for other x-ray pulse sources. A method based on the laser-assisted photoelectric effect (LAPE) has been

Wide-area phase-contrast X-ray imaging using large X-ray interferometers

Energy Technology Data Exchange (ETDEWEB)

Momose, Atsushi E-mail: momose@exp.t.u-tokyo.ac.jp; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

2001-07-21

Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mmx20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

Wide-area phase-contrast X-ray imaging using large X-ray interferometers

Science.gov (United States)

Momose, Atsushi; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

2001-07-01

Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mm×20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.