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Heuer PV, Haberberger D, Ivancic ST, Dorrer C, Walsh CA, Davies JR. Improved filters for angular filter refractometry. Rev Sci Instrum 2024; 95:023501. [PMID: 38341714 DOI: 10.1063/5.0185898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/07/2024] [Indexed: 02/13/2024]
Abstract
Angular filter refractometry is an optical diagnostic that measures the absolute contours of a line-integrated density gradient by placing a filter with alternating opaque and transparent zones in the focal plane of a probe beam, which produce corresponding alternating light and dark regions in the image plane. Identifying transitions between these regions with specific zones on the angular filter (AF) allows the line-integrated density to be determined, but the sign of the density gradient at each transition is degenerate and must be broken using other information about the object plasma. Additional features from diffraction in the filter plane often complicate data analysis. In this paper, we present an improved AF design that uses a stochastic pixel pattern with a sinusoidal radial profile to minimize unwanted diffraction effects in the image caused by the sharp edges of the filter bands. We also present a technique in which a pair of AFs with different patterns on two branches of the same probe beam can be used to break the density gradient degeneracy. Both techniques are demonstrated using a synthetic diagnostic and data collected on the OMEGA EP (extended performance) laser.
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Affiliation(s)
- P V Heuer
- University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA
| | - D Haberberger
- University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA
| | - S T Ivancic
- University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA
| | - C Dorrer
- University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA
| | - C A Walsh
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J R Davies
- University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA
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Adrian PJ, Bachmann B, Betti R, Birkel A, Heuer PV, Johnson MG, Kabadi NV, Knauer JP, Kunimune J, Li CK, Mannion OM, Petrasso RD, Regan SP, Rinderknecht HG, Stoeckl C, Séguin FH, Sorce A, Shah RC, Sutcliffe GD, Frenje JA. X-ray-imaging spectrometer (XRIS) for studies of residual kinetic energy and low-mode asymmetries in inertial confinement fusion implosions at OMEGA (invited). Rev Sci Instrum 2022; 93:113540. [PMID: 36461452 DOI: 10.1063/5.0101655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/05/2022] [Indexed: 06/17/2023]
Abstract
A system of x-ray imaging spectrometer (XRIS) has been implemented at the OMEGA Laser Facility and is capable of spatially and spectrally resolving x-ray self-emission from 5 to 40 keV. The system consists of three independent imagers with nearly orthogonal lines of sight for 3D reconstructions of the x-ray emission region. The distinct advantage of the XRIS system is its large dynamic range, which is enabled by the use of tantalum apertures with radii ranging from 50 μm to 1 mm, magnifications of 4 to 35×, and image plates with any filtration level. In addition, XRIS is capable of recording 1-100's images along a single line of sight, facilitating advanced statistical inference on the detailed structure of the x-ray emitting regions. Properties such as P0 and P2 of an implosion are measured to 1% and 10% precision, respectively. Furthermore, Te can be determined with 5% accuracy.
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Affiliation(s)
- P J Adrian
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - B Bachmann
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Betti
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - A Birkel
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - P V Heuer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - M Gatu Johnson
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - N V Kabadi
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - J P Knauer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J Kunimune
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - C K Li
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - O M Mannion
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - R D Petrasso
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - H G Rinderknecht
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C Stoeckl
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - F H Séguin
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - A Sorce
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R C Shah
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - G D Sutcliffe
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
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Rinderknecht HG, Heuer PV, Kunimune J, Adrian PJ, Knauer JP, Theobald W, Fairbanks R, Brannon B, Ceurvorst L, Gopalaswamy V, Williams CA, Radha PB, Regan SP, Johnson MG, Séguin FH, Frenje JA. A knock-on deuteron imager for measurements of fuel and hotspot asymmetry in direct-drive inertial confinement fusion implosions (invited). Rev Sci Instrum 2022; 93:093507. [PMID: 36182458 DOI: 10.1063/5.0099301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/04/2022] [Indexed: 06/16/2023]
Abstract
A knock-on deuteron imager (KoDI) has been implemented to measure the fuel and hotspot asymmetry of cryogenic inertial confinement fusion implosions on OMEGA. Energetic neutrons produced by D-T fusion elastically scatter ("knock on") deuterons from the fuel layer with a probability that depends on ρR. Deuterons above 10 MeV are produced by near-forward scattering, and imaging them is equivalent to time-integrated neutron imaging of the hotspot. Deuterons below 6 MeV are produced by a combination of side scattering and ranging in the fuel, and encode information about the spatial distribution of the dense fuel. The KoDI instrument consists of a multi-penumbral aperture positioned 10-20 cm from the implosion using a ten-inch manipulator and a detector pack at 350 cm from the implosion to record penumbral images with magnification of up to 35×. Range filters and the intrinsic properties of CR-39 are used to distinguish different charged-particle images by energy along the same line of sight. Image plates fielded behind the CR-39 record a 10 keV x-ray image using the same aperture. A maximum-likelihood reconstruction algorithm has been implemented to infer the source from the projected penumbral images. The effects of scattering and aperture charging on the instrument point-spread function are assessed. Synthetic data are used to validate the reconstruction algorithm and assess an appropriate termination criterion. Significant aperture charging has been observed in the initial experimental dataset, and increases with aperture distance from the implosion, consistent with a simple model of charging by laser-driven EMP.
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Affiliation(s)
- H G Rinderknecht
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - P V Heuer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J Kunimune
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - P J Adrian
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J P Knauer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - W Theobald
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R Fairbanks
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - B Brannon
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - L Ceurvorst
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - V Gopalaswamy
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C A Williams
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - P B Radha
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - M Gatu Johnson
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - F H Séguin
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Kaloyan M, Ghazaryan S, Constantin CG, Dorst RS, Heuer PV, Pilgram JJ, Schaeffer DB, Niemann C. Raster Thomson scattering in large-scale laser plasmas produced at high repetition rate. Rev Sci Instrum 2021; 92:093102. [PMID: 34598480 DOI: 10.1063/5.0059244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
We present optical Thomson scattering measurements of electron density and temperature in a large-scale (∼2 cm) exploding laser plasma produced by irradiating a solid target with a high-energy (5-10 J) laser pulse at a high repetition rate (1 Hz). The Thomson scattering diagnostic matches this high repetition rate. Unlike previous work performed in single shots at much higher energies, the instrument allows for point measurements anywhere inside the plasma by automatically translating the scattering volume using motorized stages as the experiment is repeated at 1 Hz. Measured densities around 4 × 1016 cm-3 and temperatures around 7 eV result in a scattering parameter near unity, depending on the distance from the target. The measured spectra show the transition from collective scattering close to the target to non-collective scattering at larger distances. Densities obtained by fitting the weakly collective spectra agree to within 10% with an irradiance calibration performed via Raman scattering in nitrogen.
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Affiliation(s)
- M Kaloyan
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - S Ghazaryan
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - C G Constantin
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - R S Dorst
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - P V Heuer
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - J J Pilgram
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - D B Schaeffer
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540, USA
| | - C Niemann
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
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Dorst RS, Heuer PV, Schaeffer DB, Constantin CG, Niemann C. Measurements of ion velocity distributions in a large scale laser-produced plasma. Rev Sci Instrum 2020; 91:103103. [PMID: 33138584 DOI: 10.1063/5.0013447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
Laser-produced plasma velocity distributions are an important, but difficult quantity to measure. We present a non-invasive technique for measuring individual charge state velocity distributions of laser-produced plasmas using a high temporal and spectral resolution monochromator. The novel application of this technique is its ability to detect particles up to 7 m from their inception (significantly larger than most laboratory plasma astrophysics experiments, which take place at or below the millimeter scale). The design and assembly of this diagnostic is discussed in terms of maximizing the signal to noise ratio, maximizing the spatial and temporal resolution, and other potential use cases. The analysis and results of this diagnostic are demonstrated by directly measuring the time-of-flight velocity of all ion charge states in a laser produced carbon plasma.
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Affiliation(s)
- R S Dorst
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California 90095, USA
| | - P V Heuer
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California 90095, USA
| | - D B Schaeffer
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540, USA
| | - C G Constantin
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California 90095, USA
| | - C Niemann
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California 90095, USA
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