1
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Dwyer RH, Meaney KD, Geppert-Kleinrath H, Loomis EN, Robey HF, Mohamed ZL, Fry C, Kim Y. Optimization of the gamma reaction history diagnostic for double-shell pusher areal density and reaction history measurements on the National Ignition Facility. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:033504. [PMID: 38497838 DOI: 10.1063/5.0189085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/21/2024] [Indexed: 03/19/2024]
Abstract
The double-shell inertial confinement fusion campaign, which consists of an aluminum ablator, a foam cushion, a high-Z pusher (tungsten or molybdenum), and liquid deuterium-tritium (DT) fuel, aims for its first DT filled implosions on the National Ignition Facility (NIF) in 2024. The high-Z, high density pusher does not allow x-rays to escape the double-shell capsule. Therefore, nuclear diagnostics such as the Gamma Reaction History (GRH) diagnostic on the NIF are crucial for understanding high-Z implosion performance. To optimize the GRH measurement of fusion reaction history and the pusher's areal density, the MCNP6.3-based forward model of the detector was built. When calculating the neutron-induced inelastic gamma ray production, the interaction of neutrons with the compressed fuel was additionally included. By folding the calculated gamma ray spectrum output and the previously calibrated GRH detector responses, the optimum set of GRH energy thresholds for measuring the pusher areal density is determined to be 2.9 and 6.3 MeV for DT double-shell experiments. In addition, the effect of the down-scattering of neutrons on the gamma ray spectrum, the minimum required yield for measurements, and the attenuation of the gamma rays through the pusher are analyzed.
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Affiliation(s)
- R H Dwyer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627, USA
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - E N Loomis
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H F Robey
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Z L Mohamed
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Fry
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Y Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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2
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Wong CS, Strehlow J, Broughton DP, Luedtke SV, Huang CK, Bogale A, Fitzgarrald R, Nedbailo R, Schmidt JL, Schmidt TR, Twardowski J, Van Pelt A, Alvarez MA, Junghans A, Mix LT, Reinovsky RE, Rusby DR, Wang Z, Wolfe B, Albright BJ, Batha SH, Palaniyappan S. Robust unfolding of MeV x-ray spectra from filter stack spectrometer data. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:023301. [PMID: 38341719 DOI: 10.1063/5.0190679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/17/2024] [Indexed: 02/13/2024]
Abstract
We present an inversion method capable of robustly unfolding MeV x-ray spectra from filter stack spectrometer (FSS) data without requiring an a priori specification of a spectral shape or arbitrary termination of the algorithm. Our inversion method is based upon the perturbative minimization (PM) algorithm, which has previously been shown to be capable of unfolding x-ray transmission data, albeit for a limited regime in which the x-ray mass attenuation coefficient of the filter material increases monotonically with x-ray energy. Our inversion method improves upon the PM algorithm through regular smoothing of the candidate spectrum and by adding stochasticity to the search. With these additions, the inversion method does not require a physics model for an initial guess, fitting, or user-selected termination of the search. Instead, the only assumption made by the inversion method is that the x-ray spectrum should be near a smooth curve. Testing with synthetic data shows that the inversion method can successfully recover the primary large-scale features of MeV x-ray spectra, including the number of x-rays in energy bins of several-MeV widths to within 10%. Fine-scale features, however, are more difficult to recover accurately. Examples of unfolding experimental FSS data obtained at the Texas Petawatt Laser Facility and the OMEGA EP laser facility are also presented.
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Affiliation(s)
- C-S Wong
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J Strehlow
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D P Broughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S V Luedtke
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C-K Huang
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A Bogale
- Center for Energy Research, University of California - San Diego, La Jolla, California 92093, USA
| | - R Fitzgarrald
- Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - R Nedbailo
- Center for High Energy Density Science, University of Texas, Austin, Texas 78712, USA
| | - J L Schmidt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T R Schmidt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J Twardowski
- Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - A Van Pelt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for High Energy Density Science, University of Texas, Austin, Texas 78712, USA
| | | | - A Junghans
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L T Mix
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R E Reinovsky
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D R Rusby
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - Z Wang
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wolfe
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B J Albright
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S H Batha
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Palaniyappan
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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3
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Moore AS, Schlossberg DJ, Eckart MJ, Hartouni EP, Hilsabeck TJ, Jeet JS, Kerr SM, Nora RC, Kilkenny J. Constraining time-dependent ion temperature measurements in inertial confinement fusion (ICF) implosions with an intermediate distance neutron time-of-flight (nToF) detector. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113536. [PMID: 36461534 DOI: 10.1063/5.0099933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/19/2022] [Indexed: 06/17/2023]
Abstract
A concept for using an intermediate distance (0.3-3.0 m) neutron time-of-flight (nToF) to provide a constraint on the measurement of the time-dependence of ion temperature in inertial confinement fusion implosions is presented. Simulated nToF signals at different distances are generated and, with a priori knowledge of the burn-averaged quantities and burn history, analyzed to determine requirements for a future detector. Results indicate a signal-to-noise ratio >50 and time resolution <20 ps to constrain the ion temperature gradient to ∼±25% (0.5 keV/100 ps).
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Affiliation(s)
- A S Moore
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - D J Schlossberg
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - M J Eckart
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - E P Hartouni
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - T J Hilsabeck
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - J S Jeet
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - S M Kerr
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - R C Nora
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA
| | - J Kilkenny
- General Atomics, San Diego, California 92121, USA
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4
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Hohenberger M, Kerr S, Yeamans C, Rusby D, Meaney KD, Hahn K, Heredia R, Sarginson T, Blue B, Mackinnon AJ, Hsing WW. A combined MeV-neutron and x-ray source for the National Ignition Facility. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103510. [PMID: 36319336 DOI: 10.1063/5.0101816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/11/2022] [Indexed: 06/16/2023]
Abstract
In support of future radiation-effects testing, a combined environment source has been developed for the National Ignition Facility (NIF), utilizing both NIF's long-pulse beams, and the Advanced Radiographic Capability (ARC) short pulse lasers. First, ARC was used to illuminate a gold foil at high-intensity, generating a significant x-ray signal >1 MeV. This was followed by NIF 10 ns later to implode an exploding pusher target filled with fusionable gas for neutron generation. The neutron and x-ray bursts were incident onto a retrievable, close-standoff diagnostic snout. With separate control over both neutron and x-ray emission, the platform allows for tailored photon and neutron fluences and timing on a recoverable test sample. The platform exceeded its initial fluence goals, demonstrating a neutron fluence of 2.3 ×1013 n/cm2 and an x-ray dose of 7 krad.
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Affiliation(s)
- M Hohenberger
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Kerr
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Yeamans
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D Rusby
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K Hahn
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Heredia
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - T Sarginson
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - B Blue
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A J Mackinnon
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - W W Hsing
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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5
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Springstead MP, Zylstra AB, Kim Y, Meaney KD, Geppert-Kleinrath H, Leatherland A, Wilson L, Herrmann HW, Young CS, Polk P, Hamilton C. Solid Cherenkov detector for studying nucleosynthesis in inertial confinement fusion. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:073503. [PMID: 32752853 DOI: 10.1063/5.0002874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Measuring gamma rays emitted from nuclear reactions gives insight into their nuclear structure. Notably, there are several nuclear reactions that produce gamma rays at ∼1 MeV-3 MeV energies such as T(4He, γ)7Li, 4He(3He, γ)7Be, and 12C(p, γ)13N, which may solve questions lingering about big-bang nucleosynthesis and stellar nucleosynthesis. To observe 1 MeV-3 MeV gamma rays in an inertial confinement fusion system, a new style of the Cherenkov detector was developed using aerogel and fused silica as a Cherenkov medium. Utilizing the OMEGA laser facility, both aerogel and fused silica media were compared with the existing gas-medium Cherenkov detector to validate the concept. Gamma ray measurements from high yield inertial confinement fusion implosions (deuterium-tritium and deuterium-3He) demonstrated that aerogel and fused silica were viable Cherenkov media, paving the way for a potential optimized detector to make these cross section measurements on OMEGA or the National Ignition Facility.
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Affiliation(s)
- M P Springstead
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A B Zylstra
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Y Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - A Leatherland
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - L Wilson
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C S Young
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - P Polk
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Hamilton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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6
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Meaney KD, Kim YH, Geppert-Kleinrath H, Herrmann HW, Hopkins LB, Hoffman NM. Diagnostic signature of the compressibility of the inertial-confinement-fusion pusher. Phys Rev E 2020; 101:023208. [PMID: 32168628 DOI: 10.1103/physreve.101.023208] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 02/06/2020] [Indexed: 11/07/2022]
Abstract
Carbon shell areal density measurements from many types of inertial confinement fusion implosions at the National Ignition Facility (NIF) demonstrate that the final state of the outside portion of the shell is set primarily by capsule coast time, the coasting period between main laser shut off and peak fusion output. However, the fuel areal density does not correlate with the increasing carbon compression. While two-dimensional (2D) radiation-hydrodynamic simulations successfully capture the carbon compression, energy must be added to the simulated fuel-ice layer to reproduce fuel areal density measurements. The data presented demonstrates that the degradation mechanisms that reduce the compressibility of the fuel do not reduce the compressibility of the ablator.
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Affiliation(s)
- K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | | | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - L Berzak Hopkins
- Lawerence Livermore National Laboratory, Livermore, California, 94550, USA
| | - N M Hoffman
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
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7
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Meaney KD, Kim YH, Herrmann HW, Geppert-Kleinrath H, Hoffman NM. Improved inertial confinement fusion gamma reaction history 12C gamma-ray signal by direct subtraction. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:113503. [PMID: 31779396 DOI: 10.1063/1.5092501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 10/18/2019] [Indexed: 06/10/2023]
Abstract
The Gamma Reaction History (GRH) diagnostic located at the National Ignition Facility (NIF) measures time resolved gamma rays released from inertial confinement fusion experiments by converting the emitted gamma rays into Cherenkov light. Imploded capsules have a bright 4.4 MeV gamma ray from fusion neutrons inelastically scattering with carbon atoms in the remaining ablator. The strength of the 4.4 MeV gamma ray line is proportional to the capsule's carbon ablator areal density and can be used to understand the dynamics and energy budget of a carbon-based ablator capsule implosion. Historically, the GRH's four gas cells use the energy thresholding from the Cherenkov process to forward fit an estimation of the experiment's complete gamma ray spectrum by modeling the surrounding environment in order to estimate the 4.4 MeV neutron induced carbon gamma ray signal. However, the high number of variables, local minima, and uncertainties in detector sensitivities and relative timing had prevented the routine use of the forward fit to generate carbon areal density measurements. A new, more straightforward process of direct subtraction of deconvolved signals was developed to simplify the extraction of the carbon areal density. Beryllium capsules are used as a calibration to measure the capsule environment with no carbon signal. The proposed method is then used to appropriately subtract and isolate the carbon signal on shots with carbon ablators. The subtraction algorithm achieves good results across all major capsule campaigns, achieving similar results to the forward fit. This method is now routinely used to measure carbon areal density for NIF shots.
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Affiliation(s)
- K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - N M Hoffman
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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8
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Dymoke-Bradshaw AKL, Hares JD, Milnes J, Herrmann HW, Horsfield CJ, Gales SG, Leatherland A, Hilsabeck T, Kilkenny JD. Development of an ultra-fast photomultiplier tube for gamma-ray Cherenkov detectors at the National Ignition Facility (PD-PMT). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10I137. [PMID: 30399690 DOI: 10.1063/1.5039327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
A new ultra-fast photomultiplier tube and associated drivers have been developed for use in the next generation of gamma-ray high pressure gas Cherenkov detectors for inertial confinement fusion experiments at the National Ignition Facility. Pulse-dilation technology has been applied to a standard micro-channel-plate-based photomultiplier tube to improve the temporal response by about 10×. The tube has been packaged suitably for deployment on the National Ignition Facility, and remote electronics have been designed to deliver the required non-linear waveforms to the pulse dilation electrode. This is achieved with an avalanche pulse generator system capable of generating fast arbitrary waveforms over the useful parameter space. The pulse is delivered via fast impedance-matching transformers and isolators, allowing the cathode to be ramped on a sub-nanosecond time scale between two high voltages in a controlled non-linear manner. This results in near linear pulse dilation over several ns. The device has a built-in fiducial system that allows easy calibration and testing with fiber optic laser sources. Results are presented demonstrating the greatly improved response time and other parameters of the device.
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Affiliation(s)
| | - J D Hares
- Kentech Instruments Ltd., Oxfordshire OX10 8BD, United Kingdom
| | - J Milnes
- Photek Ltd., St Leonards on Sea TN38 9NS, United Kingdom
| | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C J Horsfield
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - S G Gales
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - A Leatherland
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - T Hilsabeck
- General Atomics, San Diego, California 92186, USA
| | - J D Kilkenny
- General Atomics, San Diego, California 92186, USA
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9
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Herrmann HW, Kim YH, Zylstra AB, Geppert-Kleinrath H, Meaney KD, Young CS, Lopez FE, Fatherley VE, Pederson BJ, Oertel JA, Hernandez JE, Carrera J, Khater H, Rubery MS, Horsfield CJ, Gales S, Leatherland A, Hilsabeck T, Kilkenny JD, Malone RM, Batha SH. Progress on next generation gamma-ray Cherenkov detectors for the National Ignition Facility. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10I148. [PMID: 30399772 DOI: 10.1063/1.5039378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
Fusion reaction history and ablator areal density measurements for Inertial Confinement Fusion experiments at the National Ignition Facility are currently conducted using the Gamma Reaction History diagnostic (GRH_6m). Future Gas Cherenkov Detectors (GCDs) will ultimately provide ∼100x more sensitivity, reduce the effective temporal response from ∼100 to ∼10 ps, and lower the energy threshold from 2.9 to 1.8 MeV, relative to GRH_6m. The first phase toward next generation GCDs consisted of inserting the existing coaxial GCD-3 detector into a reentrant well which puts it within 4 m of the implosion. Reaction history and ablator gamma measurement results from this Phase I are discussed here. These results demonstrate viability for the follow-on Phases of (II) the use of a revolutionary new pulse-dilation photomultiplier tube to improve the effective measurement bandwidth by >10x relative to current PMT technology; and (III) the design of a NIF-specific "Super" GCD which will be informed by the assessment of the radiation background environment within the well described here.
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Affiliation(s)
- H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A B Zylstra
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - K D Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C S Young
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F E Lopez
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - V E Fatherley
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B J Pederson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J A Oertel
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J E Hernandez
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J Carrera
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H Khater
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M S Rubery
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - C J Horsfield
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - S Gales
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - A Leatherland
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - T Hilsabeck
- General Atomics, San Diego, California 92186, USA
| | - J D Kilkenny
- General Atomics, San Diego, California 92186, USA
| | - R M Malone
- Mission Support and Test Services, LLC, Los Alamos, New Mexico 87544, USA
| | - S H Batha
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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10
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Gales SG, Horsfield CJ, Meadowcroft AL, Leatherland AE, Herrmann HW, Hares JD, Dymoke-Bradshaw AKL, Milnes JS, Kim YH, Kleinrath HG, Meaney K, Zylstra AB, Parker S, Hussey D, Wilson L, James SF, Kilkenny JD, Hilsabeck TJ. Characterisation of a sub-20 ps temporal resolution pulse dilation photomultiplier tube. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:063506. [PMID: 29960515 DOI: 10.1063/1.5031110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A pulse-dilation photomultiplier tube (PD-PMT) with sub-20 ps temporal resolution has been developed for use with γ-ray-sensitive gas Cherenkov detectors at the National Ignition Facility to improve the diagnosis of nuclear fusion burn history and the areal density of the remaining capsule ablator. The pulse-dilation mechanism entails the application of a time-dependent, ramp waveform to a photocathode-mesh structure, introducing a time-dependent photoelectron accelerating potential. The electric field imparts axial velocity dispersion to outgoing photoelectrons. The photoelectron pulse is dilated as it transits a drift region prior to amplification in a microchannel plate and read out with a digital oscilloscope. We report the first measurements with the prototype PD-PMT demonstrating nominal <20 ps FWHM across a 400 ps measurement window and <30 ps FWHM for an extracted charge up to 300 pC. The output peak areas are linear to within 20% over 3 orders of magnitude of input intensity. 3D particle in cell simulations, which included space charge effects, have been carried out to investigate the device temporal magnification, resolution, and linearity.
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Affiliation(s)
- S G Gales
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | - C J Horsfield
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | | | | | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Hares
- Kentech Instruments Ltd., Wallingford OX10 8BD, United Kingdom
| | | | - J S Milnes
- Photek Ltd., St Leonards-on-Sea TN38 9NS, United Kingdom
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H G Kleinrath
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K Meaney
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A B Zylstra
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Parker
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | - D Hussey
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | - L Wilson
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | - S F James
- AWE plc, Aldermaston, Reading RG7 4PR, United Kingdom
| | - J D Kilkenny
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - T J Hilsabeck
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
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11
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Zylstra AB, Herrmann HW, Kim YH, McEvoy AM, Schmitt MJ, Hale G, Forrest C, Glebov VY, Stoeckl C. Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:053504. [PMID: 28571443 DOI: 10.1063/1.4983923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H2+T2 gas-fueled implosion for the first time. Using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.
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Affiliation(s)
- A B Zylstra
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A M McEvoy
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M J Schmitt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - G Hale
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Forrest
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - V Yu Glebov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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Herrmann HW, Kim YH, Young CS, Fatherley VE, Lopez FE, Oertel JA, Malone RM, Rubery MS, Horsfield CJ, Stoeffl W, Zylstra AB, Shmayda WT, Batha SH. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11E124. [PMID: 25430303 DOI: 10.1063/1.4892553] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ∼400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.
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Affiliation(s)
- H W Herrmann
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Y H Kim
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C S Young
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - V E Fatherley
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F E Lopez
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J A Oertel
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R M Malone
- National Security Technologies, LLC, Los Alamos, New Mexico 87544, USA
| | - M S Rubery
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - C J Horsfield
- Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom
| | - W Stoeffl
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A B Zylstra
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - W T Shmayda
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - S H Batha
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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13
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Hoffman N, Herrmann H, Kim Y, Hsu H, Horsfield C, Rubery M, Wilson D, W. Stoeffl W, Young C, Mack J, Miller E, Grafil E, Evans S, Sedillo T, Glebov V, Duffy T. In situcalibration of the Gamma Reaction History instrument using reference samples (“pucks”) for areal density measurements. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20135913019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Rinderknecht HG, Johnson MG, Zylstra AB, Sinenian N, Rosenberg MJ, Frenje JA, Waugh CJ, Li CK, Sèguin FH, Petrasso RD, Rygg JR, Kimbrough JR, MacPhee A, Collins GW, Hicks D, Mackinnon A, Bell P, Bionta R, Clancy T, Zacharias R, Döppner T, Park HS, LePape S, Landen O, Meezan N, Moses EI, Glebov VU, Stoeckl C, Sangster TC, Olson R, Kline J, Kilkenny J. A novel particle time of flight diagnostic for measurements of shock- and compression-bang times in D3He and DT implosions at the NIF. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D902. [PMID: 23126906 DOI: 10.1063/1.4731000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The particle-time-of-flight (pTOF) diagnostic, fielded alongside a wedge range-filter (WRF) proton spectrometer, will provide an absolute timing for the shock-burn weighted ρR measurements that will validate the modeling of implosion dynamics at the National Ignition Facility (NIF). In the first phase of the project, pTOF has recorded accurate bang times in cryogenic DT, DT exploding pusher, and D(3)He implosions using DD or DT neutrons with an accuracy better than ±70 ps. In the second phase of the project, a deflecting magnet will be incorporated into the pTOF design for simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions using D(3)He protons and DD-neutrons, respectively.
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Hoffman NM, Wilson DC, Herrmann HW, Young CS. Using gamma-ray emission to measure areal density of inertial confinement fusion capsules. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:10D332. [PMID: 21033852 DOI: 10.1063/1.3478690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Fusion neutrons streaming from a burning inertial confinement fusion capsule generate gamma rays via inelastic nuclear scattering in the ablator of the capsule. The intensity of gamma-ray emission is proportional to the product of the ablator areal density (ρR) and the yield of fusion neutrons, so by detecting the gamma rays we can infer the ablator areal density, provided we also have a measurement of the capsule's total neutron yield. In plastic-shell capsules, for example, (12)C nuclei emit gamma rays at 4.44 MeV after excitation by 14.1 MeV neutrons from D+T fusion. These gamma rays can be measured by a new gamma-ray detector under development. Analysis of predicted signals is in progress, with results to date indicating that the method promises to be useful for diagnosing imploded capsules.
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Affiliation(s)
- N M Hoffman
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA.
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