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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Transport and spatial energy deposition of relativistic electrons in copper-doped fast ignition plasmas

Fast electron transport and spatial energy deposition are investigated in integrated cone-guided Fast Ignition experiments by measuring fast electron induced copper K-shell emission using a copper tracer added to deuterated plastic shells with a geometrically reentrant gold cone. Experiments were carried out at the Laboratory for Laser Energetics on the OMEGA/OMEGA-EP Laser where the plastic shells were imploded using 54 of the 60 OMEGA60 beams (3ω, 20 kJ), while the high intensity OMEGA-EP (BL2) beam (1 ω, 10 ps, 500 J, I peak > 10 19 W/cm 2 ) was focused onto the inner cone tip. Here, a retrograde analysis using the hybrid-PIC electron transport code, ZUMA, is performed to examine the sensitivity of the copper Kα spatial profile on the laser-produced fast electrons, facilitating the optimization of new target point designs and laser configurations to improve the compressed core areal density by a factor of 4 and the fast electron energy coupling by a factor of 3.5.

42 ENGINEERING↗
DOE OSTI2016

Flash Kα radiography of laser-driven solid sphere compression for fast ignition

Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm{sup 2}. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Final Project Report "Advanced Concept Exploration For Fast Ignition Science Program"

The Fast Ignition (FI) Concept for Inertial Confinement Fusion has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy (IFE) reactors. FI differs from conventional “central hot spot” (CHS) target ignition by decoupling compression from heating: using the laser (or heavy ion beam or Z pinch) drive pulse (10’s of ns) to create a dense fuel and a second, much shorter (~10 ps) high intensity pulse to ignite a small region of it. There are two major physics issues concerning this concept; controlling the laser-induced generation of large electron currents and their propagation through high density plasmas. This project has addressed these two significant scientific issues in Relativistic High Energy Density (RHED) physics. Learning to control relativistic laser matter interaction (and the limits and potential thereof) will enable a wide range of applications. While these physics issues are of specific interest to inertial fusion energy science, they are also important for a wide range of other HED phenomena, including high energy ion beam generation, isochoric heating of materials, and the development of high brightness x-ray sources. Generating, controlling, and understanding the extreme conditions needed to advance this science has proved to be challenging: Our studies have pushed the boundaries of physics understanding and are at the very limits of experimental, diagnostic, and simulation capabilities in high energy density laboratory physics (HEDLP). Our research strategy has been based on pursuing the fundamental physics underlying the Fast Ignition (FI) concept. We have performed comprehensive study of electron generation and transport in fast-ignition targets with experiments, theory, and numerical modeling. A major issue is that the electrons produced in these experiments cannot be measured directly—only effects due to their transport. We focused mainly on x-ray continuum photons from bremsstrahlung and x-ray line radiation from K-shell fluorescence. Integrated experiments, which combine target compression with short-pulse laser heating, yield additional information on target heating efficiency. This indirect way of studying the underlying behavior of the electrons must be validated with computational modeling to understand the physics and improve the design. This program execution required a large, well-organized team and it was managed by a joint Collaboration between General Atomics (GA), Lawrence Livermore National Laboratory (LLNL), and the Laboratory for Laser Energetics (LLE). The Collaboration was formed 8 years ago to understand the physics issues of the Fast Ignition concept, building on the strengths of each partner. GA fulfills its responsibilities jointly with the University of California, San Diego (UCSD), The Ohio State University (OSU) and the University of Nevada at Reno (UNR). Since RHED physics is pursued vigorously in many countries, international researchers have been an important part of our efforts to make progress. The division of responsibility was as follows: (1) LLE had primary leadership for channeling studies and the integrated energy transfer, (2) LLNL led the development of measurement methods, analysis, and deployment of diagnostics, and (3) GA together with UCSD, OSU and UNR studied the detailed energy-transfer physics. The experimental program was carried out using the Titan laser at the Jupiter Laser Facility at LLNL, the OMEGA and OMEGA EP lasers at LLE and the Texas Petawatt laser (TPW) at UT Austin. Modeling has been pursued on large computing facilities at LLNL, OSU, and UCSD using codes developed (by us and others) within the HEDLP program, commercial codes, and by leveraging existing supercomputer codes developed by the NNSA ICF program. This Consortium brought together all the components—resources, facilities, and personnel—necessary to accomplish its aggressive goals. The ACE Program has been strongly collaborative, taking advantage of the expertise of the participating institutions to provide a research effort that is far greater than the sum of its parts. The results of this work have firmly strengthened the scientific foundation from which the viability of FI and other applications can be evaluated. Program execution has also led to improved diagnostics for probing dense, hot plasmas, detailed understanding of high-current, relativistic electron energy generation and transport across boundaries and into dense plasmas, and greatly enhanced predictive modeling capabilities. One important aspect of this program was the involvement and training of young scientists including postdoctoral fellows and graduate students. During the entire 8 years of FI and ACE project period since 2005, more than fifteen graduate students completed their doctoral dissertations including three from OSU and two from UCSD in last three years. This project generated an impressive forty articles in high quality journals including nine (including two under review) in Physical Review Letters during the last funding period since 2011.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

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

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.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

Advanced Concept Exploration for Fast Ignition Science Program (Final Report)

The Fast Ignition (FI) Concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy reactors. FI differs from conventional “central hot spot” (CHS) target ignition by decoupling compression from heating: using a laser (or heavy ion beam or Z pinch) drive pulse (10’s of nanoseconds) to create a dense fuel and a second, much shorter (~10 picoseconds) high intensity pulse to ignite a small volume within the dense fuel. The physics of fast ignition process was the focus of our Advanced Concept Exploration (ACE) program. Ignition depends critically on two major issues involving Relativistic High Energy Density (RHED) physics: The laser-induced creation of fast electrons and their propagation in high-density plasmas. Our program has developed new experimental platforms, diagnostic packages, computer modeling analyses, and taken advantage of the increasing energy available at laser facilities to advance understanding of the fundamental physics underlying these issues.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Laser–plasma interactions for fast ignition

In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser- plasma interactions (LPI) relevant to fast ignition. Increases in computational and modeling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multidimensional particle-in-cell (PIC) simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity, f-number and wavelength are considered, as well as the dependence on plasma parameters. Different numerical modeling approaches and configurations are addressed, providing an overview of the modeling capabilities and limitations. In addition, we discuss the comparison of simulation results with experimental observables. In particular, we address the question of surrogacy of today's experiments for the full-scale fast ignition problem.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Visualizing fast electron energy transport into laser-compressed high-density fast-ignition targets

Understanding of fast electron generation inside the cone and their subsequent transport into hot dense plasmas is crucial to the success of the cone guided fast ignition (FI) scheme of inertial confinement fusion. In our prior work, we developed a new platform that measured, for the first time, the spatial map of fast electron transport in the vicinity of the core of an imploded shell in joint OMEGA and OMEGA EP experiments. In this University of California San Diego-led NLUF project we are using the same platform to investigate several methods of improving coupling efficiency into an imploded CH/CD shell attached to a re-entrant gold cone targets. The shell has an outer diameter of 870 µm consisting of a 15 µm thick outer CH ablator and a 23 µm thick inner CD layer. A Cu dopant (at ~ 1% atomic number density of CD) is added to the CD layer of the shell, which allows characterization of fast electrons transport via their induced Cu K-shell fluorescence radiation.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Improved ion heating in fast ignition by pulse shaping

The fast ignition paradigm for inertial fusion offers increased gain and tolerance of asymmetry by compressing fuel at low entropy and then quickly igniting a small region. Because this hotspot rapidly disassembles, the ions must be heated to ignition temperature as quickly as possible, but most ignitor designs directly heat electrons. A constant-power ignitor pulse, which is generally assumed, is suboptimal for coupling energy from electrons to ions. Using a simple model of a hotspot in isochoric plasma, a novel pulse shape to maximize ion heating is presented in analytical form. Bounds are derived on the maximum ion temperature attainable by electron heating only. Moreover, arranging for faster ion heating allows a smaller hotspot, improving fusion gain. As a result, under representative conditions, the optimized pulse can reduce ignition energy by over 20%.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

Elliptical magnetic mirror generated via resistivity gradients for fast ignition inertial confinement fusion

The elliptical magnetic mirror scheme for guiding fast electrons for Fast Ignition proposed by Schmitz et al. (Plasma Phys. Controlled Fusion 54, 085016 (2012)) is studied for conditions on the multi-kJ scale which are much closer to full-scale Fast Ignition. When scaled up, the elliptical mirror scheme is still highly beneficial to Fast Ignition. An increase in the coupling efficiency by a factor of 3–4 is found over a wide range of fast electron divergence half-angles.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Development and Benchmarking of a Hybrid PIC Code For Dense Plasmas and Fast Ignition (Final Report)

Radiation processes play an important role in the study of both fast ignition and other inertial confinement schemes, such as plasma jet driven magneto-inertial fusion, both in their effect on energy balance, and in generating diagnostic signals. In the latter case, warm and hot dense matter may be produced by the convergence of a plasma shell formed by the merging of an assembly of high Mach number plasma jets. This innovative approach has the potential advantage of creating matter of high energy densities in voluminous amount compared with high power lasers or particle beams. An important application of this technology is as a plasma liner for the flux compression of magnetized plasma to create ultra-high magnetic fields and burning plasmas. HyperV Technologies Corp. has been developing plasma jet accelerator technology in both coaxial and linear railgun geometries to produce plasma jets of sufficient mass, density, and velocity to create such imploding plasma liners. An enabling tool for the development of this technology is the ability to model the plasma dynamics, not only in the accelerators themselves, but also in the resulting magnetized target plasma and within the merging/interacting plasma jets during transport to the target. Welch pioneered numerical modeling of such plasmas (including for fast ignition) using the LSP simulation code. Lsp is an electromagnetic, parallelized, plasma simulation code under development since 1995. It has a number of innovative features making it uniquely suitable for modeling high energy density plasmas including a hybrid fluid model for electrons that allows electrons in dense plasmas to be modeled with a kinetic or fluid treatment as appropriate. In addition to in-house use at Voss Scientific, several groups carrying out research in Fast Ignition (LLNL, SNL, UCSD, AWE (UK), and Imperial College (UK)) also use LSP. A collaborative team consisting of HyperV Technologies Corp., Voss Scientific LLC, FAR-TECH, Inc., Prism Computational Sciences, Inc. and Advanced Energy Systems Inc. joined efforts to develop new physics and numerical models for LSP in several key areas to enhance the ability of LSP to model high energy density plasmas (HEDP). This final report details those efforts. Areas addressed in this research effort include: adding radiation transport to LSP, first in 2D and then fully 3D, extending the EMHD model to 3D, implementing more advanced radiation and electrode plasma boundary conditions, and installing more efficient implicit numerical algorithms to speed complex 2-D and 3-D computations. The new capabilities allow modeling of the dominant processes in high energy density plasmas, and further assist the development and optimization of plasma jet accelerators, with particular attention to MHD instabilities and plasma/wall interaction (based on physical models for ion drag friction and ablation/erosion of the electrodes). In the first funding cycle we implemented a solver for the radiation diffusion equation. To solve this equation in 2-D, we used finite-differencing and applied the parallelized sparse-matrix solvers in the PETSc library (Argonne National Laboratory) to the resulting system of equations. A database of the necessary coefficients for materials of interest was assembled using the PROPACEOS and ATBASE codes from Prism. The model was benchmarked against Prism's 1-D radiation hydrodynamics code HELIOS, and against experimental data obtained from HyperV's separately funded plasma jet accelerator development program. Work in the second funding cycle focused on extending the radiation diffusion model to full 3-D, continued development of the EMHD model, optimizing the direct-implicit model to speed up calculations, add in multiply ionized atoms, and improved the way boundary conditions are handled in LSP. These new LSP capabilities were then used, along with analytic calculations and Mach2 runs, to investigate plasma jet merging, plasma detachment and transport, restrike and advanced jet accelerator design. In addition, a strong linkage to diagnostic measurements was made by modeling plasma jet experiments on PLX to support benchmarking of the code. A large number of upgrades and improvements advancing hybrid PIC algorithms were implemented in LSP during the second funding cycle. These include development of fully 3D radiation transport algorithms, new boundary conditions for plasma-electrode interactions, and a charge conserving equation of state that permits multiply ionized high-Z ions. The final funding cycle focused on 1) mitigating the effects of a slow-growing grid instability which is most pronounced in plasma jet frame expansion problems using the two-fluid Eulerian remap algorithm, 2) extension of the Eulerian Smoothing Algorithm to allow EOS/Radiation modeling, 3) simulations of collisionless shocks formed by jet merging, 4) simulations of merging jets using high-Z gases, 5) generation of PROPACEOS EOS/Opacity databases, 6) simulations of plasma jet transport experiments, 7) simulations of plasma jet penetration through transverse magnetic fields, and 8) GPU PIC code development. The tools developed during this project are applicable not only to the study of plasma jets, but also to a wide variety of HEDP plasmas of interest to DOE, including plasmas created in short-pulse laser experiments performed to study fast ignition concepts for inertial confinement fusion.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Fast ignition inertial fusion energy using laser-driven ion beams

Ion fast ignition (IFI), or fusion fast ignition initiated by a laser-driven ion beam, is a promising path to high-gain inertial fusion energy (IFE). In IFI, cold, dense deuterium-tritium (DT) fuel is first assembled using lasers or pulsed power drivers. Then, a high-power ion beam is focused onto a small volume within the fuel (the hot spot), heating the fuel rapidly to conditions where fusion ignition takes place. Fusion burn in this hot spot propagates to the fuel surrounding the hot spot, leading to burnup of a significant fraction of this fuel and the possibility of high gain (G~100), as needed for inertial fusion energy. IFI uses separate drivers for the two basic elements, fuel compression and ignition, allowing maximum control and optimization of each. On the other hand, conventional laser fusion uses multiple beams of the same driver to compress the fuel and shock-heat its very center to ignite a burn wave. Despite impressive progress in conventional laser fusion, the precise spatial symmetry, temporal pulse shaping and timing required for high gain and IFE remain a serious unmet challenge.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Fast ignition integrated experiments and high-gain point design

Here, integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast electron heating of cone-in-shell targets, large-energy short-pulse laser beam lines were constructed and became operational: OMEGA-EP at Rochester and LFEX at Osaka. Neutron enhancement due to heating with a ~kJ short-pulse laser has been demonstrated in the integrated experiments at Osaka and Rochester. The neutron yields are being analyzed by comparing the experimental results with simulations. Details of the fast electron beam transport and the electron energy deposition in the imploded fuel plasma are complicated and further studies are imperative. The hydrodynamics of the implosion was studied including the interaction of the imploded core plasma with the cone tip. Theory and simulation studies are presented on the hydrodynamics of a high-gain target for a fast ignition point design.

42 ENGINEERING↗
DOE OSTI2016

Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser–plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >10{sup 9}. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding plasma. Following the above improvements, conversion of 13% of the LFEX laser energy to a low energy portion of the REB, whose slope temperature is 0.7 MeV, which is close to the ponderomotive scaling value, was achieved. To meet the second requirement, the compression of a solid spherical ball with a diameter of 200-μm to form a dense core with an areal density of ∼0.07 g/cm{sup 2} was induced by a laser-driven spherically converging shock wave. Converging shock compression is more hydrodynamically stable compared to shell implosion, while a hot spot cannot be generated with a solid ball target. Solid ball compression is preferable also for compressing an external magnetic field to collimate the REB to the fuel core, due to the relatively small magnetic Reynolds number of the shock compressed region. To meet the third requirement, we have generated a strong kilo-tesla magnetic field using a laser-driven capacitor-coil target. The strength and time history of the magnetic field were characterized with proton deflectometry and a B-dot probe. Guidance of the REB using a 0.6-kT field in a planar geometry has been demonstrated at the LULI 2000 laser facility. In a realistic FI scenario, a magnetic mirror is formed between the REB generation point and the fuel core. The effects of the strong magnetic field on not only REB transport but also plasma compression were studied using numerical simulations. According to the transport calculations, the heating efficiency can be improved from 0.4% to 4% by the GEKKO and LFEX laser system by meeting the three requirements described above. This efficiency is scalable to 10% of the heating efficiency by increasing the areal density of the fuel core.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Ion beam requirements for fast ignition of inertial fusion targets

Ion beam requirements for fast ignition are investigated by numerical simulation taking into account new effects, such as ion beam divergence, not included before. We assume that ions are generated by the TNSA scheme in a curved foil placed inside a re-entrant cone and focused on the cone apex or beyond. From the focusing point to the compressed core, ions propagate with a given divergence angle. Ignition energies are obtained for two compressed fuel configurations heated by proton and carbon ion beams. The dependence of the ignition energies on the beam divergence angle and on the position of the ion beam focusing point has been analyzed. Comparison between TNSA and quasi-monoenergetic ions is also shown.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Los Alamos LDRD Appraisal Final Report for 20190124ER [Hot Electron Beam Generation and Transport for Fast Ignition]

This project was successful in addressing key technical issues of the cone-guided electron fast ignition concept for ICF. The development of an e-beam to deliver energy of 10’s of kilojoules to HED targets would be useful for myriad experimental applications relevant to the Laboratory’s mission. For example, ICF ignition and the development of a burning plasma is a high priority for the national high energy density physics effort and this work is aligned with that mission. Moreover, other technologies (e.g., MeV laser radiography) would be advanced by the R&D advancements from this project, so this work has broader implications for other LANL missions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Heating a plasma by a broadband stream of fast electrons: Fast ignition, shock ignition, and Gbar shock wave applications

An exact analytic solution is found for the steady-state distribution function of fast electrons with an arbitrary initial spectrum irradiating a planar low-Z plasma with an arbitrary density distribution. The solution is applied to study the heating of a material by fast electrons of different spectra such as a monoenergetic spectrum, a step-like distribution in a given energy range, and a Maxwellian spectrum, which is inherent in laser-produced fast electrons. The heating of shock- and fast-ignited precompressed inertial confinement fusion (ICF) targets as well as the heating of a target designed to generate a Gbar shock wave for equation of state (EOS) experiments by laser-produced fast electrons with a Maxwellian spectrum is investigated. A relation is established between the energies of two groups of Maxwellian fast electrons, which are responsible for generation of a shock wave and heating the upstream material (preheating). The minimum energy of the fast and shock igniting beams as well as of the beam for a Gbar shock wave generation increases with the spectral width of the electron distribution.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition

A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10{sup 7} cm/s and 1.0 ± 0.3 × 10{sup 7} cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5–1 keV and neutron yield of more than 10{sup 9} neutrons/shot.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

An electron/ion spectrometer with the ability of low energy electron measurement for fast ignition experiments

An electron energy spectrometer (ESM) is one of the most fundamental diagnostics in the fast ignition experiment. It is necessary to observe the spectra down to a low energy range in order to obtain the accurate deposition efficiency toward the core. Here, we realize the suitable ESM by using a ferrite magnet with a moderate magnetic field of 0.3 T and a rectangular magnetic circuit covered with a steel plate in the inlet side.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗