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Kα radiation generated by interaction of an ultrashort (1 ps) laser with thin (25 μm) Ti foils at high intensity (2× 1016 W cm2) is analyzed using data from a spherical Bragg crystal imager and a single hit charge-coupled device spectrometer together with Monte Carlo simulations of Kα brightness. Laser to Kα and electron conversion efficiencies have been determined. We have also measured an effective crystal reflectivity of 3.75±2%. Comparison of imager data with data from the relatively broadband single hit spectrometer has revealed a reduction in crystal collection efficiency for high Kα yield. This is attributed to a shift in the K -shell spectrum due to Ti ionization. © 2005 American Institute of Physics.

Protons accelerated by a picosecond laser pulse have been used to radiograph a 500μm diameter capsule, imploded with 300 J of laser light in 6 symmetrically incident beams of wavelength 1.054μm and pulse length 1 ns. Point projection proton backlighting was used to characterize the density gradients at discrete times through the implosion. Asymmetries were diagnosed both during the early and stagnation stages of the implosion. Comparison with analytic scattering theory and simple Monte Carlo simulations were consistent with a 3±1g/cm3 core with diameter 85±10μm. Scaling simulations show that protons >50MeV are required to diagnose asymmetry in ignition scale conditions. © 2006 The American Physical Society.

Some of the planned core diagnostics for National Ignition Facility (NIF) will use neutron time-of-flight (TOF) spectroscopy techniques to gather information for primary neutron yield measurement or neutron imaging. TOF methods will be used to observe target fuel areal density (ρR) (radial integral of density) via measuring the number of primary 14.1 MeV neutrons that are down-scattered to lower energies by nuclear collisions inside the compressed target core. The large number of primary neutrons scattered by the target chamber and structures at NIF will contribute a significant background signal during (pR) measurements. The optimum detector locations outside the target chamber or target bay wall are proposed. Appropriate collimators at the chamber port and the bay wall (between the neutron source at target chamber center (TCC) and detector) that maximize detection of signal neutrons while minimizing the background from scattered neutrons and neutron induced gamma rays are presented.

Layered and characterized cryogenic D2 capsules have been imploded using both low- and high-adiabat (α, the ratio of the electron pressure to the Fermi-degenerate pressure) pulse shapes on the 60-beam OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] at the Laboratory for Laser Energetics (LLE). These experiments measure the sensitivity of the direct-drive implosion performance to parameters such as the inner-ice-surface roughness, the adiabat of the cryogenic fuel during the implosion, the laser power balance, and the single-beam nonuniformity. The goal of the direct-drive program at LLE is to demonstrate a high neutron-averaged fuel ρR at a significant fraction of the predicted one-dimensional (1-D) neutron yield using an energy-scaled, low-adiabat (α∼3) ignition pulse shape driving a hydrodynamically scaled deuterium–tritium ignition capsule. New results are reported from implosions of ∼920-μm-diam, thin (∼5 μm) polymer shells containing 100 μm D2-ice layers with characterized inne...

We characterize the response of chemical vapor deposition (CVD) diamond detectors to inertial confinement fusion (ICF) neutrons generated at the OMEGA laser fusion facility in Rochester, NY. Four detectors are tested: three utilizing “optical grade” CVD diamond, and one utilizing “electronic grade” CVD diamond. Using a 50 Ω measurement system, we find that the optical grade wafers, biased to 1000 V/mm, have an average sensitivity of 0.24 μV ns/n for 2.5 MeV (DD fusion) neutrons and 0.62 μV ns/n for 14.0 MeV (DT fusion) neutrons. At the same E field, the electronic grade wafer has a sensitivity of 0.56 and 1.43 μV ns/n for 2.5 and 14 MeV neutrons, respectively. Linear dynamic range for the optical grade material is shown to be at least 105. Average full width at half maximum response times, as measured with pulsed laser and 3 GHz scope, are 376 and 880 ps for optical and electronic grades, respectively. These characteristics make CVD diamond suitable for ICF applications such as neutron time-of-flight spec...

A detector for fuel areal density measurements in inertial confinement fusion capsules has been designed. Observation of neutrons scattered in an imploded deuterium capsule (0.27–0.6 MeV) is a promising method for areal density measurements in the National Ignition Facility DD surrogate capsules. In order to detect scattered neutrons, we need to (1) suppress interference due to the strong direct neutron burst and (2) suppress the background produced by neutrons scattering on nontarget material (mainly from the target chamber). In our detector system, we suppress direct neutrons by gating the detector. We suppress the nontarget background neutrons by placing the detector outside the target chamber and limiting the view of the detector with collimators. In addition, we are developing a lithium-glass scintillation-fiber detector (LG-SCIFI) to detect the scattered neutrons. The LG-SCIFI will work as a multichannel scintillator array. The scintillation signal will be amplified by a microchannel plate image int...

The success of the National Ignition Facility program will depend on diagnostic measurements which study the performance of inertial confinement fusion (ICF) experiments. Neutron yield, fusion-burn time history, and images are examples of important diagnostics. Neutron and x-ray images will record the geometries of compressed targets during the fusion-burn process. Such images provide a critical test of the accuracy of numerical modeling of ICF experiments. They also can provide valuable information in cases where experiments produce unexpected results. Although x-ray and neutron images provide similar data, they do have significant differences. X-ray images represent the distribution of high-temperature regions where fusion occurs, while neutron images directly reveal the spatial distribution of fusion-neutron emission. X-ray imaging has the advantage of a relatively straightforward path to the imaging system design. Neutron imaging, by using energy-resolved detection, offers the intriguing advantage of ...

High-resolution spectrometry of charged particles from inertial-confinement-fusion (ICF) experiments has become an important method of studying plasma conditions in laser-compressed capsules. In experiments at the 60-beam OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], utilizing capsules with D2, D3He, DT, or DTH fuel in a shell of plastic, glass, or D2 ice, we now routinely make spectral measurements of primary fusion products (p, D, T, 3He, α), secondary fusion products (p), “knock-on” particles (p, D, T) elastically scattered by primary neutrons, and ions from the shell. Use is made of several types of spectrometers that rely on detection and identification of particles with CR-39 nuclear track detectors in conjunction with magnets and/or special ranging filters. CR-39 is especially useful because of its insensitivity to electromagnetic noise and its ability to distinguish the types and energies of individual particles, as illustrated here by detailed calibrations of its response to 0.1–13.8 MeV protons from a Van de Graaff accelerator and to p, D, T, and α from ICF experiments at OMEGA. A description of the spectrometers is accompanied by illustrations of their operating principles using data from OMEGA. Sample results and discussions illustrate the relationship of secondary-proton and knock-on spectra to capsule fuel and shell areal densities and radial compression ratios; the relationship of different primary fusion products to each other and to ion temperatures; the relationship of deviations from spherical symmetry in particle yields and energies to capsule structure; the acceleration of fusion products and the spectra of ions from the shell due to external fields; and other important physical characteristics of the laser-compressed capsules.

Initial results from direct-drive spherical cryogenic target implosions on the 60-beam OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)] are presented. These experiments are part of the scientific base leading to direct-drive ignition implosions planned for the National Ignition Facility (NIF) [W. J. Hogan, E. I. Moses, B. E. Warner et al., Nucl. Fusion 41, 567 (2001)]. Polymer shells (1-mm diam with walls

Direct-drive implosions on the OMEGA laser [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)] have been diagnosed using a wide range of techniques based on neutrons, charged particles, and x rays. These implosions use full single-beam smoothing (distributed phase plates, 1-THz-bandwidth smoothing by spectral dispersion and polarization smoothing). The beam-to-beam power imbalance is ⩽5%. Fuel areal densities close to those in one-dimensional (1-D) simulations are inferred for implosions with calculated convergence ratios ∼15. The experimental neutron yields are ∼35% of 1-D yields. The complementary nature of the experimental observables is exploited to infer fuel shell mix in these implosions. Data suggest that this mix occurs at relatively small scales. Analysis of the experimental observables results in a picture of the core and mix region indicating that nearly 70% of the compressed fuel areal density is unmixed, and about 20% of the compressed shell areal density is in the...

The performance of gas-filled, plastic-shell implosions has significantly improved with advances in on-target uniformity on the 60-beam OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)]. Polarization smoothing (PS) with birefringent wedges and 1-THz-bandwidth smoothing by spectral dispersion (SSD) have been installed on OMEGA. The beam-to-beam power imbalance is ⩽5% rms. Implosions of 20-μm-thick CH shells (15 atm fill) using full beam smoothing (1-THz SSD and PS) have primary neutron yields and fuel areal densities that are ∼70% larger than those driven with 0.35-THz SSD without PS. They also produce ∼35% of the predicted one-dimensional neutron yield. The results described here suggest that individual-beam nonuniformity is no longer the primary cause of nonideal target performance. A highly constrained model of the core conditions and fuel–shell mix has been developed. It suggests that there is a “clean” fuel region, surrounded by a mixed region, that accounts for half of the fuel areal density.

The LLNL Petawatt Laser has achieved focussed intensities up to 6×10 20 W/cm 2 , which has opened a new, higher energy regime of relativistic laser–plasma interactions in which the quiver energy of target electrons exceeds several MeV. Recent experiments revealed an intense, collimated beam of high-energy protons emitted normal to the rear surface of thin, solid targets. Up to 10 13 particles were emitted in a pulse less than 10 ps resulting in a current in the MA regime. With an overall energy content of 30 J, up to 7% of the incident laser energy is converted into protons. The beam shows a broad particle energy spectrum with a sharp cut off above 55 MeV. Based on our current understanding of the accelerating process, it may be possible to shape and focus the ion beam by using special target geometries. With their short pulse duration, high particle energy and large luminosity these beams are promising candidates in numerous applications, such as short-pulse injectors for large accelerators or as the ignitor for fast ignition ICF. Using intense proton beams the fast ignitor concept may become more attractive in heavy-ion fusion due to the possibility to work with indirectly driven targets. Finally, the acceleration is not restricted to protons and using tailored target surfaces may allow acceleration of more massive ions to similar energy per nucleon.

With the operation of successively more intense and powerful lasers, such as the NOVA petawatt laser with I∼3×1020 W/cm2, several novel (to laser physics) nuclear diagnostics were used to determine the nature of the laser/matter interaction at the target surface. A broad beam of hot electrons, whose centroid varied from shot to shot, width was remarkably constant, and intensity was about 40% of the incident laser energy was observed. New nuclear phenomenon included photonuclear reactions [e.g., (γ,xn)], photofission of 238U and intense beams of ions. Photonuclear reactions were observed and quantified in Cu, Ni, and Au samples, and produced activation products as neutron deficient as 191Au [a (γ,6n) reaction!], requiring gamma rays exceeding 50 MeV in energy. The spectral features of the gamma-ray source have been investigated by comparing activation ratios in Ni and Au samples, and angular distributions of higher energy photons have been measured with activation of spatially distributed Au samples. Extra...

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, will provide unprecedented opportunities for the use of nuclear diagnostics in inertial confinement fusion experiments. The completed facility will provide 2 MJ of laser energy for driving targets, compared to the approximately 40 kJ that was available on Nova and the approximately 30 kJ available on Omega. Ignited NIF targets are anticipated to produce up to 1019 DT neutrons. In addition to a basic set of nuclear diagnostics based on previous experience, these higher NIF yields are expected to allow innovative nuclear diagnostic techniques to be utilized, such as neutron imaging, recoil proton techniques, and gamma-ray-based reaction history measurements.

A model independent method to determine fuel 〈ρR〉 is to measure the energy spectrum and yield of elastically scattered primary neutrons in deuterium–tritium (DT) plasmas. As is the case for complementary methods to measure fuel 〈ρR〉 (in particular from knock-on deuterons and tritons [S. Skupsky and S. Kacenjar, J. Appl. Phys. 52, 2608 (1981); C. K. Li et al. (unpublished)]), minimizing the background is critical for successful implementation. To achieve this objective, a novel spectrometer for measurements of neutrons in the energy range 10–18 MeV is proposed. From scattered neutrons (10–13 MeV), the DT fuel 〈ρR〉 will be measured; from primary neutrons (∼14 MeV), the ion temperature and neutron yield will be determined; and from secondary neutrons, in the energy range 12–18 MeV, the fuel 〈ρR〉 in deuterium plasmas will be inferred at the National Ignition Facility. The instrument is based on a magnetic spectrometer with a neutron-to-deuteron (nd) conversion foil for production of deuteron recoils at nearly...

Spectral measurements have been made of charged fusion products produced in deuterium + helium-3 filled targets irradiated by the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Comparing the energy shifts of four particle types has allowed two distinct physical processes to be probed: Electrostatic acceleration in the low-density corona and energy loss in the high-density target. When the fusion burn occurred during the laser pulse, particle energy shifts were dominated by acceleration effects. Using a simple model for the accelerating field region, the time history of the target electrostatic potential was found and shown to decay to zero soon after laser irradiation was complete. When the fusion burn occurred after the pulse, particle energy shifts were dominated by energy losses in the target, allowing fundamental charged-particle stopping-power predictions to be tested. The results provide the first experimental verification of the general form of stopping power theories over ...

We have developed a hybrid Ti:sapphire-Nd:glass laser system that produces more than 1.5 PW of peak power. The system has produced up to 680 J of energy on target at 1054 nm in a compressed 440/spl plusmn/20-fs pulse by use of 94-cm diffraction gratings. A focused irradiance of up to 6/spl times/10/sup 20/ W/cm/sup 2/ was achieved using an on-axis parabolic mirror and adaptive optic wavefront control. Experiments with the petawatt laser system focused the beam on solid targets and produced a strongly relativistic interaction. Energy content, spectra, and angular pattern of the photon, electron, and ion radiations were diagnosed in a number of ways, including several nuclear activation techniques. Approximately 40-50% of the laser energy was converted to broadly beamed hot electrons, with an associated bremsstrahlung beam. High luminosity ion beams were observed normal to the rear surface of various targets with energies up to /spl ges/55 MeV, representing /spl sim/7% of the laser energy. These and other results are presented.

Recent work has resulted in the first high-resolution, spectroscopic measurements of energetic charged particles on OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 496 (1997)]. Energy spectra of charged fusion products have been obtained from two spectrometers, and have been used to deduce various physical quantities in imploded capsules. In this paper the first use of 14.7 MeV deuterium–helium3 (D–3He) proton spectra for diagnosing shell areal density (ρR) and fuel ion temperature (Ti) is discussed. For thick-plastic shell capsules, shell areal densities between 20 and 70 mg/cm2 and ion temperatures between 3 and 5 keV have been determined. The spectral linewidths associated with such capsules are found to be wider than the doppler widths. This effect, the focus of future study, is the result of ρR evolution during the burn; or is the result of an extended burn region; or results from nonuniformities in the shell. For thin-glass shell capsules, the spectral linewidths are dominated by the do...

In recent Petawatt laser experiments at Lawrence Livermore National Laboratory, several hundred joules of 1 μm laser light in 0.5–5.0-ps pulses with intensities up to 3×1020 W cm−2 were incident on solid targets and produced a strongly relativistic interaction. The energy content, spectra, and angular patterns of the photon, electron, and ion radiations have all been diagnosed in a number of ways, including several novel (to laser physics) nuclear activation techniques. About 40%–50% of the laser energy is converted to broadly beamed hot electrons. Their beam centroid direction varies from shot to shot, but the resulting bremsstrahlung beam has a consistent width. Extraordinarily luminous ion beams (primarily protons) almost precisely normal to the rear of various targets are seen—up to 3×1013 protons with kTion∼several MeV representing ∼6% of the laser energy. Ion energies up to at least 55 MeV are observed. The ions appear to originate from the rear target surfaces. The edge of the ion beam is very shar...

X-ray imaging will be an important diagnostic tool for inertial confinement fusion (ICF) research at the National Ignition Facility (NIF). However, high neutron yields will make x-ray imaging much more difficult than it is at current smaller facilities. We analyze the feasibility and performance of an Ignition X-Ray Imager to be used on cryogenic DT implosions at NIF. The system is intended to provide time-integrated, broadband, moderate-energy x-ray core images of imploding ICF capsules. Highly magnified, spectrally-filtered images created using an array of pinholes placed close to the target will be projected onto a scintillator placed at the target chamber wall. A telescope will be used to relay the scintillator emission to a distant optical detector that is time-gated in order to minimize backgrounds, in particular from neutrons. The system is optimized with respect to spatial-resolution, signal-to-background and signal-to-noise ratios.

A review of recent progress on the design of a diagnostic system proposed for ignition target experiments on the National Ignition Facility (NIF) will be presented. This diagnostic package contains an extensive suite of optical, x ray, gamma ray, and neutron diagnostics that enable measurements of the performance of both direct and indirect driven NIF targets. The philosophy used in designing all of the diagnostics in the set has emphasized redundant and independent measurement of fundamental physical quantities relevant to the operation of the NIF target. A unique feature of these diagnostics is that they are being designed to be capable of operating in the high radiation, electromagnetic pulse, and debris backgrounds expected on the NIF facility. The diagnostic system proposed can be categorized into three broad areas: laser characterization, hohlraum characterization, and capsule performance diagnostics. The operating principles of a representative instrument from each class of diagnostic employed in this package will be summarized and illustrated with data obtained in recent prototype diagnostic tests.

The design and fabrication of a new diagnostic that measures the energy spectra of charged particles from targets on the Omega Upgrade are actively underway. Using seven 512×512 charge coupled devices (CCDs) and a 7.5 kG permanent magnet, this instrument will uniquely determine particle identities and measure particle energies from 1 MeV up to the maximum charged particle energies of interest for ρR measurements (10.6 MeV knock-on tritons, 12.5 MeV knock-on deuterons and 30.8 MeV tertiary protons). The resolution of the diagnostic will be better than 5%. We have tested the response of SITe back-illuminated CCDs to 1.2–13.6 MeV protons from our Cockcroft–Walton accelerator and to alpha particles from an Am241 source, and the results agree extremely well with predictions. With its high density picture elements, each CCD has 105 single-hit detectors. In the case of a low DT yield of 109 neutrons, about 100 knock-on charged particles will be detected when the spectrometer aperture is 60 cm from the implosion....

We examine various options for calibration of the National Ignition Facility neutron detectors in the energy range E

We have measured the characteristics of high energy Kα sources created with the Vulcan Petawatt laser at RAL and the JanUSP laser at Lawrence Livermore National Laboratory. High energy x-ray backlighters will be essential for radiographing high energy-density experimental science targets for NIF projects especially to probe implosions and high areal density planar samples. Hard Kα x-ray photons are created through relativistic electron plasma interactions in the target material after irradiated by short pulse high intensity lasers. For our Vulcan experiment, we employed a CsI scintillator charge coupled device (CCD) camera for imaging and a CCD camera for single photon counting. We have directly measured the 22 keV Ag Kα source size using the RAL petawatt laser and performed knife-edge measurements of a 40 keV Sm Kα source using the JanUSP laser. The measured source sizes are both ∼60 μm full width half maximum. We have also measured the Ag Kα conversion efficiencies. At laser intensities of 1×1018 W/cm2 range, the conversion efficiency at 22 keV is ∼1×10−4.

High-resolution crystal spectrometer measurements of the {ital K}{beta} spectrum of heliumlike Ar{sup 16+} covering the wavelength region from 3.34 to 3.50 A are presented and compared with detailed theoretical analyses. The measurements were made on the Princeton Large Torus tokamak and test the theoretical atomic data in the low-density limit at an electron density {ital n}{sub {ital e}}{le}2{times}10{sup 13} cm{sup {minus}3} and temperature {ital T}{sub {ital e}}=2.3 keV. Satellite transitions of the type 1{ital s}{sup 2}2{ital l}-1{ital s}2{ital l}3{ital l}{prime} and 1{ital s}{sup 2}3{ital l}-1{ital s}3{ital l}3{ital l}{prime} from lithiumlike Ar{sup 15+} and 1{ital s}{sup 2}2{ital l}2{ital l}{prime}-1{ital s}2{ital l}2{ital l}{prime}3{ital l}{prime}{prime} from berylliumlike Ar{sup 14+} are identified that are produced by either dielectronic recombination or electron-impact excitation. Good agreement between the predicted and measured intensities of the strong dielectronic satellites is found. The agreement demonstrates the utility of {ital K}{beta} spectra as a diagnostic of the electron temperature of low-density plasmas, such as those found in the Sun or magnetic fusion facilities. Poorer agreement is found for the weaker dielectronic satellite transitions, including the 1{ital s}3{ital l}3{ital l}{prime} satellites that play an important role in the analysis of high-density plasma produced in laser fusion. Their intensity is underestimated bymore » the calculations by about 50%. And it is shown that direct electron-impact excitation rates underestimate the relative intensity of the 1{ital s}{sup 2} {sup 1}{ital S}{sub 0}--1{ital s}2{ital p} {sup 3}{ital P}{sub 1} transition in heliumlike Ar{sup 16+} by a factor of 2, indicating the need for including additional excitation processes and possible blends with high-lying dielectronic satellites of the type 1{ital s}{sup 2}{ital nl}{prime}-1{ital s}3{ital lnl}{prime} with {ital n}{ge}4 in the theoretical models.« less

C.B. Yeamans, W. Cassata, J.A. Church, D.N. Fittinghoff, M. Gatu Johnson, N. Gharibyan, R. Hatarik, D.B. Sayre, H.W. Sio, R.M. Bionta, D.L. Bleuel, J.A. Caggiano, C.J. Cerjan, G.W. Copper, M.J. Eckart, E.R. Edwards, S.A. Faye, C.J. Forrest, J.A. Frenje, V.Yu. Glebov, P.F. Grant, G.P. Grim, E.P. Hartouni, H.W. Herrmann, J.D. Kilkenny, J.P. Knauer, A.J. Mackinnon, F.E. Merrill, K.J. Moody, M.J. Moran, R.D. Petrasso, T.W. Phillips, H.G. Rinderknecht, D. H. G. Schneider, S.M. Sepke, D.A. Shaughnessy, W. Stoeffl, C.A. Velsko, P. Volegov 1 Lawrence Livermore National Laboratory, Livermore, California, USA 2 General Atomics, San Diego, California, USA 3 Los Alamos National Laboratory, Los Alamos, New Mexico, USA 4 Massachusetts Institute of Technology, Cambridge, Massachusetts, USA 5 University of California, Berkeley, Berkeley, California, USA 6 University of New Mexico, Albuquerque, New Mexico, USA 7 University of Rochester, Laboratory for Laser Energetics, Rochester, New York, USA yeamans1@llnl.gov

Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries.

We performed a detailed measurement of the Kβ spectrum of He-like Al 11+ , including the dielectronic satellite spectrum excited by the KLM resonances, and comparisons with theoretical predictions from multi-configuration Dirac-Fock calculations are made. We investigated the possibility of a line overlap between the (1s 2 2s) J= 1 2 –(1s2s3p) J= 3 2 transition in Li- like Al 10+ and the (2s 2 2p 6 ) J=0 –(2s 2 2p 5 1 2 3s) J=1 transition in Ne-like Rb 27+ , situated near 1826 eV, to examine their s uitability for use in a photopumped X-ray laser scheme. In this scheme with lasing at 46 A, the Rb 27+ line pumps the Al 10+ upper lasing level. The measured difference in the line energies is 0.7 ± 0.1 eV or 380 ppm.

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

The viability of fast-ignition (FI) inertial confinement fusion hinges on the efficient transfer of laser energy to the compressed fuel via multi-MeV electrons. Preformed plasma due to the laser prepulse strongly influences ultraintense laser plasma interactions and hot electron generation in the hollow cone of an FI target. We induced a prepulse and consequent preplasma in copper cone targets and measured the energy deposition zone of the main pulse by imaging the emitted K_{alpha} radiation. Simulation of the radiation hydrodynamics of the preplasma and particle in cell modeling of the main pulse interaction agree well with the measured deposition zones and provide an insight into the energy deposition mechanism and electron distribution. It was demonstrated that a under these conditions a 100 mJ prepulse eliminates the forward going component of approximately 2-4 MeV electrons.

We report the observation of high-gain lasing in laser-heated exploding-foil Ag targets at pump irradiances \ensuremath{\ge}6\ifmmode\times\else\texttimes\fi{}${10}^{14}$ W/${\mathrm{cm}}^{2}$. The measured gain coefficients on the dominant Ne-like J=2\ensuremath{\rightarrow}1 transitions are determined to be 9.4\ifmmode\pm\else\textpm\fi{}1.5 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for (2${\mathit{p}}_{3/2}$)3${\mathit{p}}_{3/2}$\ensuremath{\rightarrow}(2${\mathit{p}}_{3/2}$)3s at 9.9365 nm and 6.${4}_{\mathrm{\ensuremath{-}}1.5}^{+2.0}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for (2${\mathit{p}}_{1/2}$)3${\mathit{p}}_{3/2}$\ensuremath{\rightarrow}(2${\mathit{p}}_{1/2}$)3s at 10.0377 nm. These are the highest gain coefficients yet observed to our knowledge for any short-wavelength laser. Gain is observed on three other Ne-like lines including a J=0\ensuremath{\rightarrow}1 transition at 8.1563 nm, the shortest wavelength yet observed to our knowledge for a Ne-like x-ray laser.

Emission from oxygen in the vacuum ultraviolet (VUV) spectral range from 140 to 260 A is evaluated as a diagnostic for optically thin plasmas. A one‐dimensional Lagrangian, two‐fluid hydrodynamic simulation code, which is self‐consistently coupled to a comprehensive atomic rate equation model is used for the analysis. This model with the associated atomic rates is described and compared to recent data from laboratory experiments.

An integrated experiment relevant to fast ignition. A Cu-doped deuterated polymer spherical shell target with an inserted hollow Au cone is imploded by a six-beam 900-J, 1-ns laser. A 10-ps, 70-J laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu Kα fluorescence by comparison with a Monte Carlo model. The electrons are estimated to carry about 15% of the laser energy. Collisional and Ohmic heating are modeled, and Ohmic effects are shown to be relatively unimportant. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is calculated in the model. Enhanced scattering by instability-induced magnetic fields is suggested. An extension of this fluor-based technique to measurement of coupling efficiency to the ignition hot spot in future larger-scale fast ignition experiments is outlined. © 2008 American Institute of Physics.

We have exposed CR-39 track recording material to a number of NOVA implosions. Radiation from the implosion passed through an array of ranging filters, which aided identification of the incident particles and their energies. The etching procedure was calibrated by including a piece of track exposed to DD protons from a small accelerator. For the same shots, we quantitatively compare the DD neutron yield with the DD proton yield determined from the track. In DT implosions, tracks produced by neutron interactions prevent observation of charged-particle tracks that are produced by the processes of knock on, secondary, or tertiary fusion.

Charge-coupled devices (CCDs) are to be utilized as charged-particle detectors for ρR and implosion symmetry diagnostics on OMEGA and NOVA. Using a large range of MeV charged particles, comprehensive studies have been performed on several back-illuminated CCDs in order to establish their utility for determining particle energy and identity (e.g., H, D, or T). Issues of signal and noise (i.e., especially from neutrons and gammas interacting with the CCDs) are also being investigated.

Summary form only given. Synthetic polycrystalline diamonds produced by chemical vapor deposition (CVD) are the leading candidates for neutron time-of-flight detectors at the National Ignition Facility (NIF). The detectors based on CVD diamonds are fast and radiation hard. In the last year, significant progress was made on the 60-beam OMEGA laser system in the development of CVD diamond detectors for inertial confinement fusion (ICF) applications. Sensitivity and time response were measured on DT and DD implosions for CVD diamonds of different sizes and at different bias voltages. Characteristics of a CVD diamond detector hardened with a fluence of 1016 neutrons/cm2 were also measured. Several different housings for the CVD diamonds were developed. The sensitivity of the CVD diamond detectors to hard X-rays, gamma rays and EMP noise was studied. Two CVD diamond detectors are now permanently installed on OMEGA and are used as neutron time-of-flight detectors for yield and ion temperature measurements in high-yield implosions. The implementation of the CVD diamond detectors on the NIF will be discussed.

Summary form only given. We have implemented a wide variety of charged-particle diagnostics on OMEGA, including magnet-based spectrometers (CPS); wedge-range-filter-based spectrometers (WFR); proton core image system (PCIS); proton radiography; and proton temporal diagnostics (PTD). Recent work has resulted in the comprehensive measurements of spatial-, temporal- and spectral- resolved energetic charged particles emanating from various capsule implosions as well as from laser-plasma interactions. Such measurements provide information about fusion yield, ion and electron temperature, fuel and shell areal density, target compression asymmetry, and other physical parameters, and have been combined with other traditional diagnostics to study various aspects of ICF implosion physics, including implosion dynamics and target performance. Many fundamental issues related to high-energy density physics are also studied, including capsule charging due to laser-plasma interactions, and stopping power in high-temperature and high-density plasmas. In addition, recent studies have demonstrated feasibility and potential of a novel magnet-recoil-spectrometer (MRS) for measuring charged particles scattered by fusion neutrons at OMEGA and the NIF.

CVD diamond detector signals from Deuterium-Tritium implosions have been simulated in order to study the feasibility of measuring areal density using the ratio of downscattered to primary neutrons during the ignition campaign at the NIF. Simulated neutron spectra for three ''typical'' DT implosions were weighted with the CVD diamond sensitivity to obtain an estimated signal at several distances from the target chamber center. The 14 MeV peak was found to have an amplitude about three orders of magnitude larger than the down-scattered signal for the three spectra. At a target to detector distance of 17 m (just outside the target bay wall) and for a 1 cm{sup 2} wafer, signals are large enough to be recorded, well above any background and electronic noise. The uncertainty in the areal density measurement comes mainly from the uncertainty in the CVD diamond energy dependent sensitivity, the accuracy of the background simulation, and the effect of the saturation of both detector and electronics after the large 14 MeV peak. Nevertheless, the results found in this study are encouraging, and the remaining sources of uncertainty should now be addressed.

Laser driven proton beams have been used to diagnose transient fields and density perturbations in laser produced plasmas. Grid deflectometry techniques have been applied to proton radiography to obtain precise measurements of proton beam angles caused by electromagnetic fields in laser produced plasmas. Application of proton radiography to laser driven implosions has demonstrated that density conditions in compressed media can be diagnosed with million electron volt protons. This data has shown that proton radiography can provide unique insight into transient electromagnetic fields in super critical density plasmas and provide a density perturbation diagnostics in compressed matter.

We are studying the feasibility of utilizing K D x-ray sources in the range of 20 to 100 keV as a backlighters for imagingvarious stages of implosions and high aerial density pl anar samples driven by the NIF laser facility. The hard x-ray K Dsources are created by relativistic electron plasm a interactions in the targ et material after a radiation by short pulse highintensity lasers. In order to understand KD source characteristics such as production efficiency and brightness as a function of laser parameters, we have performed ex periments using the 10 J, 100 fs JanUSP laser. We utilized single-photon counting spectroscopy and x-ray imaging diagnostics to characterize the KD source. We find that the KDconversion efficiency from the laser energy at 22 keV is ~3 x 10 -4 .Keywords: Short pulse laser, K D source, backlighter INTRODUCTION X-ray radiography using back lighter sources has been an important tool for diagnosing and imaging various stages oflaser induced implosion. Until now, implosion experiments at Omega utilize

In the present study, we evaluated attracticides using the Last Call CM gel as a carrier for varying concentrations of permethrin and the main compound of the female-produced pheromone [(Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Oac), here referred to as ZETA]. A toxicity trial showed that even subtle contact of P. interpunctella males with attracticidal gel containing 3-18% permethrin caused a significant reduction in mating and killed male moths within 24 h. Upwind flight studies in a wind tunnel showed that male flight response to the attracticidal gel was significantly lower when the ZETA concentration was 0.32% compared to 0.16%, but P. interpunctella males showed no signs of repellency to permethrin concentration within a range of 0-18%. Hence, we recommend the use of 18% permethrin as this will reduce the likelihood of sublethal poisoning of males. From studies in semi-realistic warehouses, we conclude that the attracticidal gel may provide efficient control when used in environments in which the moth density is still at a low level.

The efficacy of different concentrations of chlorpyrifos-methyl and cyfluthrin, singly and in combination, against stored grain beetles and their progeny was evaluated (experiment 1). A new product, Storcide, containing both insecticides was also evaluated for residual activity in preventing infestations (experiment 2). In experiment 1, the insects were exposed to treated wheat at 1 day, or 4, 13 or 27 weeks after insecticide application. In experiment 2, treated wheat stored in drums were exposed to natural, fluctuating temperatures in a storage shed located in Stillwater, Oklahoma, USA, from 14 July 1999 to 12 July 2000. Grain samples were collected from the drums at 0, 4, 12, 24, 36 or 48 weeks after treatment. The beetles used were Rhyzopertha dominica, Sitophilus oryzae and Tribolium castaneum. Adult mortality was evaluated after a 7-day exposure. Progeny production was studied after seven weeks. All treatments that contained cyfluthrin effectively controlled R. dominica. S. oryzae was not controlled by either cyfluthrin or chlorpyrifos-methyl when used alone. When cyfluthrin at 2 ppm was combined with chlorpyrifos-methyl at 0.5-6 ppm, mortality of S. oryzae adults was more than 80%, and only a few progeny were produced at the lowest concentrations. T. castaneum adults were the most difficult to kill, even at the highest combinations. However, very few progeny were produced in any treatment. Treatment with Storcide (3 ppm chlorpyrifos-methyl and 2 ppm cyfluthrin) resulted in nearly 100% adult mortality for R. dominica and S. oryzae at all time periods. No R. dominica progenies were produced and there was only one S. oryzae adult produced at 48 weeks. Storcide effectiveness against adult T. castaneum decreased through time, but no progeny was produced with this treatment. Storage at warm temperatures did not appear to affect the residual activity of the insecticides. Combining insecticides at lower rates rather than applying singly may be an effective strategy for controlling stored grain insects.

The "StorMax Insector" is a new, electronic device for detecting insects in stored grain. Naturally occurring arthropods captured using Insector prototypes were compared with those captured using Grain Guard pitfall traps (GGPT) and Storgard WB Probe II traps (WBII) in 5 small bins containing wheat. Trap location within the bin and the presence or absence of sunlight were also examined for their effect on the number of arthropods collected in the 3 trap types. The arthropods captured during the study consisted of 5 species of beetles, 2 parasitic Hymenoptera, a member of the Psocidae family, and mites. As expected, all arthropods were not captured in every bin during the 2-day sampling period in November when grain temperatures averaged 22.4°C. Total insects and mites captured were affected by trap type and trap location within the bins. Significantly more arthropods were captured in the Insector and WBII traps than in the GGPT traps. Traps located on the south sides of the bins captured more arthropods than traps located in the northern portions of the bins. Presence or absence of sunlight did not affect the total number of insects and mites collected in the traps. When comparing species, more R. dominica were captured in the WBII trap than in the other two trap types and more A. advena were captured in the Insector than in the GGPT trap. More Rhyzopertha dominica were captured in traps located in the southern part of the bin than in the northern portion. Traps in bins receiving sunlight had significantly more mites than bins with no sunlight. Just the opposite was true for A. advena. Knowing that trap type, trap location, and the presence or absence of sunlight can affect trap capture is important in interpreting species counts for developing a management strategy to control pests.