scholarly journals The importance of EBIT data for Z-pinch plasma diagnostics

2008 ◽  
Vol 86 (1) ◽  
pp. 267-276 ◽  
Author(s):  
A S Safronova ◽  
V L Kantsyrev ◽  
P Neill ◽  
U I Safronova ◽  
D A Fedin ◽  
...  

The results from the last six years of X-ray spectroscopy and spectropolarimetry of high-energy density Z-pinch plasmas complemented by experiments with the electron beam ion trap (EBIT) at the Lawrence Livermore National Laboratory (LLNL) are presented. The two topics discussed are the development of M-shell X-ray W spectroscopic diagnostics and K-shell Ti spectropolarimetry of Z-pinch plasmas. The main focus is on radiation from a specific load configuration called an “X-pinch”. In this work the study of X-pinches with tungsten wires combined with wires from other, lower Z materials is reported. Utilizing data produced with the LLNL EBIT at different energies of the electron beam the theoretical prediction of line positions and intensity of M-shell W spectra were tested and calibrated. Polarization-sensitive X-pinch experiments at the University of Nevada, Reno (UNR) provide experimental evidence for the existence of strong electron beams in Ti and Mo X-pinch plasmas and motivate the development of X-ray spectropolarimetry of Z-pinch plasmas. This diagnostic is based on the measurement of spectra recorded simultaneously by two spectrometers with different sensitivity to the linear polarization of the observed lines and compared with theoretical models of polarization-dependent spectra. Polarization-dependent K-shell spectra from Ti X-pinches are presented and compared with model calculations and with spectra generated by a quasi-Maxwellian electron beam at the LLNL EBIT-II electron beam ion trap.PACS Nos.: 32.30.Rj, 52.58.Lq, 52.70.La

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. L. Shaw ◽  
M. A. Romo-Gonzalez ◽  
N. Lemos ◽  
P. M. King ◽  
G. Bruhaug ◽  
...  

AbstractLaser-plasma accelerators (LPAs) driven by picosecond-scale, kilojoule-class lasers can generate particle beams and x-ray sources that could be utilized in experiments driven by multi-kilojoule, high-energy-density science (HEDS) drivers such as the OMEGA laser at the Laboratory for Laser Energetics (LLE) or the National Ignition Facility at Lawrence Livermore National Laboratory. This paper reports on the development of the first LPA driven by a short-pulse, kilojoule-class laser (OMEGA EP) connected to a multi-kilojoule HEDS driver (OMEGA). In experiments, electron beams were produced with electron energies greater than 200 MeV, divergences as low as 32 mrad, charge greater than 700 nC, and conversion efficiencies from laser energy to electron energy up to 11%. The electron beam charge scales with both the normalized vector potential and plasma density. These electron beams show promise as a method to generate MeV-class radiography sources and improved-flux broadband x-ray sources at HEDS drivers.


2003 ◽  
Vol 74 (3) ◽  
pp. 1947-1950 ◽  
Author(s):  
A. S. Shlyaptseva ◽  
D. A. Fedin ◽  
S. M. Hamasha ◽  
S. B. Hansen ◽  
C. Harris ◽  
...  

2018 ◽  
Vol 116 (37) ◽  
pp. 18233-18238 ◽  
Author(s):  
Bruce A. Remington ◽  
Hye-Sook Park ◽  
Daniel T. Casey ◽  
Robert M. Cavallo ◽  
Daniel S. Clark ◽  
...  

The Rayleigh–Taylor (RT) instability occurs at an interface between two fluids of differing density during an acceleration. These instabilities can occur in very diverse settings, from inertial confinement fusion (ICF) implosions over spatial scales of∼10−3−10−1cm (10–1,000 μm) to supernova explosions at spatial scales of∼1012cm and larger. We describe experiments and techniques for reducing (“stabilizing”) RT growth in high-energy density (HED) settings on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. Three unique regimes of stabilization are described: (i) at an ablation front, (ii) behind a radiative shock, and (iii) due to material strength. For comparison, we also show results from nonstabilized “classical” RT instability evolution in HED regimes on the NIF. Examples from experiments on the NIF in each regime are given. These phenomena also occur in several astrophysical scenarios and planetary science [Drake R (2005)Plasma Phys Controlled Fusion47:B419–B440; Dahl TW, Stevenson DJ (2010)Earth Planet Sci Lett295:177–186].


2007 ◽  
Vol 22 (23) ◽  
pp. 4317-4323
Author(s):  
J. K. LIM ◽  
J. B. ROSENZWEIG ◽  
S. G. ANDERSON ◽  
A. M. TREMAINE

A recent development of the photo-cathode injector technology has greatly enhanced the beam quality necessary for the creation of high density/high brightness electron beam sources. In the Thomson backscattering x-ray experiment, there is an immense need for under 20 micron electron beam spot at the interaction point with a high-intensity laser in order to produce a large x-ray flux. This has been demonstrated successfully at PLEIADES in Lawrence Livermore National Laboratory. For this Thomson backscattering experiment, we employed an asymmetric triplet, high remanence permanent-magnet quads to produce smaller electron beams. Utilizing highly efficient optical transition radiation (OTR) beam spot imaging technique and varying electron focal spot sizes enabled a quadrupole scan at the interaction zone. Comparisons between Twiss parameters obtained upstream to those parameter values deduced from PMQ scan will be presented in this report.


2008 ◽  
Vol 86 (1) ◽  
pp. 191-198 ◽  
Author(s):  
M F Gu

As part of the laboratory astrophysics program at the electron beam ion traps of the Lawrence Livermore National Laboratory, L-shell X-ray emission of Fe and Ni ions have been studied extensively in the past decade. In this paper, we review these experimental efforts in line identification and wavelength surveys of Fe and Ni L-shell emission and resonance contributions to their intensities. PACS Nos.: 52.72.+v, 52.20.–j, 34.80.Kw


2011 ◽  
Vol 89 (5) ◽  
pp. 599-608 ◽  
Author(s):  
G.C. Osborne ◽  
A.S. Safronova ◽  
V.L. Kantsyrev ◽  
U.I. Safronova ◽  
P. Beiersdorfer ◽  
...  

Spectral tungsten data taken on an electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory are analyzed between 3 and 8 Å for electron beam energies between 2.5 and 4.1 keV. The advantage of using charge state balancing with the experimental EBIT spectra for the identification of lines is employed and discussed. Theoretical Hebrew University Lawrence Livermore Atomic Code (HULLAC) modeling is then benchmarked against the experimental EBIT results. In particular, Co-, Ni-, Zn-, Cu-, Ga-, and Ge-like transitions were modeled independently using HULLAC to aid in charge state balancing. This model is then compared with Z-pinch plasma data collected on Zebra, the 1.6 MA pulse power generator located in the Nevada Terawatt Facility at the University of Nevada, Reno. The model is used to calculate charge balance and average ionization levels of these experimental plasma results, with particular focus on planar tungsten arrays.


2004 ◽  
Vol 82 (11) ◽  
pp. 931-942 ◽  
Author(s):  
P Neill ◽  
C Harris ◽  
A S Safronova ◽  
S Hamasha ◽  
S Hansen ◽  
...  

M-shell spectra of W ions have been produced at the Lawrence Livermore National Laboratory EBIT-II electron beam ion trap-II at different energies of the electron beam. A survey has been performed at 2.4, 2.8, and 3.6 keV, and for steps in energy of 100 eV over the 3.9–4.6 keV energy range. The analysis of 11 W spectra has shown the presence of a wide variety of ionization stages from Se-like to Cr-like W; the appearances of these ionization stages correlate well with the energy of their production. The present paper focuses on the identification of 63 experimental features of W ions in a spectral region from 5 to 6 Å (1 Å = 10–10 m) using calculations with inclusion of all ionization stages matching this spectral region. The majority of lines in all spectra have been identified and assigned to the 4f → 3d and 4d → 3p transitions. This is the first work that lists a comprehensive identification of so many resolved spectral features of X-ray M-shell transitions in W ions recorded in such detail in the laboratory. PACS Nos.: 52.58.Lq,32.30.Rj,52.70.La


2008 ◽  
Vol 86 (1) ◽  
pp. 231-240 ◽  
Author(s):  
F S Porter ◽  
B R Beck ◽  
P Beiersdorfer ◽  
K R Boyce ◽  
G V Brown ◽  
...  

NASA’s X-ray spectrometer (XRS) microcalorimeter instrument has been operating at the electron beam ion trap (EBIT) facility at Lawrence Livermore National Laboratory since July of 2000. The spectrometer is currently undergoing its third major upgrade to become an easy to use and extremely high-performance instrument for a broad range of EBIT experiments. The spectrometer itself is broadband, capable of simultaneously operating from 0.1 to 12 keV and has been operated at up to 100 keV by manipulating its operating conditions. The spectral resolution closely follows the spaceflight version of the XRS, beginning at 10 eV FWHM at 6 keV in 2000, upgraded to 5.5 eV in 2003, and will hopefully be ~3.8 eV in the fall of 2007. Here we review the operating principles of this unique instrument, the extraordinary science that has been performed at EBIT over the last six years, and prospects for future upgrades. Specifically, we discuss upgrades to cover the high-energy band (to at least 100 keV) with a high quantum efficiency detector and prospects for using a new superconducting detector to reach 0.8 eV resolution at 1 keV and 2 eV at 6 keV with high counting rates. PACS Nos.: 52.25.Os, 52.70.La, 95.85.Nv, 32.30.Rj, 07.85.Fv, 78.70.En


2004 ◽  
Vol 22 (3) ◽  
pp. 221-244 ◽  
Author(s):  
F.V. HARTEMANN ◽  
A.M. TREMAINE ◽  
S.G. ANDERSON ◽  
C.P.J. BARTY ◽  
S.M. BETTS ◽  
...  

The Compton scattering of a terawatt-class, femtosecond laser pulse by a high-brightness, relativistic electron beam has been demonstrated as a viable approach toward compact, tunable sources of bright, femtosecond, hard X-ray flashes. The main focus of this article is a detailed description of such a novel X-ray source, namely the PLEIADES (Picosecond Laser–Electron Inter-Action for the Dynamical Evaluation of Structures) facility at Lawrence Livermore National Laboratory. PLEIADES has produced first light at 70 keV, thus enabling critical applications, such as advanced backlighting for the National Ignition Facility andin situtime-resolved studies of high-Zmaterials. To date, the electron beam has been focused down to σx= σy= 27 μm rms, at 57 MeV, with 266 pC of charge, a relative energy spread of 0.2%, a normalized horizontal emittance of 3.5 mm·mrad, a normalized vertical emittance of 11 mm·mrad, and a duration of 3 ps rms. The compressed laser pulse energy at focus is 480 mJ, the pulse duration 54 fs Intensity Full Width at Half-Maximum (IFWHM), and the 1/e2radius 36 μm. Initial X rays produced by head-on collisions between the laser and electron beams at a repetition rate of 10 Hz were captured with a cooled CCD using a CsI scintillator; the peak photon energy was approximately 78 keV, and the observed angular distribution was found to agree very well with three-dimensional codes. The current X-ray dose is 3 × 106photons per pulse, and the inferred peak brightness exceeds 1015photons/(mm2× mrad2× s × 0.1% bandwidth). Spectral measurements using calibrated foils of variable thickness are consistent with theory. Measurements of the X-ray dose as a function of the delay between the laser and electron beams show a 24-ps full width at half maximum (FWHM) window, as predicted by theory, in contrast with a measured timing jitter of 1.2 ps, which contributes to the stability of the source. In addition,K-edge radiographs of a Ta foil obtained at different electron beam energies clearly demonstrate the γ2-tunability of the source and show very good agreement with the theoretical divergence-angle dependence of the X-ray spectrum. Finally, electron bunch shortening experiments using velocity compression have also been performed and durations as short as 300 fs rms have been observed using coherent transition radiation; the corresponding inferred peak X-ray flux approaches 1019photons/s.


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