An x-ray spectral measurement system for nanosecond plasmas

Johnson, D. J.

doi:10.1063/1.1686585

Cited by 44 publications

(12 citation statements)

References 7 publications

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“…Figure 1 illustrates five response functions, used in this article, that define several superposed regions of x-ray sensitivity (or, so-called, ''spectral cuts'') between 100 eV and 5 keV. Similarly shaped responses have been reported for a variety of detectors combined as simple arrays with upstream filters and in differing spectral ranges [40][41][42][43][44][45]. Improvements to this basic design for soft x rays have been achieved by inserting additional x-ray components, upstream of the detectors [46][47][48].…”

Section: Introductionmentioning

confidence: 94%

Characterization and error analysis of anN×Nunfolding procedure applied to filtered, photoelectric x-ray detector arrays. I. Formulation and testing

Fehl

Chandler

Stygar

et al. 2010

Phys. Rev. ST Accel. Beams

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An algorithm for spectral reconstructions (unfolds) and spectrally integrated flux estimates from data obtained by a five-channel, filtered x-ray-detector array (XRD) is described in detail and characterized. This diagnostic is a broad-channel spectrometer, used primarily to measure time-dependent soft x-ray flux emitted by z-pinch plasmas at the Z pulsed-power accelerator (Sandia National Laboratories, Albuquerque, New Mexico, USA), and serves as both a plasma probe and a gauge of accelerator performance. The unfold method, suitable for online analysis, arises naturally from general assumptions about the x-ray source and spectral properties of the channel responses; a priori constraints control the illposed nature of the inversion. The unfolded spectrum is not assumed to be Planckian. This study is divided into two consecutive papers. This paper considers three major issues: (a) Formulation of the unfold method.-The mathematical background, assumptions, and procedures leading to the algorithm are described: the spectral reconstruction S unfold ðE; tÞ-five histogram x-ray bins j over the x-ray interval, 137 E 2300 eV at each time step t-depends on the shape and overlap of the calibrated channel responses and on the maximum electrical power delivered to the plasma. The x-ray flux F unfold is estimated as R S unfold ðE; tÞdE. (b) Validation with simulations.-Tests of the unfold algorithm with known static and time-varying spectra are described. These spectra included-but were not limited to-Planckian spectra S bb ðE; TÞ (25 T 250 eV), from which noise-free channel data were simulated and unfolded. For Planckian simulations with 125 T 250 eV and typical responses, the binwise unfold values S j and the corresponding binwise averages hS bb i j agreed to $20%, except where S bb ( maxfS bb g. Occasionally, unfold values S j & 0 (artifacts) were encountered. The algorithm recovered * 90% of the x-ray flux over the wider range, 75 T 250 eV. For lower T, the test and unfolded spectra increasingly diverged as larger fractions of S bb ðE; TÞ fell below the detection threshold ($ 137 eV) of the diagnostic. (c) Comparison with other analyses and diagnostics.-The results of the histogram algorithm are compared with other analyses, including a test with data acquired by the DANTE filtered-XRD array at the NOVA laser facility. Overall, the histogram algorithm is found to be most useful for x-ray flux estimates, as opposed to spectral details. The following companion paper [D. L. Fehl et al., Phys. Rev. ST Accel. Beams 13, 120403 (2010)] considers (a) uncertainties in S unfold and F unfold induced by both data noise and calibrational errors in the response functions; and (b) generalization of the algorithm to arbitrary spectra. These techniques apply to other diagnostics with analogous channel responses and supported by unfold algorithms of invertible matrix form.

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Section: Introductionmentioning

confidence: 94%

Characterization and error analysis of anN×Nunfolding procedure applied to filtered, photoelectric x-ray detector arrays. I. Formulation and testing

Fehl

Chandler

Stygar

et al. 2010

Phys. Rev. ST Accel. Beams

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“…1. A simple method using a set of filters along with PINdiode detectors was conducted [26] to analyze the energy spectrum of the X-rays. The filters included Cu (15 µm show transmission curves of the filters and the detectors' responses, respectively.…”

Section: Experimental Set Upmentioning

confidence: 99%

“…The study also includes an analysis of the energy spectrum of multi-radiation of X-rays together with its contribution during the radiation process, using a four-channel diode X-ray spectrometer (DXS) and suitable X-ray filters. [26]…”

Section: Introductionmentioning

confidence: 99%

Energy spectrum of multi-radiation of X-rays in a low energy Mather-type plasma focus device

Aghamir¹,

Behbahani²

2014

Chinese Phys. B

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“…An important part of the recent experimental studies on x-ray and particle emission from PF is oriented in interesting applications such as contact microscopy, x-ray and electron beam lithography, generation of soft x-ray spectral lines of highly charged heavy metal ions, metal coating by ion sputtering, surface modification and deposition of thin films, x-ray backlighting, radiography of biological and mechanical objects, and micromachining. [8][9][10][11][12][13][14][15][16] The x-ray emission from a given PF device depends in a rather complicated way upon the design and operating parameters such as the operating voltage and bank energy, [17][18][19] the circuit inductance, 20 the working gas nature and pressure, 12,16,21 the anode dimensions, shape, and material, [22][23][24][25][26][27] the material and configuration of insulator sleeve, 28 and preionization assisted breakdown. 29,30 It is reported that when the plasma focus is operated in hydrogen with small admixture of inert gases, the x-ray emission is strongly enhanced.…”

Section: Introductionmentioning

confidence: 99%

Effect of insulator sleeve material on the x-ray emission from a plasma focus device

et al. 2010

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The effect of insulator sleeve material on x-ray emission from a 2.3 kJ Mather type plasma focus device operated in argon-hydrogen mixture is investigated. The time and space resolved x-ray emission characteristics are studied by using a three channel p-i-n diode x-ray spectrometer and a multipinhole camera. The x-ray emission depends on the volumetric ratio of argon-hydrogen mixture as well as the filling pressure and the highest x-ray emission is observed for a volumetric ratio 40% Ar to 60% H 2 at 2.5 mbar filling pressure. The fused silica insulator sleeve produces the highest x-ray emission whereas nonceramic insulator sleeves such as nylon, Perspex, or Teflon does not produce focus or x-rays. The pinhole images of the x-ray emitting zones reveal that the contribution of the Cu K␣ line is weak and plasma x-rays are intense. The highest plasma electron temperature is estimated to be 3.3 and 3.6 keV for Pyrex glass and fused silica insulator sleeves, respectively. It is speculated that the higher surface resistivity of fused silica is responsible for enhanced x-ray emission and plasma electron temperature.

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An x-ray spectral measurement system for nanosecond plasmas

Cited by 44 publications

References 7 publications

Characterization and error analysis of anN×Nunfolding procedure applied to filtered, photoelectric x-ray detector arrays. I. Formulation and testing

Characterization and error analysis of anN×Nunfolding procedure applied to filtered, photoelectric x-ray detector arrays. I. Formulation and testing

Energy spectrum of multi-radiation of X-rays in a low energy Mather-type plasma focus device

Effect of insulator sleeve material on the x-ray emission from a plasma focus device

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