Development of affordable technologies for large X-ray simulators

Ware, K.; Gullickson, R.L.; Pierre, Jeremy; Schneider, R.; Vitkovitsky, I. M.

doi:10.1109/27.901205

Cited by 10 publications

(4 citation statements)

References 18 publications

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“…To satisfy the temporal fidelity requirements, the vacuum diodes require a power pulse of less than 100 ns. This feature accounts for the need to develop very high-power simulators to deliver this vacuum power pulse, in a manner discussed in [1]. With this very high e-beam power, the anode surface quickly forms a plasma and emit ions.…”

Section: The Challengementioning

confidence: 97%

“…Cold radiation (1-15 keV range) is obtained using high-current self-pinching plasma implosions of sufficiently high electron temperature to generate strong K-line emission. The evolution of pulse power technology and drivers to generate the hot and cold radiation has been described in [1]. This paper describes the evolution of the Defense Threat Reduction Agency's (DTRA's) high-voltage electron-beam diodes, propagation of electron beams, and plasma implosion loads, as radiation sources for the nuclear weapon effects (NWE) community.…”

Section: Introductionmentioning

confidence: 99%

“…T HE spectrum of the pulsed radiation for simulation of the nuclear weapon effects ranges from kiloelectronvolt (keV) to megaelectronvolt (MeV) and the yields range from low tens to hundreds of kilojoules, corresponding to driver output powers of the order of 1-10 TW [1], [2]. Historically, pulsed power generators and radiation loads provided "hot" radiation, gradually evolving into systems with lower photon spectra and higher fluences, as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Evolving approaches to pulsed X-ray sources

Ware

Bell

Gullickson

et al. 2002

IEEE Trans. Plasma Sci.

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Production of pulsed radiation in the kiloelectronvolt-to-megaelectronvolt range for simulation of nuclear weapon effects uses pulsed power generators with output powers of the order of 1-10 TW. Radiation in the high-energy (gamma and hot) part of the spectrum has been obtained using intense electron beams incident on solid targets of high-material to produce radiation with continuous bremsstrahlung spectra. Magnetically driven plasma implosions have been used to obtain radiation in the keV (cold) part of the spectrum, characterized by strong line emission. The efficiency of radiation, required for Defense Threat Reduction Agency tasks, relative to stored pulser energy, is only a few percent. Radiation yields in the range of 5 to 60 keV are especially low, regardless of which method of radiation production is used. This article discusses the evolving approaches to producing hot and cold X-rays, to seeking more efficient radiators of cold and warm X-rays, and to improving the spectral and temporal characteristics of the hot radiation. Integration of the pulsed power drivers, with innovative radiator load concepts, is utilized to expand the cold and hot X-ray test capability, to increase the warm X-ray yields, as well as to reduce capital costs of the test facilities.Index Terms-Plasma implosions, pulsed power, X-rays.

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Section: The Challengementioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolving approaches to pulsed X-ray sources

Ware

Bell

Gullickson

et al. 2002

IEEE Trans. Plasma Sci.

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“…This broad research area will advance considerably if we find a way to efficiently produce x rays with Z pinch loads imploded by slower-rising current pulses, 200 -300 ns or longer. Interest in longer current pulses is stimulated both by the restrictions on the voltage applied to the front end of the driver, V / I m = (here, I m is the peak current and is its rise time), and by the substantial cost reductions offered by slower pulsed power [5]. Larger initial load radii, R 0 , have been thought to be needed for matching the loads to slower drivers, as well as for accelerating the imploded loads to higher velocity, , necessary to generate harder K-shell and/or free-bound [6] radiation.…”

mentioning

confidence: 99%

Efficient Radiation Production in Long Implosions of Structured Gas-PuffZPinch Loads from Large Initial Radius

et al. 2005

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We have proposed and demonstrated successfully a new approach for generating high-yield K-shell radiation with large-diameter gas-puff Z pinches. The novel load design consists of an outer region plasma that carries the current and couples energy from the driver, an inner region plasma that stabilizes the implosion, and a high-density center jet plasma that radiates. It increased the Ar K-shell yield at 3.46 MA in 200 ns implosions from 12 cm initial diameter by a factor of 2, to 21 kJ, matching the yields obtained earlier on the same accelerator with 100 ns implosions. A new "pusher-stabilizer-radiator" physical model is advanced to explain this result.

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Bremsstrahlung target optimization for reflex triodes

et al. 2008

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The anode (tantalum) foil thickness in a reflex triode was varied from 2.5 to 250μm to maximize the dose from bremsstrahlung produced by a 1MV, 1MA, 100ns electron beam. Experiments and computer simulations show that the dose is maximized for a foil thickness of about 25μm, 1∕18th of the electron range computed from the continuous slowing down approximation. For foils thicker than optimum, self-absorption in the foil attenuates 10–100keV photons, reducing the dose. For foils thinner than optimum, the dose decreases as a result of electron migration to large radius. A simple formula that predicts the optimum thickness as a function of the beam current and voltage is derived that should be applicable to a large range of experimental parameters.

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Development of affordable technologies for large X-ray simulators

Cited by 10 publications

References 18 publications

Evolving approaches to pulsed X-ray sources

Evolving approaches to pulsed X-ray sources

Efficient Radiation Production in Long Implosions of Structured Gas-PuffZPinch Loads from Large Initial Radius

Bremsstrahlung target optimization for reflex triodes

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