Observation of Two Phases of Neutron Emission in a Low Energy Plasma Focus

Yap, S. L.; Wong, C. S.; Choi, P.; Dumitrescu, C.; Moo, S.P.

doi:10.1143/jjap.44.8125

Cited by 35 publications

(19 citation statements)

References 20 publications

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“…This particular setup offers exceptionally low jitter (on the order of ns) and sensitivity to single particles [30]. Having many of these independent detectors opens up a tremendous array of possible measurements including: time-of-flight (TOF) measurements, angular distribution of neutrons (the yield of DPFs is known to be anisotropic [27]), temporal distribution of neutron production (as in [23,27]).…”

Section: Radiation Diagnosticsmentioning

confidence: 99%

“…Running DPFs with an admixture of deuterium and a heavy noble gas has been tested by several research groups, with DPF energies ranging from 100's of Joules to 100's of kJ. The results have varied significantly with some groups reporting enhancements under optimal conditions in excess of 30× and other groups reporting reduced yields compared to pure deuterium [23][24][25][26][27][28]. Our system was the first used to test such piston gases in a 100 J-class DPF.…”

Section: Noble Gas Dopingmentioning

confidence: 99%

“…The advantages of such small devices, in the 100 J range or below, found in their low cost, compactness, and flexible operating modes, are attractive, as is the short pulse length described above. These advantages are counterbalanced by the relatively low neutron yield per pulse, and techniques have been explored, such as the use of current transformers [22] and piston gases [23][24][25][26][27][28], to mitigate the yield issue. The device we describe in this paper permits explorations of the physics of these smaller-scale DPFs.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

et al. 2018

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Recently, there has been intense interest in small dense plasma focus (DPF) devices for use as pulsed neutron and X-ray sources. Although DPFs have been studied for decades and scaling laws for neutron yield versus system discharge current and energy have been established (Milanese, M. et al., Eur. Phys. J. D 2003, 27, 77-81), there are notable deviations at low energies due to contributions from both thermonuclear and beam-target interactions (Schmidt, A. et al., Phys. Rev. Lett. 2012, 109, 1-4). For low energy DPFs (100 s of Joules), other empirical scaling laws have been found (Bures, B.L. et al., Phys. Plasmas 2012, 112702, 1-9). Although theoretical mechanisms to explain this change have been proposed, the cause of this reduced efficiency is not well understood. A new apparatus with advanced diagnostic capabilities allows us to probe this regime, including variants in which a piston gas is employed. Several complementary diagnostics of the pinch dynamics and resulting X-ray neutron production are employed to understand the underlying mechanisms involved. This apparatus is unique in its employment of a 50 fs laser-based shadowgraphy system that possesses unprecedented spatio-temporal resolution.

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Section: Radiation Diagnosticsmentioning

confidence: 99%

Section: Noble Gas Dopingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

et al. 2018

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“…However, Bernstein suggested that the experimental observed neutron emission was inconsistent with the thermonuclear assumption [9]. Abundance of results later also showed non-thermonuclear origin in the neutron emission [10][11][12]. A research group even reported that the presence of anisotropy in the neutron emission could not be interpreted solely by any single proposed model [13].…”

Section: Introductionmentioning

confidence: 99%

Parametric Optimisation of Plasma Focus Devices for Neutron Production

et al. 2015

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A large number of experimental investigations have been carried out on plasma focus devices especially at low energy level of several kJ or over 100 kJ. There are few machines operating in the middle energy range of 10-50 kJ, where the neutron yield typically in the order of 10 8 -10 9 per shot. This paper reviews the optimisation process of two different plasma focus devices (12 kJ) by applying the Lee model code. The neutron yield (Y n ) versus pressure (P) curve for several configurations of the two plasma focus provided insight of geometrical optimisation. Measured discharge current is fitted as the first step of modelling to correctly simulate the plasma dynamics. Subsequently the code is used to simulate the neutron yield of the two plasma focus devices based on beam target mechanism. Good agreement between the computed results of neutron yield versus pressure and the measured yield versus pressure is found up to the pressure where highest neutron yield is obtained. Computed highest neutron yield for most of the configuration typically differ by a factor\2.

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“…The plasma produced is of very high temperature (1-3 keV) and high density (>10 19 Particles/cm 3 ) [1]. The device is particularly interesting due to its special characteristic as intense pulsed sources of X-rays, ions, electrons and neutrons (deuterium filling) [2][3][4][5]. The early research was concentrated on the neutron emission [6,7] and yet in recent years, there is abrupt growth of researcher's interest in utilized plasma focus for its application in surface modification [8], ion implantation [9] and thin film deposition [10].…”

Section: Introductionmentioning

confidence: 99%

Diagnostics of ion beam generated from a Mather type plasma focus device

Lim¹,

Ngoi²,

Wong³

et al. 2014

AIP Conference Proceedings

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Diagnostics of ion beam emission from a 3 kJ Mather-type plasma focus device have been performed for deuterium discharge at low pressure regime. Deuterium plasma focus was found to be optimum at pressure of 0.2 mbar. The energy spectrum and total number of ions per shot from the pulsed ion beam are determined by using biased ion collectors, Faraday cup, and solid state nuclear track detector CR-39. Average energy of the ion beam obtained is about 60 keV. Total number of the ions has been determined to be in the order of 10 11 per shot. Solid state nuclear track detectors (SSNTD) CR39 are employed to measure the particles at all angular direction from end on (0˚) to side on (90˚). Particle tracks are registered by SSNTD at 30˚ to 90˚, except the one at the end-on 0 ˚.

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Observation of Two Phases of Neutron Emission in a Low Energy Plasma Focus

Cited by 35 publications

References 20 publications

Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

Parametric Optimisation of Plasma Focus Devices for Neutron Production

Diagnostics of ion beam generated from a Mather type plasma focus device

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