A Macroscopic Study of the Neutron, Gamma- and X-Ray Emissivity in the Frascati Plasma Focus

Brzosko, J.S.; Robouch, B. V.; Klobukowska, J.

doi:10.13182/fst87-a25052

Cited by 16 publications

(5 citation statements)

References 29 publications

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“…The fundamental design of the fast miniature plasma focus device 'FMPF-1' (2.4 µF, 27 nH, T /4 ∼ 400 ns, 12-15 kV, 170-270 J) [33] is based on the observation that the drive parameter (speed factor) I 0 /ap 1/2 (where I 0 is the peak discharge current, a is the anode radius and p is the deuterium filling gas pressure for the maximum neutron yield) [37] and the energy density parameter E/V p (where E is the energy stored in the capacitor bank and V p is the plasma volume) [5] are practically constant (77 ± 7 kA cm −1 mbar 1/2 and (1-10) × 10 10 Jm −3 , respectively) in the few kilojoules [25][26][27] to megajoules [28,38] energy range, neutron optimized plasma foci.…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…The coaxial electrode assembly of the plasma focus head consists of a 15 mm long, composite tapered anode of stainless steel (SS), with an initial diameter of 12 mm, tapering down to 7 mm at the tip over the last 5 mm of the anode and a squirrel cage cathode, consisting of six, 6 mm diameter SS rods, uniformly spaced on a coaxial circle of 30 mm diameter. Since, hollow anode structures have been reported to produce higher neutron yields with better stability of the pinched plasma, in comparison with solid anodes [38][39][40], a 12 mm deep cavity of 6 mm diameter has been bored at the center of the anode. An insulator sleeve of Pyrex glass with a breakdown length of 5 mm was placed between the anode and the cathode.…”

Section: Experimental Arrangementmentioning

confidence: 99%

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Experimental study of neutron emission characteristics in a compact sub-kilojoule range miniature plasma focus device

Verma

Rawat

Lee

et al. 2009

Plasma Phys. Control. Fusion

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In order to gain insight into the possible neutron production mechanism in sub-kilojoule miniature plasma foci, the anisotropy in neutron and hard x-ray emissions from a newly developed fast miniature plasma focus device (2.4 µF, 27 nH, T /4 ∼ 400 ns, 12-15 kV, 170-270 J, total mass ∼25 kg) is investigated. The system produces an average neutron yield of (1.2±0.2)×10 6 neutrons/shot into 4π sr at ∼80 kA peak discharge current and 5.5 mbar deuterium operation, as measured by a 3 He proportional counter. Relative measurements of radiation yields, to gauge the emission anisotropy, have been performed using a pair of fast scintillator-photomultiplier detectors placed along the axial (0 • ) and radial (90 • ) directions. The average forward to radial neutron yield anisotropy is found to be 1.3 ± 0.2. The average peak neutron energy for the axial and radial directions is estimated to be (2.9 ± 0.3) MeV and (2.6 ± 0.1) MeV, respectively. The observed higher fluence along the anode axis and the coincidence between occurrence of maximum neutron yield and anisotropy at 5.5 mbar deuterium filling gas pressure, suggest that the neutron production mechanism in the subkilojoule range miniature plasma focus device FMPF-1 may be predominantly beam-target in nature.

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Section: Experimental Arrangementmentioning

confidence: 99%

Section: Experimental Arrangementmentioning

confidence: 99%

Experimental study of neutron emission characteristics in a compact sub-kilojoule range miniature plasma focus device

Verma

Rawat

Lee

et al. 2009

Plasma Phys. Control. Fusion

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show abstract

“…The coaxial electrode assembly of the plasma focus tube, which is adapted from the best results of FMPF-1 [7], consists of a 15 mm long composite anode of stainless steel (SS) having a tapered length of 5 mm from the top with an initial diameter of 12 mm, tapering to 7 mm at the tip and a squirrel cage cathode, consisting of six, 6 mm diameter SS rods, uniformly spaced on a circle of 30 mm diameter, concentric with the anode axis [20]. Since hollow anode structures have been reported to produce higher neutron outputs, in comparison with solid anodes [21][22][23] a 10 mm deep cavity of 5 mm diameter has been bored at the centre of the anode. An insulator sleeve of Pyrex glass having a wall thickness of 2 mm and a breakdown length of 5 mm was placed between the anode and the cathode.…”

Section: Methodsmentioning

confidence: 99%

Realization of enhancement in time averaged neutron yield by using repetitive miniature plasma focus device as pulsed neutron source

Verma¹,

Rawat²,

Lee³

et al. 2009

J. Phys. D: Appl. Phys.

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In this paper, we report the experimental demonstration of enhancement in time averaged neutron yield by an order of magnitude, using the fast miniature plasma focus FMPF-2 in repetitive mode. The newly developed FMPF-2 device (2.4 µF, 56 nH, 13.8 kV, T/4 ∼ 575 ns) operates up to 10 Hz in the quasi-continuous mode. Using pure deuterium as the fuelling gas, the time averaged neutron output of (6.2 ± 4) × 105 neutrons s−1 at 1 Hz operation was enhanced to (6.5 ± 0.6) × 106 neutrons s−1 at 10 Hz operation for the burst length of 30 consecutive shots. The stability in neutron emission in repetitive mode of operation from 1 to 10 Hz has also been investigated and the evidenced consequential issues of critical concern that are responsible for degradation in neutron yield during the repetitive mode of operation have been highlighted.

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“…Over the past few decades, most of the experimental studies on PF devices were in medium (2-10 kJ) [6][7][8][9], large 10-500 kJ [10][11][12][13] and mega-joule [14,15] PF facilities and not many results have been reported on the sub-kilojoule range, low energy PF devices. In fact, the PF community was somewhat skeptical about reproducibility and efficient pinching in the sub-kilojoule range of PF devices.…”

Section: Introductionmentioning

confidence: 99%

Compact sub-kilojoule range fast miniature plasma focus as portable neutron source

Verma

Roshan

Malik

et al. 2008

Plasma Sources Sci. Technol.

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As a first step toward the development of a compact and portable, quasi-continuous pulsed neutron source, we have demonstrated a 'fast miniature plasma focus (PF) device' as a compact nuclear fusion apparatus. The system operates with deuterium gas and produces an average neutron yield (Y 90 • ) of (1 ± 0.27) × 10 4 neutrons/shot at ∼70 kA peak discharge current. In the range of 1.5-4 mbar, a distinct and sharp dip in the current derivative signal indicates a strong pinching action with subsequent emission of hard x-rays followed by a neutron pulse. The yield and the time history of the neutrons were measured by both active and passive detection techniques (such as a 3 He proportional counter, NE102A plastic scintillator and CR-39 SSNTDs). The overall dimensions of the apparatus, which includes a capacitor bank, sparkgap switch and the focus chamber, are 0.2 m × 0.2 m × 0.5 m and the total mass of the system is ∼25 kg. The scope of this paper is to evaluate/demonstrate the potential of such a fast miniature PF device as a compact and portable fusion apparatus producing neutrons while operating at relatively low energy.

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A Macroscopic Study of the Neutron, Gamma- and X-Ray Emissivity in the Frascati Plasma Focus

Cited by 16 publications

References 29 publications

Experimental study of neutron emission characteristics in a compact sub-kilojoule range miniature plasma focus device

Experimental study of neutron emission characteristics in a compact sub-kilojoule range miniature plasma focus device

Realization of enhancement in time averaged neutron yield by using repetitive miniature plasma focus device as pulsed neutron source

Compact sub-kilojoule range fast miniature plasma focus as portable neutron source

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