Palm top plasma focus device as a portable pulsed neutron source

Abstract

Development of a palm top plasma focus device generating (5.2 ± 0.8) × 10(4) neutrons∕pulse into 4π steradians with a pulse width of 15 ± 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 μF capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of -15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 μF, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of (3)He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.

High yield (⩾108/pulse) DD neutron generator based on a compact, transportable and low energy plasma focus device

“…The outer diameter and the effective length (exposed to plasma) of the quartz sleeve were chosen to be 25 mm and 46 mm, respectively. The insulator dimensions were decided on based on the experience gained from developing other PF devices here [19][20][21][22][23][24]32] and comparison with other devices operating worldwide in the same energy range.…”

“…In view of its wide-ranging applications, the PF device has been extensively developed and characterized in different laboratories across the world at wide operating energy ranging from 0.1 J to MJ [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] since its inception in the early 1960s independently by J W Mather [13] and N V Filippov [14]. Even after more than six decades of intensive research and development, it is still being developed worldwide for various applications as mentioned above.…”

Development of a portable pulsed fast ⩾106 neutron generator based on a flexible miniature plasma focus tube

“…Numerous portable pulsed neutron generators of neutron yield ∼10 6 neutrons/pulse or less based on the plasma focus device have been developed worldwide in different laboratories [25][26][27][28][29][30][31][32]. For example, Silva et al [25] reported a maximum neutron yield of (1.06 ± 0.13) × 10 6 neutrons/shot at 9 mbar filling pressure of D 2 gas in a very small and fast plasma focus device operated at ∼400 J.…”

A 109 neutrons/pulse transportable pulsed D-D neutron source based on flexible head plasma focus unit

“…All the above mentioned devices are stationary either due to short cables or bulkiness of the CB and the PF head, which restrict the movement and orientation of the neutron source. Several PF devices [29][30][31][32][33] have been developed by us and are operated for different applications. A compact 11.5 kJ PF device 33 was developed in which the CB (40 µF, 24 kV) is discharged to the PF head through a SG switch using flat plate transmission lines.…”