Efficient neutron production from sub-nanosecond laser pulse accelerating deuterons on target front side

Journal Article · Tue Sep 15 00:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4931460· OSTI ID:22493767

Klir, D. ^[1]; Krasa, J.; Velyhan, A. ^[2]; Cikhardt, J.; Rezac, K. ^[1]; Dudzak, R.; Krousky, E.; Pfeifer, M.; Skala, J.; Ullschmied, J. ^[3]; Sila, O. ^[1]

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1. Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague 6 (Czech Republic)
2. Institute of Physics, ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic)
3. Institute of Plasma Physics, ASCR, Za Slovankou 3, 182 00 Prague 8 (Czech Republic)

Neutron-producing experiments have been carried out on the Prague Asterix Laser System. At the fundamental wavelength of 1.315 μm, the laser pulse of a 600 J energy and 300 ps duration was focused on a thick deuterated-polyethylene target. Neutron yields reached (4.1 ± 0.8) × 10{sup 8} at the peak intensity of ≈3 × 10{sup 16 }W/cm{sup 2}. A more detailed analysis of neutron time-of-flight signals showed that a significant fraction of neutron yields was produced both by the {sup 2}H(d,n){sup 3}He reaction and by other neutron-producing reactions. Neutron energies together with delayed neutron and gamma emission showed that MeV deuterons escaped from a laser-produced plasma and interacted ≈50 ns later with a borosilicate blast-shield glass. In order to increase DD neutron yields and to characterize deuteron beams via nuclear reactions, a secondary deuterated polyethylene target was used in a pitcher-catcher scheme at the target front side. In this experimental arrangement, the neutron yield reached (2.0 ± 0.5) × 10{sup 9} with the peak neutron fluence of (2.5 ± 0.5) × 10{sup 8 }n/sr. From the neutron yield, it was calculated that the secondary target was bombarded by 2 × 10{sup 14} deuterons in the 0.5–2.0 MeV energy range. The neutron yield of 2 × 10{sup 9} at the laser energy of 600 J implied the production efficiency of 3 × 10{sup 6 }n/J. A very important result is that the efficient neutron production was achieved with the low contrast, sub-nanosecond laser pulse of the intensity of 10{sup 16 }W/cm{sup 2}. The latter parameters can be achieved in a rep-rate mode more easily than ultra-high intensities and contrasts.

• OSTI ID: 22493767
• Journal Information: Physics of Plasmas, Vol. 22, Issue 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BOROSILICATE GLASS
DELAYED NEUTRONS
DEUTERON BEAMS
DEUTERON REACTIONS
DEUTERONS
EXPERIMENT RESULTS
GAMMA RADIATION
HELIUM 3
LASER-PRODUCED PLASMA
LASERS
MEV RANGE
NEUTRON FLUENCE
POLYETHYLENES
PULSES
TIME-OF-FLIGHT METHOD