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

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 resultmore » 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.« less
Authors:
 [1] ;  [2] ;  [2] ; ;  [3] ; ;  [1] ;  [2] ; ; ; ; ;  [4] ;  [2] ;  [1]
  1. Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 16627 Prague 6 (Czech Republic)
  2. (Czech Republic)
  3. Institute of Physics, ASCR, Na Slovance 2, 182 21 Prague 8 (Czech Republic)
  4. Institute of Plasma Physics, ASCR, Za Slovankou 3, 182 00 Prague 8 (Czech Republic)
Publication Date:
OSTI Identifier:
22493767
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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