Neutron energy spectra from the laser-inducedD(d,n)3Hereaction

Abstract

Detailed neutron energy spectra were measured for the D(d,n)3He reaction induced in solid (CD2)(n) targets by irradiation with 50-fs 2 x 10(18) W/cm(2) light pulses from a 10-TW Ti:Sapphire laser. The neutrons were observed at two angles 5 degrees and 112 degrees relative to the incident laser beam. The neutron spectra at the two angles are characterized by peaks with large widths of about 700 keV full width at half maximum and a shift of 300 keV between them. Neutron energies of up to about 4 MeV were observed indicating that deuterons are accelerated up to an energy of 1 MeV in the laser produced plasma. Simulation calculations can describe qualitatively the neutron spectra by assuming isotropic deuteron acceleration and a reduction of the reaction probability by a factor of 1/3 for deuterons emitted from the front of the target. These calculations indicate in particular that it is necessary to assume deuterons moving both into and out of the front of the target in order to describe the neutron energy spectra at the two angles. The highest recorded mean neutron yield was about 10(4) neutrons per pulse. The neutron yield increases with the number of electrons emitted from the front of the target and with the intensity of the prompt gamma flash induced by the bremsstrahlung of energetic electrons.

Observation of neutrons in the interaction of high intensity laser pulses with solid targets

“…The tracks were counted with an optical microscope for the neutron yield. Assuming an isotropic neutron emission, the neutron yield is calculated to be 9 × 10 3 per shot in 4 sr, which is very close to the maximum reported neutron yield of 10 4 per shot [8] under similar experimental conditions as in the present case. The generation of neutrons from the CD 2 target was also registered in the bubble detector kept at 20 mm distance from the target.…”

“…Pretzler et al [7] have observed more than 140 neutrons per laser shot with a laser of 200 mJ pulse energy and 160 fs time duration. Similar type of experiment was also performed by Hilscher et al [8]. They observed a maximum of 10 4 neutrons in a single laser shot.…”

D-D nuclear fusion processes induced in polyethylene foams by TW Laser-generated plasma

“…The evaluation concerning the number of nuclear events is in good agreement with the values obtained in previous experiments and with literature data [12][13][14][15][16][17][18][19][20][21][22]. Fig.…”

Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source

“…To simplify the calculations, we assume: 1) the incident beam of ions exhibits azimuthal symmetry about the axis perpendicular to the secondary target, 2) a straight-line ion trajectory, and 3) neutron production is dominated by D(d,n) 3 He fusion events. Assumption number one is justified by the symmetry of the laser pulse incident upon the uniform target, and from this assumption we may further deduce that the emitted neutron spectrum will similarly exhibit azimuthal symmetry.…”