Intense, directed neutron beams from a laser-driven neutron source at PHELIX

Abstract

Laser-driven neutrons are generated by the conversion of laser-accelerated ions via nuclear reactions inside a converter material. We present results from an experimental campaign at the PHELIX laser at GSI in Darmstadt where protons and deuterons were accelerated from thin deuterated plastic foils with thicknesses in the μm and sub-μm range. The neutrons were generated inside a sandwich-type beryllium converter, leading to reproducible neutron numbers around 1011 neutrons per shot. The angular distribution was measured with a high level of detail using up to 30 bubble detectors simultaneously. It shows a laser forward directed component of up to 1.42 × 1010 neutrons per steradian, corresponding to a dose of 43 mrem scaled to a distance of 1 m from the converter.

A miniature thermal neutron source using high power lasers

“…The incident fast neutron flux can be significantly enhanced by increasing the energy and number of incident ions on the converter. In fact, fast neutron fluxes of the order of 10 10 n/sr (orders of magnitude higher than produced in the current experiment) have been recently demonstrated [22,23], which can be further improved by taking advantage of the ongoing developments in laser technology coupled to advanced laser-driven ion acceleration mechanisms [31][32][33][34]. In particular, the upcoming high repetition rate (∼ 10 Hz) diode pumped [35], Petawatt-class lasers, such as HAPLS[36], offers the possibility of producing such intense bursts of neutrons at high repetition rates (10 Hz and beyond).…”

“…By bombarding secondary targets (e.g. blocks of lithium, Beryllium or deuterated plastic) using the ions, nuclear reactions are triggered, producing high fluxes of beamed neutrons with multi-MeV energies [18][19][20][21][22][23].…”

Lézeres neutronforrás fejlesztése • Development of a Laser-based Neutron Source

“…Az akkor és azóta végrehajtott hasonló kísérleteket szinte kizárólag több J, esetenként több 10 J energiájú, viszonylag hosszú, szubpikoszekundumos lézerimpulzusokkal végezték el (3. ábra) (Kar et al, 2016;Higginson et al, 2011;Maksimchuk et al, 2013;Roth et al, 2002). Az eddigi egy lövéssel elért neutronszám csúcsértékét a német GSI intézet PHELIX-lézerével (160 J, 600 fs) érték el 2018-ban (Kleinschmidt et al, 2018). A térszögegységre eső mért neutronszám 1,42 ± 0,25 × 10 10 /str volt, amely a forrástól 1 m távolságban megfelel 430 ± 50 μSv dózisnak.…”

Low energy accelerator-driven neutron facilities—A prospect for a brighter future for research with neutrons

“…particle accelerators, laser-driven acceleration of protons or deuterons [17] might offer a prospective for further cost reduction in the future.…”