Efficient generation of fusion neutrons from cryogenically cooled heteronuclear clusters irradiated by intense femtosecond lasers

Abstract

We present experimental studies on the conversion efficiency of fusion neutrons generated from Coulomb explosion of cryogenically cooled heteronuclear deuterated methane (CD4) clusters irradiated by intense femtosecond laser pulses. A stronger nonlinear relationship between the cluster size and the stagnation temperature for CD4 clusters than that for monoatomic or diatomic clusters is revealed, resulting in marked increases in the average kinetic energy of deuterons and the fusion neutron yield. Finally, a significantly enhanced conversion efficiency of 1.9 × 107 neutrons/J of incident laser energy is achieved by lowering the stagnation temperature to 217 K under a backing pressure of 80 bars.

Acceleration of 60 MeV proton beams in the commissioning experiment of SULF-10 PW laser

“…Today, nearly one hundred 100 TW systems are operating, with about 20 systems at the PW level existing or under construction [ 3 ] , pushing laser intensities to go beyond the relativistic threshold (about 10 18 W/cm 2 for laser wavelengths of ~μm). Unprecedented extreme physical conditions can be created in laboratories [ 4 – 6 ] , which strongly motivate the studies of laser-driven particle acceleration [ 4 , 7 , 8 ] , X/gamma ray radiation [ 9 – 11 ] , laboratory astrophysics [ 6 , 12 , 13 ] , laser-driven nuclear physics [ 14 ] , etc. On the other hand, the rising interest in strong-field quantum electrodynamics calls for lasers with even higher intensities (10 22 –10 23 W/cm 2 ).…”

“…Unprecedented extreme physical conditions can be created in laboratories [4][5][6] , which strongly motivate the studies of laser-driven particle acceleration [4,7,8] , X/gamma ray radiation [9][10][11] , laboratory astrophysics [6,12,13] , laser-driven nuclear physics [14] , etc. On the other hand, the rising interest in strong-field quantum electrodynamics calls for lasers with even higher intensities (10 22 -10 23 W/cm 2 ).…”

Overrun phenomenon and neutron yield in Coulomb explosion of deuterated alkane clusters driven by intense laser field

“…[13,14] Liu's group has obtained a conversion efficiency of 1.9 × 10 7 neutrons/J from the Coulomb explosions (CE) of large-size (CD 4 ) N cluster jets under the irradiation of intense femtosecond laser pulses. [15][16][17][18] This conversion efficiency is dramatically increased as compared with that using the similar sized homonuclear (D 2 ) N clusters. The researchers also measured that the final average kinetic energy of protons from the CE of ethane (C 2 H 6 ) N clusters is higher than that from the same sized methane (CH 4 ) N clusters.…”

“…In the experiments of laser-cluster interaction, clusters are generally produced by an adiabatic expansion of gases through a conical nozzle into vacuum. [5,[12][13][14][15][16][17][18][19] At normal temperature, only methane CH 4 , ethane C 2 H 6 and propane C 3 H 8 are in gaseous state. [20] However, there is no investigation on the interaction of propane (C 3 H 8 ) N clusters with intense laser pulses, which is attributed to the fact that the physical properties of propane gas are unstable and the corresponding clusters are not easy to form.…”

Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

“…In previous theoretical and experimental works regarding laser-cluster-fusion experiments, it has been proposed that the disassembly time of the resulting fusion plasma would be on the order of r 0 / v [1,2,12,17,19,27], where r 0 is the initial radius of the plasma [approximately equal to the radius of the incident intense (>10 16 W/cm 2 ) laser beam on the cluster jet] and v is the mean speed of the energetic deuterium ions within the fusion plasma. In this article, we examine the validity of this assumption by applying a more realistic fusion yield model, one in which the number density of energetic deuterium ions drops as the cylindrical fusion plasma expands in time.…”