A group of scientists from the Moscow Institute of Physics and Technology, JIHT RAS and FI RAS has developed a compact ultra-intense neutron source, the efficiency of which is comparable to the operation of a huge particle accelerator with room dimensions of the facility itself. Neutron sources are in great demand in various studies, but the capabilities of existing accelerators are no longer sufficient for new experiments. Russian technology solves this problem, and its construction and operation is much cheaper than the operation of the accelerator. laser “PHELIX” with a power of 1015 W and directed its beam at a target made of polymer foam. Cellulose triacetate material was used for it, the density of which is only 2 mg/cm3. The first 1 nanosecond laser pulse ionizes the target atoms to create a plasma cloud. The next pulse lasts a picosecond and accelerates the electrons in the plasma, transferring hundreds of megaelectronvolts of energy to them.
Electrons are decelerated by a thin plate of gold, which allows their energy to be converted into gamma quanta. It is a kind of photon with a very short wavelength, about ten thousandth of a nanometer. It turns out a stream of gamma radiation, in which trillions of high-energy gamma quanta fly in a given direction. When they reach a nearby tantalum foil, the metal nuclei absorb gamma rays, a photonuclear reaction occurs, and neutrons are produced. During one iteration, the source generates up to 60 billion neutrons, the efficiency of laser energy has reached 0.05%.
It is reported that in the course of work on the installation, Russian scientists set a record for the efficiency of converting laser energy into gamma rays with energies above 10 MeV – of the order of
Source — MIPT
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