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Copious positron production by femto-second laser via absorption enhancement in a microstructured surface target
摘要： Laser-driven positron production is expected to provide a non-radioactive, controllable, radiation tunable positron source in laboratories. We propose a novel approach of positron production by using a femto-second laser irradiating a microstructured surface target combined with a high-Z converter. By numerical simulations, it is shown that both the temperature and the maximum kinetic energy of electrons can be greatly enhanced by using a microstructured surface target instead of a planar target. When these energetic electrons shoot into a high Z converter, copious positrons are produced via Bethe-Heitler mechanism. With a laser (wavelength λ = 1 μm) with duration ~36 fs, intensity ~5.5 × 1020 W/cm2 and energy ~6 Joule, ~109 positrons can be obtained.
关键词： femto-second laser,positron production,microstructured surface target,Bethe-Heitler mechanism
更新于2025-09-23 15:19:57
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Simulation of channeling radiation and positron production in thick diamond structures and a tungsten single crystal
摘要： The process of de-channeling for electrons of energy 2 GeV channeled in the (110) plane of silicon and tungsten single crystals has been studied. The dynamics of the particle distribution density has been investigated in dependence on both the energy and scattering distribution of the initial electron beam. The influence of de-channeling on the spectral intensity of channeling radiation has been investigated by solving the Fokker-Planck equation. A non-conventional positron source is described based on the generation of radiation by relativistic electrons channeled along different crystallographic planes or axes of W, Si, Ge and C (diamond) single crystals and the subsequent conversion of the radiation into e+e?-pairs in an amorphous tungsten target. The simulation of channeling radiation and its dependence on the incidence angle into the crystal has been carried out by means of our Mathematica codes. The conversion of the radiation into e+e?-pairs and the energy distribution of positrons have been simulated using the GEANT4 package.
关键词： Tungsten,Channeling radiation,Silicon,Positron production
更新于2025-09-19 17:15:36