Computer simulation of electron-positron pair production by channeling radiation in amorphous converter

We consider the radiator-converter approach at 200 MeV channeled electrons (the SPARC_LAB LNF facility energies) for the case of using W crystalline radiator and W amorphous converter. A comparison of the positron production by the axial channeling radiation and the bremsstrahlung is performed. The positron stopping in the convertor is studied by means of computer simulations. It is shown that for the maximum yield of positrons the thickness of the W amorphous converter should be taken 0.35 cm in the case of using the axial channeling radiation resulting to total yield of positrons 5 10-3 e+/e- and 0.71 cm in the case of using the bremsstrahlung resulting to total yield of positrons 3.3 10-3 e+/e-

Orbital angular momentum of channeling radiation from relativistic electrons in thin Si crystal

We propose to use channeling radiation (CR) from relativistic electrons as a source of high energy twisted photons in the MeV range. We calculate numerically the orbital angular momentum (OAM) of radiation produced by electrons with the energies 155:2500 MeV for the axial and planar channeling in the thin Si crystal. We obtain that the average OAM of CR in this case is approximately 1:6h per photon with the photon energies about 1:2 MeV

Hybrid scheme of positron source at SPARC_LAB LNF facility

The hybrid scheme of the positron source for SPARC_LAB LNF facility (Frascati, Italy) is proposed. The comparison of the positron yield in a thin amorphous W converter of 0.1 mm thickness produced by bremsstrahlung, by axial 〈1 0 0〉 and planar (1 1 0) channeling radiations in a W crystal is performed for the positron energy range of 1 ÷ 3 MeV. It is shown that the radiation from 200 MeV electrons (parameters of SPARC_LAB LNF Frascati) in a 10 μm W crystal can produce positrons in the radiator of 0.1 mm thickness with the rate of 10–102 s−1 at planar channeling, of 102–103 s−1 at bremsstrahlung and of 103–104 s−1 at axial channeling

Computer simulation of electron-positron pair production by channeling radiation in amorphous converter

We consider the radiator-converter approach at 200 MeV channeled electrons (the SPARC_LAB LNF facility energies) for the case of using W crystalline radiator and W amorphous converter. A comparison of the positron production by the axial channeling radiation and the bremsstrahlung is performed. The positron stopping in the convertor is studied by means of computer simulations. It is shown that for the maximum yield of positrons the thickness of the W amorphous converter should be taken 0.35 cm in the case of using the axial channeling radiation resulting to total yield of positrons 5 10-3 e+/e- and 0.71 cm in the case of using the bremsstrahlung resulting to total yield of positrons 3.3 10-3 e+/e-

Total yield and spectra of positrons produced by channeling radiation from 0.1 - 1.6 GeV electrons

The hybrid scheme of positron source involving channeling radiation from 0.1 ÷ 1.6 GeV 〈1 0 0〉 channeled electrons in a crystalline W target (radiator) and subsequent electron-positron pair production in a downstream thick amorphous W target (converter) is investigated by means of computer simulation using the BCM-1 code. Computer simulation is carried out taking into account positron energy loss in a thick converter. Total yield of positrons as a function of the thickness of the converter as well as the energy spectrum of positrons for the chosen converter thickness are obtained. According to the calculations, the total yield of positrons produced by channeling radiation from 0.1 ÷ 1.6 GeV electrons in a 10 µm W crystal equals 0.5 ÷ 160 positrons per 103 incident electrons, respectively, with the maximum of positron energy spectrum in the energy range 1 ÷ 3 MeV. Calculations are performed within the framework of the planned experimental program at SPARC_LAB LNF

Hybrid scheme of positron source at SPARC_LAB LNF facility

The hybrid scheme of the positron source for SPARC_LAB LNF facility (Frascati, Italy) is proposed. The comparison of the positron yield in a thin amorphous W converter of 0.1 mm thickness produced by bremsstrahlung, by axial 〈1 0 0〉 and planar (1 1 0) channeling radiations in a W crystal is performed for the positron energy range of 1 ÷ 3 MeV. It is shown that the radiation from 200 MeV electrons (parameters of SPARC_LAB LNF Frascati) in a 10 μm W crystal can produce positrons in the radiator of 0.1 mm thickness with the rate of 10–102 s−1 at planar channeling, of 102–103 s−1 at bremsstrahlung and of 103–104 s−1 at axial channeling

Total yield and spectra of positrons produced by channeling radiation from 0.1 - 1.6 GeV electrons

The hybrid scheme of positron source involving channeling radiation from 0.1 ÷ 1.6 GeV 〈1 0 0〉 channeled electrons in a crystalline W target (radiator) and subsequent electron-positron pair production in a downstream thick amorphous W target (converter) is investigated by means of computer simulation using the BCM-1 code. Computer simulation is carried out taking into account positron energy loss in a thick converter. Total yield of positrons as a function of the thickness of the converter as well as the energy spectrum of positrons for the chosen converter thickness are obtained. According to the calculations, the total yield of positrons produced by channeling radiation from 0.1 ÷ 1.6 GeV electrons in a 10 µm W crystal equals 0.5 ÷ 160 positrons per 103 incident electrons, respectively, with the maximum of positron energy spectrum in the energy range 1 ÷ 3 MeV. Calculations are performed within the framework of the planned experimental program at SPARC_LAB LNF