A Method to Produce Intense Positron Beams via Electro Pair Production on Electrons

Abstract

Intense positron beams can be prepared via electro production with the reaction e − + e − → e − + e + + e − + e − due to the availability of high current electron beams. Head on collisions inside of a magnetic field of a solenoid are used to produce unpolarized/polarized positrons via e − − e + -pair production. A flux of unpolarized positrons, Npositron = 6.55 • 10 11 s −1 , has been obtained as a result of calculations for a special case of parameters with beam currents for both electron beams of Ie=10 mA and beam momenta of p beam1 =0.63 MeV/c and p beam2 =10.0 MeV/c. Intensities are an order of magnitude smaller in the case of polarized positrons due to a reduced current of one of the electron beams. Suitable cuts on momenta of the positrons allow to achieve a polarization transfer from electrons to positrons of ≥ 85% reducing, however, the intensity to 27%.