Generation of polarized positron beams via collisions of ultrarelativistic electron beams

A scheme is proposed for generating a polarized positron beam via multiphoton Breit-Wheeler process during the collision of a 10-GeV-level, 20-pC seeding electron beam with a second 10-GeV, multi-nC driving electron beam. The high-density driving beam with the length and transverse size less than 1...

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Bibliographic Details
Main Authors: Huai-Hang Song, Wei-Min Wang, Yu-Tong Li
Format: Article
Language:English
Published: American Physical Society 2021-09-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.3.033245
Description
Summary:A scheme is proposed for generating a polarized positron beam via multiphoton Breit-Wheeler process during the collision of a 10-GeV-level, 20-pC seeding electron beam with a second 10-GeV, multi-nC driving electron beam. The high-density driving beam with the length and transverse size less than 1 μm provides a strong self-generated field. The field experienced by the seeding beam can be unipolar by incorporating a proper impact parameter, which is crucial to realizing the positron polarization. We employ semiclassical Monte Carlo simulations to calculate the spin- and polarization-resolved photon emission and electron-positron pair production in the locally constant-field approximation. The simulation results show that a highly polarized positron beam with a polarization degree above 40% can be generated in several femtoseconds, which is robust against the beam parameters. The positron polarization degree can be further increased to 60% provided the seeding beam is initially polarized.
ISSN:2643-1564