Description

The importance of polarized and unpolarized positron beams for the Hadronic Physics science explored at the Continuous Electron Beam Accelerator Facility (CEBAF) of Jefferson Lab (JLab) motivates a sustained physics and accelerator R&D effort. The high duty cycle and polarization of the required positron beams put very stringent constraints on the positron source technology. The PEPPo (Polarized Electrons for Polarized Positrons) method demonstrated at the CEBAF injector proved the most appropriate technique for delivering beams of interest. Its implementation at JLab is the purpose of the Ce+BAF Initiative which aims at the development of a novel positron injector at CEBAF. It involves a high intensity (I>1 mA) polarized electron source (P>80%) with a 100-300 MeV energy, a high-power positron production target, a magnetic and Radio Frequency (RF) collection system and further magnetic chicane and accelerating structure to select positron momentum and produce a beam suitable for CEBAF acceleration. As a first step in this endeavor, the construction of a 10 MeV/c pre-injector is considered to support Ce+BAF R&D and enable a low-energy physics program.
This project consists in the conception and design of a low-energy positron beam line for physics measurements. It involves the creation of a secondary beam from its generation to its delivery on a target for physics or in a specific characterization line. Positron polarimetry is particularly one of the major developments to achieve.

Skills required

Knowledge in accelerator physics Strong knowledge in physics Knowledge in informatics and simulations Confirmed level in english language

Bibliography

J. Grames et al. IPAC2023 (2023) MOPL152; arXiv:2309.15581
S. Habet, Thèse de Doctorat, Université Paris-Saclay (2023) 2023UPASP170
S. Habet, A. Ushakov, E. Voutier, arXiv:2401.04484
E. Voutier, EPJ Web Conf. 303 (2024) 06003; arXiv:2401.16223

Keywords

Positron production, Beam optics, Beam dynamics, Polarimetry