Scientists propose spin filter method for polarized electron acceleration in plasma wakefields

Scientists propose spin filter method for polarized electron acceleration in plasma wakefields
Fig.1 A typical laser wakefiled acceleration structure and field distributions. Credit: SIOM

High-energy polarized electron beams are widely used in high-energy physics (linear colliders), nuclear physics and material science. However, such polarized electron beams are usually generated on conventional accelerators that are typically very large and expensive.

Recently, a research team from Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (CAS) proposed a spin filter method for wakefiled acceleration of highly polarized electron beams. The concept promises an all optical approach to provide polarized electron sources in a cost-efficient and compact way. The study was published in Physical Review Applied.

A high-intensity laser or particle beam propagating into a pre-polarized target will drive a bubble wakefield to accelerate the electrons. During this process, precess in the bubble field.

By means of three-dimensional particle-in-cell simulations including spin dynamics, scientists found that the showed a unique dependence on the azimuthal angle in phase space for transversally polarized target. In particular, in a certain region of the phase space, the spin precession was significantly suppressed.

Therefore, they proposed an X-shaped filter to filter out the electrons of low polarization and let pass the highly polarized section. This simple method efficiently purified the polarization from about 35% to >80%.

Scientists propose spin filter method for polarized electron acceleration in plasma wakefields
Fig.2 The sketch for the spin filter. Credit: SIOM

The spin filter method was further benchmarked by simulations and the robustness was discussed in detail.

This idea relaxes the parameter limitations for obtaining highly polarized via wakefield acceleration and motivates the development of laser-driven polarized electron sources for potential applications such as future electron-positron colliders.


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More information: Yitong Wu et al. Spin Filter for Polarized Electron Acceleration in Plasma Wakefields, Physical Review Applied (2020). DOI: 10.1103/PhysRevApplied.13.044064
Citation: Scientists propose spin filter method for polarized electron acceleration in plasma wakefields (2020, May 26) retrieved 10 August 2020 from https://phys.org/news/2020-05-scientists-filter-method-polarized-electron.html
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