An improved source of spin-polarized electrons based on spin exchange in optically pumped rubidium vapor

被引：1

作者：

Ahrendsen, K. J. ^{[1
]}

Trantham, K. W. ^{[2
]}

Tupa, D. ^{[3
]}

Gay, T. J. ^{[4
]}

机构：

[1] Univ Nebraska, Jorgensen Hall, Lincoln, NE 68588 USA

[2] Univ Nebraska Kearney, Phys Dept, Kearney, NE 68849 USA

[3] Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA

[4] Univ Nebraska Lincoln, Phys Dept, Lincoln, NE 68588 USA

来源：

REVIEW OF SCIENTIFIC INSTRUMENTS | 2023年 / 94卷 / 08期

基金：

美国国家科学基金会;

关键词：

AFFINITY GAAS;

D O I：

10.1063/5.0149691

中图分类号：

TH7 [仪器、仪表];

学科分类号：

0804 ; 080401 ; 081102 ;

摘要：

We have improved a polarized electron source in which unpolarized electrons undergo collisions with a mixture of buffer gas molecules and optically spin-polarized Rb atoms. With a nitrogen buffer gas, the source reliably provides spin polarization between 15% and 25% with beam currents >4 mu A. Vacuum pump upgrades mitigate problems caused by denatured diffusion pump oil, leading to longer run times. A new differential pumping scheme allows the use of higher buffer gas pressures up to 800 mTorr. With a new optics layout, the Rb polarization is continuously monitored by a probe laser and improved pump laser power provides more constant high polarization. We have implemented an einzel lens to better control the energy of the electrons delivered to the target chamber and to preferentially select electron populations of higher polarization. The source is designed for studies of biologically relevant chiral molecule samples, which can poison photoemissionbased GaAs polarized electron sources at very low partial pressures. It operates adjacent to a target chamber that rises to pressures as high as 10(-4) Torr and has been implemented in a first experiment with chiral cysteine targets.

引用

页数：13