Abstract A new GaAs(100) spin polarized electron source with an optical polarimeter, which is employed in the field of polarized electron and gas atom collision, is presented in detail. The apparatus is passive-magnetic-shielded by a box and a cylinder made of nickel--iron--molybdenum soft magnetic alloy without Helmholtz coil arrangement. And a uniformly distributed residual magnetic field of less than 5×10-7 T is obtained near the collision area. The spin polarized electron beam is transmitted and focused onto collision point from photocathode by a set of electron optics with more than 25% transmission 95cm distance through an 1mm diameter aperture. Construction and operation of the apparatus, such as vacuum and magnetic shielding system, photocathode, laser optics, electron optics and polarimeter are discussed. The polarization of the spin polarized electron beam is determined to be 30.8$\pm$3.5% measured with a He optical polarimeter.
Received: 17 November 2006
Revised: 22 August 2006
Accepted manuscript online:
Fund: Project supported by the National
Natural Science Foundation of China (Grant No 10134010).
Cite this article:
Ding Hai-Bing(丁海兵), Pang Wen-Ning(庞文宁), Liu Yi-Bao(刘义保), and Shang Ren-Cheng(尚仁成) Passive magnetic shielded spin polarized electron source with optical electron polarimeter 2007 Chinese Physics 16 51
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