Progress on the Rubidium Spin Filter

We report the most recent advances in the development of a novel source of spin-polarized electrons: the Rb Spin Filter [1]. Polarized electron beams are produced by driving an unpolarized beam of thermionically emitted electrons through a target cell containing a mixture of spin-polarized Rb vapor at 1/3 mTorr and N₂ at 400 mTorr. The apparatus has been updated to incorporate a differential pumping region, as well as a target chamber for our continuing studies of asymmetries in the interaction between longitudinally spin-polarized electrons and chiral molecules[2]. Our improved system can regularly obtain electron polarizations between 15% and 25% at currents of up to 1 µA. We have collected preliminary data investigating the chiral asymmetry in secondary electron emission coefficients from both enantiomers of cysteine.

[1]M. Pirbhai et al., Phys. Rev. A 88, 060701(R) (2013).

[2]J. M. Dreiling et al., Phys. Rev. Lett. 116, 093201 (2016).