[Triumf-seminars] TRIUMF Accelerator Seminar today at 11:00

[TRIUMF Seminars]

Date/Time: Fri 2023-07-21 at 11:00

Location:  ISAC II Conf Room   

Speaker:   Haruka Maruyama (Dept. of applied physics, Tokyo A&M University)

Title:     Spin-dependent metastable He (23S) atom scattering from ferromagnetic surfaces: Potential application to polarized-gas production

Abstract: ABSTRACT:

Spin-dependent metastable He (23S) atom scattering from ferromagnetic surfaces: Potential application to polarized-gas production

A spin-polarized triplet metastable helium (He*) beam has been used as a probe for surface magnetism, but changes in the spin state during scattering from a surface remain unclear. In the present study, we explored this issue by constructing an apparatus that allows us to direct a spin-polarized He* beam to a surface and measure the spin polarization of He* scattered from the surface. Magnetic hexapoles were used for both the beam polarization and the spin analysis. The results of the spin-dependent He* scattering experiments on clean Fe3O4(100), H-terminated Fe3O4(100), benzene-adsorbed Fe3O4(100), and nonmagnetic Cu(100) surfaces indicated that, although the spin direction of He* was mostly preserved during scattering from these surfaces, spin-flop scattering of surviving He* occurred with a probability up to approximately 0.1. Our results showed that the survival probability was higher when the spins of He* and the Fe3O4(100) film were parallel, which can be understood based on the lower He* resonance ionization rate for this spin orientation. Based on our findings, we estimate that a nonpolarized He* gas becomes 10% spin-polarized after a single collision with a clean Fe3O4(100) surface.

Refreshments available



______________________________

General TRIUMF seminar information available at http://www.triumf.ca/home/upcoming-events/about-seminars-lectures