Résumé du preprint Irfu-12-54
| Irfu-12-54 |
|---|
| Muonium Emission into Vacuum from Mesoporous Thin Films at Cryogenic Temperatures |
| A. Antognini, P. Crivelli, T. Prokscha, K. S. Khaw, B. Barbiellini, L. Liszkay, K. Kirch, K. Kwuida, E. Morenzoni, F. M. Piegsa, Z. Salman, and A. Suter |
| We report on Muonium (Mu) emission into vacuum following Mu+ implantation in mesoporous thin SiO2 films. We obtain a yield of Mu into vacuum of (38+-4)% at 250 K temperature and (20+-4)% at 100 K for 5 keV Mu+ implantation energy. From the implantation energy dependence of the Mu vacuum yield we determine the Mu diffusion constants in these films: Dsup{250K}sub{Mu} = (1.6 +- 0.1) x 10-4 cm2/s and Dsup{100K}sub{Mu} = (4.2+-0.5)x10-5 cm2/s. Describing the diffusion process as quantum mechanical tunneling from pore-to-pore, we reproduce the measured temperature dependence of approximately Tsup{3/2} of the diffusion constant. We extract a potential barrier of (-0.3+-0.1) eV which is consistent with our computed Mu work-function in SiO2 of [-0.3,-0.9] eV. The high Mu vacuum yield even at low temperatures represents an important step towards next generation Mu spectroscopy experiments. |