%0 Journal Article %1 a0111 %A Wunnik, J. N. M Van %A Geerlings, J. J. C. %A Granneman, E. H. A. %A Los, J. %D 1983 %J Surface Science %K astronomy ibex imported physics science space thesis %N 1 %P 17--33 %T The scattering of hydrogen from a cesiated tungsten surface %U http://www.sciencedirect.com/science/article/B6TVX-46T38XS-18N/2/d87762e5c22d08c8942bc8174b321d28 %V 131 %X The reflection of protons from a partially cesiated tungsten surface is studied in the energy domain between 100 and 2000 eV and in the angular domain between 75degree sign and 85degree sign with respect to the surface normal. The study is performed by measuring the angular and energy distribution of the scattered negative ions. The reflection can take place along two paths. One path is reflection from the cesium surface layer, the other one is reflection from the tungsten substrate. A dependence of the final charge state on the path is observed. It is inferred that this phenomenon is due to incomplete neutralization of the protons scattered from the cesium layer. The energy loss of the reflected ions cannot be accounted for by using only the binary collision model. Also the electronic stopping of the atoms by the metal electrons is shown to be an important energy loss mechanism. Total conversion measurements of H+ to H- combined with the measurements of the negatively charged fraction of the scattered particles, as reported in the proceeding paper, yield the particle reflection coefficient as a function of the angle of incidence. These reflection coefficients show that for angles of incidence less than 75degree sign already more than 50% of the particles do not reflect from the surface. Total conversion efficiency measurements with H- ions as primary ions show that the influence of the initial charge state on the total conversion is very small.

@article{a0111, abstract = {The reflection of protons from a partially cesiated tungsten surface is studied in the energy domain between 100 and 2000 eV and in the angular domain between 75[degree sign] and 85[degree sign] with respect to the surface normal. The study is performed by measuring the angular and energy distribution of the scattered negative ions. The reflection can take place along two paths. One path is reflection from the cesium surface layer, the other one is reflection from the tungsten substrate. A dependence of the final charge state on the path is observed. It is inferred that this phenomenon is due to incomplete neutralization of the protons scattered from the cesium layer. The energy loss of the reflected ions cannot be accounted for by using only the binary collision model. Also the electronic stopping of the atoms by the metal electrons is shown to be an important energy loss mechanism. Total conversion measurements of H+ to H- combined with the measurements of the negatively charged fraction of the scattered particles, as reported in the proceeding paper, yield the particle reflection coefficient as a function of the angle of incidence. These reflection coefficients show that for angles of incidence less than 75[degree sign] already more than 50% of the particles do not reflect from the surface. Total conversion efficiency measurements with H- ions as primary ions show that the influence of the initial charge state on the total conversion is very small.}, added-at = {2007-07-24T21:36:23.000+0200}, author = {Wunnik, J. N. M Van and Geerlings, J. J. C. and Granneman, E. H. A. and Los, J.}, biburl = {https://www.bibsonomy.org/bibtex/27be0f3e68ddf5089966537fa058b9054/essential.beatfinger}, description = {ScienceDirect - Surface Science : The scattering of hydrogen from a cesiated tungsten surface}, interhash = {c5c2dbb73f4321a67a5147246253eb59}, intrahash = {7be0f3e68ddf5089966537fa058b9054}, journal = {Surface Science}, keywords = {astronomy ibex imported physics science space thesis}, month = {#aug#}, number = 1, pages = {17--33}, timestamp = {2007-07-24T21:36:23.000+0200}, title = {The scattering of hydrogen from a cesiated tungsten surface}, url = {http://www.sciencedirect.com/science/article/B6TVX-46T38XS-18N/2/d87762e5c22d08c8942bc8174b321d28}, volume = 131, year = 1983 }