Khatri, R. | Search NASA

NASA NTRS1990

Positronium reflection and positronium beams

Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 + or - 0.15)A for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbants on it. Two methods for producing Ps beams are described.

Weber, M.↗

NASA NTRS1983

Tracking and data acquisition system for the 1990's. Volume 7: TDAS space technology assessment

The results of the TDAS and user spacecraft technology assessment effort are provided. For each TDAS Satellite enhancement and user spacecraft element previously enumerated, the technology issues are identified and the R&D needed to resolve these issues is delineated. Subsequently, taking into account developments taking place elsewhere, the addition unique TDAS satellite module and user spacecraft element R&D efforts needed are identified, and conclusions are drawn in each case. From these conclusions, it is evident that with additional unique R&D efforts carried out for TDAS and appropriate user spacecraft elements the desired TDAS' capabilities for the 1990's can be realized and user spacecraft can be implemented that adequately interface with the projected TDAS.

Khatri, R.↗