On the design of capillary and effusive gas dosers for surface science

摘要: We present a theoretical analysis of flux distributions and enhancement factors for dosers two types: capillary arrays effusive sources. Our introduces an important distinction between the per solid angle unit area sample, encompasses array diameters both smaller larger than sample. find, contrary to earlier assertions, that single source gives unacceptably large gradients unless it is located so far from sample its factor negligible. Arrays small number sources near edge, however, are competitive with doser‐to‐sample distances comparable radius, readily adapted or unusually shaped samples. Capillary outperform at all distances, particularly effective when placed very close If uniformity concern, doser should generally be least 20% Additional effects due trapping by cold surfaces in chamber multiple collisions emitted molecules discussed qualitatively.