Position, Energy, and Transit Time Distributions ina Hemispherical Deflector Analyzer with PositionSensitive Detector

[摘要] Practical analytic equations, for the ideal field, and numerical results from SIMION simulations, for the fringing field, are presented for the exit radiusrπand transit timetπof electrons in a hemispherical deflector analyzer (HDA) over a wide range of analyzer parameters. Results are presented for a typically dimensioned HDA with mean radiusR-=101.6 mm and interradial separationΔR=R2-R1=58.4 mm able to accommodate a 40 mm diameter position sensitive detector (PSD). Results for three different entry positionsR0are compared:R0=R-(the conventional central entry) and two displaced (paracentric) entries:R0=82.55 mm andR0=116 mm. Exit spreadsΔrπ,Δtπand base energy resolutionΔEBare computed for HDA pass energiesE0=10, 100, 500, and 1000 eV, entry aperture sizesΔr0≤1.5 mm, entry angular spreads|αmax|≤5°, and an electron beam with relative energy spreadδE/E0≤0.4%. Overall, under realistic conditions,bothparacentric entries demonstratenear idealfield behavior and clear superiority over the conventional entry atR0=R-. TheR0=82.55 mm entry has betterabsoluteenergy and time spread resolutions, while theR0=116 mm has betterrelativeenergy resolutions, both offering attractive alternatives for time-of-flight and coincidence applications where both energy and timing resolutions are important.

[学科分类] 光谱学