The calibration, transmission, and resolution of a 127° cylindrical electrostatic velocity selector are examined as functions of the individual voltages applied to the electrodes. The calibration and resolution calculated using first order orbit theory are compared with numerically determined orbits obtained using the exact electrostatic field within the selector. The calibration and transmission are found to be strongly dependent on the electrode potentials while the resolution is insensitive to these parameters. The experimentally determined resolution is in good agreement with the calculations. Variation of the transmission with the individually applied voltage is shown to be the result of vertical focusing.
REFERENCES
1.
2.
3.
4.
5.
6.
R. L.
Champion
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8.
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10.
P. R. Bevington, Data Reduction and Error Analysis for the Physical Sciences (McGraw‐Hill, New York, 1969).
11.
Top and bottom plate boundary conditions actually introduce a small correction to For the geometry of this instrument as calculated from Eq. (11); this is in contrast to calculated from Eq. (1). Use of this latter equation for computation of as a function of ΔV results in no significant changes in Eq. (10).
12.
When vertical focusing plays a role any angular divergence of the beam in the z direction leads to poorer base resolution by an increment equal to In this experiment focusing elements preceding the selector make this correction several times smaller than the radial effects considered here. Compare Ref. 8 and
H. Z.
Sar‐El
, Rev. Sci. Instrum.
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© 1971 The American Institute of Physics.
1971
The American Institute of Physics
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