Design of a High-Resolution High-Efficiency Magnetic Spectrometer for Electron Spectroscopy

A theoretical design study was carried out for a high‐resolution high‐efficiency double‐focusing magnetic spectrometer intended for general use in electron spectroscopy. With the proposed design it should be possible to operate with good intensity at energy resolutions as high as 0.01%. The air‐cored system of coils used in the design gives a fieldform with electron‐optical properties very close to those of the $\text{1/}\sqrt{r}$ field. The design thus has very good focal‐plane properties and, in conjunction with a multichannel detector, should yield data‐acquisition rates approximately 100 times higher than in single‐channel operation. The present design is superior in this respect to any previous air‐cored magnetic spectrometer. All coils in the design are of smaller radii than the electron orbits, giving very high access to the source and detector regions. There appear to be no great difficulties in the construction of a spectrometer with this design. Most features of the design compare very favorably with other spectrometers currently used in electron spectroscopy. The effects of extraneous magnetic field perturbations on the performance of double‐focusing spectrometers were also calculated.