A New Magnetic Spectrograph for the Study of X-Ray Photo-Electrons

Qualitative experiments with the new Geiger-Müller ion-counter furnish information on the theory of operation of this instrument. Careful tests have established the limits of validity of a small Geiger-Müller tube of a nature typical of ion-counters which will be used for the measurement of beams of electrons and several precautions to be observed in the use of such a tube are given, together with a simple test of the worth of the anode wire in the tube. The smallness of the length to diameter ratio of the tubes used in this investigation has fortuitously made it possible to develop a corrective theory for the comparison of various rates of counting. This theory can be applied to tubes of greater size. A means of restricting the active volume in a small tube has been found, and the operation of a tube in the specialized form recommended has proved very satisfactory. In this form, the Geiger-Müller tube has been built into a magnetic spectrograph of new design. Measurements taken with this spectrograph show that it possesses a very high resolving power, and that it will be of value in discovering new "lines" or peaks. Several new lines found are given, some of which could be attributed to mercury which was undoubtedly present in the sputtered gold film which was used. This suggests a means of accurately measuring the M level values in the mercury atom. LI electrons ejected from gold by Mo Kα2 were detected, showing that the new method will be efficacious where relatively slow electrons are measured. An attempt was made to measure the angular distribution of LIII electrons ejected from a very thin sputtered film of gold by Mo Kα1, and the distribution curve obtained agrees well in its indications with inferences recently drawn from spectra obtained with the photographic method.