A photoelectric study of line intensities in the iron arc spectrum

• Main Author: Hefferlin, Ray Alden
• Format: Others
• Published: 1955
• Online Access: https://thesis.library.caltech.edu/51/1/Hefferlin_ra_1955.pdf; Hefferlin, Ray Alden (1955) A photoelectric study of line intensities in the iron arc spectrum. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/83GV-4951. https://resolver.caltech.edu/CaltechETD:etd-01072004-114556 <https://resolver.caltech.edu/CaltechETD:etd-01072004-114556>

Measurements were made on the 5-meter Paschen-Runge spectrograph with a photoelectric photometer. Special carriages were designed to keep the photocells focused and properly aligned with the grating while the spectrum is scanned. The circuit of the photometer is of an AC ratio type, and the ratios of the intensities of the scanned iron arc lines are recorded automatically by a Brown Recorder. The temperature and self-absorption present in different parts of the arc, and in the arc under different operating conditions, have been determined with this apparatus. No self-reversal was observed in the iron arc lines; if present, it was covered by deviations from the values, calculated on the basis of equilibrim considerations, of the intensities of all lines within a multiplet. These variations are different for different multiplets. The possibility that the effect is due in part to systematic error is recognized and discussed, but it appears that the remainder of the effect is due to some mechanism in the arc. Corrections are applied to f-values given in the literature.