Accession Number:

AD0272604

Title:

THE PHOTOELECTRIC K-ABSORPTION CROSS SECTION OF HELIUM AND LITHIUM

Descriptive Note:

Corporate Author:

CORNELL UNIV ITHACA N Y

Personal Author(s):

Report Date:

1962-02-01

Pagination or Media Count:

1.0

Abstract:

The absorption cross section of Helium in the spectral region near the K-edge was measured. Results were in good agreement with calculations. The absorption cross section of Lithium near its K-edge was measured with an uncertainty of 10. Observations agree with the results of a calculation performed using the published calculations on Helium as a guide. The measurement of the absorption cross section differed from that of previous investigators in that a small cell was used to confine the gas, whereas in other investigations the entire optical path of a gasfilled spectrometer served as the absorbing sample. An advantage which accrues from the use of a gas cell is the possibility of carrying out absorption measurements utilizing a soft x-ray emission band as a source and a photomultiplier as a detector. Such a combination provided an accurate attenuation measurement for Helium at 180 A, the short wavelength end of the spectral range of interest. At all longer wavelengths 200 to 600 A, a condensed spark served as the source of radiation which was detected photographically. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE