Accession Number : ADA115439

Title :   X-Ray Induced Electron Emission.

Descriptive Note : Final rept.,


Personal Author(s) : Aeby,Charles A

PDF Url : ADA115439

Report Date : Apr 1982

Pagination or Media Count : 206

Abstract : The development and use of a magnetic spectrograph for the measurement of X-ray induced electron emission is described. Results are presented for metal and dielectric targets ranging in atomic number from Z=6 to Z-82. Materials studied were lead, tantalum, copper, aluminum, magnesium, solar cell cover glass, silica cloth, thermal control paint, Kevlar, Mylar, and conducting/nonconducting epoxy. Direct measurement was made of the quantum yield and energy distribution of electrons emitted at angles of 0 deg, 30 deg, 45 deg and 60 deg with respect to the surface normal of targets exposed to normal incidence filtered and unfiltered 50kV bremsstrah lung X-rays. Experimental results are compared with previous measurements where possible, and with computer code predictions where predictive capability matches the measurement range. The experimental results corroborates the cos theta angular dependence predicted by simple theoretical models, particularly for medium and high Z materials. A trend toward isotropic emission distribution is noted for the lower Z materials. Compared to the measured results, the emission yields predicted by a commonly used analytical model are low by approximately a factor of 2 for the unfiltered X-ray spectrum.

Descriptors :   *Electron emission, *X ray spectra, *Photoelectric emission, *Metals, Spectroscopy, Measurement, Computer programs, Mathematical prediction, Isotropism, Distribution, Magnesium, Silicon dioxide, Solar cells, Paints, Copper, Magnetic fields, Polymeric films

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Nuclear Physics & Elementary Particle Physics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE