Accession Number:

AD0489088

Title:

DETERMINATION OF THE HALF-LIFE OF HF-178M.

Descriptive Note:

Master's thesis,

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1966-05-01

Pagination or Media Count:

46.0

Abstract:

Coincidence counting techniques were used in the determination of the half-life of Hf-178m. The experimental sample, essentially a mixture of Hf-177 and Hf-178, was irradiated with thermal neutrons to produce Hf-178m and Hf-179m isomers. The isomeric transition of Hf-178m is followed by a cascade of gammas .427, .326, .214, and .093 mev. The isomeric transition of Hf-179m approximately 18-second half-life is followed by a .215 mev gamma. The decay data of Hf-178m was effectively isolated from that of Hf-179m by counting coincidences between any two of three specific Hf-178m gammas .427, .326, and .214 mev. After being corrected for change coincidence counts, this counting data was processed by a computer program FRANTIC. By using the least-squares techniques, the FRANTIC program fitted a calculated exponential decay curve to the counting data from a single experiment and also computed the half-life for that data. The average half-life of Hf-178m, derived from seven decay experiments, had a value of 3.94 seconds and an uncertainty of 0.5. The additional uncertainties due to gain instability and background count-rate were estimated. The half-life of Hf-178m was found to be 3.94 or - 0.04 seconds, all uncertainties included. Author

Subject Categories:

  • Radioactivity, Radioactive Wastes and Fission Products
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE