Accession Number : AD0887806

Title :   Nuclear Resonance Absorption as a Diagnostic and Investigative Technique.

Descriptive Note : Final rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Cohen,Leslie ; Wolicki,E. A.

Report Date : 19 AUG 1971

Pagination or Media Count : 18

Abstract : The report reviews the process of resonance absorption of electromagnetic radiation by nuclei of a given species whose atoms comprise part or all of a solid material. The absorption process results in having nuclei in a short-lived excited state which may have several modes of decay. The authors pay special attention to the case where there exists a long-lived state between the excited state and the ground state of the nucleus; and where a significant fraction of the decays of the excited state populate this long-lived state, and where the latter state then decays predominantly by the emission of an observable gamma ray. They suggest the use of this process, i.e., of absorption and delayed re-emission of electromagnetic radiation, as a diagnostic tool to aid in obtaining the energy spectrum of a source of pulsed radiation, where the pulse duration is short compared to the lifetime of the intermediate state. In a test, a specially fabricated disk of elemental selenium was exposed to a burst of radiation at the GAMBLE I facility and then examined with a scintillation detector. The experiment was successful in detecting the 18.1-sec activity of the 161-keV state in 77Se, thus demonstrating the feasibility of the approach. It is suggested that the procedure can be reversed. (Author)

Descriptors :   (*RESONANCE ABSORPTION, *GAMMA RAY SPECTROSCOPY), (*SELENIUM, RESONANCE ABSORPTION), NUCLEAR ENERGY LEVELS, RADIOACTIVE ISOTOPES

Subject Categories : Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE