Cobaltous Oxide (I): A Compact Single-Line Source

Abstract

Mössbauer experiments using CoO sources usually show two lines at room temperature when used with a narrow unsplit absorber. These correspond to different chemical environments and have been identified with Fe²⁺ and Fe³⁺. By a combination of Mössbauer, X-ray, and chemical techniques, we have been able to prepare stopchiometric CoO sources which have only the Fe²⁺ component, or alternatively only the Fe³⁺ component, The Fe²⁺ component gives a narrow single line, with a recoil-free fraction at room temperature exceeding that of Co⁵⁷-doped copper sources. The effective Mössbauer characteristic temperature for Fe²⁺ in CoO(I) was measured to be 510°K. By contrast the unsplit Fe³⁺ line associated with CoO(II) has a very broad line width and a Mössbauer characteristic temperature of only 320°K.Our Prescription for Co⁵⁷O(I) should permit the fabrication of very strong, single-line, sources with minimum electronic absorption.

Work supported in part by the U.S. Atomic Energy Commission, Contract AT(11–1) 1616.