Absolute measurement of Ho-166m radioactivity and development of sealed sources for standardization of gamma-ray emitting nuclides

Holmium-166m has a long half life (1200 yr) and emits a large number of gam ma-rays between 89 and 1400 keV. These characteristics are very suitable fo r gamma-ray calibration sources, therefore, the absolute activity of Ho-166 m was measured and several sealed sources were produced to be used as refer ence sources for the secondary standardization systems for gamma-ray emitti ng nuclides. In this project, seven metal sealed sources and ten point sour ces were produced and several of these sources were transferred to the seco ndary standard laboratories to complete the traceability scheme. (C) 2000 E lsevier Science Ltd. All rights reserved.