Gamma densitometry for the measurement of skeletal density

摘要: A method is described for the measurement of density calcium carbonate materials from attenuation a narrow, collimated beam gamma photons. For slices, approximately 0.5 to 1.0 cm thick, skeletons reef building corals, optimum energy 30–34 keV; and practical 22 100 keV. The potential utilities five commercially available isotopic sources (109Cd,125I,253Gd,210Pb and241Am) are evaluated. Methods results presented densitometry using210Pb and241Am. The210Pb point source had its principal emission at 46.5 Bremsstrahlung high (800 keV) emissions associated with the210Pb decay grand-daughter were detected, procedures developed accommodate contribution these overall count rate. rate by aluminium aragonite absorbers closely followed simple theoretical considerations provided that narrow window settings used radiation monitor. These take account material absorbing radiation, hence could be determined beam. Increased accuracy was achieved use of241Am speed counting equipment.241Am has 59.6 this follows targets mass thicknesses 0 6 g cm-2. Aragonite shell giant clam found have slightly different properties in absorption photons coral skeleton. differences small but statistically significant.