Emanation Thermal Analysis Study of Brannerite

摘要

Radon emanation thermal analysis (ETA) during "step by step" heating to selected temperatures up to 1200 deg C in argon and subsequent cooling yielded detailed information on the annealing of radiation damage and macrosocpic defects in natural brannerite.Thermogravimetry showed mass losses in the tempreature ranges 230-315,570-760 and 840-1040 deg C.Mass spectrometry of the evolved gases indicated M/Z=44,i.e.CO_2.Crystallization of initially amorphous brannerite was indicated by ETA in the temperature range 900-1200 deg C,in agreement with the X-ray diffraction results.From the radon diffusion activation energy values determined in ETA,the degree of structural ordering was assessed at different temperatures.