222Rn and 220Rn emanations from powdered samples of samarskite as a function of annealing temperature

Abstract

Abstract Emanation coefficients for radon (222Rn) and thoron (220Rn) were measured from fully metamict samarskite collected from Centennial Cone after 1 h and 24 h annealing in argon from 473 to 1373 K. For the 1 h annealing run, 222Rn emanation coefficients ranged from 5 × 10-6 to 2.1 × 10-5 %, while 220Rn coefficients varied from 6.3 × 10-3 to 2 × 10-2 %. For the 24 h annealing run, 222Rn coefficients ranged from 5.8 × 10-6 to 2.3 × 10-5 %, while 220Rn coefficients varied from 4.1 × 10-3 to 1.5 × 10-2 %. The 222Rn and 220Rn emanation coefficients vs. annealing temperature data can be described by an exponentially decreasing sinusoidal function. Both 222Rn and 220Rn emanation coefficient values after annealing considerably exceeded those measured from an unheated powder reference sample and from the original samarskite sample.