Fundamental mechanisms of ³ He relaxation on glass

We present a model of 3 He relaxation on the surface of borosilicate glass which accurately predicts observed relaxation rates and their temperature dependence. Above room temperature 3 He dissolves into Pyrex, where interactions with Fe 3+ ions result in a relaxation time of ≈1 ms. Gas exchange across the glass surface of an enclosed vessel leads to T 1-1 = A/V (3.9 ± 1.4) × 10 -2 cm/h at room temperature, where A/V is the surface-to-volume ratio. The activation energy for relaxation is 13.7 ± 0.7 kJ/mol and is dominated by the activation energy of 3H e diffusion in glass. This is the first successful confirmation of predicted 3 He relaxation rates in glass vessels. © 2003 Elsevier Science B.V. All rights reserved.

Duke Scholars

Author Bastiaan Driehuys Radiology