Radiation-Induced Outgassing from Several Metals

Abstract

Radiation-induced outgassing was measured for several metals exposed to ⁶⁰Co gamma radiation. The metals, in the form of tubes or rods, were placed in a Type 304 stainless-steel vacuum system. It was determined that the array of the pins (either square or hexagonal) did not significantly affect the results. The measurements for Type 304 stainless steel varied from (1.42 ± 1.75) × 10⁻⁹ (p^a − ℓ)/(cm^{2 ·}s) per Mrad/h for a surface-to-volume (S/V) ratio of 8.64 cm⁻¹ to (9.58 ± 3.81) ×10⁻¹⁰(p_a − ℓ)/(cm²·s) for an S/V ratio of 3.08 cm⁻¹. For Type 316 stainless steel, the determination was (1.18 ± 0.49) × 10⁻⁹ (p_a − ℓ)/(cm²·s) per Mrad/h, for aluminum the value was (6.24 ± 17.2) × 10⁻¹⁰ and for carbon (2.28 ± 0.59) × 10⁻⁹ (p_a - ℓ.)/(cm²·s) per Mrad/h. The determinations were made by comparing the rate-of-rise pressure curves with and without gamma radiation, and large errors resulted when the differences were small.