Radiation Induced Outgassing in an Aluminum System

The establishment of high vacuum in the intense radiation field of a reactor core is limited by: (1) poor conducting geometry, i.e. systems with a large length to diameter radio; (2) suitable reactor materials, i.e. materials having low neutron absorption; and (3) radiation induced outgassing. This work constitutes an investigation of the magnitude of the radiation induced outgassing rate of a well cleaned and baked 6061-6063 aluminum system. Measurements performed in both the NBS 32 KC Co60 gamma irradiation facility and the NRL 1 MW reactor facility disclosed that the phenomenon of radiation induced outgassing was principally due to the gamma and its associated electron field rather than to the fast neutron field. The magnitude of the effect observed was (7 + 4) 10-11 torr liters/sec cm2 per watt/gm.