High-vacuum gamma irradiation facilities for synergistic effects testing on optoelectronic components and materials

The assessment of the durability of candidate space components and materials requires the use of ground laboratory testing facilities when no reliable information exists in the published literature. Accelerated tests simulating the radiation/temperature/vacuum environment need to be performed to investigate possible synergistic degradation effects. An irradiation chamber combining high vacuum and thermal cycling with a large range of gamma dose rates has been designed and constructed for this purpose at SCK.CEN, the Belgian Nuclear Research Center. The irradiation chamber module with actively-controlled vacuum is designed to fit in our gamma irradiation facilities. The vacuum irradiation module operates in the high-vacuum regime even in the presence of moderate outgassing from polymer materials. A pressure of [10.sup.-5] mbar can be routinely achieved but lower pressure can be obtained in the case of inert and mineral materials. In addition to the facility description, our paper discusses preliminary results of radiation-assisted outgassing of common polymers obtained using this new vacuum irradiation module. Index Terms--Gamma radiation, hardness assurance, irradiation facility, radiation assessment, vacuum.