High-flux irradiation of open samples

The irradiation of large samples of biological material in a high neutron f lux enables the extention of trace element analysis into the ng to pg range , but raises several problems as gamma heating and radiolysis degrade the s amples. Gamma heating increases the pressure to a point where either a very large irradiation container is necessary or a container which can endure t he high pressure. Several methods to overcome these problems have been publ ished. The irradiation of open samples was performed as an alternative to t hese methods. Temperature effects on biological material during irradiation in a high and in a low neutron flux were compared. As an example, wheat wa s irradiated in open containers allowing simultaneous temperature measureme nt in the sample during irradiation.