Chemische Strahlenmessung

Abstract

In the large and rapidly growing work, connected with atomic energy radiation chemistry is becoming more and more important in different fields of research and industry. In this connection problems and methods of radiation dose measurements are of essential interest. Many of these problems cannot be resolved by conventionel measuring principles or devices. It is obvious that irreversible changes of chemical compounds by ionizing radiations may be used as a measuring principle for these radiations. In the past years different radiation chemical methods for radiation dose measurements have been worked out, which are of special importance in radiation chemical work. The present paper gives a critical view on the best known chemical dose measuring reactions and their applications to special problems of dosimetry. Using convenient reactions, such as oxidation of ferrous sulphate, reduction of ceric salts and formation of halogenic acids from halogene containing hydrocarbons in aqueous solutions, dose measurements can be performed with almost the same degree of accuracy as by conventionel methods. Two problems of fundamental interest have been investigated and described in some detail. The yields of the best known chemical reactions for dosimetrical purposes are not quite constant over the whole range of photon energies, compared with careful ionization measurements. At very low photon energies the yields fall down and at very high energies they rise slightly. Over the whole range of conventional photon radiations, including all those produced by radioactive substances, the yields are practically constant, so that dose measurements within this field can be made without corrections, if not very high accuracies are needed. The variations of the radiation chemical yields, used for dosimetrical purposes are probably due to the variation of linear energy transfer at low photon energies which, at high energies, is not completely compensated by the polarization effect. These facts are discussed and the results are compared with well established values from the literature.