Bubble Detectors and the Assessment of Biological Risk from Space Radiations

Experiments using bubble detectors in several space missions have provided important data on neutron fields inside satellites. These data, in conjunction with irradiations of bubble detectors using high energy ions, have prompted a re-examination of the applicability of terrestrial radiation dosimetry techniques in a space environment where the radiation is so vastly different. These investigations have raised questions on the approach being used for space dosimetry and the relevance of conventional dosimetric quantities for assessments of biological detriment. The basic mechanisms behind the bubble detector and several models of biological damage have been compared. It appears that the bubble detector can be formulated to mimic the biological behaviour predicted or explained by the models. This is perhaps not surprising since the bubble detector is based on energy deposition over distances of tens of nanometres and is, therefore, a true nanodosemeter. Perhaps the bubble detector can provide a direct and better indicator of true biological detriment from space radiation than dosimetric quantities currently derived from a variety of radiation detection devices.