A Novel Neutron Area-Monitor Based on the Bubble Detector

A novel instrument (RAISA) based on bubble detectors has been developed to meet the needs for radiation monitoring for long-term space missions. RAISA uses two bubble detectors, but at any time, only one of the detectors is used as the radiation sensor. When a maximum number of bubbles has accumulated in this detector, a microprocessor turns on the second detector and recompresses the first detector. By switching back and forth, RAISA can operate continuously for many years. Although built for space needs, RAISA can obviously be used for radiation monitoring on earth. RAISA has been used in our own neutron calibration facility to check its performance. In addition to instantaneous display of ambient doseiate, RAISA records information in memory every second. Retrieval of contents of the memory provides a historical record of the dose over the entire monitoring period.