Superheated-Droplet Neutron-Detection Technology and the CRTI Project

摘要

Many radiation detection systems currently deployed for counter-terrorism applications detect onlyrngamma radiation. Although recommended by both the IAEA and the U.S. DHS, widespread use ofrnneutron detection equipment has been historically limited because of high costs and technicalrncomplexities. Superheated droplet technology offers high sensitivity for detection of neutrons andrnlow sensitivity to gamma rays, is low cost, and can be used effectively with little or no training. Therndetector consists of a clear, pocket-sized tube filled with a polymeric gel that contains tiny dropletsrnof a superheated detector liquid. When a neutron interacts with a droplet, the superheated liquidrnvaporizes and forms a visible gas bubble that is trapped in the gel. The number of bubbles is directlyrnproportional to the amount of neutron radiation; hence, the device provides a quantitative, real-timernmeasurement of radiation exposure. The bubble detectors are reusable. After independent work onrnelectronic readout technology and its integration with communications technology, BNL became arnparticipant in the Defender Nuclear Detection Web project, a unique international collaborationrnorganized by the Canadian developer of superheated droplet technology, Bubble TechnologyrnIndustries Inc, and supported by the Government of Canada through its Chemical, Biological,rnRadiological and Nuclear Research & Technology Initiative (CRTI). Defender? neutron detectorsrnwill be electronically instrumented with a digital readout, alarm capability, GPS and wirelessrncommunication for transmission of data to a central command center. The detectors will then berninterfaced to a data management network that will enable the radiation readings from a broadrngeographical area to be monitored in real time. BNL will test the system using protocols developedrnfor DHS to evaluate radiation equipment before its deployment in the New York City area andrnelsewhere. If successful, the Defender system will provide neutron-detection technology ofrnsufficiently low cost for wide deployment in homeland security and counterterrorism applicationsrnalong both coasts of North America and along the US-Canada border. BNL work with theserntechnologies and the status of the CRTI collaboration will be presented.