Development of low-power wireless networked radioactive material sensor

Abstract

Abstract — Our team at the United States army research laboratory (ARL) has implemented the design and development of a low-power, compact, wireless-networked radiation sensor array. The sensor system was developed to provide high sensitivity event detection and remote warning for a broad range of radioactive materials. The sensor can identify the presence of 1µCi Cs 137 at a distance of 1.5m. The networked array operates well as a facility sensor however the architecture is designed to be operated outside the laboratory environment as well. The performance of the facility radiation measurement system is described and benchmarked to readily available check sources such as Cs 137 . Photomultiplier, Scintillator, Geiger counter, Xbee, Wireless Network, Sensors. I. NTRODUCTION I The US Army Research Laboratory is the corporate research arm of the US Army. Its history of sensor development goes back to the first proximity fuses on bombs from WWII. Now the organization focuses on semiconductor, sensor, and device development on a variety of projects requiring advanced sensors. Our radiation sensor work was inspired by an interest in low-power wireless networked sensors. We identified commercially available self-contained wireless transmitters based on the IEEE 802.15.4 communications network. This network protocol was chosen to take advantage of low-power consumption and ability to connect a large number of devices into a single ad-hoc network. We studied existing anti-terrorism systems designed to provide high sensitivity and spectroscopic identification not possible with Geiger counters. Some applications include counter-terrorism and field inspection such as the systems pictured in Figure 1. These systems tend to be large and require power-hungry computation and thermal management resources. The benefits of this system however are not only in spectroscopic identification of a target at a distance but instead detection of slight changes in background radiation. This approach combined with background cancellation strategies allow for a very high gain measurement from long distances. However uncertain the health effects of low-level increases of radiation, detection systems such as the ones discussed here can immediately identify the slightest increase in background radiation. Given people's fears about radiation exposure, it would be panic, rather than the numbers of dead or hurt that would give the terrorists their success. It is this psychological impact combined with their ease of assembly that makes radiological devices so attractive to terrorists.[1]-[3]