A miniaturized version of a dosimeter, a portable device used for measuring exposure to ionizing radiation that can provide life-saving early detection in the event of a nuclear accident or dirty bomb may soon be available.
This high-tech plastic card, called the Citizen's Dosimeter, would be as convenient and affordable as a subway card, with the capability to measure the amount of radiation on a person or in a given area.
The National Urban Security Technologies Laboratory (NUSTL) located in New York City and managed by the Department of Homeland Security's (DHS) Science and Technology Directorate (S&T) earned a patent that covers the development of radiation dosimetry technologies.
Currently, workers wear personal radiation dosimeter badges in nuclear plants, but you can't read a plant dosimeter on the spot. It must go to a processing lab to determine an individual's radiation dose. While a final prototype is not quite ready, a workable blueprint for a wallet-sized card that can detect radiation in real time is now in place.
"We were inspired by the Metro cards we use every day to get around Manhattan, and envisioned a dosimeter with that level of convenience," said Gladys Klemic, a NUSTL physicist who managed the project from Illinois. Klemic believes a dosimeter in this form could benefit emergency responders and the general public.
Klemic and her team set out to create a dosimeter that would meet American National Standards Institute (ANSI) requirements for personal radiation dosimeter badges, and incorporate commercially available components to decrease the size and lower the price tag.
NUSTL began by using radiation-sensitive material from Landauer, Inc., a commercial dosimetry provider in Illinois, testing materials of varying thicknesses and combinations to determine how thin they could make the card while still achieving the targeted performance.
After testing nearly a half a dozen materials, the NUSTL scientists determined that using the chemical element tantalum allowed them to obtain accurate readings with minimal thickness. Combining this element in a double-layer, stainless steel filter helped to reduce false positives. That was the design that led to the patent.
The next step is to develop a card reader to reveal the radiation dose measured by the Citizen's Dosimeter. In the event of a nuclear incident, first responders equipped with a card reader would immediately be able to measure radiation exposure for anyone carrying the Citizen's Dosimeter.