The field of radiation detection is vital to answer multiple security and safety concerns both nationally and in the workplace. Yet radiation detection itself can be a complex process, particularly when there are multiple sources of radiation which can be very similar in response. Noise in the detection process as well as the background radiation that is present at all times increases uncertainty and must be differentiated from sources in question. Background radiation can include naturally occurring radiation found in minerals as well as cosmic radiation from outer space. In fact, the average American is exposed to approximately 3 millisievert (mSv) per year of background radiation, varying according to geographical location .
Modern situational safety needs combined with the difficulty of detecting certain critical materials drives us toward interesting problems which require innovative answers. How can we improve detection amidst variable weather conditions? How can we determine the directional source of radiation? What are low-cost ways that we can monitor human exposure to radiation? Here are some exciting developments in 2018 which serve to answer these questions and more.
Graphene Radiation Detector
In 2010, the Nobel prize for physics was presented to Andre Geim and Kostya Novoselov at the University of Manchester for their creativity in using a “sticky tape” technique to obtain a carbon sheet only one-atom thick called graphene . Graphene is the first man-made material in two dimensions, and it is 200 times stronger than steel . Until recently, there wasn’t much work being done with graphene, but there are revolutionary applications now emerging which utilize this amazing material, including batteries, running shoes, and bulletproof accessories for law enforcement and military defense applications .
Thermoelectricity is one of the special properties of graphene and was employed in the recent development of the graphene radiation detector at Chalmers University of Technology in Sweden . This detector converts heat from radiation into electricity, allowing a measurement of radiation in terms of variation in voltage. An interesting feature is the capacitive coupling to an antenna, as opposed to a DC coupling . Initial research demonstrated that a graphene bolometer, unlike its counterparts, has a fast response and performs consistently in a wide range of temperatures.
Directional Radiation Detection
Los Alamos National Laboratory’s (LANL) has teamed with Quaesta Instruments to develop the Lighthouse, a directional radiation detector that can focus on one particular area or source of radiation at a time . Lighthouse detectors rely on differential attenuation to discover a radiation field’s vector components. LANL’s communication office compares them to an antiquated TV antenna in the simplicity of their design, yet showcases their speed and sensitivity in detection .
There are many applications for this device, not least of which is the ability to determine the directional source of radiation. Many of these applications are being demonstrated on a regular basis at LANL, including HAZMAT robots, geological surveys, inventory and measurement, and oceanic surveys . One of the most promising applications is in providing “positive evidence of a negative result.” In other words, one can use lighthouse radiation detectors to conclude whether there is no radiation present. .
Yeast Radiation Detection
Radiology workers at hospitals and nuclear facilities wear dosimeters on their person daily in order to attempt to track accumulated radiation exposure. It is unknown how much exposure a person has had until the dosimeters are read by a third party, often weeks later. Researchers at Purdue have developed a badge that can be read immediately at the workplace, and it is made very cheaply using a surprise ingredient: yeast.
The yeast “micro-breweries”, as they are affectionately called by their makers, are inserted into badges that are composed of freezer paper, aluminum and tape . These badges are easy and inexpensive to make, and can be recycled after use. The technology relies on the adverse effects of radiation on yeast’s cells.
“We use the change in electrical properties of the yeast to tell us how much radiation damage it incurred,” states Rahim Rahimi, a Purdue researcher. “A slow decrease in electrical conductivity over time indicates more damage.” 
Rock West is aware of the challenges of radiation detection, and we have experience with both the development of spectroscopic detectors as well as the analysis of resulting data. We design and build radiation detector systems to help our customers solve critical, challenging problems in this field. Read more about our Radiation Detection capabilities.
- Grigory Skoblin et al, Graphene bolometer with thermoelectric readout and capacitive coupling to an antenna, Applied Physics Letters (2018). DOI: 10.1063/1.5009629