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Environmental Radiation Monitoring Specialist Lynn Karr prepares to run a check on the inner workings of a new gamma ion chamber being tested at the CEMP station on DRI’s Las Vegas campus. |
If your vintage VHS videocassette recorder is the hub of your otherwise state-of-the-art home theater system, and it goes on the fritz, you’d no doubt replace it. But would you buy another VCR? Probably not.
In the fast-moving world of consumer electronics, you have many affordable upgrade options—digital video recorders, recordable DVD units and lots more. So moving forward instead of backward makes sense technologically and economically. The same is true in science.
That’s why DRI is testing a new gamma ion chamber for its Community Environmental Monitoring Program—or CEMP—stations. With 26 monitoring locations throughout Nevada and Utah, CEMP instrument stations are in place to detect any traces of lingering radioactivity from nuclear weapons tests at the Nevada Test Site.
CEMP pressurized ion chambers, or PICs, measure the levels of gamma radiation exposure in the environment. Similar to X-rays, gamma rays are high-energy radiation that can pass completely through the human body. This penetration can cause “ionization” which may cause changes at the cellular level with potential negative health effects. Gamma rays can also be beneficial to human health, and they are used in cancer treatment. But in the environment, of course, they bear watching.
All CEMP stations routinely report radiation at background levels—the amount occurring naturally in the environment—and these data are posted on the Internet at http://cemp.dri.edu/ for easy public access.
Developed by San Diego, Calif-based General Atomics, the new chamber requires no pressurization. Current models rely on pressurized argon gas and are about the size of a basketball.
DRI’s Ted Hartwell, who manages CEMP, is optimistic about the new chamber. “It’s a cylinder that’s smaller than a football, it requires far less energy than the pressurized version and its batteries can last for years,” Hartwell says. In addition, the new model is much easier to install, is less expensive to purchase and costs less to ship because it’s not pressurized.
“We can also do our own calibrations on these unlike the old models that have to be sent to the factory for this,” Hartwell says.
Evaluation of the new chambers will take place during the next year.
CEMP stations went up in 1981, helping give residents in areas surrounding the test site an active role in understanding and protecting their own health and well-being.
Funded by the U.S. Department of Energy’s National Nuclear Security Administration, CEMP enlists local residents at each site to supervise and maintain an instrument package that provides visible, real-time status reports of radiation levels and weather conditions.
Similar to a citizen-based program in Pennsylvania that resulted after the Three Mile Island nuclear reactor incident in 1979, CEMP was designed to help build public confidence through community involvement.
Each CEMP station consists of a sampler that collects airborne particulates, including radioactive particles, by pulling air through a paper filter; a thermoluminescent dosimeter that determines the cumulative radiation exposure at a location; and a PIC that continuously measures radiation exposure rates.
A microbarograph measures and records barometric pressure for use in interpreting the record of radiation exposure. Changes in atmospheric pressure affect the escape of naturally occurring radioactive gases like radon, which changes natural background radioactivity levels.
Meteorological instruments record air temperature, humidity, wind speed and direction, solar radiation, barometric pressure and precipitation.
If the new sleek gamma ion chambers prove successful, the older basketball-sized pressurized models will be replaced as they wear out, much like those old videocassette recorders in home theaters.
–Ron Kalb
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