Measurement of the Background Gamma Dose Rates in Houston, Texas: A Descriptive Summary of an Undergraduate Research...

Natural background radiations include cosmic, terrestrial, and medical sources. Cosmic radiation is mostly shielded by the magnetic field of the Earth; however, those that penetrate can produce nuclear interactions within the Earth's atmosphere yielding cosmic ray showers. Terrestrial and medical sources of radioactivity are typically identified through radionuclide-specific decay signatures. Medical sources of radiation mainly result from diagnostic x rays, which attenuate into the environment. These x rays also contribute slightly to background radiation. The purpose of this study was to have students involved with the Texas Southern University (TSU) health physics program measure and report background gamma dose rates in Houston, Texas, using the Canberra InSpector 1000 Digital Hand-Held Multichannel Analyzer. The results were compared with the average gamma dose rate on Earth. Of note, TSU is one of the largest historically black colleges and universities (HBCUs) in the nation and currently boasts the only undergraduate health physics program in Houston. Targeted locations were selected within the I-610 loop of Houston covering an area of approximately 100 km. Measurements were performed at nine locations and verified by GPS latitude and longitude coordinates. The dose rate was measured over a 100 m area at each location, while spectral analysis was simultaneously performed for natural gamma-emitters. Our results suggest the dose rate averaged over all geographical locations in this study was 0.114 ± 0.001 μSv h and thus, consistent with most literature. The only radionuclide identified in the spectra in all measurements was K due to the limited energy resolution of the InSpector 1000.