Observation of natural background radiation during the Great American Eclipse. (December 2018)

• Record Type: Journal Article
• Authors: Chichester, David L.; Johnson, James T.; Watson, Scott M.; Hix, Jay D.; Thompson, Scott J.
• Is Part Of: Applied radiation and isotopes. Volume 142(2018:Dec.)
• Page Start: 151
• Page End: 159
• Publication Date: 2018-12
• Subjects: Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2018.09.008
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: Observations of photon and neutron background radiation were made in Rigby, Idaho, during the Great American Eclipse on August 21, 2017. Photon measurements were made using a mechanically-cooled, high-purity germanium gamma-ray spectrometer, segmenting the data into four energy bands of < 1 MeV, 1–2 MeV, 2–3 MeV, and 3–7 MeV. Neutron measurements were made using 3 He proportional counter arrays embedded in polyethylene, either bare or wrapped with Cd or B filters. All data was analyzed in 900-s intervals starting one day before the eclipse and extending to one day after the eclipse. More detailed analyses were made in 90-s intervals for the photon data and 110-s intervals for the neutron data. Meteorological data was simultaneously recorded in 60-s intervals, recording solar radiance, temperature, air pressure, relative humidity, and dew point. For the observations described here, no statistically-significant (> 3σ) variations in signal count rates were observed in either the photon or neutron data. This level corresponds to the lack of observed photon variations exceeding 2.1%, 12.2%, 21.6%, or 43.2% of mean values in the four photon energy groups, respectively; it corresponds to a lack of observed neutron variations exceeding 25.3%, 25.6%, or 16.1% of mean values in the three neutron detector arrays, respectively. Highlights: Conflicting results have been previously reported regarding how natural background radiation changes during total solar eclipses. Observation of photon background radiation in a total solar eclipse in four energy windows showed no 3-σ statistically significant variations. Observation of neutron background radiation in a total solar eclipse in three overlapping energy bands for 3 He detectors in polyethylene that is bare, covered in Cd, or covered in B, showed no 3-σ statistically significant variations exceeding 25.3%, 25.6%, or 16.1% of mean values, respectively. Weather variations surrounding a total solar eclipse agreed with previous reported observations.