PNNL has developed two low-background gamma-ray spectrometers in a new shallow underground laboratory, thereby significantly improving its ability to detect low levels of gamma-ray emitting fission or activation products in airborne particulate in samples from the IMS (International Monitoring System). The combination of cosmic veto panels, dry nitrogen gas to reduce radon and low background shielding results in a reduction of the background count rate by about a factor of 100 compared to detectors operating above ground at our laboratory.
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http://dx.doi.org/10.1016/j.apradiso.2016.12.034 | DOI Listing |
Environ Monit Assess
January 2024
Geological Institute of Romania, 1, Caransebes str, 012271, Bucharest, Romania.
To estimate the radiation hazard due to the natural terrestrial radioactivity, 598 samples of soil covering the entire Romanian territory were collected and analyzed for the distribution of natural radionuclides K, Ac, and Ra. The ultra-low background Slanic-Prahova underground laboratory was used to determine the gamma-ray-specific activity of these radioactive isotopes with an uncertainty between 5 and 20%. All these data permitted to establishing a set of 2D maps illustrating the distribution of specific activity of each radionuclide as well as of the resulting air dose rate, all of them illustrating an heterogeneous distribution, increased values being displaced on the western and south-western territory.
View Article and Find Full Text PDFAppl Radiat Isot
August 2023
Unit of Nuclear Engineering, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel.
A ground-level prototype system for low-background measurements was developed and tested. The system consists of a high-purity germanium (HPGe) detector used for detecting γ rays and coupled to a liquid scintillator (LS) used for detecting α and β particles. Both detectors are surrounded by shielding materials and anti-cosmic detectors ("veto") used to suppress background events.
View Article and Find Full Text PDFPhys Med
May 2023
Faculty of Science and Engineering, Waseda University, Japan.
Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, such imaging has so far been conducted only for pencil beams without a multi-leaf collimator (MLC). The use of spread-out Bragg peak (SOBP) with an MLC may increase the scattered prompt gamma photons and decrease the contrast of the images of prompt X-rays.
View Article and Find Full Text PDFAppl Radiat Isot
May 2023
Libyan Society for Meteorites and Space Observations, Tripoli, Libya.
The L6 chondritic meteorite, HaH-346, fell in Libya. However, neither the exact date of the fall nor the exact size of the original meteoroid or asteroid is known. A specimen of the meteorite, weighing 488 g, was measured using ultra low-background gamma-ray spectrometry in the 225 m deep underground facility HADES.
View Article and Find Full Text PDFAppl Radiat Isot
April 2023
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
This proceeding presents the CONRAD high-purity germanium spectrometer with a large diode (2.2 kg mass) employing electrical cryocooling. The detector is an ideal tool to characterize background up to high energies of ∼12 MeV.
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