High-energy tailing is an often-overlooked component in high-purity germanium gamma-ray spectrometry when performing the non-linear least squares fit of a full-energy peak. This component comes from the incomplete restoration of the baseline prior to the next pulse being processed and therefore is an issue of increased count rates. In the current work, the impact of this oversight is shown through the dynamics and decay characteristics of Ra and its radioactive decay progeny. Multiple measurements of two samples, separated from the decay progeny and at differing activities, have been made. The results of full-energy peak fitting of the convoluted 238.6 keV and 241.0 keV full-energy peaks with and without the high energy tailing component are presented. Trends in the observed activity that approximate the ingrowth of Pb have been observed where no high-energy tailing component is used, with maximum relative differences of 2% and 5% determined.
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http://dx.doi.org/10.1016/j.apradiso.2019.109021 | DOI Listing |
Materials (Basel)
April 2024
College of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China.
The pyrolysis separation of calcium and magnesium from phosphate tailings is an important process due to its high-value resource utilization. In this paper, aiming to address the problems of high energy consumption, a slow decomposition rate and the low activity of decomposition products in the high-temperature pyrolysis of phosphate tailings, the medium-temperature pyrolysis of phosphate tailings under a HO atmosphere was carried out, and the phase reconstruction and activation of pyrolysis process were discussed. The results showed that compared with N, air and CO atmospheres, the pyrolysis process of phosphate tailings in a HO atmosphere was changed from two stages to one stage, the starting decomposition temperature was reduced to 500 °C and the decomposition time was shortened to 30 min.
View Article and Find Full Text PDFJ Hazard Mater
May 2024
MIRARCO Mining Innovation, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada; Goodman School of Mines, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada.
Arsenopyrite and pyrite often coexist in metal deposits and tailings, thus simultaneous bioleaching of both sulfides has economic (as well as environmental) significance. Important targets in bio-oxidation operations are high solubilization rates and minimized accumulation of Fe(III)/As-bearing secondary products. This study investigated the role of pyrite bioleaching in the enhancement of arsenopyrite dissolution.
View Article and Find Full Text PDFJ Am Chem Soc
March 2024
Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
Photocatalysis has found increasing applications in biological systems, for example, in localized prodrug activation; however, high-energy light is usually required without giving sufficient efficiency and target selectivity. In this work, we report that ion pairing between photocatalysts and prodrugs can significantly improve the photoactivation efficiency and enable tumor-targeted activation by red light. This is exemplified by a gold-based prodrug () functionalized with a morpholine moiety.
View Article and Find Full Text PDFSci Total Environ
February 2024
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Engineering Research Center of Carbon Emission Reduction in Development and Utilization of Metal Resources, Ministry of Education, Central South University, Changsha 410083, China.
The recovery of low grade and fine particle copper ore usually requires sufficient dissociation, which reduces the particle size to the submicron level, presenting new challenges in subsequent copper tailings disposal. Flocculants can improve tailings sedimentation efficiency, but they also change the rheological properties of the slurry, resulting in low efficiency and high energy consumption during long-distances pumping. To address this issue, this study introduced polycarboxylate ether (PCE) superplasticizers as auxiliary additives for tailings treatment to improve fine particles sedimentation efficiency while enhancing slurry flowability.
View Article and Find Full Text PDFEJNMMI Phys
May 2022
Medical Radiation Physics, Lund, Lund University, Lund, Sweden.
Background: Semiconductor gamma-camera systems based on cadmium zinc telluride (CZT) detectors present new challenges due to an energy-response that includes effects of low-energy tailing. In particular, such energy tails produce effects that need to be considered when imaging radionuclides with multiple emissions such as [Formula: see text]. Monte Carlo simulation can be used to investigate the behaviour of such systems and optimise their use, provided that the detector model closely reflects the real physical detector.
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