scholarly journals The application of full spectrum analysis to NaI(Tl) gamma spectrometry for the determination of burial dose rates

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Minqiang Bu ◽  
Andrew S. Murray ◽  
Myungho Kook ◽  
Jan-Pieter Buylaert ◽  
Kristina J. Thomsen
Keyword(s):  
High Resolution ◽  
Gamma Spectrometry ◽  
Spectrum Analysis ◽  
Accurate Determination ◽  
Precise Determination ◽  
Laboratory Method ◽  
Least Square ◽  
Full Spectrum ◽  
Dose Rates

Abstract In this study, we explored the potential of a NaI(Tl) scintillator-based gamma spectrometer for the accurate determination of burial dose rates in natural geological samples using a full spectrum analysis (FSA) approach. In this method, an iterative reweighted least-square regression is used to fit calibration standard spectra (40K, and 238U and 232Th series in equilibrium) to the sample spectrum, after subtraction of an appropriate background. The resulting minimum detection limits for 40K, 238U, and 232Th are 4.8, 0.4 and 0.3 Bq·kg–1, respectively (for a 0.23 kg sample); this is one order of magnitude lower than those obtained with the three-window approach previously reported by us, and well below the concentrations found in most natural sediments. These improved values are also comparable to those from high-resolution HPGe gamma spectrometry. Almost all activity concentrations of 40K, 238U, and 232Th from 20 measured natural samples differ by ≤5% from the high resolution spectrometry values; the average ratio of dose rates derived from our NaI(Tl) spectrometer to those from HPGe spectrometry is 0.993 ± 0.004 (n=20). We conclude that our scintillation spectrometry system employing FSA is a useful alternative laboratory method for accurate and precise determination of burial dose rates at a significantly lower cost than high resolution gamma spectrometry.

Full spectrum analysis with the non-negative least square constraint for laboratory HPGe gamma spectrometry

2019 ◽  
Vol 322 (2) ◽  
pp. 961-967 ◽  
Author(s):  
Mai Thanh Man ◽  
Vu Ngoc Ba ◽  
Dang Thi Thao My ◽  
Dang Nguyen Phuong ◽  
Truong Thi Hong Loan ◽  
...  
Keyword(s):  
Gamma Spectrometry ◽  
Spectrum Analysis ◽  
Least Square ◽  
Full Spectrum ◽  
Hpge Gamma Spectrometry

scholarly journals Analysis of the 40K levels in soil using gamma spectrometry

2005 ◽  
Vol 48 (spe2) ◽  
pp. 221-228 ◽  
Author(s):  
José Araújo dos Santos Júnior ◽  
Jorge João Ricardo Ferreira Cardoso ◽  
Cleomacio Miguel da Silva ◽  
Suêldo Vita Silveira ◽  
Romilton dos Santos Amaral
Keyword(s):  
Gamma Spectrometry ◽  
Absorbed Dose ◽  
Soil Samples ◽  
Spectrometry Method ◽  
Dose Rates ◽  
Elemental Concentrations ◽  
High Purity Germanium ◽  
Specific Activities ◽  
Potassium 40

Potassium-40 was determined in soil in an area with 40,000 m² situated in the western State of Pernambuco, Brazil. For radiometric measurements, the gamma spectrometry method with a high purity germanium (HPGe) detector was used. Sampling of 78 soil samples has been performed at intervals of 25 m. The specific activities of 40K were calculated based on the photopeak of 1.46 MeV. Values from 541 to 3,572 Bq kg-1 were obtained (mean of 1,827 Bq kg-1). These values allowed the determination of the elemental concentrations as well as the absorbed dose rates in air, 1 m above the ground. The values varied from 1.7 to 11.5% (mean of 6%) and from 23.4 to 154.3 nGy h-1 (mean of 79 nGy h-1), respectively.

scholarly journals Portable Light Pen 3D Vision Coordinate Measuring System- Probe Tip Center Calibration

2013 ◽  
Vol 13 (4) ◽  
pp. 194-199 ◽  
Author(s):  
Shugui Liu ◽  
Hongling Zhang ◽  
Yinghua Dong ◽  
Shaliang Tang ◽  
Zhenzhu Jiang
Keyword(s):  
Accurate Determination ◽  
Least Square ◽  
Measuring System ◽  
Translation Vector ◽  
3D Vision ◽  
Fitting Method ◽  
Center Position ◽  
Tip Position ◽  
Light Pen

For different tasks, probe tip should be changed in the 3D vision coordinate measuring system and the accurate determination of probe tip center position is critical. A novel and simple approach for calibrating the probe tip center position of the light pen is presented in this paper. Hundreds of images of the light pen with different postures are collected while the probe tip is kept in firm contact with a reference conical hole. The probe tip position is determined by computing the rotation matrix and translation vector from the obtained images by using the least square fitting method. The experimental results demonstrate the effectiveness of the proposed approach. Its repeatability reaches 0.033 mm, 0.030 mm, and 0.043 mm in x, y, and z axes, respectively, and its convergence speed is satisfactory.

Accurate determination of the cell dimensions of magnetite

1957 ◽  
Vol 31 (237) ◽  
pp. 431-442 ◽  
Author(s):  
E. Z. Basta
Keyword(s):  
Accurate Determination ◽  
Precise Determination ◽  
Defect Structures ◽  
Precision Data ◽  
X Ray ◽  
Cell Dimensions ◽  
Glass Tubes ◽  
Ideal Composition ◽  
The Ideal

SummaryAn analysed magnetite from Bisperg, Säter, Dalecarlia, Sweden, gave the formula , which corresponds closely to the ideal composition. A precise determination of the cell dimensions gave a 8·3963±0·0005 Å. at 18° C. Gentle heating of the powdered magnetite in evacuated silica glass tubes, before X-ray examination, resulted in sharply defined lines with high Bragg angles; an improvement which enabled precision data to be obtained. Four other new analyses of magnetites are also given and their lattice parameters are determined in the same way and are found to range from 8·3960 Å. to 8·3970 Å. The Bisperg magnetite being the purest sample examined, the value of its cell edge is taken as representative of pure magnetite.The effect of the different ionic substitutions on the cell dimensions of natural magnetites is discussed. An attempt is also made to explain the great variations among the published values of cell dimensions of artificial preparations; one main reason being the presence of defect structures with varying oxygen contents in excess of the formula requirements.

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