scholarly journals A hybrid analytical-numerical method for efficiency calculations of spherical scintillation NaI(Tl) detectors and arbitrarily located point sources

2017 ◽  
Vol 32 (2) ◽  
pp. 140-147 ◽  
Author(s):  
Salam Noureldine ◽  
Mohamed Badawi ◽  
Mahmoud Abbas
Keyword(s):  
Numerical Method ◽  
Active Medium ◽  
Point Sources ◽  
Data Set ◽  
Attenuation Coefficients ◽  
Energy Peak ◽  
Full Energy Peak Efficiency ◽  
Detector Surface ◽  
Path Lengths ◽  
Detector Configurations

The present work is essentially concerned to introduce a hybrid analytical-numerical method to calculate the geometrical, the total, and the full-energy peak efficiency of the spherical NaI(Tl) detector for using isotropic radiating g-ray point sources. In addition, it calculates the average path lengths travelled by the photon inside the detector active medium, in order to study the characteristics of the source-to-detector configurations. This method was depended mainly on the calculation of the solid angle subtended by the radioactive point sources, which were situated at various locations from the detector surface and the photons path lengths through the detector active medium. Also, taking into account the attenuation coefficients of all the absorbers between the source and the detector material itself. The obtained results were compared against one data set published to show the method's possibility in the calibration process.

Calibration of HPGe Detector Efficiencies With Self-Absorption Correction of Gas Sphere Sources

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Waseem Khan ◽  
Chaohui He
Keyword(s):  
Point Sources ◽  
Full Energy Peak ◽  
Wall Material ◽  
Correction Factors ◽  
Peak Efficiency ◽  
Good Efficiency ◽  
Full Energy ◽  
Absorption Correction ◽  
Energy Peak ◽  
Full Energy Peak Efficiency

Several types of radioactive gases are released from the nuclear reactor. In order to measure the activity of such gases, it is necessary to calculate the accurate efficiency. Practically, efficiency calibration with gaseous sources is not very easy because of the low half-lives of the noble gases. For this purpose, Monte Carlo (MC) simulation was performed to study the full energy peak efficiency of two n-type high-purity Germanium (HPGe) detectors. Two spheres of xenon and krypton composition sources with two nuclides (Xe133 and Kr85) and two-point sources were simulated, covering the energy range from 81 keV to 604 keV. Self-absorption correction factors were calculated with GEANT4 for two gas sphere samples and obtained good efficiency agreement with the experimental results. The simulation was performed for various gas samples with different densities and observed their effects on the full energy peak efficiency value of two detectors. The corresponding self-absorption correction factors were calculated for each gaseous sample and investigated that the self-absorption correction factors not only depend on the sample characteristics but also on the detector geometry and source to detector distance. The dependence of the full energy peak efficiency on the side cap wall material and their thicknesses were also carried out for some particular photon energies.

scholarly journals NaI(Tl) Detector Efficiency Computation Using Radioactive Parallelepiped Sources Based on Efficiency Transfer Principle

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Mohamed S. Badawi ◽  
Mona M. Gouda ◽  
Ahmed M. El-Khatib ◽  
Abouzeid A. Thabet ◽  
Ahmed A. Salim ◽  
...  
Keyword(s):  
Scintillation Detector ◽  
Theoretical Method ◽  
Simulation Method ◽  
Wide Energy Range ◽  
Peak Efficiency ◽  
Energy Peak ◽  
Full Energy Peak Efficiency ◽  
Detector Surface ◽  
Wide Energy ◽  
Effective Solid Angle

The efficiency transfer (ET) principle is considered as a simple numerical simulation method, which can be used to calculate the full-energy peak efficiency (FEPE) of3″×3″NaI(Tl) scintillation detector over a wide energy range. In this work, the calculations of FEPE are based on computing the effective solid angle ratio between a radioactive point and parallelepiped sources located at various distances from the detector surface. Besides, the attenuation of the photon by the source-to-detector system (detector material, detector end cap, and holder material) was considered and determined. This method is straightforwardly useful in setting up the efficiency calibration curve for NaI(Tl) scintillation detector, when no calibration sources exist in volume shape. The values of the efficiency calculations using theoretical method are compared with the measured ones and the results show that the discrepancies in general for all the measurements are found to be less than 6%.

scholarly journals TNO-MACC_II emission inventory; a multi-year (2003–2009) consistent high-resolution European emission inventory for air quality modelling

2014 ◽  
Vol 14 (20) ◽  
pp. 10963-10976 ◽  
Author(s):  
J. J. P. Kuenen ◽  
A. J. H. Visschedijk ◽  
M. Jozwicka ◽  
H. A. C. Denier van der Gon
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
High Resolution ◽  
Emission Inventory ◽  
Point Sources ◽  
Air Quality Modelling ◽  
Emission Data ◽  
Data Set ◽  
Spatially Distributed ◽  
Reported Data

Abstract. Emissions to air are reported by countries to EMEP. The emissions data are used for country compliance checking with EU emission ceilings and associated emission reductions. The emissions data are also necessary as input for air quality modelling. The quality of these "official" emissions varies across Europe. As alternative to these official emissions, a spatially explicit high-resolution emission inventory (7 × 7 km) for UNECE-Europe for all years between 2003 and 2009 for the main air pollutants was made. The primary goal was to supply air quality modellers with the input they need. The inventory was constructed by using the reported emission national totals by sector where the quality is sufficient. The reported data were analysed by sector in detail, and completed with alternative emission estimates as needed. This resulted in a complete emission inventory for all countries. For particulate matter, for each source emissions have been split in coarse and fine particulate matter, and further disaggregated to EC, OC, SO4, Na and other minerals using fractions based on the literature. Doing this at the most detailed sectoral level in the database implies that a consistent set was obtained across Europe. This allows better comparisons with observational data which can, through feedback, help to further identify uncertain sources and/or support emission inventory improvements for this highly uncertain pollutant. The resulting emission data set was spatially distributed consistently across all countries by using proxy parameters. Point sources were spatially distributed using the specific location of the point source. The spatial distribution for the point sources was made year-specific. The TNO-MACC_II is an update of the TNO-MACC emission data set. Major updates included the time extension towards 2009, use of the latest available reported data (including updates and corrections made until early 2012) and updates in distribution maps.

scholarly journals Dynamics of the cyanobacterial water bloom with focus to Microcystis and its relationship with environmental factors in Brno reservoir

2013 ◽  
Vol 61 (5) ◽  
pp. 1383-1390
Author(s):  
Lucie Straková ◽  
Radovan Kopp ◽  
Eliška Maršálková ◽  
Blahoslav Maršálek
Keyword(s):  
Environmental Factors ◽  
Point Sources ◽  
Water Bloom ◽  
Data Set ◽  
New Information ◽  
Phytoplankton Communities ◽  
Management Effort ◽  
Phosphate Loading ◽  
Treatment Facilities

Our paper brings new information about long-term changes of the phytoplankton communities in the Brno reservoir with the focus on the Microcystis abundance using the semi-monthly monitoring data covering the period 2006–2012. The main aim is to extract from this long-term data set differences in number of Microcystis cells depending on environmental factors. The development of cyanobacteria in Brno reservoir is caused by excessive phosphate loading from wastewater treatment facilities upstream and from non–point sources along the Svratka river. It focuses management effort on upstream controls of reservoir condition. High abundance in millions of cyanobacteria cells in 1ml observed in Brno reservoir before was reduced to values in the order of thousands cells in 1ml in last two years through a combination of measures (liming, precipitation of phosphorus on inflow, aeration and destratification). Phytoplankton composition was also changed and at the expense of cyanobacteria promoted the development of green algae and diatoms.

scholarly journals Progress in radionuclide characterisation in marine sediments using an underwater gamma-ray spectrometer in 2π geometry

2019 ◽  
Vol 21 ◽  
pp. 29
Author(s):  
E. G. Androulakaki ◽  
C. Tsabaris ◽  
M. Kokkoris ◽  
G. Eleftheriou ◽  
D. L. Patiris ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Detection System ◽  
Full Energy Peak ◽  
Gamma Ray Spectrometry ◽  
Peak Efficiency ◽  
Full Energy ◽  
Effective Manner ◽  
Energy Peak ◽  
Full Energy Peak Efficiency

The in-situ gamma-ray spectrometry is a well suited method for seabed mapping applications, since it provides rapid results in a cost effective manner. Moreover, the in-situ method is preferable to the commonly applied laboratory measurements, due to its beneficial characteristics. Therefore, the development of in-situ systems for seabed measurements continuously grows. However, an efficiency calibration of the detection system is necessary for obtaining quantitative results in the full spectral range. In the present work, an approach for calculating the full-energy peak efficiency of an underwater insitu spectrometer for measure- ments on the seabed is presented. The experimental work was performed at the coastal site of Vasilikos (Cyprus). The experimental full-energy peak efficiency of the in-situ was determined in the energy range 1400–2600 keV, by combining the in-situ and laboratory reference measurements. The experimental effi- ciency results were theoretically reproduced by means of Monte Carlo (MC) simulations, using the MCNP5 code.

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