A new analytical method to calibrate cylindrical phoswich and LaBr3(Ce) scintillation detectors

Abbas, Mahmoud I.

doi:10.1016/j.nima.2010.05.025

Cited by 29 publications

(22 citation statements)

References 29 publications

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“…In this section, a new numerical simulation method (NSM) based on the direct method [20][21][22][23][24][25][26][27][28][29][30][31] will be functional to obtain the total and the full-energy peak efficiency of the well-type detector. The well-type detector of outer radius R 2 , cavity radius R 1 , outer height L and cavity depth S will be considered as shown in Figure. 1.…”

Section: A Total and Full-energy Peak Efficienciesmentioning

confidence: 99%

“…[29][30][31] The full-energy peak efficiency ε p(Cylinder) of the well-type detectors can be given based on the following equation: [29][30][31] The double integrals in the both methods, the direct mathematical method and the numerical simulation method (NSM) [20][21][22][23][24][25][26][27][28][29][30][31] for the total and the full-energy peak efficiency of the well-type detector can be evaluated numerically using the trapezoidal rule. A computer program has been written in BASIC programming language to evaluate the efficiency of a well-type detector with respect to the source-to-detector separation.…”

Section: A Total and Full-energy Peak Efficienciesmentioning

confidence: 99%

“…T.A S .P (E) .e −λt .TCS (24) where P(E) is the absolute γ-ray emission probability, N o (E) is the net peak area in counts in presense of coincidence, A S is the activity of source at the time of standardization, t is the elapsed time since standardization, λ is the decay constant, TCS is the correction factor for the coincidence summing and T is the measuring time (in seconds). The uncertainty σ ε of the measured full energy peak efficiency is given by: 34,35 σ ε = ∂ε ∂A where σ A , σ P and σ N are the uncertainties associated with the quantities A S , P(E) and N(E) respectively.…”

Section: Measurements Data Recording and Processingmentioning

confidence: 99%

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Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

et al. 2017

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The 4π NaI(Tl) γ-ray detectors are consisted of the well cavity with cylindrical cross section, and the enclosing geometry of measurements with large detection angle. This leads to exceptionally high efficiency level and a significant coincidence summing effect, much more than a single cylindrical or coaxial detector especially in very low activity measurements. In the present work, the detection effective solid angle in addition to both full-energy peak and total efficiencies of well-type detectors, were mainly calculated by the new numerical simulation method (NSM) and ANGLE4 software. To obtain the coincidence summing correction factors through the previously mentioned methods, the simulation of the coincident emission of photons was modeled mathematically, based on the analytical equations and complex integrations over the radioactive volumetric sources including the self-attenuation factor. The measured full-energy peak efficiencies and correction factors were done by using 152Eu, where an exact adjustment is required for the detector efficiency curve, because neglecting the coincidence summing effect can make the results inconsistent with the whole. These phenomena, in general due to the efficiency calibration process and the coincidence summing corrections, appear jointly. The full-energy peak and the total efficiencies from the two methods typically agree with discrepancy 10%. The discrepancy between the simulation, ANGLE4 and measured full-energy peak after corrections for the coincidence summing effect was on the average, while not exceeding 14%. Therefore, this technique can be easily applied in establishing the efficiency calibration curves of well-type detectors.

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Section: A Total and Full-energy Peak Efficienciesmentioning

confidence: 99%

Section: A Total and Full-energy Peak Efficienciesmentioning

confidence: 99%

Section: Measurements Data Recording and Processingmentioning

confidence: 99%

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Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

et al. 2017

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“…Based on the direct mathematical method [10][11][12][13][14][15][16][17], a new theoretical approach was introduced to determine the detector ef iciency by the use of isotropic radiating axialpoint sources located at different heights from the cylindrical detector upper surface. This method depends on the accurate analytical calculation of the average path length covered by the photon inside the detector active volume and the effective solid angle Ω eff .…”

Section: Mathematical Treatmentmentioning

confidence: 99%

Using Mathematical Procedure to Compute the Attenuation Coefficient in Spectrometry Fields

2017

J Radiol Oncol

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In gamma-ray spectrometry, the analysis of the environmental radioactivity samples (soil, sediment and ash of a living organism) needs to know the linear attenuation coeffi cient of the sample matrix. This coeffi cient is required to calculate the self-absorption correction factor through the sample bulk. In addition, these parameters are very important because the unidentifi ed samples can be different in the composition and density from the reference liquid sources which are usually used for effi ciency calibration in the radioactive monitoring process. The present work is essentially concerned to introduce a mathematical method to calculate the linear attenuation coeffi cient without using any collimator. This method was based mainly on the calculations of the effective solid angle subtended by the source-to-the detector confi gurations, the effi ciency transfer technique and the average path lengths through the samples itself. The method can be used as a tool for the calculation of the linear attenuation coeffi cient of unidentifi ed materials with good facility to use it in the calibration process of γ-ray detectors, particularly in the study of soil samples. The results are compared with the data from NIST-XCOM to show how much the results are in close agreement and to give the validity of the approach.

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“…Most of the authors report agreement with experimentally obtained efficiency values within 10%. One useful way to stun these complications is the use of the straightforward direct mathematical method [4][5][6][7][8][9][10][11][12][13][14][15][16][17] and the experimental measurements. For the polar ( ) and azimuthal ( ) angles, the azimuthal angle, , earns the values from 0 to 2 , while the polar angle, ( ), earns four different values built on the source-to-detector configuration.…”

mentioning

confidence: 99%

Calibration of the Absolute Efficiency of Well-Type NaI(Tl) Scintillation Detector in 0.121–1.408 MeV Energy Range

Oraini

2018

Science and Technology of Nuclear Installations

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Well-type NaI(Tl) detectors are beneficial for low-level photon activity measurements because of the near 4 solid angle that can be gained with them. The detection efficiency can differ with the source-to-detector system geometries, the absorption of the photon in the detector material, and attenuation layers in front of the detector face. For these purposes, the absolute efficiency and the coincidence corrections of the well-type sodium iodide detector have been measured at 0.121-1.408 MeV energy range (obtained from 152 Eu, 137 Cs, and 60 Co radioactive isotopes). The covenant between the experimental (present work) and the published theoretical values is good, with the high discrepancies being less than 1%. Theoretical ViewpointIn the case where an isotropic radiating axial point source is in the detector well-cavity at a distance, ℎ, from cavity bottom (see Figure 1), the path of the photon is well defined by the geometrical solid angle, Ω, subtended by the source-to-detector system at the point of entry. The solid angle is given asThe usage of well-type gamma spectrometry systems is useful for low-level gamma activity measurements. To measure the sample's activity, the photopeak efficiency (FEPE) of the detector for each photon energy is needed. This is usually obtained by the efficiency calibration by the use of standard radioactive sources of identical geometrical shape and dimensions with the samples under study [1]. However, the MC simulations consider the detailed characteristics of the source-to-detector system in calculating the photopeak efficiency. This approach (MC) is inadequate in its accuracy because of the inaccuracy in the parameters accompanying the detector's geometrical dimensions and the structure of the sample [2]. The accuracy is also affected by the uncertainty in nuclear data and the calculation uncertainties of the MC code [3], but these are likely to be as important as the parameters linked with the detector's geometrical dimensions and the material composition of the sample. The physical dimensions provided by suppliers are usually unsatisfactory for accurate efficiency calculations because any slight change in some of these geometrical parameters can cause significant deviations from experimental values. Several studies of the response of -ray spectrometers using MC simulations have been published. Most of the authors report agreement with experimentally obtained efficiency values within 10%. One useful way to stun these complications is the use of the straightforward direct mathematical method [4][5][6][7][8][9][10][11][12][13][14][15][16][17] and the experimental measurements. For the polar ( ) and azimuthal ( ) angles, the azimuthal angle, , earns the values from 0 to 2 , while the polar angle, ( ), earns four different values built on the source-to-detector configuration.

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A new analytical method to calibrate cylindrical phoswich and LaBr3(Ce) scintillation detectors

Cited by 29 publications

References 29 publications

Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

Using Mathematical Procedure to Compute the Attenuation Coefficient in Spectrometry Fields

Calibration of the Absolute Efficiency of Well-Type NaI(Tl) Scintillation Detector in 0.121–1.408 MeV Energy Range

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