Analytical-numerical formula for estimating the characteristics of a cylindrical NaI(Tl) gamma-ray detector with a side-through hole

Thabet Abouzeid A.,Badawi Mohamed S. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10

NaI(Tl) scintillation materials are considered to be one of many materials that are used exclusively for gray detection and spectroscopy. The gamma-ray spectrometer is not an easy-to-use device, and the accuracy of the numerical values must be carefully checked based on the rules of the calibration technique. Therefore, accurate information about the detection system and its effectiveness is of greater importance. The purpose of this study is to estimate, using an analytical-numerical formula (ANF), the purely geometric solid angle, geometric efficiency, and total efficiency of a cylindrical NaI(Tl) g-ray detector with a side-through hole. This type of detector is ideal for scanning fuel rods and pipelines, as well as for performing radio-immunoassays. The study included the calculation of the complex solid angle, in combination with the use of various points like gamma sources, located axially and non-axially inside the through detector side hole, which can be applied in a hypothetical method for calibrating the facility. An extended g-ray energy range, the detector, source dimensions, “source-to-detector” geometry inside the side-through hole, path lengths of g-quanta photons crossing the facility, besides the photon average path length inside the detector medium itself, were studied and considered. This study is very important for an expanded future article where the radioactive point source can be replaced by a volume source located inside the side-trough hole of the detector, or by a radioactive pipeline passing through the well. The results provide a good and useful approach to a new generation of detectors that can be used for lowlevel radiation that needs to be measured efficiently.

Poster Session : PS 0027 ; Cardiology : “Elite Child Athletes are Our Future” Cardiac Adaptation to Swim Training in Prepubertal Egyptian Athletes

( Magdy Abouzeid ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: The elite child athletes are one who has superior athletic talent. Monofi n (a single surface swim fi n) swimming already proved to be the most effi cient method of swimming for human being. This is a novel descriptive study examining myocardial function indices in prepubertal monofi n children. Methods: 14 elite monofi n children aged 11.95 years (± 1.09 yr) took part for (LTMT). All subjects underwent two-dimension, M-mode, and Doppler echocardiography before and after training to evaluate cardiac dimensions and function; septal and posterior wall thickness. Statistical methods of SPSS, means ± SD and paired t test, % of improvement were used Results: There was signifi cant difference (p<0.01) and % improvement for all echocardiography parameter after (LTMT). Inter ventricular septal thickness in diastole and in systole increased by 27.9 % and 42.75 %. Left ventricular end systolic dimension and diastole increased by 16.81 % and 42.7 % respectively. Posterior wall thickness in systole very highly increased by 283.3 % and in diastole increased by 51.78 %. Left ventricular mass in diastole and in systole increased by 44.8 % and 40.1 % respectively. Stroke volume (SV) and resting heart rate (HR) signifi cant changed (sv) 25 %, (HR) 14.7 %. Conclusions: Monofi n training is an effective sport to enhance “Heart athlete`s” for children, because the unique swim fi n tool and create propulsion and overcome resistance. Further researches are needed to determine the effects of monofi n training on right ventricular in child athletes.

New mathematical approach to calculate the geometrical efficiency using different radioactive sources with gamma-ray cylindrical shape detectors

Thabet, Abouzeid A.,Hamzawy, A.,Badawi, Mohamed S. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

The geometrical efficiency of a source-to-detector configuration is considered to be necessary in the calculation of the full energy peak efficiency, especially for NaI(Tl) and HPGe gamma-ray spectroscopy detectors. The geometrical efficiency depends on the solid angle subtended by the radioactive sources and the detector surfaces. The present work is basically concerned to establish a new mathematical approach for calculating the solid angle and geometrical efficiency, based on conversion of the geometrical solid angle of a non-axial radioactive point source with respect to a circular surface of the detector to a new equivalent geometry. The equivalent geometry consists of an axial radioactive point source with respect to an arbitrary elliptical surface that lies between the radioactive point source and the circular surface of the detector. This expression was extended to include coaxial radioactive circular disk source. The results were compared with a number of published data to explain how significant this work is in the efficiency calibration procedure for the γ-ray detection systems, especially in case of using isotropic radiating γ-ray sources in the form of point and disk shapes.

Opportunistic Spectrum Access Based on a Constrained Multi-Armed Bandit Formulation

Ai, Jing,Abouzeid, Alhussein A. The Korea Institute of Information and Commucation 2009 Journal of communications and networks Vol.11 No.2

Tracking and exploiting instantaneous spectrum opportunities are fundamental challenges in opportunistic spectrum access (OSA) in presence of the bursty traffic of primary users and the limited spectrum sensing capability of secondary users. In order to take advantage of the history of spectrum sensing and access decisions, a sequential decision framework is widely used to design optimal policies. However, many existing schemes, based on a partially observed Markov decision process (POMDP) framework, reveal that optimal policies are non-stationary in nature which renders them difficult to calculate and implement. Therefore, this work pursues stationary OSA policies, which are thereby efficient yet low-complexity, while still incorporating many practical factors, such as spectrum sensing errors and a priori unknown statistical spectrum knowledge. First, with an approximation on channel evolution, OSA is formulated in a multi-armed bandit (MAB) framework. As a result, the optimal policy is specified by the wellknown Gittins index rule, where the channel with the largest Gittins index is always selected. Then, closed-form formulas are derived for the Gittins indices with tunable approximation, and the design of a reinforcement learning algorithm is presented for calculating the Gittins indices, depending on whether the Markovian channel parameters are available a priori or not. Finally, the superiority of the scheme is presented via extensive experiments compared to other existing schemes in terms of the quality of policies and optimality.

Study on the Effect of the Self-Attenuation Coefficient on γ-ray Detector Efficiency Calculated at Low and High Energy Regions

Ahmed. M. El-Khatib,ABOUZEID. A. THABET,MOHAMED. A. ELZAHER,MOHAMED. S. BADAWI,BOHAYSA. A. SALEM 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.2

The present work used the efficiency transfer method used to calculate the full energy peak efficiency (FEPE) curves ofthe (2"*2" & 3"*3") NaI (Tl) detectors based on the effective solid angle subtended between the source and the detector. Thestudy covered the effect of the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius)on the detector efficiency. 152 An Eu aqueous radioactive source covering the energy range from 121.78 keV up to 1408.01keV was used. In this study an empirical formula was deduced to calculate the difference between the measured and thecalculated efficiencies [without self attenuation] at low and high energy regions. A proper balance between the measured andcalculated efficiencies [with self attenuation] was achieved with discrepancies less than 3%, while reaching 39% forcalculating values [without self attenuation] due to working with large sources, or for low photon energies.

Opportunistic Spectrum Access Based on a Constrained Multi-Armed Bandit Formulation

Jing Ai,Alhussein A. Abouzeid 한국통신학회 2009 Journal of communications and networks Vol.11 No.2

Tracking and exploiting instantaneous spectrum opportunities are fundamental challenges in opportunistic spectrum access (OSA) in presence of the bursty traffic of primary users and the limited spectrum sensing capability of secondary users. In order to take advantage of the history of spectrum sensing and access decisions, a sequential decision framework is widely used to design optimal policies. However, many existing schemes, based on a partially observed Markov decision process (POMDP) framework, reveal that optimal policies are non-stationary in nature which renders them difficult to calculate and implement. Therefore, this work pursues stationary OSA policies, which are thereby efficient yet low-complexity, while still incorporating many practical factors, such as spectrum sensing errors and a priori unknown statistical spectrum knowledge. First, with an approximation on channel evolution, OSA is formulated in a multi-armed bandit (MAB) framework. As a result, the optimal policy is specified by the wellknown Gittins index rule, where the channel with the largest Gittins index is always selected. Then, closed-form formulas are derived for the Gittins indices with tunable approximation, and the design of a reinforcement learning algorithm is presented for calculating the Gittins indices, depending on whether the Markovian channel parameters are available a priori or not. Finally, the superiority of the scheme is presented via extensive experiments compared to other existing schemes in terms of the quality of policies and optimality.

Human Resource Management and Organizational Performance-The Mediating Role of Organizational Commitment : Empirical Evidence from the Public Sector in a Non-Western Context

ZEIDAN, SUSAN,FARAH, ASSAAD,ABOUZEID, SHADI 이화여자대학교 국제통상협력연구소 2012 Asian International Studies Review Vol.13 No.1

Research in the field of strategic human resource management has attracted a great deal of interest because of its likely impact on bottom line outcomes. Recent work in this area posits that organizational commitment can mediate the relationship between human resource management (HRM)practices and organizational performance. However, most of the studies conducted in this area were concentrated on samples gathered from private organizations, and mainly in western countries. In this paper, the impact of HRM on organizational performance is assessed. Furthermore, this research attempts to shed more light on the ‘black box’ between human resource practices and organizational performance by investigating the mediating function of organizational commitment in two public sector entities within the United Arab Emirates (UAE). The mediating factor was tested through regression of the data collected from a sample of 371 workers who are employed within the two aforementioned public sector entities. The main findings are in line with the outcomes of earlier HRM-performance studies conducted in western public and private sectors, where employers can expect improved organizational performance when their employees' perceptions of the HRM practices within the organization tend to foster an increase in their organizational commitment.

Calibration of cylindrical NaI(Tl) gamma-ray detector intended for truncated conical radioactive source

Mohamed S. Badawi,Abouzeid A. Thabet 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.4

The computation of the solid angle and the detector efficiency is considering to be one of the mostimportant factors during the measuring process for the radioactivity, especially the cylindrical g-rayNaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health,the gamma-ray radiation detectors grow to be the main essential instruments in radiation protectionsector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiencyof the g-ray spectrometry setup is established. The formulas are suitable for any type of source-todetector shape and can be valuable to determine the full-energy peak and the total efficiencies andP/T ratio of cylindrical g-ray NaI(Tl) detector setup concerning the truncated conical radioactivesource. This methodology is based on estimate the path length of g-ray radiation inside the detectoractive medium, inside the source itself, and the self-attenuation correction factors, which typically useto correct the sample attenuation of the original geometry source. The calculations can be completedin general by using extra reasonable and complicate analytical and numerical techniques than thestandard models; especially the effective solid angle, and the detector efficiency have to be calculatedin case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be usedfor the straight calculations of the g-ray detector efficiency after the computation of improvement thatneed in the case of g-g coincidence summing (CS). The (NSM) confirmation of the development createdby the efficiency transfer method has been achieved by comparing the results of the measuringtruncated conical radioactive source with certified nuclide activities with the g-ray NaI(Tl) detector,and a good agreement was obtained after corrections of (CS). The methodology can be unlimited tofind the theoretical efficiencies and modifications equivalent to any geometry by essential sufficientlythe physical selective considered situation.

STUDY ON THE EFFECT OF THE SELF-ATTENUATION COEFFICIENT ON γ-RAY DETECTOR EFFICIENCY CALCULATED AT LOW AND HIGH ENERGY REGIONS

El-Khatib, Ahmed M.,Thabet, Abouzeid A.,Elzaher, Mohamed A.,Badawi, Mohamed S.,Salem, Bohaysa A. Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.2

The present work used the efficiency transfer method used to calculate the full energy peak efficiency (FEPE) curves of the (2"*2" & 3"*3") NaI (Tl) detectors based on the effective solid angle subtended between the source and the detector. The study covered the effect of the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius) on the detector efficiency. $^{152}$ An Eu aqueous radioactive source covering the energy range from 121.78 keV up to 1408.01 keV was used. In this study an empirical formula was deduced to calculate the difference between the measured and the calculated efficiencies [without self attenuation] at low and high energy regions. A proper balance between the measured and calculated efficiencies [with self attenuation] was achieved with discrepancies less than 3%, while reaching 39% for calculating values [without self attenuation] due to working with large sources, or for low photon energies.

Combined Measurement of the Higgs Boson Mass inppCollisions ats=7and 8 TeV with the ATLAS and CMS Experiments

Aad, G.,Abbott, B.,Abdallah, J.,Abdinov, O.,Aben, R.,Abolins, M.,AbouZeid, O. S.,Abramowicz, H.,Abreu, H.,Abreu, R.,Abulaiti, Y.,Acharya, B. S.,Adamczyk, L.,Adams, D. L.,Adelman, J.,Adomeit, S.,Adye, American Physical Society 2015 Physical Review Letters Vol.114 No.19

<P>A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H --> gamma gamma and H --> ZZ --> 4l decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is m(H) = 125.09 +/- 0.21 (stat) +/- 0.11 (syst) GeV.</P>