فهرس المقالات Neutron

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  1 - Number-projected isovector neutron-proton pairing effect in odd mass nuclei
  Amine Berbiche Mohamed Fellah Nassima H Allal
  10.1186/2251-7235-8-2
  AbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd mass nuclei. With this aim, we had to first establish the expression of the projector for such أکثر

  AbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd mass nuclei. With this aim, we had to first establish the expression of the projector for such systems. Expressions of the ground state and its energy have been exhibited. The model has been numerically tested in the framework of a schematic model.PACS21.60.-n; 21.30.Fe تفاصيل المقالة
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  2 - Fast and thermal neutron radiographies based on a compact neutron generator
  Jacob G Fantidis Bandekas V Dimitrios Potolias Constantinos Vordos Nick
  10.1186/2251-7235-6-20
  AbstractFast neutrons that are produced via compact neutron generators have been used for thermal and fast neutron radiographies. In order to investigate objects with different sizes and produce radiographs of variable qualities, the proposed facility has been considere أکثر

  AbstractFast neutrons that are produced via compact neutron generators have been used for thermal and fast neutron radiographies. In order to investigate objects with different sizes and produce radiographs of variable qualities, the proposed facility has been considered with a wide range of values for the parameters characterizing the thermal and fast neutron radiographies. The proposed system is designed according to article 4 of the Restriction of Hazardous Substances Directive 2002/95/EC, hence, excluded the use of cadmium and lead, and has been simulated using the MCNP4B code. The Monte Carlo calculations were carried out using three different neutron sources: deuterium-deuterium, deuterium-tritium, and tritium-tritium neutron generators. تفاصيل المقالة
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  3 - Investigation of the optimal material type and dimension for spallation targets using simulation methods
  Seyed Amir Hossein Feghhi S. A. H. Feghhi Zohreh Gholamzadeh C. Tenreiro Claudio Tenreiro
  10.1186/2251-7235-8-1
  AbstractAccelerator-driven systems are extensively developed to generate neutron sources for research, industrial, and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons. Computational methods are efficiently utiliz أکثر

  AbstractAccelerator-driven systems are extensively developed to generate neutron sources for research, industrial, and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons. Computational methods are efficiently utilized to simulate neutronic behavior of a spallation target. MCNPX 2.6.0 is used as a powerful code based on Monte Carlo stochastic techniques for spallation process computation. This code has the ability to transport different particles using different physical models.In this paper, MCNPX has been utilized to calculate the leaked neutron yield from Pb, lead-bismuth eutectic (LBE), W, Ta, Hg, U, Th, Sn, and Cu cylindrical heavy targets. The effects of the target thickness and diameter on neutron yield value have been investigated via the thickness and diameter variations between 5 to 30 cm and 5 to 20 cm, respectively. Proton-induced radionuclide production into the targets as well as leaked neutron spectra from the targets has been calculated for the targets of an optimum determined dimension. The 1-GeV proton particle has been selected to induce spallation process inside the targets. The 2-mm spatial FWHM distribution has been considered for the 1-mA proton beam.Uranium target produced the highest leaked neutron yield with a 1.32 to 3.7 factor which overweighs the others. A dimension of 15 × 60 cm is suggested for all the cylindrical studied spallation targets. Th target experienced the highest alpha emitter radionuclide production while lighter elements such as Cu and Sn bore the lowest radiotoxicity. LBE liquid spallation target competes with the investigated solid targets in neutronic point of view while has surpass than volatile liquid Hg target. تفاصيل المقالة
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  4 - Number projected isovector neutron–proton pairing effect in odd-mass nuclei
  Amine Berbiche Mohamed Fellah Nassima H. Allal
  10.1007/s40094-014-0118-8
  AbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd-mass nuclei. With this aim, we had to first establish the expression of the projector for such أکثر

  AbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd-mass nuclei. With this aim, we had to first establish the expression of the projector for such systems. Expressions of the ground state and its energy have been exhibited. The model has been numerically tested in the framework of a schematic model. تفاصيل المقالة
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  5 - Generalization of the analytical solution of neutron point kinetics equations with time-dependent external source
  M. Seidi S. Behnia R. Khodabakhsh
  10.1007/s40094-014-0150-8
  AbstractPoint reactor kinetics equations with one group of delayed neutrons in the presence of the time-dependent external neutron source are solved analytically during the start-up of a nuclear reactor. Our model incorporates the random nature of the source and linear أکثر

  AbstractPoint reactor kinetics equations with one group of delayed neutrons in the presence of the time-dependent external neutron source are solved analytically during the start-up of a nuclear reactor. Our model incorporates the random nature of the source and linear reactivity variation. We establish a general relationship between the expectation values of source intensity and the expectation values of neutron density of the sub-critical reactor by ignoring the term of the second derivative for neutron density in neutron point kinetics equations. The results of the analytical solution are in good agreement with the results obtained with numerical solution. تفاصيل المقالة
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  6 - تعیین دز جذبی نسبت به بافت کبد در عمل رادیوتراپی توسط نوترون
  سید علیرضا موسوی شیرازی
  در این مقاله ، یک بافت کبد واقعی همراه با بافت‎های نرمی که در قسمت جلوی آن قرار دارند (مانند چربی و پوست) به عناصر تشکیل دهندۀشان تجزیه شده‎است و سپس مورد تابش دهی به‎وسیلۀ نوترون در عمل رادیوتراپی قرار گرفته‎است. این مطالعه می تواند برای همۀ بافت های کب أکثر

  در این مقاله ، یک بافت کبد واقعی همراه با بافت‎های نرمی که در قسمت جلوی آن قرار دارند (مانند چربی و پوست) به عناصر تشکیل دهندۀشان تجزیه شده‎است و سپس مورد تابش دهی به‎وسیلۀ نوترون در عمل رادیوتراپی قرار گرفته‎است. این مطالعه می تواند برای همۀ بافت های کبد درخصوص درمان سرطان قرار گیرد. مقادیر دز جذبی در یک بافت کبد در نتیجۀ برخورد بین نوترون ها با هستۀ عناصر تشکیل دهندۀ بافت کبد تعیین شده‎است. در این مطالعه‌ی توصیفی – مقطعی بافت کبد ، مورد تابش دهی به وسیلۀ نوترون قرار داده‎شد و مقادیر دز جذبی یا انرژی جذب شده در هر یک از مواد تشکیل دهندۀ بافت کبد بدست آورده‎شد. نتایج با استفاده از آمار توصیفی با استفاده از نرم افزار Excel V2010 و SPSS V16 تجزیه و تحلیل شدند. یافته‎های مطالعه‌ حاکی از آن ‎است که اگر ترکیبات موجود در بافت کبد ، پی و پوست به عناصر تشکیل دهنده شان نظیر هیدروژن ، اکسیژن ، کربن ، نیتروژن ، سولفور و سدیم تجزیه شوند ، مقادیر دزهای جذبی نسبت به عناصر تشکیل دهندۀ بافت کبد ، پی و پوست که هر یک دارای اعداد جرمی مختلف می باشند. بیشترین مقادیر دز جذبی به عنصر هیدروژن و به سبب فراوانی آن مربوط است. تفاصيل المقالة