Master's Thesis from the year 2013 in the subject Physics - Quantum Physics, grade: -, Shahjalal University of Science and Technology (Department of Physics), course: Nanostructure Physics, language: English, abstract: We have numerically investigated parametric variations of transmission peaks of symmetric rectangular double barrier in non-tunneling regime. We have compared the variations with those for tunneling regime. One of the three variations in non-tunneling regime is completely different from that for tunneling regime warranting rapid dissemination. The book contains background on Quantum Mechanics, Microelectronics and Nanostructure Physics to enable readers assimilate the book completely.

The study of the nucleon-nucleon interaction has a long history, going back to 1932 (just after the discovery of the neutron by James Chadwick). The force is responsible for binding protons and neutrons into atomic nuclei but, unlike the cases of Coulomb or Newtonian gravitational laws, the form of the fundamental NN strong interaction and its constants are a priori unknown. The subject is nevertheless important because the energy associated with the binding of protons and neutrons to form atomic nuclei is the energy used in nuclear power. The authors of the present volume deliver accounts of current research on various aspects of the forces between two or more nucleons and how they relate to experiments in nuclear physics. General overviews, illustrated by appropriate examples, are given both the theoretical and experimental knowledge of nuclear physics that are prerequisites for the understanding of the strong interaction. Two- and three-nucleon forces are among the topics that are addressed and discussed including, for example, how nuclear forces emerge from low-energy QCD via chiral effective field theory. A comprehensive overview is presented of realistic free nucleon-nucleon interactions and also two-nucleon dynamics in a nuclear medium.

Master's Thesis from the year 2011 in the subject Physics - Quantum Physics, grade: -, Shahjalal University of Science and Technology (Department of Physics), course: Nanostructure Physics, language: English, abstract: This book contains a comprehensive account of application of WKB method to pure Physics of nanostructures containing single or symmetric double barrier V(x) in their band model in presence of longitudinal magnetic field applied along x direction. It concentrates on effects on transmission coefficient of single and symmetric double barriers by three dimensional electron gas (3DEG). Analytical expressions for longitudinal magnetic field dependent transmission coefficient of single and symmetric double barrier of general shape are obtained first. These general expressions are then used to obtain analytical expressions of longitudinal magnetic field dependent transmission coefficient of single and symmetric double barriers of many different shapes we encounter in studying nanostructure Physics. This is followed by thorough numerical investigation to bring out effects of longitudinal magnetic field on transmission coefficient of all these barriers. Comparisons with standard results where available showed excellent agreements. Results of numerical investigation have been explained completely. The book makes well documented, with thorough calculation and discussion, pure Physics of semiconductor nanostructures.

In April of 2012 the Plutonium Sustainment program at LANL completed or addressed the following high-level activities: 1) Construction activities on the Low Voltage Electron Beam (LVEB) Welder and Analytical Chemistry gloveboxes have started, successfully closing out MRT L2 Milestone 4195; 2) Completed installation of the Surface Preparation unit in PF4. The unit will be functionally tested in May; 3) Completed casting of the first two near net shape W87 hemishells; 4) Delivered Revision 3 of the Plutonium Sustainment and Manufacturing Study; 5) Completed machining and inspecting the first set of Pollux parts on Precitech 1; 6) Attended the Pu Sustainment Second Quarter Mid-Year Review and the Pit Production Integrated Project Team meeting in Livermore, providing technical updates across the Plutonium Sustainment portfolio; 7) Analyzed the program impact of the LANL Voluntary Separation Program. The analysis determined an impact of 24.6 FTEs and a budget impact of approximately $3.2 Million Dollars of pull back; 8) The Power Supply Assembly Area project received a LANL Pollution Prevention "Gold" award in the category of Cradle-to-Cradle - Cleanouts. A gold award is presented to the number one project in its pollution prevention category. There are currently no major issues associated with achieving MRT L2 Milestones 4195-4198 or the relevant PBIs associated with Plutonium Sustainment. There are no budget issues associated with FY12 final budget guidance. Table 1 identifies all Baseline Change Requests (BCRs) that were initiated, in process, or completed during the month. The earned value metrics overall for LANL are within acceptable thresholds, so no high-level recovery plan is required.

This book dispels popular myths and misconceptions about the dangers of radiation and puts radiation exposures in perspective by showing how much radiation we receive from nature without harm. It also discusses the theories of radiation effects on health and the risks from various sources such as plutonium and the Fukushima reactor leaks.

This work is a study of scintillator-based radiation detectors, and how they perform using both traditional and modern photodetectors. More specifically, we examine how a radiation detector utilizing silicon photomultiplier-based readout performs compared to a traditional photomultiplier tube-based detector. Silicon photomultipliers show great promise in contemporary particle physics for their small size, robustness, and efficiency compared to traditional photodetector systems. We investigated the practicality and efficiency of using silicon photomultipliers in radiation detectors.

This book presents one of the latest measurements (2012 May) of the neutrino velocity performed with the OPERA detector in the CNGS beam. This analysis is different from the previous ones for two main factors. From the CERN side, it uses a dedicated bunched beam instead of the standard high intensity OPERA beam, which allows a better time distribution of the events; while at the LNGS the analysis has been performed using a a dedicated time measurement based on the RPC sub-detector, which is partially independent from the standard OPERA timing system. The obtained result is the one with the smallest statistical uncertainty with respect to the other LNGS experiments and to the OPERA standard analysis. The book starts with an introduction to neutrino physiscs and OPERA experiment. Then, all the measurement details will be explained in order to end up, in the fifth chapter, to the data analysis. As in all the other LNGS experiments, the results consists in the measurement the neutrino Time of Flight with respect to the light Time of Flight. Using the CNGS spectrum the result is then expressed in term of a mass limit on the neutrino.

In this work are used two types of detectors scintillation NaI(Tl) sizes (2"x2"), (1"x1.5")for a comparative study between them and are used two sources of radioactive cobalt Co-60 has two energy (1.33&1.73 MeV), cesium has energy (0.662 MeV) . and calculating the total area of the spectrum space scattering and area of peak optical and portability energy analysis, found the size large for crystal detector leads to probability escape photons outside the crystals to be less because it can reveal again and recorded pulse with pulse recorded by the electron apostate so increase the value of portability energy analysis, and increase the volume of detectors cause increased probability for scattering Compton, In other words the increase in the probability of interaction effect photoelectric be less than the increase in the probability of interaction scattering Compton so the Net Area under the peak at less an increase of scattering spectrum

The vertical position of elongated tokamak plasmas is unstable on the time scale of the eddy currents in the axisymmetric conducting structures. In the absence of feedback control, the plasma would drift vertically and quench on the wall, a situation known as Vertical Displacement Event (VDE), with serious consequences for machine integrity. As tokamaks approach reactor regimes, VDE's cannot be tolerated: vertical feedback control must be robust against system uncertainty and the occurrence of noise and disturbances. At the same time, adaptive routines should be in place to handle unexpected events. The problem of robust control of the vertical position can be formulated in terms of identifying which variables affect vertical stability and which ones are not directly controlled/controllable; identifying the physical region of these variables, and the corresponding most unstable equilibria; and designing the control system to stabilize all equilibria with sufficient margin. The margin should be enough to allow the system to tolerate realistic scenarios of noise and disturbances.

X-ray Computed Tomography (CT) is an invaluable diagnostic imaging tool in clinical practice. However in recent years due to the widespread availability and burgeoning use of Multi-Slice CT (MSCT) scanners, cumulative lifetime radiation dose has increasingly become an issue of public concern. Currently, no real-time radiation dosimeter exists in the diagnostic radiology clinic to directly verify patient skin doses. Moreover, existing CT dose measures such as the Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP) as displayed on the MSCT scanner console do not directly relate to patient dose. The objective of this work is to investigate if the MOSkin dosimeter, based on real-time MOSFET technology, developed at the Centre for Medical Radiation Physics (CMRP) at the University of Wollongong, Australia, may be applied in clinical diagnostic x-ray CT photon beams as a potential clinical CT radiation dosimeter.

In this book, we introduced the concept of Internal transport barrier (ITB) which is generally indulged to grow up the regions of reduced transport which can be helpful for tokomak operation. Internal transport barriers are created near the low order rational surface. i.e. (q = 2, 5/2 and 3). These ITBs are reactive to some conditions with regards to MHD instabilities, which generate a considerable plasma flow, creating magnetic islands, which are wished as probable mechanisms for the development of ITB. Double tearing modes become active due to electron viscosity and the MHD flows in the development the modes is extended from quasi-linear solution in a slab geometry to nonlinear solution in cylindrical geometry for the torus of large aspect ratio. The DTM mediated by electron viscosity is considered to trigger an ITB with non-monotonic q- profiles in advance tokomak (AT) operation.

Experimental and theoretical study of nucleus-nucleus collisions is a diverse field, allowing to address a wide range of fundamental physics. In each domain of beam energies, from the Coulomb barrier to ultrarelativistic energies, characteristic reaction mechanisms contribute and offer possibility to obtain information on the properties of nuclear matter under specific conditions, what allows to determine a global equation of the state and construct a phase diagram of the strongly interacting nuclear matter. The properties of nuclear matter play role in understanding various phenomena in nuclear astrophysics and astro-particle physics, from the primordial nucleosynthesis through production of heavy nuclei, properties of neutron stars, supernova explosions, to the physics of the early Universe. The nucleus-nucleus collisions can be also used as a practical tool for production of very exotic neutron-rich nuclei, thus allowing to enter this yet completely unknown domain with the potential for future discoveries of new nuclear phenomena.

The top quark was not discovered until 1995. Hence, many of its properties could not be measured at a high precision or even not be investigated at all so far. Since the top quark is so heavy, it might play a special role in electroweak symmetry breaking. Especially its coupling to the electroweak (EW) gauge bosons could reveal hints to New Physics, if there were deviations from the predictions by the Standard Model. The total cross section of the top quark pair production process with the additional emission of a photon has been determined with the ATLAS experiment as a first measurement of the couplings of EW gauge bosons to the top quark, since this process provides the largest cross section compared to other EW couplings. The tt cross section measurement has been performed in the semi-leptonic (e/ +jets) decay channel using a template fit method with 1.04 ifb of ATLAS data collected at a center-of-mass energy of 7 TeV in 2011. Various background sources have been investigated, using data-driven methods whenever possible; the impact of systematic uncertainties has been evaluated using a statistical ensemble of pseudo experiments.

This book deals with the elemental profile of some medicinal plants in Bangladesh. In this book authors discussed about the significance of medicinal plants which has a great importance for pharmaceuticals industries for medicine and drug production. Medicinal plants are a unique type of natural product requiring special consideration due to their potential impact on human health. At this modern society medicinal plants are being used as the raw material for the drug industries. Analysis of elemental profile, concentration of major and trace element in different medicinal plants are essential for the betterment of living being. The well-established powerful ion beam analytical technique, Particle Induced X- ray Emission (PIXE) has been utilized in the Van de Graff and Tandem Accelerator facility of Bangladesh Atomic Energy Commission, Savar, Dhaka for the study of elemental profile in different matrices accurately and to obtain information on the total elemental composition related to the morphology of the samples. Similar further study may provide sufficient knowledge to evaluate significance of importance specially related to human health.

This book deals with some of the current problems in nuclear structure and reaction physics. It emphasizes the recent developments on various nuclear cross-section measurements for exploring unstable nuclei using both non-relativistic Skyrme-Hartree-Fock and relativistic mean field theories in conjunction with Glauber model. The diverse properties of nuclei in normal as well as exotic situations are taken into account for discussions. Investigations are also done to demonstrate the possible path for the formation of super-heavy and super super-heavy nuclei. This book gives a clear picture about the formation of heavier nuclei through various nuclear reaction processes.

This book contains detail information on the various reactor physics calculations for core conversion studies of Research Reactor. It provides detail information about the procedure for generating fine group and broad-group cross section libraries for the HEU and the proposed LEU fueled Nigeria Research Reactor (NIRR-1). It also provides information about various reactor models used in the generation of broad group cross section library for reactor physics calculation. In addition, detail information about the development of a 2-D RZ computational model for the HEU and the proposed LEU core configuration can be found in this book. The reactor design parameters generated for the two cores of NIRR-1 were as expected and the result from the preliminary calculation was used to verify the accuracy of the broad group cross section generation process. The data and models developed in this book can be very helpful in future analyses of the HEU/LEU fueled research reactors (i.e. NIRR-1). It can serve as a very useful material during the start up activities and operations of the proposed LEU fueled NIRR-1.

An integrated model for the risk assessment is developed for abandoned radioactive logging sources (Am-241 and Cs-137) in Nigerian oil wells. The model is composed of four components: Source term, Barrier failure model, a geosphere model, a biosphere model, and finally a dose and health effect model to analyse the radionuclide dispersion phenomenon from the abandoned source term to the risk of serious health effects on members of the public (cancer death). In addition to time-dependent annual release rate and dose rate for each radionuclide, the ultimate risk in terms of cancer death rate is estimated. The results show that the highest value of the annual dose for the abandoned radioactive logging sources is less than the individual dose limit to the human body, and the calculated highest cancer death rate is much lower than that of background radiation but higher than that of low-level waste repository. It is concluded that the use of simplified mathematical modelling for the risk assessment of abandoned radioactive sources in oil wells could be an effective tool for development of efficient and acceptable abandonment procedure.