Amirmohammad Beigzadeh; Mohamamdreza Basaadat; Hadi Ardiny
Abstract
This study investigates the response of interferometric calorimeters to ionizing radiations through modeling. These calorimeters are promising devices for research in the field of energy physics of ionizing radiations due to their high precision and low sensitivity to energy loss of ionizing particles ...
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This study investigates the response of interferometric calorimeters to ionizing radiations through modeling. These calorimeters are promising devices for research in the field of energy physics of ionizing radiations due to their high precision and low sensitivity to energy loss of ionizing particles and special features. However, their response to ionizing radiations is not well understood. We develop a simulation framework to modeling the energy deposition and signal production in the main part of the calorimeter. The simulation includes effects such as heat transfer, changes in interference patterns and absorbing energy in calorimetric system. We use the simulation to study the behavior of interferometric calorimeters in various radiation scenarios, including changing the direction of radiation, passage of time and change in the geometry of the absorbing material. The results show that the response of interferometric calorimeters to ionizing radiation is complex and depends on time and absorbing environment. These findings will help in the optimization of interferometric calorimeters for experiments in the field of nuclear physics.
Narges Naghdiani; Amir Abbas Sabouri Dodaran
Abstract
Phosphorene as an anisotropic crystal has been attracted a lot of attention. Since the anisotropy of the crystal is related to the anisotropic properties and it has wide applications, we decided to investigate the thermal and phononic properties of this material. In this article, the band structure and ...
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Phosphorene as an anisotropic crystal has been attracted a lot of attention. Since the anisotropy of the crystal is related to the anisotropic properties and it has wide applications, we decided to investigate the thermal and phononic properties of this material. In this article, the band structure and phonon spectrum of single layer phosphorene have been calculated and then the spectral energy density has been obtained using the molecular dynamics method. The thermal conductivity of phosphorene is calculated for different phonon branches separately, which shows that in the zigzag direction just the LA branch and in the armchair direction both LA and TA branches play very important roles. Among the optical branches, the Bg1 has the greatest effect in both directions. On the other hand, with calculation of figure of merit (ZT) the phosphorene is known as a thermoelectric material.
Mostafa Mehdipoor
Abstract
In this work, the stability and instability of low- frequency electrostatic waves (i.e., ion-acoustic waves) in a dusty plasma consisting of cold ions and non-thermal electrons with a combined Kappa-Cairns distribution are investigated. The basic equations to describe the plasma and the dynamic equation ...
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In this work, the stability and instability of low- frequency electrostatic waves (i.e., ion-acoustic waves) in a dusty plasma consisting of cold ions and non-thermal electrons with a combined Kappa-Cairns distribution are investigated. The basic equations to describe the plasma and the dynamic equation of the present system are determined. It is observed that the presence of the high -energy electrons has a significant effect on the ion-acoustic wave structures. The numerical results have shown that dust particles can also change the stability of the system. Moreover, according to phase space analysis, the presence of homoclinic, nonlinear periodic as well as super-periodic circuits have also been investigated for different conditions. Therefore, in this system, due to a small change in the value of plasma parameters, we will see different behavior for the ion-acoustic waves.
Jamileh Seyedyazdi; Seyed Mohammad Hosseiny; Milad Norouzi
Abstract
In this paper, we use a direct detection in an optical parametric amplifier (OPA) receiver in a lossy and noisy environment and obtain the quantum enhancement factor (QEF) and error probability, which improve the quantum illumination (QI) performance. QI uses the entanglement between the signal and the ...
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In this paper, we use a direct detection in an optical parametric amplifier (OPA) receiver in a lossy and noisy environment and obtain the quantum enhancement factor (QEF) and error probability, which improve the quantum illumination (QI) performance. QI uses the entanglement between the signal and the idler to detect the target. Different parameters of the assumed scheme help us to improve the target detection in the current configuration. Thus, we show that the channel transmissivity function from the transmitter output to the receiver input plays an significant role in improving the QI performance. In addition, we state that the QEF increases with the increase of detector quantum efficiency and transmissivity. One of the most important applications of this work is the manufacturing of QI with optimal performance, which is very beneficial in the country's defense and research industries.
Younes Abedian khorasani; mohsen hatami
Abstract
Recently, array waveguides have been considered for the design of ultra-fast optical processors, especially in the field of artificial intelligence. In this article, we first obtained the propagation constant of each waveguide separately with Lumerical software and calculated the supermodes of a waveguide ...
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Recently, array waveguides have been considered for the design of ultra-fast optical processors, especially in the field of artificial intelligence. In this article, we first obtained the propagation constant of each waveguide separately with Lumerical software and calculated the supermodes of a waveguide array consisting of 6 waveguides using MATLAB software. By using coupled mode theory, we designed a waveguide array with 6 waveguides which consisting of chalcogenide core on the insulator then we obtained the corresponding supermodes. We have shown that the use of chalcogenide materials can be used cause to reduce length of integrate optical circuits, in addition, it can be used for designing of non-linear optical devices due to the high non-linear coefficient of chalcogenide materials.
simin mahnia; Arash phirouznia
Abstract
In this paper, we have modeled and studied a graphene-based system connected to two semi-infinite channels where light (with linear and circular polarizations) shines vertically into the system. Assuming the existence of adjustable Rashba-type spin-orbit coupling caused by the presence of gate voltage, ...
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In this paper, we have modeled and studied a graphene-based system connected to two semi-infinite channels where light (with linear and circular polarizations) shines vertically into the system. Assuming the existence of adjustable Rashba-type spin-orbit coupling caused by the presence of gate voltage, electron and spin transport in the system was investigated. Non-equilibrium Green's function method and tight-binding model have been used for quantum transport calculations. According to the results, it was observed that the spin response is different for the X and Y polarizations, while the two circular polarizations, i.e. right-handed and left-handed, have completely identical behavior in the production of spin polarization. It was also observed that, at zero bias voltage, the amount of electric current generated by light is very low while the generated spin polarization is significantly high. The difference in the spin current created by different polarizations in the system increases with the increase of spin-orbit interaction. Considering the different signs of the spin current for linear polarizations of light in X and Y directions, it can be used as a spin detector of linear polarization of light. It was also observed that the Rashba coupling has no significant effect on the electric current produced by light. At zero bias, the light can produce a weak electric current, the direction of which completely depends on the polarization of the incident light.
Maryam Akbari Nasaji; Dariush Rostamifard; Noushin Pishbin; Ali Nasiri
Abstract
The primary radiation rays in focal plasma is a soft X-ray. Pin diode detectors are generally used to measure soft X-rays in an integral and time-lapse manner. PBX65 can be mentioned among the most common pin diodes used in soft x-ray detection of miniature generators. This article uses attenuating filters ...
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The primary radiation rays in focal plasma is a soft X-ray. Pin diode detectors are generally used to measure soft X-rays in an integral and time-lapse manner. PBX65 can be mentioned among the most common pin diodes used in soft x-ray detection of miniature generators. This article uses attenuating filters (beryllium and aluminum) to measure soft X-rays in front of the pin diode spectrometer channels. In addition, the effect of thickness on soft X-ray intensity has been investigated experimentally. Finally, the lower thickness of the filter shows a higher transmission of X-rays. There are several factors in photodiode response and X-ray efficiency measurement of devices. The geometry of the filter maker, quantum efficiency of the photodiode, absorbers like the device, and production of X-rays from the working gas of the device. The effect of these factors has been investigated in this article.
Mohammadreza Farahmand; Mahmood Moradi; Abdolrasoul Gharaati
Abstract
sources, among which, semiconductor quantum dots are particularly attractive thereby quantum dots embedded in semi-conductor nanowires. Quantum dots with different energy levels and wave functions which leeds the absorption and emission of different photons, can have various applications. In this article, ...
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sources, among which, semiconductor quantum dots are particularly attractive thereby quantum dots embedded in semi-conductor nanowires. Quantum dots with different energy levels and wave functions which leeds the absorption and emission of different photons, can have various applications. In this article, firstly, the electronic properties of two indium arsenide quantum dots located symmetrically at the center of galium arsenide quantum wire were investigated. This is done by numerically solving the Schrodinger equation, using Comsol software and the finite element method. The energy eigenvalues, and eigenfunctions were calculated and compared with other similar works. The main research here is solving and using the self-consistent Poisson-Schrödinger equation for the various nanostructures. Then, by using the self-consistent Poisson-Schrödinger equation, the effect of impurities on the electronic properties of the quantum nano wire and the structure of the two quantum spheres inside the quantum wire has been obtained. These results are compared with the results of solving the Schrödinger equation in limiting conditions. The obtained results indicate that the effect of impurities are significant, while the effect of temperature from low temperatures to ambient temperature is insignificant, but the effect of changes in internal radii and the amount of contaminated impurity on the electronic properties of the nanostructure is significant and can be calculated.
Fatemeh Moslemi; Masoomeh Nemati
Abstract
The transmission spectrum and faraday rotation of a magnetophotonic crystal structure with symmetric arrangment of (AB)m InAs (BA)m are investigated using the 4×4 transfer matrix method. A, B layers are the common dielectric materials and InAs anisotropic semiconductor acts as the defect layer. ...
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The transmission spectrum and faraday rotation of a magnetophotonic crystal structure with symmetric arrangment of (AB)m InAs (BA)m are investigated using the 4×4 transfer matrix method. A, B layers are the common dielectric materials and InAs anisotropic semiconductor acts as the defect layer. In the photonic band gap of the structure, two defect mode are appeared with faraday rotation in the same frequency region of the defect modes. In this paper, it is shown that by changing structural parameters, number of periodicity and defect layer thickness, it is possible to design a structure to enhance the faraday rotation with a relavity high transmission. The effect of the external parameters, magnetic field intensity and incident angle, on enhancing the faraday rotation and transmission are studied and optimized. The highest faraday rotation with relatively high transmission achieved in this work occur in 20o incident angle is -44.23o . The results show that frequency location of the defect modes in the transmission spectrum and faraday rotation depend on incident field direction and the defect layer thickness but are independent of the changes of the magnetic field and the number of the structure period.
Mohaddeseh Rezakhaninezhad; Hamid Reza Baghshahi; Mohammad Javad Faghihi
Abstract
In this paper, a new class of nonclassical states of radiation is presented. For this purpose, after clarifying the application of displaced number states align with expressing the significance of noiseless signal amplification, amplified displaced number states are introduced. Then, examining some of ...
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In this paper, a new class of nonclassical states of radiation is presented. For this purpose, after clarifying the application of displaced number states align with expressing the significance of noiseless signal amplification, amplified displaced number states are introduced. Then, examining some of the most important criteria, such as Mandel’s parameter, second-order correlation function, Vogel’s characteristic function, and Wigner distribution function, the nonclassicality of the introduced quantum states is studied. In each case, the roles of gain factor and number of photons of the number states in the above-mentioned physical quantities are discussed. The numerical results show remarkable values of sub-Poissonian statistics of the field and photon antibunching. Afterward, as the necessary and sufficient condition for the nonclassicality of a quantum state, the behavior of the Vogel’s characteristic function is analyzed. We will see that the Vogel function for quantum states of interests goes beyond the value of characteristic function of the ground state, which results in the nonclassicality of the introduced states. Moreover, the negativity of the Wigner–Weyl distribution function, as another appearance of the nonclassicality of the considered states, is also observed. Consequently, the mentioned evidence implies that the amplified displaced number states can be regarded as successful candidates for nonclassical light.
Seyed Mohammad Ghazi; Fahimeh Behzadi
Abstract
In this article, a theoretical study has been done using quantum calculations in the framework of density functional theory on the stability of structures, electronic properties and vibrational frequencies of sodium nanoclusters Na_n (n=10-48). By calculating the coordination number, it was determined ...
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In this article, a theoretical study has been done using quantum calculations in the framework of density functional theory on the stability of structures, electronic properties and vibrational frequencies of sodium nanoclusters Na_n (n=10-48). By calculating the coordination number, it was determined that the first motif that is created and repeated in these nanoclusters is an icosahedron, and as the number of atoms increases, the number of these icosahedra is also increased. The second difference of energy and the gap between the last occupied level and the first unoccupied level show that the more stable nanoclusters have an even number of electrons and also have a more spherical shape than the rest of them. The two sharp peaks in the second difference of energy diagram are related to Na_20 and Na_40 respectively, which indicate the greater stability of these two nanoclusters compared to the others and also match the magic numbers.In terms of geometrical shape, the nanoclusters were divided into 4 categories using the shape deformation parameter, and their correlation and relationship with the infrared intensity spectrum was investigated
Hamzeh Ghorbani; parviz kameli; mahin eshraghi
Abstract
Ferrites are one of the magnetic ceramics that, due to their wide application in various industries, scientists have always tried to optimize their structural, magnetic, electrical, etc. properties. One of the analyzes that scientists use for structural characterization is Raman spectroscopy. In this ...
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Ferrites are one of the magnetic ceramics that, due to their wide application in various industries, scientists have always tried to optimize their structural, magnetic, electrical, etc. properties. One of the analyzes that scientists use for structural characterization is Raman spectroscopy. In this research, cobalt ferrite nanoparticles doped with cadmium, as well as cadmium-chromium were synthesized. In order to confirm the spinel structure and obtain the structural parameters, X-ray diffraction analysis was performed. The particle size obtained between 53 and 59 nm and the lattice parameter between 8.39 and 8.52 angstroms. The photographs obtained from the Field Emission-Scanning Electron Microscope (FE-SEM) showed that the structure of nanoparticles consists of multi-particle aggregates consisting of spherical nanometer particles. Then the synthesized nanoparticles were subjected to Raman analysis, in addition to determining the spinel type of the samples, the changes in the cations distribution in the spinel lattice were investigated. In this analysis, it was observed that in addition to the five active Raman modes (A1g, Eg, 3T2g) that are characteristic of the spinel structure, other peaks that are characteristic of the mixed spinel structure are also visible in the Raman spectrum of the samples.