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1
Content available remote

Simulation of LYSO Crystal for the TAC-PF Electromagnetic Calorimeter

100%
Kocak F., Tapan I.
Acta Physica Polonica A
|
2017
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vol. 131
|
issue 3
527-529
EN
In addition to PWO and CsI(Tl) crystals, cerium doped LYSO crystal is considered for the electromagnetic calorimeter part of the Turkish Accelerator Center Particle Factory (TAC-PF) detector, because of its high light yield, fast decay time and good radiation hardness. In this work, LYSO crystals arranged in 3× 3 and 5× 5 matrices have been simulated against photons in the energy range between 50 MeV and 2 GeV, using Geant4 simulation code. Energy resolutions have been estimated considering the contribution of photoelectron statistics coming from the avalanche and PIN photodiodes.
2
Content available remote

Evaluation of Positron Implantation Profiles in Various Materials for ²²Na Source

100%
Dubov L., Akmalova Y., Stepanov S., Shtotsky Y., Shtotsky Y.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 5
1482-1485
EN
Positron implantation profiles in various materials for ²²Na isotope source are discussed. The spatial distribution of positrons in materials with densities from 1 to 21 g/cm³ are simulated using GEANT4 code. The results indicate that depth distributions of thermalized positrons in any homogeneous medium can be described by the sum of two exponential functions. Contribution of the short-range exponent is about 11% in the materials. The both absorption coefficients can be well represented as a function of material density and atomic number. Proposed empirical model agrees well with available experimental data.
3
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Neutron Shielding Properties of Concrete and Ferro-Boron

80%
Sarıyer D., Küçer R., Küçer N.
Acta Physica Polonica A
|
2015
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vol. 128
|
issue 2B
B-201-B-202
EN
The problem of shielding against high-energy neutrons has always attracted a great deal of attention. Neutron shielding requires slowing down energetic neutrons and absorbing with a shield material. Concrete is one of the best known materials for neutron shielding and ferro-boron is described as an alternative shielding material in this study. FLUKA Monte Carlo simulation code was used for the application of shielding calculation. When the simulation results are compared, it is clear that ferro-boron is more effective in neutron shielding than the concrete.
4
Content available remote

The Mathematics of Human Contact: Developing a Model for Social Interaction in School Children

80%
Ashton S., Scalas E., Georgiou N., Kiss I.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 6
1421-1432
EN
In this paper, we provide a statistical analysis of high-resolution contact pattern data within primary and secondary schools as collected by the SocioPatterns collaboration. Students are graphically represented as nodes in a temporally evolving network, in which links represent proximity or interaction between students. This article focuses on link- and node-level statistics, such as the on- and off-durations of links as well as the activity potential of nodes and links. Parametric models are fitted to the on- and off-durations of links, inter-event times and node activity potentials and, based on these, we propose a number of theoretical models that are able to reproduce the collected data within varying levels of accuracy. By doing so, we aim to identify the minimal network-level properties that are needed to closely match the real-world data, with the aim of combining this contact pattern model with epidemic models in future work.
5
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Radiaton Effects on TAC-PF Electromagnetic Calorimeter

80%
Pilicer E., Kocak F., Kilic A., Pilicer F., Tapan I.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 1
190-192
EN
The proposed particle factory detector for Turkish Accelerator Center (TAC-PF) being a regional facility in Turkey will operate at the center of mass energy about 3.77 GeV with designed luminosity of the order of 10³⁴ cm¯² s¯¹. The electromagnetic calorimeter part of the detector is considered to have PbWO₄ and CsI(Tl) crystals coupled with photodiodes. In this study, the exposed dose rate to electromagnetic calorimeter during PF detector operation was estimated by FLUKA Monte Carlo tool. The irradiation effects such as the change of light yield and light transmission of these crystals were investigated to evaluate TAC-PF electromagnetic calorimeter energy resolution.
6
Content available remote

Analysis of Crystal Lattice Deformation by Ion Channeling

80%
Jóźwik P., Sathish N., Nowicki L., Jagielski J., Turos A., Kovarik L., Arey B., Shutthanandan S., Jiang W., Dyczewski J., Barcz A.
Acta Physica Polonica A
|
2013
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vol. 123
|
issue 5
828-830
EN
A model of dislocations has been developed for the use in Monte Carlo simulations of ion channeling spectra obtained for defected crystals. High resolution transmission electron microscopy micrographs show that the dominant type of defects in the majority of ion irradiated crystals are dislocations. The RBS/channeling spectrum is then composed of two components: one is due to direct scattering on randomly displaced atoms and the second one is related to beam defocussing on dislocations, which produce predominantly crystal lattice distortions, i.e. bent channels. In order to provide a correct analysis of backscattering spectra for the crystals containing dislocations we have modified the existing Monte Carlo simulation code "McChasy". A new version of the code has been developed by implementing dislocations on the basis of the Peierls-Nabarro model. Parameters of the model have been determined from the high resolution transmission electron microscopy data. The newly developed method has been used to study the Ar-ion bombarded SrTiO_3 samples. The best fit to the Rutherford backscattering/channeling spectra has been obtained by optimizing the linear combination of two kinds of defects: displaced atoms and bent channels. The great virtue of the Monte Carlo simulation is that unlike a traditional dechanneling analysis it allows quantitative analysis of crystals containing a mixture of different types of defects.
7
Content available remote

Calculations of Temperature Rise in Al, Cu and Fe Photon Collimators for 8-32~MeV Photon Beams

80%
Kuluöztürk Z., Demır N., Akkurt İ.
Acta Physica Polonica A
|
2017
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vol. 132
|
issue 3
1168-1170
EN
We have focused on temperature changes in the collimator at the TARLA bremsstrahlung photon facility. One of the important parameters during the design of an ideal collimator, especially for high-energy photons, is temperature rise in the collimator material. For this purpose, energy deposition in the collimator materials was simulated using the FLUKA Monte Carlo code. Depending on energy deposition values, temperature rise in the collimator materials of Al, Cu and Fe was calculated for photon beams with 8-32 MeV energies.
8
Content available remote

Investigation of Shot Noise in Avalanche Photodiodes

80%
Kocak F., Kilic A., Tapan I.
Acta Physica Polonica A
|
2016
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vol. 129
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issue 4
721-723
EN
PbWO₄ crystal-Hamamatsu S8148 avalanche photodiode (APD) assembly has been used in the barrel section of the CMS electromagnetic calorimeter. The shot noise of the photodiode is one of the important parameters for the energy resolution of the crystal-APD system. The major source of this noise is the statistical variations in the rate at which primary charge carriers are generated and recombine. Thus, the shot noise varies with position of the primary charge carriers generated in photodiode. In this work, the shot noise properties of the Hamamatsu S8148 APD structure and zinc sulfide-silicon (ZnS-Si) isotype heterojunction APD structure have been compared for the PbWO₄ photons. Calculations were made with a Single Particle Monte Carlo simulation technique.
9
Content available remote

Determination of 3-Dimentional Interrogation Zone in Anti-collision RFID Systems with Inductive Coupling by Using Monte Carlo Method

80%
Jankowski-Mihułowicz P., Węglarski M.
Acta Physica Polonica A
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2012
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vol. 121
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issue 4
936-940
EN
The operation of passive anti-collision RFID system is characterized by the interrogation zone which is estimated in any direction of 3D space for a group of electronic transponders. The elements of algorithm for determining the 3D interrogation zone in an inductively coupled anti-collision RFID system have been presented in this paper. The energy conditions have been analyzed in detail. The algorithm based on the Monte Carlo method and the computer program implemented in MathCAD engineering calculation software has been utilized in order to achieve the posed aims
10
Content available remote

Determination of Radiation Shielding Properties of Some Polymer and Plastic Materials against Gamma-Rays

80%
Gurler O., Akar Tarim U.
|
EN
A Monte Carlo code is proposed for determination of mass attenuation coefficients of gamma rays for some polymer and plastic materials. It is based on simulation of interaction processes of gamma rays with the energy of 59.5, 80.9, 140.5, 279, 356.5, 511, 661.6, 1173.2, 1332.5 keV with matter. The method was tested by comparison of the simulation results with the literature values (ANSI/ANS-6.4.3 and GRIC toolkit). The compatible behaviour of mass attenuation coefficients versus incident photon energy for the investigated energy range approves the use of this code for the extended energy range and several materials. Also, the values of half-value layer were calculated for assessment of shielding effectiveness of these materials.
11
Content available remote

Monte Carlo Simulation Studies of Collimator Parameters for TARLA Bremsstrahlung Facility

80%
Kuluöztürk Z., Demır N., Akkurt İ.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 3
796-800
EN
In this work, calculations of the design of bremsstrahlung photon collimator within the scope of the Turkish Accelerator Center Project are presented. At TARLA facility (Turkish Accelerator Radiation Laboratory at Ankara), bremsstrahlung photons created by the accelerated electron beams, are transferred to the experimental area through the collimator, which has a conical geometry with length of 320 cm. In this study, Al, Fe and Cu materials were selected as collimator materials. All interactions between the collimator materials and Gaussian photon beam in 8-32 MeV energy range (8 MeV, 16 MeV, 24 MeV and 32 MeV) were taken into account. The entry radius, geometry and chosen materials are important parameters for collimator design. The photon fluence from collimator, secondary particle distributions and the number of photons, scattered from the collimator, were calculated as functions of these parameters. All calculations were made with the Monte Carlo code FLUKA. According to the results of these simulations, collimator with conical geometry, made of aluminium, with 0.25 cm entry radius, was determined to be appropriate for TARLA bremsstarhlung photon facility of Turkish Accelerator Center.
12
Content available remote

A Random Matrix Approach to Dynamic Factors in Macroeconomic Data

80%
Snarska M.
Acta Physica Polonica A
|
2012
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vol. 121
|
issue 2B
B-110-B-120
EN
We show how random matrix theory can be applied to develop new algorithms to extract dynamic factors from macroeconomic time series. In particular, we consider a limit where the number of random variables N and the number of consecutive time measurements T are large but the ratio N/T is fixed. In this regime the underlying random matrices are asymptotically equivalent to Free Random Variables (FRV).Application of these methods for macroeconomic indicators for Poland economy is also presented.
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