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1
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Measurement of Energy Loss Straggling of Relativistic Electrons in Thin Aluminum Foils

100%
Ramesh Babu S., Badiger N.
Acta Physica Polonica A
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2016
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vol. 129
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issue 6
1118-1123
EN
The mean energy loss straggling per unit path length of relativistic electrons in aluminum has been determined by recording electrons with a Si(Li) detector coupled to 8K multi channel analyzer. The energy loss straggling is determined by measuring the full width at half maximum of the spectrum of the incident and transmitted internal conversion electrons of energies 942 keV and 1016 keV from Bi²⁰⁷ source. Measured values have been compared with theoretical values indicating that the present method can be used for measuring mean energy loss straggling.
2
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Stopping Power Calculations for Partially Stripped Projectiles in High Energy Region

63%
Tufan M., Köroğlu A., Gümüş H.
Acta Physica Polonica A
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2005
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vol. 107
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issue 3
459-472
EN
The electronic stopping cross-section is calculated in the spirit of the Bethe theory. Interaction potential between projectile and target is regarded to have a Coulombic character and we have modified it to take into account velocity dependences on a number of bound electrons of projectile and an effective charge of projectile and target. These velocity dependences are obtained from the Bohr adiabatic criterion using the Thomas-Fermi atomic model. We have get the electronic stopping cross-section expression using the Bethe approximation; we obtained the stopping cross-section of C and Al for C, O, and Si ions from this expression and compared our results with experiment and other theoretical calculations.
3
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Change ofα-Particle Stopping Power in Ni at the Curie Temperature

63%
Pawłowski B., Moneta M.
Acta Physica Polonica A
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2003
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vol. 103
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issue 5
433-440
EN
Experiments showing that the ion-solid state interaction characteristics change at T_C, the Curie temperature, were recapitulated. It was shown that the experimental results for the increase in theα-particles stopping power in Fe and Gd foils can be approximately described by the Bethe theory of stopping power with Stoner model for band ferromagnetism. The experimental result for increase in 5.486 MeVα-particles stopping power in 0.89 mg/cm^2 Ni foil after transition from ferro- to paramagnetic phase at T_C was presented and it was shown to be in a good correlation with the previous data and with the theoretical evaluation.
4
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Photon Attenuation Coefficients of Iron Doped Clay at 662~keV

63%
Akkurt I., Mavi B., Gunoglu K., Akyıldırım H., Canakci H.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
343-344
EN
After discovery of the radioactivity by Becquerel, radiation started to be used in large fields and it became part of our life nowadays. Using radiation from industry to medicine brings its hazardous effect and radiation protection developed in physics in parallel with the utilization of radiation. Although time, distance and shielding are the main rules to be protected from radiation, shielding is most effective way. In this case development of shielding materials becomes important. Clay is an interesting material and besides using it for different purposes it can be used as plaster material in building construction. In this study iron doped into clay samples and radiation shielding properties has been measured at 662 keV gamma rays. The measurements have been performed using gamma spectrometer system which contains NaI(Tl) and 16k multichannel analyser.
5
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Cement Paste as a Radiation Shielding Material

63%
Akkurt İ., Günoğlu K., Başyiğit C., Kılınçarslan Ş., Akkaş A.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
341-342
EN
Cement, mainly, natural limestone and clay mixture after being heated at high temperature is obtained by milling and it is defined as a hydraulic binder material. Especially, cement is used in production concrete. The photon attenuation coefficient (μ, cm^{-1}) for cement paste has been measured using gamma spectrometer containing NaI(Tl) detector and MCA at 835, 1173, and 1332 keV. Cement paste was prepared with types of Portland cement which is CEM I 52,5 R- and CEN reference sand has been used according to TS EN 196-1 standard. The mass attenuation coefficients have been calculated at photon energies of 1 keV to 100 GeV using XCOM and the obtained results were compared with the measurements at 835, 1173, and 1332 keV.
6
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Stopping of Slow H-, He-, Li- and Be-Like Projectiles in Electron Gas

63%
Moneta M.
Acta Physica Polonica A
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1998
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vol. 93
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issue 5-6
775-783
EN
Results of calculations of the electronic stopping power and the energy loss straggling for low velocity H-, He-, Li- and Be-like projectiles in the degenerate electron gas are reported. The Hartree-Fock-Slater description of the projectile and the dielectric function method were used. The size parameter Z__{min} of the charge distributions calculated from a variational principle depends on the characteristics of the medium. The stopping and straggling effective charges Z_{ef} of a projectile were analysed. They were found to differ with each other and to depend on the one-electron radius r_{s}, on the projectile atomic number Z_{i} and on the number of electrons N_{i} carried by the projectile.
7
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Effective Ion Charge

63%
Moneta M.
Acta Physica Polonica A
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1996
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vol. 89
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issue 5-6
581-594
EN
The impact parameter dependent energy transfer and random stopping power for ions carrying electrons were determined within the first-order Born approximation. The ion and atom were described by many-electron ground states. The excitations and ionizations of both collision partners were taken into account, but exchange of electrons was neglected. With the Bethe sum rule and closure relation, the random stopping was shown to have the Bethe form. For the Moliere form factors the analytical results were obtained. The effective charge was discussed in the random and channelling conditions. Comparison with some previous calculations was carried out.
8
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Characteristics of H- to Be-like Ions Immersed in Electron Gas

63%
Moneta M.
Acta Physica Polonica A
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2001
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vol. 99
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issue 6
643-653
EN
The electronic characteristics of H- to Be-like ions immersed in degenerate electron gas were calculated. The ion was described within the Hartree- Fock-Slater formalism and the medium by the dielectric function. The ion's electrons repulsion, screening and exchange effects and, additionally, the self-binding of an electron due to the polarisation of the medium were included in the description. The results were compared with the reference corresponding to the characteristics for ions in vacuum.
9
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Determination of Radiation Attenuation Coefficients of Concretes in Different Densities

63%
Akkurt İ., Günoğlu K., Başyiğit C., Akkaş A.
Acta Physica Polonica A
|
2013
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vol. 123
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issue 2
374-375
EN
The density of the concrete is important parameter for different properties. Using different types and rates of aggregates cause different densities of the concretes. Radiation shielding properties can be varied with the density and it is important to obtain optimum density for this purpose. In this study radiation attenuation coefficients were measured by comparison of five different densities of concrete that called lightweight, semi-lightweight, ordinary and semi-heavyweight and heavyweight. For this purpose concretes were produced with suitable aggregate in laboratory conditions and determined some physical and mechanical properties. The total linear attenuation coefficient measurements have been obtained by a collimated beam of gamma ray from sources ^{60}Co.
10
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Electronic Energy Loss of the Partially Stripped Boron-Like and Carbon-Like Fast Ions

63%
Gümüş H., Özalp C., Köroğlu A.
Acta Physica Polonica A
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2003
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vol. 103
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issue 4
349-363
EN
An analytical formula of the electronic stopping power expression in this study was derived for swift boron-like and carbon-like ions by using first-order perturbation theory and frozen-charge-state model. The Hartree- Fock-Slater determinant was used for the description of the bound electrons attached to ions in the ground state and orbital-screening parameter was determined by variational method. The calculated ground state energies in this study were compared with the results of Clementi-Roetti and they are in good agreement with 5%. It has been observed that the difference of energy loss for boron-like and carbon-like projectiles in a frozen-charge state increases as an atomic number increases. Furthermore, the analytical expression of the effective charge of boron-like and carbon-like projectiles was derived.
11
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Stopping Power Calculations of Compounds by Using Thomas-Fermi-Dirac-Weizsäcker Density Functional

63%
Tufan M., Gűműş H.
Acta Physica Polonica A
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2008
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vol. 114
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issue 4
703-711
EN
Electronic stopping power of compounds was calculated by using the Thomas-Fermi-Dirac-Weizsäcker density functional. Bragg's rule was employed to determine stopping power of compounds from the elemental stopping power results. Calculations were done for Be, B, O, and Si ions in Al₂O₃, SiO₂, and CO₂ targets by using the Thomas-Fermi-Dirac-Weizsäcker density functional. The obtained results were compared with other Thomas-Fermi based theoretical calculations and show that using Thomas-Fermi-Dirac-Weizsäcker density functional in stopping power calculations yields reasonably accurate results in especially light systems (with respect to the number of electrons in the system).
12
Content available remote

Radiation Shielding Properties of Shotcrete

63%
Gunoglu K., Akkurt I., Basyigit C., Çakıroğlu M., Akkaş A.
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vol. 125
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issue 2
299-300
EN
Shotcrete is a concrete spraying of concrete or mortar that may be accomplished through either a dry- or wet-mix process. It is made of normal weight aggregates which have a density of approximately 2323 kg/m^3. For the most part, shotcrete is used in underground excavations in rock and repair work in constructions. In this study, linear attenuation coefficient (μ, cm^{-1}) was measured for shotcrete produced with dry mix process. Measurements were carried out by gamma spectrometry containing NaI(Tl) detector and multichannel analyzer.
13
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Shielding Behaviors and Analysis of Mechanical Treatment of Cements Containing Nanosized Powders

51%
Mutuk H., Mutuk T., Gümüş H., Mesci Oktay B.
Acta Physica Polonica A
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2016
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vol. 130
|
issue 1
172-174
EN
In this study, we investigated linear attenuation coefficient (μ ), half value layer, tenth value layer at 243, 344, 866, 1088, 1112, 1528 keV. Mechanical properties of cements containing nanosized powders (nano-SiO₂, nano-Fe₂O₃, nano-Al₂O₃) are obtained. According to compressive strength results nano-SiO₂ added cementitious material gave the highest strength. Moreover, all the nanopowders added samples showed higher compressive strength with respect to reference sample. The experimental linear mass attenuation coefficients μ , half value layer, tenth value layer for cementitious material were compared with theoretical values obtained using XCOM. The experimental results were found to be in good agreement with the theoretical values.
14
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Energy Loss of Excited Slow Ions in Electron Gas

51%
Moneta M.
|
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vol. 96
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issue 3-4
429-436
EN
The electronic energy loss and the straggling of the energy loss of the degenerate electron gas for excited H*-, He*-, He**-, and Li*-like ions were calculated. The results were compared with the corresponding characteristics for ions kept in the ground state. The linear response theory was used. The ion was described by the Hartree-Fock-Slater formalism and the medium by the dielectric function. The stopping and straggling effective charges Z_{ef} for the energy loss were analysed and they were found to differ from each other and to depend on the one-electron radius r_{s}, on the ion atomic number Z_{i}, and on the number of electrons N_{i} carried by the ion.
15
Content available remote

Determination of the Tenth and Half Value Layer Thickness of Concretes with Different Densities

51%
Akkaş A.
Acta Physica Polonica A
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2016
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vol. 129
|
issue 4
770-772
EN
Half value layer (HVL) is the most frequently used quantitative factor for describing both the penetrating ability of specific radiations and the penetration through specific objects. The half value layers (HVL) and tenth value layers (TVL) are defined as the thickness of a shield or an absorber that reduces the radiation level by a factor of one-half and one tenth of the initial level, respectively. The concepts of HVL and TVL are widely used in shielding design. They are photon energy dependent, like the attenuation coefficient. HVL and TVL values provide useful information about the penetration of a specific radiation in a specific material. In this study, TVL and HVL thickness are calculated for concretes with different densities. For this purpose five types of concrete with different density ranges were selected, with densities between 600-1500 kg/m^{3}, called lightweight concrete, 1400-2000 kg/m^{3}, called semi lightweight concrete, 2000-2500 kg/m^{3} called ordinary concrete, 2500-3000 kg/m^{3}, semi heavyweight concrete and 3000-4000 kg/m^{3} called heavyweight concrete, respectively. For evaluated TVL and HVL thicknesses, the linear attenuation coefficients μ, were determined from measurements, using a collimated beam of gamma rays from a Cobalt-60 source.
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