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1
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Effects of Gamma Ray Irradiation and NaCl on Induced Somaclonal Variation in Arnavutköy Strawberry Cultivar

100%
Kepenek K.
Acta Physica Polonica A
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2016
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vol. 130
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issue 1
337-341
EN
Salinity stress impacts the growth and development of strawberry crop significantly in tropical and temperate regions across the world developing somaclonal variant which offers an option to develop salt stress tolerant genotypes. Somaclonal variants of Arnavutköy strawberry cultivar were produced via organogenesis by irradiating axillary shoots with gamma rays (20 and 40 Gy with ⁶⁰Co) along with imposing different NaCl concentrations (0, 250, 500, and 750 ppm). Increasing total doses of ⁶⁰Co together with NaCl concentrations significantly affected the percentage of survival rate, axillary shoots proliferation, length of axillary shoots, fresh weight of axillary shoots, leaf deformation scores and necrotic area of leaves. The variants with less deformation were selected for strawberry breeding. A gamma irradiation dose of 40 Gy was found to be the most effective dose together with 500 ppm of NaCl for to obtain the somaclonal variants without having much lethal effects and deformations of the strawberry breeding in vitro condition. If successfully applied, this methodology can lead to the identification of new strawberry cultivars resistant to NaCl within a relatively short period of time.
2
Content available remote

ESR and Electron Spin Echo Studies of Spin-Lattice Relaxation of Hydrazinium Radical in Li(N_{2}H_{5})O_{4} Single Crystal

63%
Morawski P., Hoffmann S. K., Hilczer W., Goslar J.
Acta Physica Polonica A
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1997
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vol. 91
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issue 6
1121-1129
EN
A hydrazinium ṄH-NH_{3}^{+} radical was identified by ESR in γ-irradiated Li(N_{2}H_{5})SO_{4} single crystal. Unpaired electron is strongly localized on the nitrogen atom as compared to hydrazinium radicals in other crystals. Angular variations of the multicomponent ESR spectra and computer calculations gave the isotropic hyperfine coupling parameters (in mT): a_{N1} = 1.93, a_{N2} = 0.80, a_{H1} = 2.50, a_{H1'} = 0.48 (NH_{3}), and a_{H2} = 1.40 (adjacent molecule). The radiation defects containing unpaired electrons do not influence much the protonic conductivity along the hydrazine molecule chains in the crystal. It confirms a tunelling mechanism of the conductivity activated by NH_{2}-group rotation. Spin-lattice relaxation time T_{1} varies strongly with temperature in the range from 100 ms (10 K) to 90 μs (170 K) and is governed by spectral diffusion (1/T_{1} ∝ T^{2}) and a Murphy-type mechanism (1/T_{1} ∝ cosech(Δ/T)) with Δ = 150 cm^{-1}. A distribution of the spin-relaxation times was observed with temperature independent dispersion parameter β = 0.76.
3
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Changes in Luminescence of Ce:yag Crystals Under Ionizing Radiation Treatment

63%
Kaczmarek S., Moroz Z., Kwasny M., Kisielewski J., Lukasiewicz T., Wojtkowska J., Rzewuski H.
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vol. 95
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issue 6
953-964
EN
Radiation induced changes in the luminescence spectrum under influence of UV light, γ-rays, electrons and protons for several concentrations of Ce^{3+} ions as well as Mg^{2+} ions in yttrium-aluminum garnet crystals were investigated. To irradiate with γ and electron as grown crystals were used while for proton irradiations the crystals were thermally annealed. For small concentrations of cerium ions (≈0.01 at.%) an increase in the luminescence (about 100%) was observed after gamma irradiation with a dose of 10^{5} Gy. This increase was due to the growth in Ce^{3+} ions concentration after γ-irradiation (≈50%), due to the Ce^{4+} → Ce^{3+} recharging reaction. For highly doped Ce:YAG crystals (0.1 at%, 0.2 at.%) also an increase, but much smaller (4%), for the Mg codoped crystals (0.1 at.%) was observed. After 1 MeV electron irradiation in the over-threshold type interaction a decrease in luminescence is observed due to the domination of the Ce^{3+} → Ce^{4+} ionization process. In the case of the proton irradiation, for small fluencies (≈10^{13} particles/cm^{2}) an increase in luminescence is observed due to the domination of the recharging processes of Ce^{4+} ions. For larger fluencies (>10^{14} particles/cm^{2}) a decrease takes place due to a high level of radiation defects.
4
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Effect of Annealing and Irradiation on the Optical Properties of Oxide Crystals

63%
Kaczmarek S., Berkowski M., Moroz Z., Warchoł S.
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vol. 96
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issue 3-4
417-427
EN
We described results of the effect of annealing and irradiation treatments on the optical properties of Y_{3}Al_{5}O_{12}, YAlO_{3}, SrLaGa_{3}O_{7}, LiNbO_{3}, Gd_{3}Ga_{5}O_{12}, LaGaO_{3}, ZnSe, and LiF single crystals. Changes in absorption and luminescence are presented. Recharging processes of uncontrolled impurities (e.g. Fe^{3+}, Fe^{2+}, and Mn^{2+}), and active ions (e.g. Nd^{3+}, Dy^{3+}, Cr^{4+}, Cr^{3+}, and Ce^{3+}), as well as types of color centers produced in the crystals after a particular irradiation or annealing treatment are presented.
5
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Stable Color Centers Induced in Pure and Neodymium Doped Ca_{0.28}Ba_{0.72}Nb_{2}O_{6} Crystals by Gamma Irradiation

51%
Potera P., Zhydachevskii Y., Lukasiewicz T.
Acta Physica Polonica A
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2015
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vol. 127
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issue 3
753-755
EN
The work is devoted to investigation of stable coloration induced by gamma radiation from ^{60}Co (1.25 MeV) in pure and neodymium doped Ca_{0.28}Ba_{0.72}Nb_{2}O_{6} single crystals. Nature of the induced absorption is discussed. This absorption is due to charge change of native defects or ions forming of crystals (vacancy, niobium ions, etc.). The nature of color centers responsible for induced absorption is discussed.
6
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Spectroscopy and Thermoluminescence of LuAlO_{3}:Ce

51%
Wiśniewski D., Drozdowski W., Wojtowicz A., Lempicki A., Dorenbos P., de Haas J., van Eijk C., Bos A.
Acta Physica Polonica A
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1996
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vol. 90
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issue 2
377-384
EN
The present status of the LuAlO_{3}:Ce scintillator is reviewed. Scintillation mechanism of this material is based on capture by Ce^{3+} of holes and then electrons from their respective bands. Results of spectroscopic and thermoluminescence experiments are presented to support this model.
7
Content available remote

Anharmonic Effects in the Electron Spin-Lattice Relaxation of Radiation Defects in Potassium Selenate and Rochelle Salt Single Crystals

51%
Ivanshin V., Kurkin I., Brunner W., Völkel G.
Acta Physica Polonica A
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1992
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vol. 81
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issue 3
393-396
EN
An anharmonic character for the Raman processes of the electron spin-lattice relaxation of paramagnetic defect centres in γ-irradiated potassium selenate and Rochelle salt single crystals was observed at low temperatures.
8
Content available remote

Possibility of Gamma-Induced Sensibilization Process in Rare-Earth Doped Yag Crystals

51%
Kaczmarek S., Matkovskii A., Mierczyk Z., Kopczyński K., Sugak D., Durygin A., Frukacz Z.
Acta Physica Polonica A
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1996
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vol. 90
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issue 2
285-293
EN
The influence of gamma irradiation on optical and lasing properties of Nd:YAG, Er:YAG and CTH:YAG single crystals was studied. The increase in optical output was established for rods without thermal annealing. The possible mechanisms of radiation sensibilization are discussed.
9
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Content available

Modified Positron Annihilation Model for Glassy-Like As_2Se_3

51%
Kozdras A., Shpotyuk O., Kovalskiy A., Filipecki J.
Acta Physica Polonica A
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2005
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vol. 107
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issue 5
832-836
EN
An approach to structural characterization of chalcogenide glasses based on the study of void distribution is discussed. The results of positron annihilation lifetime spectra measurements for glassy-like g-As_2Se_3 are compared with nano-void distribution data obtained from Monte Carlo simulation. In this consideration perspectives to involve the parameters of nano-voids calculated from the first sharp diffraction peak in the framework of known Elliott's model are analyzed.
10
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Luminescence and Scintillation Properties of Ce_{x}La_{1-x}F_{3} Monocrystals

51%
Wojtowicz A., Balcerzyk M., Lempicki A.
Acta Physica Polonica A
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1993
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vol. 84
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issue 5
963-968
EN
In this communication we present our results concerning luminescence and scintillation properties of mixed cerium-lanthanum trifluoride monocrystals, Ce_{x}La_{1-x}F_{3}. The luminescence, luminescence excitation spectra and decays are complex, indicating the presence of Ce^{3+} ions in regular and parasitic "perturbed" sites. The efficient energy transfer from regular Ce^{3+} ions (emitting at 286 and 303 nm) to "perturbed" Ce^{3+} ions (emitting at 340 nm) and the lack of the fast energy migration between Ce^{3+} ions are responsible for non-exponential decays of the short-wavelength emission and a relatively long rise-time of the long-wavelength emission. The short-wavelength emission decays are described by the Inokuti-Hirayama model of statistically distributed donors and acceptors. Our estimates of oscillator strengths, at 13.1 × 10^{-3} for Ce^{3+}, and 13.5 × 10^{-3} for Ce^{3+}_{per}, confirm that the d-f transition on the Ce^{3+} ion in a different site must be responsible for the long-wavelength emission. Calculations of the Ce-Ce and Ce-Ce_{per} energy transfer rates give 7.7 × 10^{5} s^{-1} and 1.56 × 10^{9} s^{-1}. The concentration of "perturbers" in good CeF_{3} samples has been reduced down to about 0.11%. It is likely that the constant and significant progress made by crystal growers (Optovac Inc.) may eventually produce a superior material for applications in high energy and nuclear physics.
11
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Study of Point Defect Distributions in Tantalum

51%
Djaafri A., Kadoun A., Driss-Khodja M., Elias A., Djaafri T.
Acta Physica Polonica A
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2018
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vol. 133
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issue 1
39-44
EN
We have investigated the point defect distributions in tantalum under irradiation by means of the Marlowe code based on the binary collision approximation. The study is carried out by simulating displacement cascades initiated with primary knock-on atom energies ranging from 5 to 20 keV. The Molière, Born-Mayer and average modified Lenz-Jensen potentials are used to describe the interactions between tantalum atoms. We have examined the creation of damage, the spatial defects distribution, and the vacancy clustering in tantalum. The results show that with an appropriate recombination radius, less than 16% of the created defects constitute permanent Frenkel pairs. Spatial configuration of defects indicates a separation between the two point defect types, vacancies and interstitials. The Molière potential favors the production of a greater number of displaced atoms and the development of voluminous cascades more than the other potentials. The cascade volume distributions deviate clearly from a Gaussian distribution. They are large and very stretched toward higher volumes for all used potentials. Only small vacancy clusters are formed in tantalum under irradiation and about 41% of the produced vacancies are considered as isolated
12
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Investigation of Electronic Structure of Zn_{1-x}Mg_{x} Mixed Crystals by Compton Spectroscopy Method

51%
Reniewicz H., Andrejczuk A., Dobrzyński L., Rećko K., Waliszewski J., Żukowski E., Firszt F., Łęgowski S., Meczyńska H., Szatkowski J.
Acta Physica Polonica A
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1996
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vol. 90
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issue 5
907-910
EN
The first experimental study of the Compton profiles of Zn_{1-x}Mg_{x}Se for x=0.25, 0.47, 0.56 mixed crystals is presented. The Compton profiles were measured with the use of the ^{241}Am radioactive source with a resolution of 0.57 a.u. The experimentally obtained Compton profiles were compared with the theoretical ones based on the free-atom model. The results are interpreted in terms of outermost electrons of Zn and Mg being promoted to the higher momentum states, and 4p-electrons of Se becoming more delocalised in a solid, being thus promoted to the lower momentum states.
13
Content available remote

Positron Annihilation in γ-Irradiated Amorphous Iron Alloys

51%
Mikhalenkov V., Chernyashevskii A., Shalaev A.
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EN
One-dimensional angular correlation of annihilation radiation was measured in a series of amorphous (Fe_{100-x}Cr_{x})_{85}B_{15} alloys (x = 0-32) exposed to γ-irradiation from intensive ^{60}Co source. The relevant shape parameters were compared with those in non-irradiated alloys. Irradiation-induced changes of those parameters were found to depend on Cr contents x. The opposite signs of these changes were observed in x < 4 and x > 4 ranges, while near x = 4 the parameters stayed unchanged. We try to interpret the results assuming that γ-quanta are able to knock out boron atoms from their positions into large cavities, thus preventing positron trapping. The crystalline embryos model of amorphous alloys suggested by Hamada and Fujita is also used for explanation of the observed effects.
14
Content available remote

Effect of Manganese Concentration on Thermoluminescent Properties of YAlO_{3}:Mn Crystals

51%
Zhydachevskii Y., Suchocki A., Berkowski M., Warchol S.
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issue 1
177-180
EN
This work is devoted to experimental study of the effect of manganese concentration on thermoluminescent properties of YAlO_{3}:Mn crystals grown by the Czochralski method. A new type of emitting centers beside of Mn^{4+} and Mn^{2+} ions was revealed at low concentration of manganese ions in the crystal. These centers are responsible for the high-temperature thermoluminescent peak at 570 K. A potential of this thermoluminescent peak for thermoluminescence dosimetry application is discussed.
15
Content available remote

New High Performance Scintillators Based on Re-Activated Insulator Materials

51%
Wojtowicz A.
Acta Physica Polonica A
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1996
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vol. 90
|
issue 1
215-222
EN
In this paper we address the problem of the host-to-ion energy transfer in some RE-activated wide band gap materials excited by ionizing radiation. We argue that, despite the expected self-localization of holes, the dominant mechanism in efficient materials involves sequential trapping of both charge carriers (holes and electrons) by an activating RE-ion followed by a radiative recombination via the ion producing scintillation light. Selected experimental results are presented to illustrate how various energy transfer processes manifest themselves in the spectroscopy of scintillator materials. Experimental results combined with simple considerations are used to identify these RE-ions which are likely to act as hole or electron traps in tri- and difluorides, thus initiating the recombination sequence leading to efficient scintillation.
16
Content available remote

Effect of Gamma Irradiation on Cement Composites Observed with XRD and SEM Methods in the Range of Radiation Dose 0-1409 MGy

38%
Łowińska-Kluge A., Piszora P.
Acta Physica Polonica A
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2008
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vol. 114
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issue 2
399-411
EN
The effect of gamma radiation in the range of 0-1409 MGy on the structure of a new mineral additive to cement based composites was investigated in the perspective of employing them as radioactive waste protection material. According to the authors knowledge, it is the first paper dealing with observations of the cement matrix, both pure and modified, treated with so giant radiation dose. The absorption of gamma radiation modifies the morphology of the additive grains, causes decomposition of cement hydrates and clinker relicts in cement paste containing the additive at twice higher radiation dose than that inducing the decomposition of the reference pure cement paste and the cement paste containing pozzolane additives.
17
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Fourier Transform Near Infrared Raman Spectroscopy in Studies on Connective Tissue

32%
Połomska M., Kubisz L., Kalawski R., Oszkinis G., Filipiak R., Mazurek A.
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issue 1
136-140
EN
Studies of tissue such as bones and veins often are carried out by means of microscopic and ultrasonographic methods. Therefore studies of changes caused by pathological or physical factors often are limited to morphological level. Application of Raman spectroscopy permits to associate morphological changes and molecular changes. The paper presents preliminary studies of temperature and ionizing radiation effects on Raman spectra of bone and collagen. Furthermore, effects of pathological factors on Raman spectra of human veins had been studied. It was noticed that heating of bone collagen up to 110°C gives the reversible changes in spectra. In the case of γ-irradiation, any effects were observed up to the dose of 1 MGy on mineral component of bone, whereas the influence on collagen was observed for doses higher than 100 kGy. The Raman spectra of varicose vs. normal veins permit to conclude some important changes observed for veins from chronic venous insufficiency patients.
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