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Tytuł:
Stability and Performance Characteristics of a Digital Positron Lifetime Spectrometer
Autorzy:
Aavikko, R.
Rytsölä, K.
Nissilä, J.
Saarinen, K.
Powiązania:
https://bibliotekanauki.pl/articles/2042175.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
06.60.Jn
07.05.Hd
78.70.Bj
07.85.Nc
Opis:
We summarize the setup and performance tests of a digital positron lifetime spectrometer presently in routine use at HUT/Laboratory of Physics. The performance of the spectrometer is found to be equal to or better than that of an analog spectrometer with similar detectors. We present also results on measuring the stability of the system, which is found to be similar to that of analog spectrometers: variation in the time-zero of the spectrometer is found to be ≈10 ps/week. We suggest that the remaining instabilities of the spectrometers originate primarily from the detectors.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 592-597
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
To the Measurements of 3γ/2γ Ratio for Positron Annihilation in Matter Using Annihilation Energy Spectrum
Autorzy:
Andrukhovich, S. K.
Berestov, A. V.
Antovich, N. M.
Metelitsa, O. N.
Powiązania:
https://bibliotekanauki.pl/articles/2024055.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
Opis:
Processes of the summation of cascadeγ-quanta usually neglected, when registering the annihilation energy spectrum for the determination of the three-photon annihilation probability P$\text{}_{3γ}$ of positronium in samples, are studied. The deviations of the actual P$\text{}_{3γ}$ value from that determined without allowance made for the summation processes are 56% and 25% for NaI(Tl) and Ge detectors placed at the distance of 3 cm from a positron source, respectively.
Źródło:
Acta Physica Polonica A; 2001, 99, 3-4; 315-320
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of YBCO-PST Composites
Autorzy:
Andrzejewski, B.
Kaczmarek, A.
Stankowski, J.
Hilczer, B.
Marfaing, J.
Régnier, S.
Caranoni, C.
Powiązania:
https://bibliotekanauki.pl/articles/2014556.pdf
Data publikacji:
2000-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.80.Bj
74.25.Ha
76.30.Fc
Opis:
The magnetic properties of granular superconductor-insulator composites were investigated. The composites were random composition of the YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ (YBCO) high-temperature superconductor and Pb(Sc$\text{}_{0.5}$Ta$\text{}_{0.5}$)O$\text{}_{3}$ (PST) ferroelectric insulator. The composites exhibited lower superconducting volume ratio than the YBCO content. For samples with YBCO content low enough no global (the whole sample) and local (separated grains) superconductivity was observed. The observed decay of the superconductivity, lowering of the critical temperature, and the increase in number of paramagnetic centres as PST content increases are explained assuming reaction among YBCO and PST phases and possible formation of an additional ones, which did not exist in the initial powders.
Źródło:
Acta Physica Polonica A; 2000, 98, 6; 739-746
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Positron Properties in Quartz Crystals and Synthetic Silica Glass
Autorzy:
Anwand, W.
Brauer, G.
Hasegawa, M.
Dersch, O.
Rauch, F.
Powiązania:
https://bibliotekanauki.pl/articles/2024077.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
Opis:
The monoenergetic positron beamline "SPONSOR" at Rossendorf has been used to investigate the positron behaviour in a naturally grown Brasilian quartz, two synthetic quartz crystals of different origin, and synthetic silica glass. The measurements allow us to obtain the positron diffusion length of free positrons and Bloch para-positronium, if formed, in these materials. In addition, hydrothermal treatment of a synthetic quartz has been used to introduce hydrogen into the crystal up to a certain depth. The presence of hydrogen is found to influence the formation of para-positronium. The depth distribution of hydrogen has been measured independently by nuclear reaction analysis, and will be discussed in comparison with the results deduced from the positron studies.
Źródło:
Acta Physica Polonica A; 2001, 99, 3-4; 321-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Changes in Flash Lamp Annealed Amorphous Si Layers Probed by Slow Positron Implantation Spectroscopy
Autorzy:
Anwand, W.
Schumann, Th.
Brauer, G.
Skorupa, W.
Xiong, S.
Wu, C.
Gebel, T.
Powiązania:
https://bibliotekanauki.pl/articles/1812451.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Ba
78.70.Bj
81.05.Ea
81.07.Bc
Opis:
Flash lamp annealing was applied to the modification of thin amorphous Si layers on $SiO_2$ and glass. Slow positron implantation spectroscopy was used for the characterisation of the microstructure before and after flash lamp annealing. Changes in the structure down to a depth of some micrometres below the surface observed with slow positron implantation spectroscopy will be presented and discussed.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1273-1278
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free Volume in Epoxy-Coal Resins Studied by Positron Annihilation
Autorzy:
Baranowski, A.
Dębowska, M.
Jerie, K.
Kurzeja, L.
Hennek, K.
Rudzińska-Girulska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1933465.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
81.20.Sh
78.70.Bj
82.30.Hk
Opis:
In this paper the macroscopic properties of the tetrafunctional epoxy resin (N, N'-tetraglycidyl ether of diaminodiphenylmethane) cured by 4, 4'-diaminodiphenylmethane, were studied. For the system the influence of various curing conditions on the glass temperature was investigated. Results obtained for two compositions: an unmodified one and a modified with coal were compared with information on the free volume given by the positron annihilation technique.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 43-49
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Liquid Crystalline Polyurethanes Studied by Positron Annihilation Method
Autorzy:
Baranowski, A.
Dębowska, M.
Jankowski, A.
Jerie, K.
Penczek, P.
Rudzińska-Girulska, J.
Szczepaniak, B.
Wolińska-Grabczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1933462.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
81.20.Sh
78.70.Bj
82.30.Hk
Opis:
A series of liquid crystalline polyurethanes of different both flexible spacer length and mesogenic group content was studied by means of positron annihilation method. The investigated polymers were targeted on the separation of aromatic hydrocarbons from their mixtures with aliphatic ones. The effect of modification of the liquid crystalline polyurethane chain on the polyurethane free volume size and free volume distribution was determined on the basis of the positron annihilation lifetime spectra. In the positron annihilation lifetime spectra measured for the samples under study two long components of several nanoseconds, characteristic of o-Ps decaying by pick-off, occurred. The correlation of the values of the o-Ps lifetime with the size of the free volume region allowed to recover the free volume distributions with the use of the method employing the numerical Laplace inversion technique. The obtained results were compared with the diffusion data on the mobility of liquid hydrocarbons in the liquid crystalline polyurethanes enabling the correlations between polymer structure and its transport properties to be evaluated.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 21-27
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation in and Adiabatic Compressibility of Ethylene Glycol Aqueous Solutions
Autorzy:
Baranowski, A.
Jerie, K.
Gliński, J.
Orzechowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1933468.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.25.Em
78.70.Bj
Opis:
The positron annihilation lifetime and ultrasonic velocity in aqueous ethylene glycol solutions were measured. A comparison between the concentration and temperature dependences of the above parameters suggests that there is a competition of hydrophobic (interstitial) and hydrophylic (substitutional) hydration.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 59-66
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation in Chloropolystyrenes
Autorzy:
Baranowski, A.
Dębowska, M.
Jerie, K.
Mirkiewicz, G.
Rudzińska-Girulska, J.
Sikorski, R. T.
Powiązania:
https://bibliotekanauki.pl/articles/1928863.pdf
Data publikacji:
1993-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
81.20.Sh
82.30.Hk
Opis:
Results of angular correlation of annihilation radiation and positron annihilation lifetime measurements are presented for atactic polystyrene and chloropolystyrenes. The inhibition of positronium formation follows the chlorine introduction as the decrease in intensities of the narrow component in angular correlation of annihilation radiation curves and of the longest-lived component in positron annihilation lifetime spectra prove. In general, the chlorine "activity" towards positrons seems to depend on its position in the polymer structure. The annihilation rate distribution as well as the radius and volume distributions of free-volume sites where positronium is assumed to be formed obtained with the use of CONTIN program for the raw sample in the 2nd series are given additionally.
Źródło:
Acta Physica Polonica A; 1993, 83, 3; 239-249
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation with Core Electrons in 3d-Transition Metals
Autorzy:
Baranowski, A.
Dębowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/1933461.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
71.90.+q
Opis:
Recently we have been able to resolve the rare gas core contribution in long-slit angular correlation of annihilation radiation curves for some d-metals when applying a new model to fit the experimental data. In the present paper the model is applied to angular correlation of annihilation radiation spectra for the whole series of the 3d-transition metals from Sc to Cu. The model corresponds to recent theoretical predictions for the metals from the second half of the series and allows one to find the contribution of the core electrons to the whole annihilation process for these metals. Probably a different description of the angular correlation of annihilation radiation data for the metals from the beginning of the 3d-series should be searched.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 13-19
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation with Electrons of Admixture Atoms in Some Binary Nickel Alloys
Autorzy:
Baranowski, A.
Kostrzewa, M.
Szuszkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2042168.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
78.30.Er
Opis:
Weighted difference curves have been shortly presented as a proper tool allowing to analyze in another way two-detector Doppler spectra regarding positron annihilation with admixture electrons in some nickel alloys. The analysis of low and middle momentum parts of Doppler spectra for investigated alloys reflects the annihilation of positrons with admixture electrons. There is no distinct signal of annihilations with admixture electrons from the positron lifetime data for well-annealed samples.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 570-575
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relativistic Phenomena in Two-Quantum Annihilation of Electron-Positron Pairs
Autorzy:
Baranowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047121.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
03.30.+p
Opis:
The kinematics of e$\text{}^{+}$e$\text{}^{-}$ pair and annihilation quanta momentum vectors have been presented basing on ellipse and spheroid properties. Using the formulae resulting from the Lorentz transformation of momentum and energy there was pointed out that the aberration and the longitudinal and transversal Doppler effects are inseparably associated.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 551-558
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying of Nickel Alloys with 1 at.% of Ge, Zn, In, Zr and Pb by Positron Annihilation Methods
Autorzy:
Baranowski, A.
Kostrzewa, M.
Szuszkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2024150.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
78.30.Er
Opis:
The measurements of cold rolled nickel alloys with 1 at.% of Ge, Zn, In, Zr, Pb and additionally Ti and Sb by positron lifetime and Doppler broadening techniques have been done. Monovacancies were a dominating type of defects in the alloys. The authors of the present paper connect the differences between the annihilation parameters of the investigated samples with the existence of the vacancy-impurity atom pairs. A direct proportionality between the vacancy lifetime and the product of vacancy-impurity binding energy and atomic radius of impurity atom has been found.
Źródło:
Acta Physica Polonica A; 2001, 99, 3-4; 329-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test Measurements of Modernized Version of Two-Detector Doppler Spectrometer
Autorzy:
Baranowski, A.
Kostrzewa, M.
Szuszkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2007881.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
07.85.-m
Opis:
Basing on the electronic analogue modules in adding and subtracting branches of pulses, a modernized two-detector Doppler spectrometer has been constructed using only one multichannel analyser. Doppler spectra for Al, Ni, Ag have been measured. ACARFIT computer program was used to compare the Doppler and angular correlation of annihilation radiation results.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 439-447
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of a High-Resolution Digital Positron-Lifetime Spectrometer
Autorzy:
Bečvář, F.
Čížek, J.
Procházka, I.
Powiązania:
https://bibliotekanauki.pl/articles/1812465.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
Opis:
This work describes a digital positron-lifetime spectrometer based on two ultrafast digitizers. Performance of the digital spectrometer in conditions of a routine measurement is compared with an analogue setup connected to the same detectors. It was found that engagement of the digital setup leads to an improvement of timing resolution (FWHM for $\text{}^{22}Na$) from 169 ps for the traditional analogue setup to 146 ps for the digital setup. The coincidence count rate for 1.2 MBq $\text{}^{22}Na$ source is 75-80 coinc./s for both configurations. These results clearly demonstrate the advantages of the digital timing over the traditional analogue setup.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1279-1284
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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