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1

Prototype Silicon Position-Sensitive Detector Working with Bragg-Brentano Powder Diffractometer

100%

Zięba A., Dąbrowski W., Gryboś P., Powroźnik W., Stobiecki T., Świentek K., Słowik J., Wiącek P.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

629-634

EN

A prototype 64-channel detector module, comprising a silicon strip detector with strip pitch of 100μm and 64-channel ASIC RX64, was tested with the X-Pert Philips MPD diffractometer. Basic parameters of the detector module, energy resolution, and detection efficiency, were evaluated as a function of the counting rate. Energy resolution of 1.1 keV FWHM for photon rate up to 1×10^7 photon/s per 1 cm of the active width of the detector was demonstrated. The prototype detector, when applied in a diffractometer utilizing Bragg-Brentano focusing principle, allows to increase the counting rate by about 2 orders of magnitude with respect to a single counter. Exemplary diffraction patterns of polycrystalline samples of Si and SiO_2 (quartz peak cluster) are presented.

2

New Experimental Approach to the Detection of Positron Annihilation in Flight Process

100%

Dryzek J.

Acta Physica Polonica A

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2008

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vol. 113

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issue 5

1339-1346

EN

Positron annihilation in flight, when mainly positron contributes to the energy and momentum of the annihilating pair, is rarely observed in condensed matter due to its small probability. Additionally, this process does not manifest itself by any characteristic features, which would help in observation. Hence, our knowledge about that process is poor. In the paper we propose the new experimental method which allows us to detect this process. We applied the conventional positron lifetime spectrometer, which after changing photon energy ranges and layout of detectors was suitable for that detection. The first measurements allow us to estimate that in pure aluminum almost 4.76% of all implanted positrons from isotope source ^{22}Na annihilate in flight.

3

Test Measurements of Modernized Version of Two-Detector Doppler Spectrometer

100%

Baranowski A., Kostrzewa M., Szuszkiewicz M.

Acta Physica Polonica A

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1999

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vol. 95

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issue 4

439-447

EN

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.

4

Investigation of Radiation Absorption Properties of Some India Granites

100%

Mavi B., Akkurt I.

Acta Physica Polonica A

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2015

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vol. 128

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issue 2B

B-370-B-371

EN

The radiation shielding properties of India granites have been investigated. Gamma-ray attenuation coefficients of some India granites were determined for different energies, 662, 1173, and 1332 keV. The results were compared with the calculation of XCOM at the photon energy of 1-10 GeV. Good agreement between experimental and theoretical results has been observed.

5

Special X-Ray Silicon Detectors for Medical Applications

100%

Halmagean E., Wagner D., Tsoi E., Misiakos K., Ohanisian M., Veron A., Cimpoca V., Lazarovici D.

Acta Physica Polonica A

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1997

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vol. 91

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issue 4

789-792

EN

The paper presents some results concerning the technology and behaviour of X-ray silicon detectors intended for controlling low radiation levels in interventional cardiology. An improved planar process was used for obtaining large area guard-ring test structures. The electrical characteristics, their modification after exposure to radiation and the results of spectroscopic X-ray measurements are discussed.

6

X-ray Holography with a Position Sensitive Detector

80%

Lausi A., Kopecky M., Busetto E., Savoia A.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

621-628

EN

Integrating photon collection on position sensitive detectors used in combination with an absorption filter offers many advantages in X-ray fluorescence holography experiments: (i) the simultaneous recording of the full hologram allows us to overcome most of the difficulties - notably the large number of experimental points and the precision requirements - that make the practical realization of the measurement of holographic patterns very difficult and time demanding also when using powerful synchrotron radiation sources; (ii) the high angular resolution and the very precise detection of intensities make the reconstruction of images of distant as well as light atoms possible; (iii) area detectors are readily available at most crystallography dedicated beamlines at synchrotron radiation sources, so there is no need of complex, dedicated instrumentation. As an example, the hologram of a CoO single crystal recorded on an imaging plate is reported, evidencing the images of atoms located up to more than 7Å far from the emitter and also of the light oxygen atoms.

7

On the Possibility of Determining the Distribution of a Substance Penetrating into a Dense Medium Using Gamma-Ray Detection and Ranging Approach

80%

Gurdev L., Dreischuh T., Stoyanov D., Protochristov C.

Acta Physica Polonica A

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2010

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vol. 118

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issue 4

540-549

EN

The possibility has been investigated of determining, using graydar (Gamma RAY Detection And Ranging) approach, the in-depth partial-density profile of some substance absorbed in a dense medium. Analytical algorithms have been derived for retrieving the in-depth profile of the partial density of the absorbed substance on the basis of the conjecturally known in-depth profile of the extinction of the absorbing medium and the experimentally determinable graydar profile. The retrieval error under the Poisson noise conditions has also been estimated analytically. The simulations performed of the Poisson-noise effect concern the case of soil moisture. The results obtained confirm the validity of the derived retrieval algorithms and error estimates and show that the soil moisture profile may be accurately determined to depths of 50 cm, depending on the dry-soil bulk density, the sensing photon flux, and the measurement time.

8

Resonant Photoemission Study οf 4f Electrons on the Surface οf Semiconductors

80%

Orłowski B., Kowalski B., Pietrzyk M., Buczko R.

Acta Physica Polonica A

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2008

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vol. 114

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issue S

S-103-S-114

EN

The contribution of 4f electrons to the electronic structure of the semiconductor clean surface caused by the surface doping of it by rare-earth metal atoms (Eu, Sm) will be presented. The surface doping was performed by the controlled, sequential deposition of the rare-earth metal atoms on the clean surface in UHV conditions (Sm on GaN or CdTe) or by the doping of the layer volume of (EuGd)Te. After each deposition or surface treatment the synchrotron radiation was used to measure in situ the resonant photoemission spectra (the Fano type resonance) to study the contribution of 4f electrons of divalent and trivalent Sm and Eu ions to the valence band electronic structure of created sample. The first stages of the metal atoms deposition lead to the surface doping. Further metal atoms deposition leads to the growth of the metallic islands on the surface and causes the appearance of the sharp metallic Fermi edge in the energy distribution curves. Proper coverage and annealing of the sample surface with metal atoms leads to the diffusion of the metal atoms into the sample and results in an increase in the crystal doping and decrease in the metallic islands contribution to the measured spectra. As a result, the new electronic structure of the valence band can be created and investigated in situ.

9

Novel Route to Prepare Magnetic Material Co_3V_2O_8 and Structural Characterization

51%

Celik G., Kurtulus F., Guler H.

Acta Physica Polonica A

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2012

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vol. 121

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issue 1

203-204

EN

Co_3V_2O_8 is a member of kagomé staircase oxides, represented by general formula M_3V_2O_8 (M = Ni, Co, Mn). It attracted great attention due to strong magnetic anisotropy, magnetic phase transition, genuine macroscopic quantum effects, strong quantum fluctuations, low-temperature ferroelectricity, field-induced magnetic transitions, complicated phase diagram and displays long-range magnetic order because of geometrical frustration. Different routes to prepare the frustrated magnetic material was reported such as floating zone technique and conventional high temperature method. Co_3V_2O_8 (International Centre for Diffraction Data (ICDD): 16-675) was synthesized with Co_3O_4 (ICDD: 80-1536) as binary phase by microwave assisted preparation using Co(NO_3)_2 ·6H_2O and NH_4VO_3. The synthesized material was characterization by powder X-ray diffraction, the Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis.

Refine search results

Prototype Silicon Position-Sensitive Detector Working with Bragg-Brentano Powder Diffractometer

New Experimental Approach to the Detection of Positron Annihilation in Flight Process

Test Measurements of Modernized Version of Two-Detector Doppler Spectrometer

Investigation of Radiation Absorption Properties of Some India Granites

Special X-Ray Silicon Detectors for Medical Applications

X-ray Holography with a Position Sensitive Detector

On the Possibility of Determining the Distribution of a Substance Penetrating into a Dense Medium Using Gamma-Ray Detection and Ranging Approach

Resonant Photoemission Study οf 4f Electrons on the Surface οf Semiconductors

Novel Route to Prepare Magnetic Material Co_3V_2O_8 and Structural Characterization