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1
Content available remote

The Design Aspects for Ultra Low-Power, Low-Noise 90 nm CMOS Charge Sensitive Amplifier for the Active Pixel Detector

100%
Barzdenas V., Navickas R.
Acta Physica Polonica A
|
2009
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vol. 115
|
issue 6
1139-1140
EN
A falling particle in the digital registration systems for elementary particles active pixel detector induces electric charge, the value of which describes the parameters of the particle in the detector. Since the electric charge induced by a single particle is relatively weak, the detector signal is first processed (amplified and shaped) right in the zone of irradiation and only then transmitted further. This paper analyses the primary analogical registration electronics for digital registration systems for elementary particles active pixel detectors, which is charge sensitive amplifiers operating in the nanoampere region.
2
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Electron Charge Noise Minimization in 130 nm CMOS Preamplifiers

100%
Barzdenas V., Navickas R.
Acta Physica Polonica A
|
2008
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vol. 113
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issue 3
825-828
EN
In this paper we present the design aspects for low-power, low-noise CMOS charge sensitive preamplifier that uses a leakage current compensation circuit for use with radiation sensors. The preamplifier has unipolar response with the peaking time of about 45 ns and the gain about 115-145 mV/ke. Equivalent noise charge (ENC) is less than 80 e, when the input charge is 1-20 ke and the sensors capacitance is equal to 30 fF. In this work we present the quality function of the charge sensitive preamplifier, which characterizes best the optimal input transistor width W, with respect to equivalent noise charge and to the power consumptions.
3
Content available remote

Ionization of Short-Lived Isotopes in Spherical Hot Cavities

80%
Turek M.
Acta Physica Polonica A
|
2015
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vol. 128
|
issue 5
935-938
EN
The numerical model of ionization of short-lived nuclides in spherical hot cavities is presented. Two different cavity configurations are considered: one of them (the hemispherical one) resembles that known from already existing ion sources while the other (closer to the full sphere) could be more efficient for short-lived isotopes. Changes of ionization efficiency with the half-life period as well as with the particle average sticking time are presented and discussed. Influence of the extraction opening radius on ionization efficiency is also under investigation.
4
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Tailoring the Internal Evaporator for Effective Ion Beam Production - Volatile vs. Non-Volatile Substances

80%
Turek M., Droździel A., Pyszniak K., Prucnal S.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
939-942
EN
Two different designs of the internal evaporator in an arc discharge ion source are presented, suitable either for volatile, or high-melting point substances. A matter of the evaporator size and placement in order to obtain its appropriate temperature and, therefore, a stable and intense ion beam, is considered. Basic ion source characteristics, i.e. the dependences of ion current and discharge voltage on the discharge and filament currents as well as on the external magnetic field flux density are shown and discussed in order to find optimal working conditions. The results of measurements for both volatile (P, Zn, Se, S) and non-volatile (Pd) are presented, showing the applicability of the design for ion implantation purposes.
5
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Kinetics of Charge Transport in Wide-Band Semiconductors at the Detection of X-Ray Radiation

80%
Degoda V., Sofienko A.
Acta Physica Polonica A
|
2010
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vol. 117
|
issue 1
155-160
EN
As a result of absorption of X-ray quantum in a semiconductor, the generation of electron-hole pairs takes place in a small volume (diameter < 0.5 μm). Their surplus energy is lost due to the scattering on phonons of the crystal lattice. Spatial distribution of the charge carriers makes the form of current pulse on electrodes of the crystal complicated when an external electric field is applied. We present a logical chart of construction of basic kinetic model of X-ray conductivity (XRC) in semiconductors that uses the successive in time calculation of the spatial distribution of free charge carriers and the diffusive-drift model of motion of free carriers in a solid. The basic form of current pulse in an external circle was obtained in the analytical kind for the case of an ideal semiconductor, e.g. that does not contain deep traps and recombination centers, as well as for the case of a crystal with dominant shallow or deep traps of electrons and holes.
6
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Production of Mo^{+} Beams Using an Arc Discharge Ion Source

80%
Turek M., Droździel A., Pyszniak K., Prucnal S., Mączka D.
Acta Physica Polonica A
|
2014
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vol. 125
|
issue 6
1388-1391
EN
A new method of Mo^{+} ion beam production is presented in the paper. The method bases on the chemical sputtering/etching of the molybdenum parts (e.g. anode) of the arc discharge ion source by the chloride containing plasma. A mixture of CCl_4 (or CHCl_3) vapor and air was used as the feeding substance. The separated Mo^{+} beam current of approximately 18 μA was achieved. The measurements of the ion current dependences on the discharge and filament currents as well as on the magnetic field flux density from the electromagnet surrounding the discharge chamber were performed in order to find the optimal working parameters of the ion source.
7
Content available remote

Effects of Electron Impact on Ionization of Short-Lived Isotopes in a Hot Cavity

80%
Turek M.
Acta Physica Polonica A
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2014
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vol. 125
|
issue 6
1384-1388
EN
A Monte Carlo method based numerical model of hot cavity surface ion source that takes into account radioactive decay and the delay due to the sticking of particles to ionizer surface is considered. The influence of electron impact ionization by thermionic electrons accelerated by the extraction field is investigated. It is shown that the contribution from that process rises with decreasing half-life period and cannot be neglected, especially for substances of small surface ionization coefficient. The changes of relative yields from electron impact and surface processes with the length of the average sticking time are also studied.
8
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Modeling of Ionization in a Spherical Surface Ionizer

80%
Turek M.
Acta Physica Polonica A
|
2011
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vol. 120
|
issue 1
188-191
EN
A Monte Carlo method-based model of a hot cavity surface ion source with a spherically shaped ionizer is presented. A numerical code enables studies of ion source efficiency as a function of an extraction voltage, geometry of the ionizer and its temperature, the size of extraction aperture and many other factors. The calculation results for a variety of mentioned parameters are presented. A novel configuration of surface ion source is proposed and discussed - the efficiency of the source with an almost spherically shaped ionizer could be much higher than that of currently used constructions of ion sources.
9
Content available remote

Surface Ionization of Radioactive Nuclides - Numerical Simulations

80%
Turek M.
Acta Physica Polonica A
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2013
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vol. 123
|
issue 5
847-850
EN
The Monte Carlo method based model of the ionization in the hot cavity taking into account radioactive decay of nuclides is presented. The code upgraded compared to the previous version enables calculation of the ion source ionization efficiency not only for different geometries and temperatures of the ionizer, extraction voltages etc. but also gives opportunity of setting different values of the nuclide half-life and its sticking time, which may be considered as the main factor determining the time that a particle spends in the ion source. The results of calculations are presented together with the discussion of the radioactive decay on the ion source performance.
10
Content available remote

Production of Doubly Charged Ions Using a Hollow Cathode Ion Source with an Evaporator

80%
Turek M., Droździel A., Pyszniak K., Mączka D., Słowiński B.
Acta Physica Polonica A
|
2013
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vol. 123
|
issue 5
843-846
EN
The paper describes the production of doubly charged ions from solids and gases using a hollow cathode ion source with an internal evaporator heated by a spiral cathode filament and arc discharge. The obtained currents were 15 μA for Bi^{2+}, 10 μA for As^{2+} and Al^{2+}, 8 μA for Kr^{2+} and Xe^{2+}, 5 μA for In^{2+} and Ge^{2+}, enabling moderate dose implantations ( ≈ 10^{15} cm^{-3}) with doubly charged ions. Characteristics of the ion source are presented and discussed in order to choose the optimal working parameters. A brief presentation of numerical model of doubly and singly charged ions in the ion source is given. The calculated results (dependences of ion current on the anode voltage) are in good agreement with the experimental data.
11
Content available remote

Oscillatory Regularity of Charge Carrier Trap Energy Spectra in ZnSe Single Crystals

80%
Degoda V., Gumenjuk A., Pavlova N., Sofiienko A., Sulima S.
Acta Physica Polonica A
|
2016
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vol. 129
|
issue 3
304-309
EN
This article presents the results of an experimental investigation of the energy spectra of charge carrier traps in undoped high-resistivity ZnSe single crystals. Fourteen peaks were found in the thermostimulated luminescence spectra of the ZnSe samples at temperatures between 8 K and 450 K, and the thermal activation energies of the charge carrier traps were estimated for the most intense peaks. It was found that the energy spectra of the charge carrier traps in ZnSe exhibit oscillatory regularity, and the energy of a vibrational quantum was estimated to be ħω = 206 cm¯¹, which is in good agreement with the vibrational mode in the Raman spectrum. Additionally, a linear relationship was observed between the thermal activation energies of the charge carrier traps and the temperature positions of the maxima in the thermostimulated luminescence of ZnSe.
12
Content available remote

Plasma Ion Source with an Internal Evaporator

80%
Turek M., Droździel A., Pyszniak K., Prucnal S., Mączka D.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 1
184-187
EN
A new construction of a hollow cathode ion source equipped with an internal evaporator heated by a spiral cathode filament and arc discharge is presented. The source is especially suitable for production of ions from solids. The proximity of arc discharge region and extraction opening enables production of intense ion beams even for very low discharge current (I_{a} = 1.2 A). The currents of 50 μA (Al^{+}) and 70 μA (Bi^{+}) were obtained using the extraction voltage of 25 kV. The source is able to work for several tens of hours without maintenance breaks, giving possibility of high dose implantations. The paper presents the detailed description of the ion source as well as its experimental characteristics like dependences of extracted currents and anode voltage on anode and cathode currents.
13
Content available remote

Spatial Resolution Test of a Beam Profile Monitoring System for the Double Electrostatic Ion Storage Ring

80%
Das S., Källberg A.
Acta Physica Polonica A
|
2014
|
vol. 125
|
issue 1
13-17
EN
A beam profile monitoring system based on the imaging of low energy electrons created when the ion beam impinges on a metal plate was built to monitor the beam profile and to cover the wide range of beam intensities and energies for the DESIREE (Double ElectroStatic Ion Ring ExpEriment) beam line diagnostics. The spatial resolution of the system was tested with different beams of various energies and was found to be around 2 mm. A significant steering effect on the ion beam before hitting the metallic foil was observed at low energies.
14
Content available remote

Production of Molybdenum and Tantalum Ion Beams using CCl₂F₂

80%
Turek M., Droździel A., Pyszniak K., Filiks J., Prucnal S., Mączka D., Vaganov Y., Węgierek P.
Acta Physica Polonica A
|
2017
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vol. 132
|
issue 2
283-287
EN
A new method of refractory metal (like Mo and Ta) ion beam production using the arc discharge ion source and CCl₂F₂ (dichlorodifluoromethane) used as a feeding gas supported into the discharge chamber is presented. It is based on etching of the refractory metal parts (e.g. anode or a dedicated tube) Cl and F containing plasma. The results of measurements of the dependences of ion currents on the working parameters like discharge and filament currents as well as on the magnetic field flux density of an external electromagnet coil are shown and discussed. The separated Mo⁺ and Ta⁺ beam currents of approximately 22 μA and 2 μA, respectively, were obtained.
15
Content available remote

Ionisation Efficiency in Conical Hot Cavities

80%
Turek M.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 2
259-263
EN
Surface ionisation in a new type of hot cavity characterised by the shape of a truncated cone is considered in the paper. Influence of the hot cavity shape and its temperature on the ionisation efficiency of stable and long-lived nuclides is under investigation and the supremacy of elongated conical cavities is proven. The role of the extraction opening size is studied and its optimal diameter ( ≈ 1 mm) is found for the considered cavity shapes. It is shown that the extraction voltages of 1-2 kV are large enough to obtain high efficiencies and saturation of the current-voltage curves is observed above these values. Changes of ionisation effciency with the ioniser temperature are investigated - increase of ion yield with T is observed. It was proven that cold spots inside the ioniser cavity (near the extraction opening - in the considered case) can degrade ion source performance by several tens percent.
16
Content available remote

Calculations of Ion Beam Emittance for Hot Cavity Ion Source

70%
Turek M.
Acta Physica Polonica A
|
2015
|
vol. 128
|
issue 5
931-934
EN
Emittance of short-lived nuclide beams produced in hot cavity ion sources is calculated. Influence of half-life period as well as the average sticking time on beam emittance is under investigation. Two different shapes of ionizer cavity are considered: almost fully spherical and hemispherical ones. Changes of beam emittance due to the extraction channel geometry (its diameter and length) are studied. A new concept of scaled efficiency (ion source brightness analogon) is introduced in order to compare the two-ion source configurations. Phase space portraits of the extracted beams are presented.
17
Content available remote

Two-Dimensional Simulations of H¯ Ions Extraction

70%
Turek M.
Acta Physica Polonica A
|
2017
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vol. 132
|
issue 2
254-258
EN
The 2D particle-in-cell method based model of a negative ion source is presented. The spatial distributions of electrostatic potential and plasma component densities are presented. Changes of negative ion distribution and potential as well as the extracted H¯ current with the plasma grid bias voltage are investigated. The presence of the potential well near the plasma grid surface that traps the negative ions is shown. Increase of the H¯ ions density inside the chamber with the negative bias voltage is demonstrated. Influence of the H¯ ion flux outgoing from the plasma grid on the extracted current was checked: increase by factor 2 is observed when the flux rises 4 times. Current-voltage characteristics of the ion source are presented, saturation of the curve is observed above 50 kV.
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