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Właściwości optyczne cienkich warstw krzemionkowych wytwarzanych metodą zol-żel
No full textThe main aim of this study was to determine the optical properties of thin silica films with varying degrees of porosity produced by the sol-gel method on glass and silicon substrates, and to determine the optical parameters of the films. The studies were carried out using spectrophotometry and spectroscopic ellipsometry, and the very important element of the work was to compare the results obtained by both methods. These studies have been completed by structural studies, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and interference contrast (Nomarski) microscopy that enables three-dimensional imaging surface. The main results of this work can be summarized as follows:
1. Structural studies have shown the presence of macropores (the size of 90 – 1300 nm) and their contribution to the total porosity of the silica films has been estimated to be approximately 5%.
2. Ellipsometric and spectrophotometric investigations of the glass substrate have allowed to determine its absorption edge [λcut-off = 280 nm (4.43 eV)], Urbach energy (EU = 0.34 eV), which is a measure of disorder in amorphous materials, and dispersion relations of the refractive index that can be described by the Sellmeier formula.
3. Based on the spectrophotometric studies of reflection and transmission for the films on glass substrates and the reflectivity of films on silicon it has been found that silica films act as antireflective layers greatly reducing the average reflection, and thereby increasing an average transmission.
4. The joint analysis of the elipsometric and spectrophotometric results obtained for the silica films on glass allowed to determine their thickness, and the refractive index dispersions that can be described by the Sellmeier formula. It has been found that the differences between the values of optical paths determined by both methods are small and do not exceed 4%. The values of the refractive indices have been found to be much lower than the value of this coefficient for thermal silica that is caused by the porosity of films lying in the range 17 – 39%.
5. Spectrophotometric studies of the silicon p-type doped (Si:B) substrate have allowed to determine the dispersion dependence of the absorption coefficient that indicates a mechanism of energy absorption of electromagnetic radiation by the free carriers (holes) in the energy range below the energy gap of silicon (Eg = 1.1 eV).
6. The joint analysis of the elipsometric and spectrophotometric studies obtained for silica films on silicon has allowed to determine their thickness, and the refractive index dispersions that can be described by the Sellmeier formula. It has been found that the differences between the values of optical paths determined by both methods, below 4 eV, do not exceed 4%, however, above this energy the difference increases with the photon energy which may follow from the difference between the optical constants of Si:B used in this work and those of intrinsic silicon used in the elipsometric data analysis. Similarly as for the silica films on glass, the refractive indices for the silica films on silicon have been found to be significantly lower than the value of this coefficient for thermal silica, due to the presence of pores in the volume of the investigated films, the porosity of which lies in the range of 33 – 41%.
7. The results have allowed to establish a correlation between the conditions of technological, and geometric and optical parameters of the films studied. On the one hand, the refractive index is, to a good approximation, a linear function of porosity, and on the other hand, the refractive index decreases with increasing film thickness, approaching a constant value (n ≈ 1.25) for thicker films (above 800 nm).
8. Comparison of the total porosity determined from optical studies (17 – 41%) with the porosity estimated from structural studies (approx. 5%) indicates that a large contribution to the porosity of the silica films is due to the presence of pores with sizes less than 100 nm.
The performed measurements, analysis and interpretation of experimental data made it possible to determine the properties, and geometric and optical parameters, as well as their correlation with the preparation conditions of thin silica films by sol-gel method and thus fully achieve the objective of the present work. This work has shown that effective and cheap sol-gel method of preparation of porous silica thin films enables significant and controlled reduction of the refractive index, and thus gives the possibility of their use as antireflective layers in various types of optical systems
Pomiar funkcji struktury protonu w obszarze małych przekazów czteropędu Q2 na akceleratorze HERA
No full textSearch for Charged Lepton Flavour Violation at LHCb experiment
No full textThe thesis describes searches for charged lepton flavour violation in the process τ−→ μ−μ+μ−. The study is performed at the LHCb experiment data sample corresponding to an integrated luminosity of 3 fb-1 of proton-proton collisions at a centre-of-mass energy of 7 TeV (8 TeV), collected in 2011 (2012), respectively. No significantly statistical signal of the decay in question has been found and as a result the upper limit was set: B(τ−→μ−μ+μ−) < 4.6 × 10 − 8 at 90% confidence level. The limit was then interpreted in terms of an effective field theory approach including beyond the Standard Model operators with different lepton chirality structures. We found that the limits are within the range: (4.1−6.8)×10−8 at 90% confidence level.
The thesis presents also the combination of upper limits for all lepton flavour violating τ lepton decays. For the decay in question, i.e. τ−→μ−μ+μ−, the combination leads to the upper limit of B(τ−→μ−μ+μ−) < 1:2 ×10−8 at 90% confidence level.11
Zastosowanie techniki μSR w badaniach własnosci magnetycznych wybranych magnetyków molekularnych
No full textThe subject of this paper is an application of the muon spin research (μSR) in
study of critical properties of molecule-based magnetic materials, particularly
the novel cyano-bridged molecular networks. Among several elementary particles commonly used in condensed matter science, the positive muon is fast establishing itself alongside the electron, the positron and the neutron. Although it would be an exaggeration to describe the muon as a universal microscopic probe, but only a few restrictions exist as to the suitability of the examined material. Research involving muons
provides a wealth of structural and dynamical information on the atomic scale on metallic systems, on magnetic materials, on semiconductors and on insulators, including organic and molecular materials. μSR spectroscopy makes use of implanted muons to probe properties of matter at the microscopic level. According to one of the earliest definition of μSR - appeared on the cover of the first issue of the μSR Newsletter in 1974 -: “μSR stands for Muon Spin Relaxation, Rotation, Resonance, Research or
what have you”. Generally speaking, the abbreviation covers any study of the
interactions of the muon’s magnetic moment with its surrounding following
implantation in matter of choice. μSR is a relatively new nuclear method,
that can be classified in between NMR and diffraction techniques. .However,
a key difference is the fact that in μSR one does not relay on internal nuclear
spins, making use of the muon’s spin instead. Moreover, no radio-frequency
technique alignment of the probing spin is required. Another clear distinction
between the μSR technique and those involving neutrons or X-rays is that
scattering is not involved. Neutron diffraction techniques, for example, use
the change in energy and/or momentum of a scattered neutron to deduce
the sample properties. In contrast to the neutron diffraction techniques, the
implanted muons are not diffracted but remain in a sample until the time of
their natural decay. A careful analysis of the decay positrons provides information
about the interaction between the implanted muon and environment
it is probing. The [M(CN)8]n− complexes, are universal building blocks for a moleculebased magnets, leading to various spatial structures, depending on the surrounding ligands and the choice of the metal ions. With these complexes
many novel, functional magnetic compounds of different network dimensionality and unique physical properties have been recently developed. Research
on functionality of organic and metalorganic systems receives still growing
attention, since in case of molecular material it is possible to design it’s properties
through careful preparation of the chemical synthesis path. Molecular
magnets predominantly belong to the class of compounds involving well localized
magnetic moments. Unprecedented properties of novel molecule-based
magnetic materials are due to interplay of unique molecular network architectures
and magnetic anisotropy induced by different coordination patterns.
Such features together with the fact that the nature and symmetry of magnetic
interactions is encrypted in the critical behaviour makes them a perfect
testing ground of the existing theoretical spin models. The μSR experimental
method allows to study magnetic properties of such materials in zero applied
field. Therefore it is perfectly suited to study magnetic fluctuations and spin
dynamics in the vicinity of phase transition, supplying complete set of static
and dynamic critical exponents. Present dissertation concerns study of critical behaviour for six molecular magnets based on [M(CN)8]n− building blocks (M = WV,MoV, NbIV) and
d-electron spin centres such as CuII,MnII, FeII. First part of this monograph provides a brief descrption of muon as a elementary particle and it’s interaction in condensed matter. The second part contains general introduction to the μSR experimental technique itself as well as it’s aplication in study of critical properties of magnetic materials.
The second part was also meant to serve as a basic handbook, for students
and possible new users, wishing to utylize this experimantal method in their
research. Therefore author tried to make it possibly comprehensive. The
third part of this monography is devoted to analysis of μSR data obtained
for six compounds exhibiting different dimensionalities of crystall and magnetic
structures. The fourth and last part of this paper summarizes main conclusions presented in this habilitation thesis. This dissertation intends to be an example of application of the μSR technique in study of critical phenomena in molecule-based magnetic materials. The author’s intention was, that this work could be a handy guide for those, (students, researchers) wishing to use μSR method for the first time
Studies of time dependent CP violation in charm decays of B 0 s mesons
No full textThe thesis describes the world-first, time-dependent measurement of charge-parity (CP ) violation in B 0 s → D∓ s K± decays. The study is performed at the LHCb experiment using data sample corresponding to an integrated luminosity of 1.0 fb− 1 of proton-proton collisions at a center-of-mass energy of √ s = 7 TeV, recorded in 2011. The CP violating observables are found to be: C = 0.52 ± 0.25 ± 0.04, D f = 0.29 ± 0.42 ± 0.17, D ¯ f = 0.14 ± 0.41 ± 0.18, S f = − 0.90 ± 0.31 ± 0.06, S ¯ f = − 0.36 ± 0.34 ± 0.06, where the first (second) uncertainty is statistical (systematic). These observables are used to perform the first measurement of the Cabibbo-Kobayashi-Maskawa angle γ in B 0
s → D∓ s K± decays, finding γ = (113 +30 − 44 )◦ modulo 180◦ at 68% CL, where the error contains both statistical and systematic uncertainties.16
Produkcja cząstek naładowanych w oddziaływaniach ołów-ołów przy energii √SNN=2.76 TeV i proton-ołów przy energii √SNN=5.02 TeV w eksperymencie ATLAS
No full textThe LHC (Large Hadron Collider) at CERN is dedicated to physics of proton-proton collisions at the highest energies. Since 2010 it provides data at new maximal energies obtained in the laboratory, currently at 13 TeV. In addition to proton beams the lead beams are
also accelerated for some fraction of time, which allowed to measure P b + P b collisions at √ sNN= 2.76 TeV and p+P b collisions at √ sNN
= 5.02 TeV - which are analysed in this work. The main objective of the high-energy heavy ion physics programme is the search and
studies of properties of the Quark-Gluon Plasma (QGP). This state of matter was present in the early Universe (before 10− 12 s) and can be created in the collisions of heavy nuclei. One of the basic properties of these collisions and subject of one of the first measurements
is the charged particle multiplicity. It can be used to estimate the energy density of the system created in the collision and provides a basic test of theoretical models. Before first measurements at the LHC the number of produced charged particles followed a logarithmic
dependence on the energy of collisions, but new observations revealed a faster growth of this observable. This thesis describes a new method for a measurement of the charged particle mul-
tiplicity and the pseudorapidity density, applied to the data from the ATLAS experiment, which is based on counting signals (pixel clusters) from the first layer of the pixel detector. The main advantage of this method is that is fully uses the acceptance of the innermost part
of the pixel detector, which is larger in pseudorapidity η than that available for other methods based on track reconstruction. In addition, this method allows to include particles with very small transverse momenta, which give signal only in the first layer of the pixel detector because either they stop before reaching even the second layer or their path is too curved by the magnetic field. The main disadvantage of this method is a strong dependence on corrections from Monte Carlo simulations. Using the pixel cluster method the charged particle density in the pseudorapidity range | η | <2.5 for P b + P b collision and | η | < 3.1 for p + P b collisions is measured. Charged particle multiplicity and angular distribution of particles are obtained separately for different intervals of the collision centrality. The charged particle multiplicity in the | η | < 0.5 range in P b + P b collisions increases fast with centrality, starting from dN ch /dη = 28.66 (centrality
75-80%) up to 1742.84 (centrality 0-1%). Mean number of charged particles per a pair of nucleons participating in the collision increases slowly with centrality of P b + P b collisions. Pseudorapidity density distributions for different centralities are similar while small differences between them can be attributed to a lower longitudinal momentum of particles produced in the central collisions than in the peripheral collisions. The charged particle density in p + P b collisions increases with the centrality of the collision. Also the shape of it changes due to an enhanced particle production in the Pb- going region (η > 0). In the central collisions (0-1%) charged particle density in Pb-going side reaches 70 particles while in the p-going side it is about 35. For peripheral collisions (60-90%)dN ch /dη is nearly flat in the full η range | η | < 3.1 and does not exceed 10. The average value of the charged particles density per a pair of nucleons participating in the collision is strongly depend on the method which is used to calculate N part for p + P b collisions. Three versions of the Glauber’s model used give very different dependences of this observable on N part . All presented results from the pixel clusters method are consistent with results obtained by the ATLAS experiment using other methods and with results of the ALICE experiment.14
Symulacja Monte-Carlo odpowiedzi otworowej sondy geofizycznej gamma-gamma w ceramicznym ośrodku modelowym stanowiska kalibracyjnego w Zielonej Górze
No full textPraca wykonana została w ramach realizacji umowy pt. ”Opracowanie modeli cyfrowych trzech typów sond otworowej geofizyki jądrowej (gamma-gamma, neutron - neutron epitermiczne i termiczne, neutron - neutron termiczne) w formie zestawów danych wejściowych dla oprogramowania MCNP i wykonanie obliczeń testowych przy użyciu tych modeli dla zadanego ośrodka skalnego” w ramach współpracy z Wydziałem Geologii, Geofizyki i Ochrony Środowiska Akademii Górniczo-Hutniczej w Krakowie. Umowa nr ZDN/035/140/2015.Responses of the spectrometric gamma-gamma density tool in borehole were numerically simulated by means of the MCNP code. The rock medium has been modelled as a few layers of some ceramic materials with well-known chemical composition and mudstones of 2, 5, 9 and 15 % porosity
Eksploatacja stanowiska r adioterapi i protonow ej nowotworów oka w IFJ PAN w latach 2013-2015
No full textProton radiotherapy is an effective treatment modality for ocular cancer patients with choroidal melanoma. In 2011 a proton radiotherapy facility at the Institute of Nuclear Physics Polish Academy of Sciences was commissioned and went into clinical operation. By the end of the year 2015, a total of 128 ocular patients of the University Hospital in Kraków were irradiated at this facility, of whom 113 were treated under contract from the National Health Fund
Method of interpretation of measurements of delayed neutrons in the DET-12 device
No full textDET-12 is a device to measure delayed neutrons from fissions in fissionable material samples which were activated in the primary neutron flux from D-T or D-D reactions in hot plasma of big fusion devices (tokamaks, stellarators). In the paper, a method is outlined how to interpret the registered time decay of delayed neutrons in order to obtain information on intensity of the primary neutron flux. The method combines a restoration of the decay function (multi-exponential) from the data stored in a multiscaler regime and a Monte Carlo calculation of a basic approximation of the neutron energy spectrum.The work has been performed within the framework of the strategic research project “Technologies supporting development of safe nuclear power engineering” financed by the National Centre for Research and Development (NCBiR). Research task „Research and development of techniques for the controlled thermonuclear fusion”, Contract No. SP/J/2/143234/11
Projekt modernizacji systemów dostępu i bezpieczeństwa cyklotronu AIC-144
No full textThe goal of this report is to present to possibility of modernization of AIC-144 cyclotron's safety systems. The actual status is described and possible solution offered. The core of the new safety system is Siemens Simatic S7-200 PLC which delivers satisfactory quantity of I/Os and also allows further development by ie. implementing Ethernet communication and control over the remote program. The methodology of control algorithms construction is also presented