Graduate Seminar, 9th April

Speaker: Sarah Allen

Title: Simulation and analysis of detective quantum efficiency in mammography

Abstract: The detective quantum efficiency (DQE) of an imaging device describes its ability to preserve the signal to noise ratio from the radiation field to the resulting image data. Since in X-ray imaging the noise of the radiation field is heavily dependent on the air kerma, DQE values are used to describe the dose efficiency of a device. In this seminar, I will outline why DQE is used to quantify image quality in radiographic systems and how it is calculated. I will also discuss these things in context of a mammography unit.

Graduate Seminar, 26th March

Speaker: Artur Miroszewski

Title: Evolution in classical and quantum systems

Abstract: Although people tend to understand intuitively the passage of time, its status in physical theories is still puzzling. During the talk I will distinguish between notions of time and clocks and I will motivate why only the latter has a physical significance. Using this assumption I will introduce reformulated theory of classical mechanics in which one can easily change clock (so called pseudo-canonical transformations) with respect to which the dynamics is observed.
I will then quantize the new theory and study what impact the new formulation has on our basic understanding of quantum mechanics.

Graduate Seminar, 19th March

SpeakerVarvara Batozskaya

Title: Measurement of CP observables in B0s->J/psi(ee)Phi(KK) decay at the LHCb experiment

Abstract: The determination of the CP-violating phase phi_s in B0s->J/psiPhi decays is one of the key goals of the LHCb experiment. Its value is predicted to be very small in the Standard Model. However, it can be significantly enhanced by contributions from effects of new physics. The first measurement of the CP-violating parameters in electron mode of the B0s->J/psiPhi decay using Run1 data collected at the LHCb will be discussed.

Graduate Seminar, 12th March

Speaker:  Chetan Bavdhankar

Title: Our velocity and acceleration in the Universe are in the same direction! (Local Group Motion using Supernova type Ia)

Abstract: Supernova type Ia (SN Ia) are one of the accurate distance indicators which are used to measure the distances to distant galaxies. Using the redshift of the galaxy and it’s distance (estimated from SN Ia) we can measure its peculiar velocity. Nearby galaxies in the Universe are bound gravitationally and these bound systems of galaxies are called galaxy groups. We are part of such group which is called ‘The Local Group’ (LG), Andromeda galaxy is also member of this group. These galaxy groups show motion due to nearby masses such as other groups, clusters and superclusters. Our Local Group is also showing such motion and this motion can be seen in CMB dipole. To estimate the responsible masses for this motion of Local Group, dipole in peculiar velocities is useful. This dipole in peculiar velocities has the information about effective distance that can cause our group’s motion. In my work, I have tried to calculate that distance. As SN Ia are not very frequent events, we don’t have enough data points to get very accurate results so we need to generate artificial data more realistically. I have used velocity fields in the Local Universe to generate such a artificial SN Ia data and got the results which says that ‘Our velocity and acceleration in the Universe are in the same direction!’

Graduate seminar, 5th March

Speaker: Piotr Warzybok

Title: Modelling of Processes Governing Selective Laser Melting

Abstract: The processing parameters of Selective Laser Melting (SLM) technique have a significant impact on the functional properties of the materials. It is known that time efficient fabrication of high-quality parts with desired microstructures requires understanding of their interactions in more detail than by calculating energy density. During the talk I will introduce mechanical and structural properties of standard 316L stainless steel fabricated using SLM technique. The basics of the modelling of physical phenomena governing SLM will be discussed.

Graduate Seminar, 26th February

Speaker: Szymon Nakoneczny

Title: Natural language processing methods in biological activity prediction and quasar detection in large scale photometric surveys.

Abstract: The first part will focus on my master ‘s thesis. Virtual screening is a process in which databases of chemical compounds are searched in order to f ind structures characterized with a high biological activity, possible drug candidates. The goal is to classify active compounds by combining the natural language processing methods with a text representation of compounds. The second part is going to cover an approach of detecting quasars with means of machine learning. Because it is not possible to fully sample extragalactic objects with spectroscopy, quasars analysis requires a proper automated approach based on photometric surveys. We are going to focus on describing a problem and showing preliminary results of our approach.

Graduate Seminar, 19th February

SpeakerGrzegorz Żarnecki

Title: Measurement of muon-antineutrino charged current cross section with single pion production in the near detector of T2K experiment

Abstract: Cross section measurement is a basic tool to examine agreement between theoretical models and experimental data. The fundamental struggle is to separate signal sample from background events. Decent measurement requires nontrivial methods in order to minimize dependency on the default model and include characteristics of the detector. This will be illustrated on the example of muon-antineutrino CC interaction on carbon with single pion production in ND280 detector of the T2K experiment.

Thesis topic proposal

Design, construct and test a prototype neutron detector

Helium-3 isotope is commonly used as detection medium in detectors applied for neutron detection in many fields of industry and physics. The world crisis of He-3 isotope is forcing for a research and development of other neutron detection methods. Recently, a multigrid gas detector based on boron coated blades has been developed at Institut Laue-Langevin (ILL) in Grenoble as an alternative for commonly applied He-3 proportional counters in neutron scattering experiments. However, it may be considered to use this solution for other applications.

Continue reading Thesis topic proposal

Graduate Seminar 22nd January

Speaker: Joanna Reszczyńska

Title: Hyper-radiosensitivity phenomenon and significance of human individual radiosensitivity in modeling of Low Dose Radiation Biological Effects.

Abstract: For ionization radiation (IR) induced cancer, a linear non-threshold (LNT) model at very low doses is the default used by a number of international organizations and in regulatory law. However, experimental observations and theoretical biology have found that other dose-response curves can exist at those very low doses. This approach includes detailed, molecular descriptions of cells mechanisms to develop a dose-response model either through a set of nonlinear, differential equations or a stochastic approach based on Monte Carlo simulations. Both methods are subject to the body’s reaction.The existence of heritable radiosensitivity syndromes and clinical observations in radiotherapy patients suggests that human cellular radiosensitivity differs among individuals. The assessment of the more radiation-sensitive and the more cancer-prone people is very important issue. This seminar discusses the bases of low-dose hyper-radiosensitivity (HRS) with reference to the molecular regulation of DNA repair and cell cycle control processes. The aim of the presented study was to examine, using the micronucleus (MN) assay, the low-dose radiation response of blood cells lymphocytes from healthy donors and to determine whether the method can be used to verify the hypothesis of the HRS phenomenon occurrence in general population.