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We demonstrate how the latest generation of hybrid pixel detectors of the Timepix family can be used to reconstruct 3 dimensional particle tracks on a microscopic scale, additionally determining the stopping power along the particles’ paths. In an experiment, a Timepix3 detector with a 2 mm thick planar CdTe sensor was irradiated in a 40 GeV/c pion beam and used in a similar way to a time-projection chamber: The coordinates x and y were given by the trajectory projection (pixel pitch: \\[55\\, m\\]), the z-coordinate was reconstructed from the charge carrier drift time measurement (time binning: 1.5625 ns). The achievable z-resolution was studied at different bias voltages. Systematic inaccuracies due to an imprecise drift time model were determined and separated from the intrinsic uncertainty given by the time resolution. It was shown that a z-resolution of \\[60\\, m\\] could be achieved by a perfect modeling of the drift time. With the presented z-reconstruction methodology, we studied the charge collection efficiency as a function of interaction depth, which was then used to apply a charge loss correction to the per-pixel energy measurements. 3D event displays of pion, muon and electron tracks are shown.

Timepix3 detectors are the latest generation of hybrid active pixel detectors of the Medipix/Timepix family. Such detectors consist of an active sensor layer which is connected to the readout ASIC (application specific integrated circuit), segmenting the detector into a square matrix of 256 × 256 pixels (pixel pitch 55 μ m). Particles interacting in the active sensor material create charge carriers, which drift towards the pixelated electrode, where they are collected. In each pixel, the time of the interaction (time resolution 1.56 ns) and the amount of created charge carriers are measured. Such a device was employed in an experiment in a 120 GeV/c pion beam. It is demonstrated, how the drift time information can be used for “4D” particle tracking, with the three spatial dimensions and the energy losses along the particle trajectory (dE/dx). Since the coordinates in the detector plane are given by the pixelation ( x , y ), the x - and y -resolution is determined by the pixel pitch (55  μ m). A z -resolution of 50.4 μ m could be achieved (for a 500 μ m thick silicon sensor at 130 V bias), whereby the drift time model independent z -resolution was found to be 28.5  μ m.

This article presents the outcome of a series of in-plane shear tests on non-traditional masonry walls under unstrengthened and strengthened conditions. The uniqueness of the experiments arises from the testing of unfired clay and earth (adobe) bricks, which are typical for numerous historical buildings and which have significantly different mechanical properties in comparison with the nowadays commonly used fired bricks, concrete blocks, etc. The applicability and suitability of two different strengthening techniques, which do not require significant structural intervention, were investigated with the use of two evaluation procedures. The first technique was realised using steel wire ropes that were mechanically fastened to the wall and arranged in an X shape. The other technique comprised of the application of a geo-net to the surface of the wall, which was then covered with a layer of adobe plaster. Two different types of geo-nets were tested. The paper focuses on the assessment of the influences of both strengthening techniques in changing the structural resistance of the walls loaded by a combination of constant vertical compression and a cyclic horizontal loading. Other mechanical parameters, e.g. ductility or damping, were also investigated in detail. In addition, the geo-net retrofitting technique applied to a previously damaged wall was studied. Conclusions and practical recommendations for preventive strengthening of adobe and dry brick masonry walls or for remedial work on damaged masonry in regions with high seismic risk are given.

The effect of relative humidity on the convective heat exchange between a solid surface and an ambient air stream is analyzed in this study. In the experimental part, a unique closed-circuit climatic wind tunnel is utilized, allowing full-scale experiments to be conducted with full control over the environmental parameters defining the experimental boundary conditions. The experimental configuration, which includes a specific design of a specimen to promote a controlled heat flow through the specimen body, might bring new insights into the field of energy-related calculations or prediction of building energy consumption. The novelty of this work lies in the implementation of relative humidity as an independent factor within thermal modelling, which might contribute to increasing the accuracy of building energy simulation models. The computational analysis of experimental results indicates relative humidity as an important parameter, which can affect the convective heat transfer coefficient by up to 37%. The major effects have been observed after exceeding a relative humidity of 50–55%.

This study describes the experimental and numerical dynamic analysis of a kinematically excited spherical pendulum. The stability of the response in the vertical plane was analyzed in the theoretically predicted auto-parametric resonance domain. Three different types of the resonance domain were investigated the properties of which depended significantly on the dynamic parameters of the pendulum and the excitation amplitude. A mathematical model was used to represent the nonlinear characteristics of the pendulum, which includes the asymmetrical damping. A special frame was developed to carry out the experiments, which contained the pendulum supported by the Cardan joint and two magnetic units attached to the supporting axes of rotation, and this was able to reproduce linear viscous damping for both of the principal response components. The stability analysis of the system was compared with the numerical solution of the governing equations and experimental observation. The most significant practical outcomes for designers are also summarized.

Four Timepix3 detectors were installed in the ATLAS experiment at different positions to study their capabilities to measure luminosity during pp -collisions at$$\\sqrt{s} = 13$$s = 13  TeV in 2018. While the detectors were operated independently of the ATLAS triggering and acquisition scheme, continuous (dead-time free) measurement together with an orbit clock trigger allowed for synchronization with the LHC. The detectors benefit from a fine segmentation, a pixel pitch of 55 $$\\mu $$μ m, and a per-pixel time resolution of 1.6 ns allowing for a high-quality track reconstruction and particle identification. One of the 500 $$\\mu $$μ m thick silicon sensors was equipped with a$^{6}$$6 LiF neutron converter, extending the particle identification capabilities. The installed system was used to study luminosity in different time frames: long term (run-by-run), short term (within a single run) and instantaneous (for each bunch crossing). For the long- and short-term luminosity, partly-independent algorithms: cluster and thermal neutron counting are proposed. A comprehensive analysis of the signal from induced radioactivity and its consecutive removal is presented together with a study demonstrating that the activation-corrected Timepix3 luminosity measurement provides good linearity with respect to the pile-up parameter$$\\mu $$μ . For measurement of the instantaneous luminosity, a cluster classification scheme was employed to decompose the measured response to the colliding bunch signal. Selecting a subset of the cluster categories, the signal-to-background ratio was improved and the impact of delayed particles from previous bunches could be reduced. Comparisons performed to the primary bunch-by-bunch luminosity measurement of the ATLAS experiment, provided by the LUCID-2 Cherenkov detector, show a good agreement.

Four Timepix3 detectors were installed in the ATLAS experiment at different positions to study their capabilities to measure luminosity during pp -collisions at s = 13  TeV in 2018. While the detectors were operated independently of the ATLAS triggering and acquisition scheme, continuous (dead-time free) measurement together with an orbit clock trigger allowed for synchronization with the LHC. The detectors benefit from a fine segmentation, a pixel pitch of 55  μ m, and a per-pixel time resolution of 1.6 ns allowing for a high-quality track reconstruction and particle identification. One of the 500  μ m thick silicon sensors was equipped with a 6 LiF neutron converter, extending the particle identification capabilities. The installed system was used to study luminosity in different time frames: long term (run-by-run), short term (within a single run) and instantaneous (for each bunch crossing). For the long- and short-term luminosity, partly-independent algorithms: cluster and thermal neutron counting are proposed. A comprehensive analysis of the signal from induced radioactivity and its consecutive removal is presented together with a study demonstrating that the activation-corrected Timepix3 luminosity measurement provides good linearity with respect to the pile-up parameter μ . For measurement of the instantaneous luminosity, a cluster classification scheme was employed to decompose the measured response to the colliding bunch signal. Selecting a subset of the cluster categories, the signal-to-background ratio was improved and the impact of delayed particles from previous bunches could be reduced. Comparisons performed to the primary bunch-by-bunch luminosity measurement of the ATLAS experiment, provided by the LUCID-2 Cherenkov detector, show a good agreement.

The response of 4H-SiC detectors to 17 MeV neutrons was experimentally analysed using detectors composed solely of carbon or silicon. The detectors were tested using three different neutron energies (14.5 MeV, 15 MeV and 17 MeV) at two different facilities with T(d,n) neutron generators, the Van de Graaff laboratory at IEAP CTU in Prague and at the DANAIDES facility at CEA research center in Cadarache. The calibration via interactions on 28 Si nuclei, the (n, α) nuclear reaction to ground and excited states of 25 Mg, was made. The standard deviation of experimental values measured by Si detector from prepared calibration curve, was of 0.073 MeV, which represents the uncertainty of less than 1% in this energy range (≈ 10 MeV). The experiment showed that the pulse height defect affects the measured spectra the way that the peak energies from the C interactions are shifted by about 0.5 MeV to higher values when the calibration from the Si interactions is used.

A small-scale wind turbine model was designed and manufactured to study its aerodynamic thrust force and the harvested flow energy. To provide a good understanding of the aerodynamics of the small-scale wind turbine at the low Reynolds number, the performance of three different types of blade airfoils was studied. The main motivation for the design of a new miniature wind turbine model was to achieve realistic values of the thrust force and the power coefficient on the model scale. A new blade profile with a thickness of 10% was designed and employed to reach the high tip-speed ratio, which is characteristic of contemporary wind turbines.

Significance of full-scale experiments, analysing wind conditions and local wind pressures on tall buildings are evident from the attention that has been dedicated by researchers to these programs in the recent past. This paper presents some recent results measured from a tall building located on the left banks of the Dnieper River of Kiev, Ukraine. In the first part of this study, attention is devoted to the full-scale measurements of the wind flow atop a high-rise building as a comprehensive investigation on wind velocity and local wind pressures on surfaces using wind tunnel simulation. In the second part was concentrated on the comparison results of mean wind pressures, mean pressure coefficients obtained from full-scale measurements, and scale modelling in the wind tunnel.