Péter Major

The NanoPET/CT represents the latest generation of commercial preclinical PET/CT systems. This article presents a performance evaluation of the PET component of the system according to the National Electrical Manufacturers Association (NEMA) NU-4 2008 standard.The NanoPET/CT consists of 12 lutetium yttrium orthosilicate:cerium modular detectors forming 1 ring, with 9.5-cm axial coverage and a 16-cm animal port. Each detector crystal is 1.12 × 1.12 × 13 mm, and 1 module contains 81 × 39 of these crystals. An optical light guide transmits the scintillation light to the flat-panel multianode position-sensitive photomultiplier tubes. Analog-to-digital converter cards and a field-programmable gate array-based data-collecting card provide the readout. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with the NEMA NU-4 standard. Energy and temporal resolution measurements and a mouse imaging study were performed in addition to the standard.Energy resolution was 19% at 511 keV. The spatial resolution, measured as full width at half maximum on single-slice rebinning/filtered backprojection-reconstructed images, approached 1 mm on the axis and remained below 2.5 mm in the central 5-cm transaxial region both in the axial center and at one-quarter field of view. The maximum absolute sensitivity for a point source at the center of the field of view was 7.7%. The maximum noise equivalent counting rates were 430 kcps at 36 MBq and 130 kcps at 27 MBq for the mouse- and rat-sized phantoms, respectively. The uniformity and recovery coefficients were measured with the image-quality phantom, giving good-quality images. In a mouse study with an (18)F-labeled thyroid-specific tracer, the 2 lobes of the thyroid were clearly distinguishable, despite the small size of this organ. The flexible readout system allowed experiments to be performed in an efficient manner, and the system remained stable throughout.The large number of detector crystals, arranged with a fine pitch, results in excellent spatial resolution, which is the best reported for currently available commercial systems. The absolute sensitivity is high over the field of view. Combined with the excellent image quality, these features make the NanoPET/CT a powerful tool for preclinical research.

nanoScan is a high-resolution integrated system for consecutive PET and MR imaging of small laboratory animals. We evaluated the performance of the system, using the NEMA NU 4-2008 protocol for the PET component and the NEMA MS 1-2007, MS 2-2008, and MS 3-2007 standards for the MR imaging component.The imaging system uses magnetically shielded position-sensitive photomultiplier tubes and a compact 1-T permanent-magnet MR imaging platform. Spatial resolution, sensitivity, counting rate capabilities, and image quality parameters were evaluated in accordance with the aforementioned NEMA standards. Further in vivo evaluation experiments complement the physical validation results.The spatial resolution of the PET system enabled the 0.8-mm rods of a Derenzo phantom to be resolved. With point source and 2-dimensional filtered backprojection reconstruction, the resolution varied from 1.50 to 2.01 mm in full width at half maximum in the radial direction and from 1.32 to 1.65 mm in the tangential direction within the radius of 25 mm. Peak absolute sensitivity was 8.41%. Scatter fraction was 17.3% and 34.0%, and maximum noise-equivalent counting rate was 406 and 119 kcps in the mouselike and ratlike phantom, respectively. The image quality test found a nonuniformity of 3.52% and a spillover ratio of 6.2% and 5.8% in water and air, respectively. In testing of the MR imaging component, artifact-free images with high signal-to-noise ratio were recorded. Geometric distortion was below 5%, and image uniformity was at least 94.5% and 96.6% for the 60- and 35-mm radiofrequency coils, respectively.The nanoScan integrated small-animal PET/MR imaging system has excellent spatial resolution and sensitivity. The performance characteristics of the PET and the MR imaging components are not compromised as a result of their integration onto a single platform. Because of its combination of features and performance parameters, the system provides crucial advantages for preclinical imaging studies over existing PET/CT systems, especially in neurologic and oncologic research.

<h2>Summary</h2> The Avars settled the Carpathian Basin in 567/68 CE, establishing an empire lasting over 200 years. Who they were and where they came from is highly debated. Contemporaries have disagreed about whether they were, as they claimed, the direct successors of the Mongolian Steppe Rouran empire that was destroyed by the Turks in ∼550 CE. Here, we analyze new genome-wide data from 66 pre-Avar and Avar-period Carpathian Basin individuals, including the 8 richest Avar-period burials and further elite sites from Avar's empire core region. Our results provide support for a rapid long-distance <i>trans</i>-Eurasian migration of Avar-period elites. These individuals carried Northeast Asian ancestry matching the profile of preceding Mongolian Steppe populations, particularly a genome available from the Rouran period. Some of the later elite individuals carried an additional non-local ancestry component broadly matching the steppe, which could point to a later migration or reflect greater genetic diversity within the initial migrant population.

A new multi-modality imaging tool is under development in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemo Therapy) project, supported by the European Community. The final goal is to develop a custom SPECT apparatus, that can be used as an insert for commercially available MRI systems such as 3 T MRI with 59 cm bore diameter. INSERT is expected to offer more effective and earlier diagnosis with potentially better outcome in survival for the treatment of brain tumors, primarily glioma. Two SPECT prototypes will be developed, one dedicated to preclinical imaging, the second one dedicated to clinical imaging. The basic building block of the SPECT detector ring is a small 5 cm×5 cm gamma camera, based on the well-established Anger architecture with a continuous scintillator readout by an array of silicon photodetectors. Silicon Drift Detectors (SDDs) and Silicon PhotoMultipliers (SiPM) are being considered as possible scintillator readout, considering that the detector choice plays a predominant role for the final performance of the system, such as energy and spatial resolution, as well as the useful field of view of the camera. Both solutions are therefore under study to evaluate their performances in terms of field of view (FOV), spatial and energy resolution. Preliminary simulations for both the preclinical and clinical systems have been carried out to evaluate resolution and sensitivity.

The LFER 150 PET/CT device (large-field-of-view extreme-resolution portable research imager) is a system for nonhuman primate (NHP) imaging. The objective of this study was to evaluate the performance of the system using the National Electrical Manufacturers Association NU 4-2008 standard protocol. As a preliminary in vivo evaluation of the system, a PET measurement in an NHP was also performed. Methods: Resolution, sensitivity, image quality, and noise-equivalent count rate (NECR) were measured. NECR measurement was performed with a ratlike phantom and a monkeylike phantom. A Derenzo phantom experiment was performed to test the resolution using 3-dimensional ordered-subset expectation maximization reconstruction. One cynomolgus monkey (4.5 kg, intravenous ketamine/xylazine anesthesia) was examined with the dopamine transporter radioligand 18F-FE-PE2I (94 MBq) to evaluate the in vivo performance of the system. List-mode PET data acquired for 93 min were reconstructed into 38 frames with the Tera-Tomo 3-dimensional engine. Binding potential for caudate nucleus, putamen, and substantia nigra was evaluated using the simplified reference tissue model. Results: Radial full-width half-maximum resolution using Fourier rebinning and a 2-dimensional filtered backprojection algorithm was less than 2.2 mm and less than 3.2 mm in the central 60-mm-diameter and 140-mm-diameter regions, respectively. Maximum sensitivity in the 400- to 600-keV and 250- to 750-keV energy windows was 30.03 cps/kBq (3.3%) and 49.11 cps/kBq (5.4%), respectively. The uniformity in the image-quality phantom was 3.3%, and the spillover ratio for air and water was 0.1. The peak of the NECR curve was 430 kcps (at 115 MBq) with the ratlike phantom and 78 kcps (at 139 MBq) with the monkeylike phantom. Rods of the Derenzo phantom with 1-mm diameter could be distinguished by eye. In the NHP experiment, binding potentials in the caudate, putamen, and substantia nigra (4.9, 4.9, and 1, respectively) were similar to those previously reported using the same radioligand and a high-resolution research tomograph. Conclusion: The results obtained from phantom experiments and 1 representative PET measurement in an NHP confirm that the LFER 150 is a high-resolution PET/CT system with suitable performance for brain imaging in NHPs.

In this paper we illustrate the core technologies at the basis of the European SPADnet project (www.spadnet.eu), and present the corresponding first results. SPADnet is aimed at a new generation of MRI-compatible, scalable large area image sensors, based on CMOS technology, that are networked to perform gamma-ray detection and coincidence to be used primarily in (Time-of-Flight) Positron Emission Tomography (PET). The project innovates in several areas of PET systems, from optical coupling to single-photon sensor architectures, from intelligent ring networks to reconstruction algorithms. In addition, SPADnet introduced the first computational model enabling study of the full chain from gamma photons to network coincidence detection through scintillation events, optical coupling, etc.

The goal of this Lecture Note is to prove a new type of limit theorems for normalized sums of strongly dependent random variables that play an important role in probability theory or in statistical ph

The contrast recovery coefficients (CRC) were evaluated for five different small animal PET scanners: GE Explore Vista, Genisys4, MiniPET-2, nanoScan PC and Siemens Inveon. The NEMA NU-4 2008 performance test with the suggested image quality phantom (NU4IQ) does not allow the determination of the CRC values for the hot regions in the phantom. This drawback of NU4IQ phantom motivated us to develop a new method for this purpose. The method includes special acquisition and reconstruction protocols using the original phantom, and results in an artificially merged image enabling the evaluation of CRC values. An advantageous feature of this method is that it stops the cold wall effect from distorting the CRC calculation. Our suggested protocol results in a set of CRC values contributing to the characterization of small animal PET scanners. GATE simulations were also performed to validate the new method and verify the evaluated CRC values. We also demonstrated that the numerical values of this parameter depend on the actual object contrast of the hot region(s) and this mainly comes from the spillover effect. This effect was also studied while analysing the background activity level around the hot rods. We revealed that the calculated background mean values depended on the target contrast in a scanner specific manner. Performing the artificially merged imaging procedure and additional simulations using the micro hollow sphere (MHS) phantom geometry, we also proved that the inactive wall around the hot spheres can have a remarkable impact on the calculated CRC. In conclusion, we have shown that the proposed artificial merging procedure and the commonly used NU4IQ phantom prescribed by the NEMA NU-4 can easily deliver reliable CRC data otherwise unavailable for the NU4IQ phantom in the conventional protocol or the MHS phantom.

In positron emission tomography (PET), photon scattering inside the body causes significant blurring and quantification error in the reconstructed images. To solve this problem we have developed Monte Carlo (MC) based 3D PET reconstruction algorithms implemented on the Graphics Processing Unit (GPU). Our implementation takes multiple Compton scattering into account without any significant additional cost. The performance of the scatter correction is evaluated using GATE simulation as well as by comparing reconstruction results of Tera-Tomo to the reference reconstruction implementation of the Philips Gemini TOF PET which applies attenuation correction and single scatter simulation (SSS) for scatter correction. The comparative reconstruction results are based on the NEMA NU2-2007 image quality phantom.

The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 "telescopes", with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run 2 (2015-18) of the LHC, as well as preparations for Run 3, which will begin in 2022.

Novel analytical solution to lateral buckling of pipelines based on localization of buckle patterns is proposed. Finite element study is conducted on lateral buckling of a full length pipe. Analytical and FE results are compared and advantages of analytical solution to FE model are highlighted. Interaction between lateral buckling and propagation buckling of cylindrical pipe and textured pipe under transient load path are investigated.

Positron annihilation (PA) techniques became, by now, routinely used nuclear techniques with applications which range from structural investigations of materials to biological samples and medical applications in positron emission tomography (PET). As at present, both PA spectroscopy and PET could profit from an improvement in the fast coincidence technique, it was investigated how far a fully digitized positron lifetime spectrometer (with full event storage capability for the simultaneous recording of time and energy information of the γ-rays) could offer advantages over a conventional setup employing fast analogue nuclear electronics. The additional information allows off-line analysis which could be particularly useful in separating various annihilation channels, like the positronium contribution, recently recognized to offer a new “window of observation”.

Silicon Photomultipliers have the ability to replace photomultiplier tubes when used as light sensors in scintillation gamma-ray detectors. Their timing properties, compactness, and magnetic field compatibility make them interesting for use in Time-of-Flight Magnetic Resonance Imaging compatible Positron Emission Tomography. In this paper, we present a new fully digital Single Photon Avalanche Diode (SPAD) based detector fabricated in CMOS image sensor technology. It contains 16x8 pixels with a pitch of 610x571.2 μm2. The Dark Count Rate and the Photon Detection Probability of each SPAD has been measured and the homogeneity of these parameters in the entire 92000 SPAD array is shown. The sensor has been optically coupled to a single LYSO needle and a LYSO array. The scintillator crystal was irradiated with several gamma sources and the resulting images and energy spectra are presented.

We propose a mixed analytical-ab-initio method for the accurate calculation of the conductance in monovalent atomic wires. The method relies on the most general formula for ballistic transport through a monovalent wire, whose parameters can be determined from first-principles calculations. Our central result is the demonstration of the highly non-universal behavior of the conductance, which depends on the fine details of the contacts to the leads. We are therefore able to reconcile a large number of the apparently contradictory results that have recently appeared in the literature.

A new multi-modality imaging tool is under development in the framework of the INSERT (Integrated SPECT/MRI for Enhanced Stratification in Radio-chemo Therapy) project, supported by the European Community. The final goal is to develop a custom SPECT apparatus that can be used as an insert for commercially available MRI systems. INSERT is expected to offer more effective and earlier diagnosis with potentially better outcome in survival for the treatment of brain tumors, primarily glioma. Two SPECT prototypes are being developed, one dedicated to preclinical imaging (7 and 9.4 T), the second one dedicated to clinical imaging (3 T). The fundamental unit is a 5 cm x 5 cm gamma camera, based on the well-established Anger architecture with a continuous CsI:Tl scintillator readout by an array of silicon photomultipliers (SiPMs). The photodetector matrix will be composed by 12x12 SiPMs (FBK), each one with an active area of 4x4 mm2, for an overall field of view of 50.40x51.70 mm2, considering also insensitive areas between different detectors. In order to reduce complexity and costs the 144 channels are shortcut in group of 4 and readout by a custom-designed 36 channels ASIC. Each electronic channel features a fast current conveyor stage, followed by an RC filter with selectable peaking times and the electronics necessary to provide an appropriate output for the data acquisition system. Preliminary Monte Carlo simulations suggest a spatial resolution between 0.8 and 1 mm and an energy resolution between 11% and 15% (140 keV), depending on the dark count rate of the SiPM technology (100-500 kHz/mm2). Experimental measurements are under development to confirm these results. For example, a single 4x4 SiPM (FBK, RGB-HD), coupled to a CsI:Tl scintillator, has been readout by a single channel version of the ASIC, providing an energy resolution close to 12% at 122 keV at room temperature.

We developed a complete GPU based data processing for cone-beam micro CT application which performs not only the reconstruction but also all the correction of the projection images on-the-fly. Test measurements were performed and processing times was compared on different hardware setups. The performance of the GPU together with our modified algorithm allow to process all the calculations within the shortest exposure time of the system for the highest reconstructed volume size thus makes possible the complete data processing in real-time.

This paper is the first comprehensive presentation of the SPADnet concept. SPADnet is a fully digital, networked MRI compatible time-of-flight PET system, exploiting the speed and integration density of deep-submicron CMOS technologies. The core enabling technologies of SPADnet are a sensor device comprising an array of 8×16 pixels, each composed of 4 mini-SiPMs with in situ time-to-digital conversion, a multi-ring network to filter, carry, and process data produced by the sensor devices at 2Gbps, and a 130nm CMOS process enabling mass-production of photonic modules that are optically interfaced to scintillator crystals. The SPADnet photonic modules comprise a matrix of tightly packed sensor devices; each module is networked in multiple rings, where coincidence pairs are identified and readily used in reconstruction algorithms, enabling scalable, MRI compatible pre-clinical PET systems for multi-modal imaging.

Abstract The analysis of 82386 selected K μ3 decays has been performed. Two solutions both for the vector and scalar formfactors have been obtained, and for each solution the validity of linear approximation is shown. One of the solutions which agrees with the μ-e universality hypothesis, gives the following values for the linear expansion parameters: λ + = 0.046 ± 0.008, λ O = 0.024 ± 0.011.

Positron annihilation lifetime spectroscopy was used to study the free volume parameters in polypropylene oxide-based tri-isocyanate terminated prepolymer/polycaprolactone diol bi-soft urethane/urea membranes (PU/PCL) with PCL content from 5 up to 25 wt%.Positron annihilation lifetime spectroscopy measurements carried out in the temperature range 298-324 K mirrored the phase separation of the various soft and hard segments present in the membranes.The size and amount of free volume holes determined by positron annihilation lifetime spectroscopy appear to be correlated with the CO 2 gas permeability through the membranes.

Controlled deflection of light cones from excited crystal pins has been realized in a positron emission tomography (PET) block detector that allows the enhancement of spatial resolution. The new light sharing module consists of special double prism units optically coupled to a continuous light guide. Slope angle in the prism units can be optimized for each pin in the array. We present well correlating results of light distribution measurements and simulations of single crystal pins with double prisms with different slope angles. First test results of spatial resolution improvement with optimized pixels of a block detector are also presented.

Fungal skin diseases are well-recognized diseases with public health implications. The study provides a comprehensive overview and aims to determine the rate of positive fungal cultures to identify the most common fungal species in guinea pigs and rabbits and to determine the rate of asymptomatic carriers in healthy pet animals. This knowledge is essential for understanding disease transmission dynamics and epidemiological situation problems. A total of 167 animals (64 rabbits and 103 guinea pigs) were investigated in this study. The fungi of the genus Penicillium, Rhizopus, Mucor, Cladosporium, and Aspergillus were the most common in the examined animals, and they were isolated from 162 (97%) of the animals enrolled. No fungal growth was observed in 5 animals. In 15 cases (8.98%), we found pathogenic zoonotic dermatophytes (Trichophyton mentagrophytes), which caused several health problems in two humans in contact with affected animals. This study presents the prevalence of fungal flora in pet guinea pigs and rabbits in Slovakia.

In nonhuman primates, our understanding of the effect of physical activity upon heart rate, particularly activity involving only slight, nonlocomotor movements, is poor. However, before inferring that other factors affect an animal's heart rate, the effect of physical activity upon heart rate must be considered. This study describes this effect in five adult female and seven infant rhesus macaques (Macaca mulatta). Interbeat interval (IBI), the reciprocal function of heart rate, was monitored using radiotelemetry during six categories of physical activity. IBI varied between different activities. The largest observed mean decrease in IBI was by 45% of that when sitting still, during locomotion by adult females. However, even subtle physical activity, involving no movement from a sitting position, produced a large, significant reduction in IBI. The effect of activity upon IBI was different between adults and infants. The findings indicate that measures of physical activity that consider only locomotion are insufficiently sensitive to describe the relationship between physical activity and heart rate.

The PET component of NanoPET <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TM</sup> /CT designed by Mediso Ltd. is a high resolution small animal PET system, in which every detector module contains 81×39 LYSO crystal needles of the size of 1.12×1.12×13 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Two Hamamatsu H-9500 position sensitive photomultipliers (PSPMT-s) are optically coupled to the same crystal matrix using a thin BK-7 optical glass lightguide, allowing 95 mm AFOV. The gains of the 2×256 anodes of the PSPMTs are not uniform. The gap between the two PSPMTs results in restricted light collection efficiency for the crystal needles at the middle of the module. These two effects cause non-uniform gain, that could cause improper energy gating, the loss of 511 keV (photopeak) events and the imperfect filtering of the scattered photons. We have aimed to determine a local gain map for the detector to perform a uniformity correction to avoid these disadvantages. We have developed and implemented an application called LUT-QT to solve the crystal positioning and the gain uniformity correction pixel-by-pixel. Considering the large number of crystal elements in the detector ring (37908 pcs), all of the methods were designed to run automatically, although all of them allow the possibility of manual modification in every step. This method can be applied for every PET detector module based on pixelated scintillation crystal matrix and multianode PSPMT-s.

Abstract Positron lifetime (LT) measurements have revealed that in porous media the annihilation pattern is probably dominated by a near‐saturation level trapping both for the positron and the positronium as well, which masks the contribution from the “free annihilation”, i.e., annihilation from delocalised positrons. In this work we compare positron lifetime spectra of crystalline zeolites with bulk ceramic materials fabricated by sintering from the same constituents as the zeolites and analyse common features and differences between them. For the dense ceramic samples the contribution from long‐living components to the annihilation pattern is substantially lower than that for the zeolites. The results are analysed with the aim to extract new knowledge for the zeolites and for the sensitivity limits for free volume studies in ceramics. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

The SPADnet FP7 European project is aimed at a new generation of fully digital, scalable and networked photonic components to enable large area image sensors, with primary target gamma-ray and coincidence detection in (Time-of- Flight) Positron Emission Tomography (PET). SPADnet relies on standard CMOS technology, therefore allowing for MRI compatibility. SPADnet innovates in several areas of PET systems, from optical coupling to single-photon sensor architectures, from intelligent ring networks to reconstruction algorithms. It is built around a natively digital, intelligent SPAD (Single-Photon Avalanche Diode)-based sensor device which comprises an array of 8×16 pixels, each composed of 4 mini-SiPMs with in situ time-to-digital conversion, a multi-ring network to filter, carry, and process data produced by the sensors at 2Gbps, and a 130nm CMOS process enabling mass-production of photonic modules that are optically interfaced to scintillator crystals. A few tens of sensor devices are tightly abutted on a single PCB to form a so-called sensor tile, thanks to TSV (Through Silicon Via) connections to their backside (replacing conventional wire bonding). The sensor tile is in turn interfaced to an FPGA-based PCB on its back. The resulting photonic module acts as an autonomous sensing and computing unit, individually detecting gamma photons as well as thermal and Compton events. It determines in real time basic information for each scintillation event, such as exact time of arrival, position and energy, and communicates it to its peers in the field of view. Coincidence detection does therefore occur directly in the ring itself, in a differed and distributed manner to ensure scalability. The selected true coincidence events are then collected by a snooper module, from which they are transferred to an external reconstruction computer using Gigabit Ethernet.

A new multi-modality imaging tool is under development in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemoTherapy) project, supported by the European Community. A custom SPECT apparatus, used as an insert for commercially available MRI systems, will enhance the treatment of brain tumors (primarily glioma) by offering more effective and earlier diagnosis with potentially better outcome in survival. The project aims to develop two SPECT prototypes, dedicated to preclinical and clinical imaging. The final goal is to fit the complete SPECT detection system into an existing MRI bore (diameter: 20 cm for the preclinical system and 59 cm for the clinical system). In this work, we propose the use of two possible photodetecors for the scintillator readout: Silicon Drift Detectors and Silicon PhotoMultipliers. A comparison between the main parameters of the two technologies as well as simulations about the achievable energy and spatial resolution are presented.

In the first chapter I formulate the main problems about normalized empirical distribution investigated in this work together with my motivation for their study.

The European Committee for Future Accelerators (ECFA) Early Career Researcher's (ECR) panel, which represents the interests of the ECR community to ECFA, officially began its activities in January 2021. In the first two years, the panel has defined its own internal structure, responded to ECFA requests for feedback, and launched its own initiatives to better understand and support the diverse interests of early career researchers. This report summarises the panel composition and structure, as well as the different activities the panel has been involved with during the first two years of its existence.

Nagy feladatra vállalkozott a bonni LVRLandesmuseum csapata 2021-ben, amikor elkezdték a „Das Leben des BODI: Eine Forschungsreise ins frühe Mittelalter” (BODI élete: Kutatóút a kora középkorba) című kiállítás tervezését, amit egy kiemelkedő leletanyaggal rendelkező temetkezés köré építettek fel. A 2023 márciusában megnyílt kiállítás központi témája a kora középkori elit reprezentációja, illetve az ehhez kapcsolható temetkezések és tárgyak (1. kép). Ezek közé tartoznak a fémlemezekből (lamellákból) készített páncélok, amelyek Európa különböző részein a korszak számos temetkezésében előfordulnak. Hasonló páncélok az avar kori emlékanyagban is megtalálhatók; közülük is kiemelkedik a 2019-ben Derecske-Bikás-dűlő lelőhelyen talált sír lelete. A kiállításnak a Magyar Nemzeti Múzeum gyűjteményében található, Kölked-Feketekapu B és Kiskőrös-Vágóhíd lelőhelyekről előkerült páncélrészletek is részét képezik. Írásunk röviden összefoglalja a lamellás páncélok temetkezési szokásokban betöltött szerepének rövid kutatástörténetét és értelmezésük lehetőségeit.

The team at the LVR-Landesmuseum in Bonn took on a major task in 2021 when they began planning the exhibition entitled Das Leben des BODI: Eine Forschungsreise ins frühe Mittelalter (The Life of BODI: A Research Journey into the Early Middle Ages), based around a burial site with outstanding artefacts. The central theme of the exhibition, which opened in March 2023, is the ways of social representation of the elite in the Early Middle Ages and the burials and grave finds associated with them (Fig. 1), including the lamellar armour finds from many burials of the period in different parts of Europe. Similar armours can also be found in the Avar archaeological record, the most significant specimen found in a grave at Derecske-Bikás-dűlő in 2019. The exhibition included armour fragments from the sites Kölked-Feketekapu B and Kiskőrös-Vágóhíd, lent from the collection of the Hungarian National Museum. This study summarises the brief history of research into the role of lamellar armour in the Avar funerary practice and the possibilities of its interpretation.

Positron annihilation lifetime spectroscopy (PALS) is sensitive and proved method for material structure investigations. We used it to investigate the influence of different alkali cations on the structure of zeolite precursors in order to understand better the crystallization mechanism of zeolites. Our previous PALS investigations on Li gels show different structural features obtained for differently prepared gels, indicating the importance of the way on which cations are introduced in the gel matrix. These investigations were now extended to gels containing K, Rb and Cs cations, in correlation to their ionic radius and the way of preparation.

A systematic study of zeolite precursor gels, zeolites, and products of their recrystallization to ceramics was carried out in presence of various alkali ions.The investigation of radiation damage induced by high-energy ion beam irradiation with swift heavy ions (Bi ions at 670 MeV energy with 4×10 12 ion/cm 2 fluence) was also included.The shortening of lifetimes found after irradiation in ceramics might probably be ascribed to interactions of o-Ps with free radicals and other quenching agents created through the ion irradiation.These lifetime-shortening interactions probably partly hide the o-Ps trapping in free volume sites.

SPADnet is aimed at a new generation of fully digital, scalable and networked photonic components to enable large area image sensors, with primary target gamma-ray and coincidence detection in (Time-of-Flight) PET. The SPADnet photonic module, which lies at the heart of the concept, is built around an array of tessellated single-photon TSV sensor chips, manufactured in standard CMOS technology. The resulting sensor tile is connected on the back to an FPGA-based data processing and communication unit, whereas its front size is glued to scintillator crystals. The resulting modules are then connected in a token ring structure to form the actual PET system. Coincidence detection occurs directly in the ring itself, in a differed and distributed manner to ensure scalability. We have fabricated and tested the first version of the SPADnet photosensor, a fully digital CMOS SiPM with 8×16 pixels individually capable of photon time stamping and energy accumulation, together with the corresponding sensor tiles. The sensor also provides a real-time output of the total detected energy at up to 100Msamples/s and on-chip discrimination of gamma events. These events can then be routed to the SPADnet ring network, which operates at 2 Gbps providing real-time processing and coincidence determination; this architecture simplifies the construction of the overall system and allows the scaling of the system to larger arrays of detectors. This may result in better and faster image reconstruction. SPADnet will not only impact PET scalability but also performance robustness and cost; another advantage is the capability of being compatible with magnetic resonance imaging (MRI), thus prompting advances in multimodal imaging and medical diagnostics as a whole. SPADnet is being designed with scalability in mind, with the idea of being able to redeploy at reduced effort the SPADnet photonic module in other configurations such as brain PET.

This paper describes an image processing framework capable of tracking moving objects in two or three dimensions. The objects are observed by multiple cameras and their path can be recorded without markers, special cameras or background. This paper shows how position coordinates can be acquired from the image of objects. The moving regions of a frame are specified by the difference between the frame and an adaptive background. The adaptive background is calculated from a sequence of frames, meaning that the program can also work in changing light conditions and can handle slow-moving objects. Afterwards, the identified moving regions are tracked inter-frame. The positions of objects received from cameras are then converted to a common word space coordinate system. At this point, the position coordinates are ready for further processing. The program uses a wide array of technological tools, such as hardware acceleration, multi-threaded processing, three dimensional display of objects and network data transmission among the cameras. An integrated framework has also been developed, which is easily customizable, and can be adapted to specific tasks.

Positron Emission Tomography (PET) is a widely used nuclear medical imaging technique that provides functional information of human organs. In the PET device the detector plays an important role. It stops the gamma photons and generates an electronic signal which is processed by the detector system electronics. The geometrical and optical properties of the detector block have fundamental influence on the basic characteristics of a given PET device. Accurate detector block design is required to achieve appropriate system sensitivity and detector crystal needle identifiability. In our previous work we have created and validated a DETECT2000 based modelling environment, called PetDetSim, able to simulate and analyze different PET detector block geometries. PetDetSim models the gamma photon penetration in a simplified way. This simplification significantly reduced the simulation time but sometimes leaded to inaccurate result. Consequently, a better gamma photon penetration technique should be adopted in order to provide a more precise/realistic detector response as inter-crystal scattering can lead to mispositioning detected events and can complicate calibration of PET detectors. In this work we have extended our environment with a precise gamma photon penetration model using the Geant4 based GATE simulation toolkit. The result of extending the simulation environment with GATE simulation resulted in “noise” in the detector response originating from inter-crystal scattering. The result is a more realistic PET detector response that can be simulated with our environment in order to support the development of novel detector block designs and energy- and position-discrimination algorithms.

The partial-volume effect (PVE) can compromise the quantitative accuracy of preclinical positron emission tomogprahy (PET) images. We investigated this effect by simulating a NEMA NU4 mouse Image Quality Phantom (including calculation of a spatially variant position-dependent point spread function (PSF) ) as well as measuring it. Three different types of deconvolution-based partial- volume corrections were applied: the Lucy-Richardson (LR), Van Cittert (VC) and Wiener (WNR) algorithms. For simulation and phantom measurement, partial-volume correction was applied. Based on optimal parameters the same methods were used to correct data of a mouse study acquired with the NanoPET/CT™ preclinical scanner (Mediso Ltd. Budapest, Hungary and and Bioscan Inc., Washington DC, USA). The algorithms used successfully improve the values of recovery coefficients to varying extents both in simulation and measurement. The preliminary mouse study shows improvement in quantification. Full validation is subject to further investigation.

The Committee has continued its work of building contacts with the

We present the correlation function of a Gaussian stationary field as the Fourier transform of a spectral measure and construct with its help a (Gaussian) random spectral measure. Then we express a stationary Gaussian field itself as the Fourier transform of this random spectral measure. We also describe the most important properties of spectral and random spectral measures. The proofs heavily depend on a classical result of analysis about the representation of so-called positive definite functions as the Fourier transform of positive measures and on its version about generalized functions. Hence we finish this chapter with a sub-chapter where we discuss these results, called Bochner and Bochner–Schwartz theorems in the literature.

The PET component of NanoPET™/CT (Mediso) contains dual-module detectors, in which every detector module has been built up from two Hamamatsu H-9500 position sensitive photomultipliers (PSPMTs), optically coupled to the same crystal matrix using a thin BK-7 optical glass lightguide, allowing 95 mm AFOV. This arrangement allows to detect the signals of the crystal needles between the two PSPMTs, enlarging the effective area. However, the two PSPMTs of a detector module can have different transit time. The triggering signal of a module is the sum of the dynode signals of the two PSPMTs. For the higher slope of the triggering signal it can be helpful to delay one of the PSPMT dynode signals before the summation, to correct the possible transit time differences. With the use of this delay the effective transit times of the two PSPMTs will be synchronized and the time point of the triggering will be more accurate due to the higher slope, in other words the time resolution of the modules can be improved. The second step of the timing calibration is the correction of the difference of transit times of the 12 detector modules. For this purpose there is a digital timestamp delay instead of signal cables with different lengths. We describe the measurements and data processing methods we use to perform these calibrations illustrated with measured data.

This is an extended version of a series of talks I held at the University of Bochum in 2017 about limit theorems for non-linear functionals of stationary Gaussian random fields. The goal of these talks was to give a fairly detailed introduction to the theory leading to such results, even if some of the results are presented without proof. On the other hand, I gave a simpler proof for some of the results. (The proofs omitted from this text can be found in my Springer Lecture Note Multiple Wiener--Ito Integrals. In this note first I discuss the spectral representation of the covariance function of a Gaussian stationary rendom field by means of the spectral measure and the representation of the elements of the random field by means of a random integral with respect to the random spectral measure. Then I construct the multiple random integrals with respect to the random spectral measure and prove their most important properties. Finally I show some interesting applications of these multiple random integrals. In particular, I prove some non-trivial non-Gaussian limit theorems

The European Committee for Future Accelerators (ECFA) Early Career Researcher's (ECR) panel, which represents the interests of the ECR community to ECFA, officially began its activities in January 2021. In the first two years, the panel has defined its own internal structure, responded to ECFA requests for feedback, and launched its own initiatives to better understand and support the diverse interests of early career researchers. This report summarises the panel composition and structure, as well as the different activities the panel has been involved with during the first two years of its existence.

Studia ad Archaeologiam Pazmaniensia) HU-ISSn

Supersymmetry (SUSY) is a theoretically favoured extension of the standard model (SM) since it provides solutions to several open questions. Many models employing gauge mediation (GMSB or GGM) predict the production of events with photons and significant missing transverse momentum. In this paper the results of three new searches for SUSY and a combination analysis are reported. The data sample corresponds to an integrated luminosity of 35.9 fb^−1 collected at a centre-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. The results are used to set cross section limits on gluino, squark and gaugino pair production in either the GMSB or the GGM model framework. The GGM model is favoured for the combination of the search results. By compiling previous results into a single limit setting analysis it is possible to obtain a better sensitivity with respect to individual searches.

Using a tight binding model we calculate the conductance of monovalent atomic chains for different contact geometries. The leads connected to the chains are modelled as semi-infinite fcc lattices with different orientations and couplings. Our aim is twofold: To check the validity of a three-parametric conductance formula for differently oriented leads, and to investigate the geometry dependence of the conductance oscillations. We show that the character of these oscillations depends strongly on the geometry of the chain-lead coupling.

The factorisability of the transverse proton density functions in $x$ and $y$ is assumed in the analysis of single-plane van der Meer (vdM) scans for absolute luminosity calibration. A correction to the calibration constants for nonfactorisation effects in the proton density is then determined. The precision of the evaluation of this correction is one of the dominant sources of systematic uncertainty for the Run 2 (2015-2018) luminosity measurement in CMS. The vdM calibration technique and the methods used to estimate the bias due to the factorisation assumption are discussed.

We propose a mixed analytical–ab initio method for the accurate calculation of the conductance in monovalent atomic wires. The method relies on the most general formula for ballistic transport through a monovalent wire, whose parameters can be determined from first-principles calculations. Our central result is the demonstration of the highly nonuniversal behavior of the conductance, which depends on the fine details of the contacts to the leads. We are therefore able to reconcile a large number of the apparently contradictory results that have recently appeared in the literature.

Using a tight binding model we calculate the conductance of monovalent atomic chains for different contact geometries. The leads connected to the chains are modelled as semi-infinite fcc lattices with different orientations and couplings. Our aim is twofold: To check the validity of a three-parametric conductance formula for differently oriented leads, and to investigate the geometry dependence of the conductance oscillations. We show that the character of these oscillations depends strongly on the geometry of the chain-lead coupling.

Precision luminosity calibration is critical to determine fundamental parameters of the standard model and to constrain or to discover beyond-the-standard-model phenomena at LHC. The luminosity determination at the LHC interaction point 5 with the CMS detector, using proton-proton collisions at 13 and 5.02 TeV during Run 2 of the LHC (2015-2018), is reported. The absolute luminosity scale is obtained using beam-separation ("van der Meer") scans. The dominant sources of systematic uncertainty are related to the knowledge of the scale of the beam separation provided by LHC magnets and the factorisability between the spatial components of the proton bunch density distributions in the transverse direction. When applying the van der Meer calibration to the entire data-taking period, a substantial contribution to the total uncertainty in the integrated luminosity originates from the measurement of the detector linearity and stability.

The factorisability of the transverse proton density functions in $x$ and $y$ is assumed in the analysis of single-plane van der Meer (vdM) scans for absolute luminosity calibration. A correction to the calibration constants for nonfactorisation effects in the proton density is then determined. The precision of the evaluation of this correction is one of the dominant sources of systematic uncertainty for the Run 2 (2015-2018) luminosity measurement in CMS. The vdM calibration technique and the methods used to estimate the bias due to the factorisation assumption are discussed.

We study Dyson's classical $r$-component ferromagnetic hierarchical model with a long range interaction potential $U(i,j)= -l(d(i,j)) d^{-2}(i,j)$, where $d(i,j)$ denotes the hierarchical distance. We prove a conjecture of Dyson, which states that the convergence of the series $l_1+l_2+...$, where $l_n=l(2^n)$, is a necessary and sufficient condition of the existence of phase transition in the model under consideration, and the spontaneous magnetization vanishes at the critical point, i.e. there is no Thouless' effect. We find however that the distribution of the normalized average spin at the critical temperature $T_c$ tends to the uniform distribution on the unit sphere in $\Bbb R^r$ as the volume tends to infinity, a phenomenon which resembles the Thouless effect.