Imaging Atmospheric Cherenkov Telescopes pointing determination using the trajectories of the stars in the field of view

We present a new approach to the pointing determination of Imaging Atmospheric Cherenkov Telescopes (IACTs). This method is universal and can be applied to any IACT with minor modifications. It uses the trajectories of the stars in the field of view of the IACT's main camera and requires neither dedicated auxiliary hardware nor a specific data taking mode. The method consists of two parts: firstly, we reconstruct individual star positions as a function of time, taking into account the point spread function of the telescope; secondly, we perform a simultaneous fit of all reconstructed star trajectories using the orthogonal distance regression method. The method does not assume any particular star trajectories, does not require a long integration time, and can be applied to any IACT observation mode. The performance of the method is assessed with commissioning data of the Large-Sized Telescope prototype (LST-1), showing the method's stability and remarkable pointing performance of the LST-1 telescope.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219

Reconstruction of extensive air shower images of the first Large Size Telescope prototype of CTA using a novel likelihood technique

Ground-based gamma-ray astronomy aims at reconstructing the energy and direction of gamma rays from the extensive air showers they initiate in the atmosphere. Imaging Atmospheric Cherenkov Telescopes (IACT) collect the Cherenkov light induced by secondary charged particles in extensive air showers (EAS), creating an image of the shower in a camera positioned in the focal plane of optical systems. This image is used to evaluate the type, energy and arrival direction of the primary particle that initiated the shower. This contribution shows the results of a novel reconstruction method based on likelihood maximization. The novelty with respect to previous likelihood reconstruction methods lies in the definition of a likelihood per single camera pixel, accounting not only for the total measured charge, but also for its development over time. This leads to more precise reconstruction of shower images. The method is applied to observations of the Crab Nebula acquired with the Large Size Telescope prototype (LST-1) deployed at the northern site of the Cherenkov Telescope Array.Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, Germany. https://pos.sissa.it/395/71

Characterisation of the MUSIC ASIC for large-area silicon photomultipliers for gamma-ray astronomy

Large-area silicon photomultipliers (SiPMs) are desired in many applications where large surfaces have to be covered. For instance, a large area SiPM has been developed by Hamamatsu Photonics in collaboration with the University of Geneva, to equip gamma-ray cameras employed in imaging atmospheric Cherenkov telescopes. The sensor being about 1 cm2, a suitable preamplification electronics has been investigated in this work, which can deal with long pulses induced by the large capacitance of the sensor. The so-called Multiple Use SiPM Integrated Circuit (MUSIC), developed by the ICCUB (University of Barcelona), is investigated as a potential front-end ASIC, suitable to cover large area photodetection planes of gamma-ray telescopes. The ASIC offers an interesting pole-zero cancellation (PZC) that allows dealing with long SiPM signals, the feature of active summation of up to 8 input channels into a single differential output and it can offer a solution for reducing power consumption compared to discrete solutions. Measurements and simulations of MUSIC coupled to two SiPMs developed by Hamamatsu are considered and the ASIC response is characterized

Characterisation of the MUSIC ASIC for large-area silicon photomultipliers for gamma-ray astronomy

Large-area silicon photomultipliers (SiPMs) are desired in many applications where large surfaces have to be covered. For instance, a large area SiPM has been developed by Hamamatsu Photonics in collaboration with the University of Geneva, to equip gamma-ray cameras employed in imaging atmospheric Cherenkov telescopes. The sensor being about 1 cm2, a suitable preamplification electronics has been investigated in this work, which can deal with long pulses induced by the large capacitance of the sensor. The so-called Multiple Use SiPM Integrated Circuit (MUSIC), developed by the ICCUB (University of Barcelona), is investigated as a potential front-end ASIC, suitable to cover large area photodetection planes of gamma-ray telescopes. The ASIC offers an interesting pole-zero cancellation (PZC) that allows dealing with long SiPM signals, the feature of active summation of up to 8 input channels into a single differential output and it can offer a solution for reducing power consumption compared to discrete solutions. Measurements and simulations of MUSIC coupled to two SiPMs developed by Hamamatsu are considered and the ASIC response is characterized.Postprint (published version

Imaging Atmospheric Cherenkov Telescopes pointing determination using the trajectories of the stars in the field of view

38th International Cosmic Ray Conference (ICRC2023), 26 July - 3 August, 2023, Nagoya, Japan.Mykhailo Dalchenko and Matthieu Heller on behalf of the CTA-LST Project. Luis del Peral Gochicoa, Jose Julio Lozano Bahilo and Maria Dolores Rodriguez Frias belong to the CTA-LST Project.We present a new approach to the pointing determination of Imaging Atmospheric Cherenkov Telescopes (IACTs). This method is universal and can be applied to any IACT with minor modifications. It uses the trajectories of the stars in the field of view of the IACT’s main camera and requires neither dedicated auxiliary hardware nor a specific data taking mode. The method consists of two parts: firstly, we reconstruct individual star positions as a function of time, taking into account the point spread function of the telescope; secondly, we perform a simultaneous fit of all reconstructed star trajectories using the orthogonal distance regression method. The method does not assume any particular star trajectories, does not require a long integration time, and can be applied to any IACT observation mode. The performance of the method is assessed with commissioning data of the Large-Sized Telescope prototype (LST-1), showing the method’s stability and remarkable pointing performance of the LST-1 telescope

AX-PET: A novel PET concept with G-APD readout

Abstract The AX-PET collaboration has developed a novel concept for high resolution PET imaging to overcome some of the performance limitations of classical PET cameras, in particular the compromise between spatial resolution and sensitivity introduced by the parallax error. The detector consists of an arrangement of long LYSO scintillating crystals axially oriented around the field of view together with arrays of wave length shifter strips orthogonal to the crystals. This matrix allows a precise 3D measurement of the photon interaction point. This is valid both for photoelectric absorption at 511 keV and for Compton scattering down to deposited energies of about 100 keV. Crystals and WLS strips are individually read out using Geiger-mode Avalanche Photo Diodes (G-APDs). The sensitivity of such a detector can be adjusted by changing the number of layers and the resolution is defined by the crystal and strip dimensions. Two AX-PET modules were built and fully characterized in dedicated test set-ups at CERN, with point-like 22 Na sources. Their performance in terms of energy ( R energy ≈ 11.8 % (FWMH) at 511 keV) and spatial resolution was assessed ( σ axial ≈ 0.65 mm ), both individually and for the two modules in coincidence. Test campaigns at ETH Zurich and at the company AAA allowed the tomographic reconstructions of more complex phantoms validating the 3D reconstruction algorithms. The concept of the AX-PET modules will be presented together with some characterization results. We describe a count rate model which allows to optimize the planing of the tomographic scans

The App-Runx1 Region Is Critical for Birth Defects and Electrocardiographic Dysfunctions Observed in a Down Syndrome Mouse Model

Down syndrome (DS) leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG) with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf) and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1). In addition cardiac connexins (Cx40, Cx43) and sodium channel sub-units (Scn5a, Scn1b, Scn10a) were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe