3,902 research outputs found

    Scintillation Light Detection with MAPD-3NK and MPPC-S12572-010P Readout

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    The linearity and energy resolution of two different solid-state photomultipliers (SiPMs) has been studied with reading out the LFS-8 scintillator (3x3x10 mm3). First SiPM (MAPD-3NK) from Zecotek Photonics consists of deeply burned pixels (cells) and has an active area of 3.7x3.7 mm2. The second one (MPPC-S12572-010P) from Hamamatsu has a surface cell structure and an active area of 3x3 mm2. Both SiPMs have the same pixel density of 10000 mm−2. Energy resolution and linearity of the SiPMs has been studied in the energy range of 59.6-1275 keV. It is found that both SiPMs demonstrate good linearity of signal amplitude as a function of the gamma ray energy in the studied energy range. The detector based on the MAPD-3NK provides significantly good energy resolution in comparison to the detector based on the MPPC-S12572-010P

    Meson Wave Functions From Holographic Qcd And The Role Of Infrared Renormalons In Proton-Proton Collisions

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    We calculate the contribution of the higher twist Feynman diagrams to the large-pTp_T inclusive pion production cross section in proton-proton collisions in the case of the running and frozen coupling approaches within holographic QCD. The structure of infrared renormalon singularities of the higher twist subprocess cross section and it's resummed expression are found. We compare the resummed higher twist cross sections with the ones obtained in the framework of the frozen coupling approximation and leading twist cross section. We discuss the phenomenological consequences of possible higher-twist contributions to the pion production in proton-proton collisions within holographic QCD.Comment: 19 pages, 14 figures. arXiv admin note: substantial text overlap with arXiv:1202.2632, arXiv:1107.1562, arXiv:1008.1646, arXiv:0803.019

    Pion wave functions from holographic QCD and the role of infrared renormalons in photon-photon collisions

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    In this article, we calculate the contribution of the higher-twist Feynman diagrams to the large-pTp_T inclusive single pion production cross section in photon-photon collisions in case of the running coupling and frozen coupling approaches within holographic QCD. We compare the resummed higher-twist cross sections with the ones obtained in the framework of the frozen coupling approach and leading-twist cross section. Also, we show that in the context of frozen coupling approach a higher-twist contribution to the photon-photon collisions cross section is normalized in terms of the pion electromagnetic form factor.Comment: 21 pages, 15 figures. arXiv admin note: text overlap with arXiv:0709.2072 by other author

    Portable neutron/gamma scintillation detector for status monitoring of accelerator-driven neutron source IREN

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    Accelerator-driven system (ADS) facilities world-wide opens new opportunities for nuclear physics investigations, so that a high flux of neutrons through spallation reactions can be produced at these facilities. It is known that the measurement, continuous monitoring and optimization of the particle accelerator beam intensity are among the most important actions in the operation of such facilities. Considering this point of view, this paper presents a neutron/gamma counter based on a micropixel avalanche photodiode (MAPD) and a plastic scintillator that monitors the status of the accelerator-driven intense resonance neutron source (IREN) facility by measuring the neutron-gamma intensity in the target hall. The electronics of the modular neutron counter has been designed and developed, including a bias voltage source (up to 130 V), a preamplifier (36 gain) and discriminator (>10 mV) circuit. The last product of MAPD (operation voltage- 55 V, PDE- 33 %, total number of pixels- 136900) was used as a photon readout from a plastic scintillator. The sensitive area of MAPD was 3.7*3.7 mm2 and the size of the plastic scintillator 3.7*3.7*30 mm3. The measurement was carried out in the IREN target hall, where it was necessary to monitor not only high neutron fluxes, but also gamma quanta. The experimental results demonstrated a dependence between the count rate of the detector and the frequency of the accelerator, which ranges from 2 to 50 Hz.Comment: 8 pages, 7 figure

    Contributions of semi-hadronic states Pγ;Sγ,π+πγP\gamma;S\gamma, \pi^+\pi^-\gamma to amm of muon, in frames of Nambu-Jona-Lasinio model

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    We calculate the contribution of semi-hadronic states with pseudoscalar P=π0,ηP=\pi^0, \eta and scalar (σ\sigma(550))meson accompanied with real photon as an intermediate state of a heavy photon to the anomalous magnetic moment of muon. We consider the intermediate states with π0\pi_0 and σ\sigma as a hadrons in frames of Nambu-Jona-Lasinio model. The contribution of π0γ\pi_0\gamma state is in agreement with results obtained in previous theoretical considerations as well as with experimental data aμπ0γ4.5×1010a_\mu^{\pi_0\gamma}\approx 4.5 \times 10^{-10}, besides we estimate aμηγ=0.7×1010,aμσγ1.5×1011,aμπ+πγ3.2×1010.a_{\mu}^{\eta\gamma}=0.7 \times 10^{-10}, a_{\mu}^{\sigma\gamma} \sim 1.5 \times 10^{-11}, a_{\mu}^{\pi^+\pi^-\gamma} \sim 3.2 \times 10^{-10}. We discass as well the LbL mechanism with aμlbl=10.51010.a_{\mu}^{lbl}=10.5 \cdot 10^{-10}.Comment: 6 pages, 2 figure

    Performance of a plastic scintillator developed using styrene monomer polymerization

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    This paper presents a newly developed plastic scintillator produced in collaboration with Turkiye Energy, Nuclear and Mineral Research Agency (TENMAK). The scintillator is manufactured using thermal polymerization of commercially available styrene monomer. The absorption spectrum of the scintillator exhibited two absorption bands at 225 nm and 340 nm, with an absorption edge observed at 410 nm. The wavelength of the emitted light was measured in the range of 400-800 nm, with a maximum intensity at 427 nm. Monoenergetic electrons from the 137Cs source were used to evaluate the characteristics of the new scintillator, particularly its light yield. As the light readout the MAPD-3NM type silicon photomultiplier array (4 x 4) with an active area of 15 x 15 mm2, assembled using single MAPDs with an active area of 3.7 x 3.7 mm2, was used. The light yield of the scintillator was determined to be 6134 photons/MeV. In addition, the efficiency of the scintillator for gamma rays with an energy of 662 keV was found to be approximately 1.8 %. A CmBe neutron source was employed to evaluate its fast neutron detection performance. However, neutron/gamma discrimination using pulse shape discrimination (charge integration) method was not observed. The results demonstrate the potential of a newly produced plastic scintillator for various applications, particularly in radiation monitoring and detection systems.Comment: 7 pages, 7 figure

    One-loop chiral amplitudes of Moller scattering process

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    The high energy amplitudes of the large angles Moller scattering are calculated in frame of chiral basis in Born and 1-loop QED level. Taking into account as well the contribution from emission of soft real photons the compact relations free from infrared divergences are obtained. The expressions for separate chiral amplitudes contribution to the cross section are in agreement with renormalization group predictions.Comment: 15 pages, 3 figure

    Quantum flux effects on the energy spectra and thermo-magnetic properties in 2D Schrodinger equation with Mobius square potential

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    A 2D Schrodinger equation with interacting Mobius square potential model is solved using Nikiforov-Uvarov Functional Analysis (NUFA) formalism. The energy spectra and the corresponding wave function for the linearly and exponentially varying quantum magnetic flux are obtained analytically in a closed form. The evaluated energy spectra are used to obtain an expression for the partition functions for the two cases comprises of the linearly and exponentially varying quantum magnetic flux and vis-a-vis is use to evaluate other thermodynamic and magnetic properties for the system. The results are used to study the free energy, mean energy, the entropy, specific heat, magnetization, magnetic susceptibility and the persistent current of the system. The numerical bound state energies are computed.Comment: 39 Pages, 64 figure
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