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A preliminary simulation study of influence of backsplash on the plastic scintillator detector design in HERD experiment

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Radiation Detection Technology and Methods 2021年第3期5卷 332-338页

作者： Peng Hu Zhi-gang Wang Fabio Gargano Francesca Alemanno Corrado Altomare Tian-wei Bao Yong-wei Dong Valerio Formato dimitrios Kyratzis Nicola Mori Lorenzo Pacini Zheng Quan Davide Serini Jun-jing Wang Rui-jie Wang Ming Xu Bo-bing Wu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Istituto Nazionale di Fisica Nucleare(infn) Sezione di Bari70126 BariItaly Gran Sasso Science Institute(GSSI) 67100 L’AquilaItaly Istituto Nazionale di Fisica Nucleare(infn) Laboratori Nazionali del Gran Sasso67100 L’AquilaItaly dipartimento Interateneo di Fisica dell’Universitàe del Politecnico di bari 70125 BariItaly Istituto Nazionale di Fisica Nucleare(infn) Sezione di Roma Tor Vergata00133 RomeItaly Istituto Nazionale di Fisica Nucleare(infn) Sezione di Firenze50019 Sesto FiorentinoItaly

Background The plastic scintillator detector(PSD)is one of the detectors in the high energy cosmic radiation detection(HERD)facility,which is designed for gamma-ray detection and a redundant charge measurement.Backsplash will lead to a decrease in PSD’s performance of gamma-ray detection and charge measurement,which should be carefully considered.Purpose Two preliminary segmentation schemes of the PSD and two veto strategies have been proposed to suppress the backsplash effect.In this paper,we focus on the influence of the backsplash caused by gamma rays.The gamma-ray trigger efficiency and identification efficiency were studied in the case of different cell sizes and veto strategies,which can provide guidance on the PSD design.Methods A Monte Carlo simulation based on Geant4 has been performed.To simplify the simulation,the PSD is segmented into 1 cm3 cubes which can be easily aggregated into cells with different sizes during analysis.Results and conclusion Side_Veto can be used as a baseline design of veto strategy,whereas Smart_Veto can be selected as an upgraded design.Both the PSD bar cell with a width of less than 11 cm and the PSD tile cell with a width of less than 20 cm can achieve a sufficiently high gamma-ray trigger efficiency(>80%),which realizes the primary goal of the PSD.Meanwhile,both the PSD bar cell with a width of less than 3 cm and the PSD tile cell with a width of less than 20 cm can ensure a sufficiently high gamma-ray identification efficiency(>80%)for photons up to 800 GeV.

关键词： Plastic scintillator detector Gamma-ray detection Backsplash Veto

Alpha Magnetic Spectrometer (AMS02) experiment on the International Space Station (ISS)

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Nuclear Science and Techniques 2003年第3期14卷 182-194页

作者： Behcet ALPAT infn sezione di Perugia Via A.Pascoli06123PerugiaItaly

The Alpha Magnetic Spectrometer experiment is realized in two phases. A precursor flight (STS-91)with a reduced experimental configuration (AMS01) has successfully flown on space shuttle discovery in June 1998.The final version (AMS02) will be installed on the International Space Station (ISS) as an independent module inearly 2006 for an operational period of three years. The main scientific objectives of AMS02 include the searches forthe antimatter and dark matter in cosmic rays. In this work we will discuss the experimental details as well as the im-proved physics capabilities of AMS02 on ISS.

关键词： α磁分光仪国际空间站反物质暗物质

Competition between fusion-evaporation and multifragmentation in central collisions in ^(58)Ni+^(48)Ca at 25A MeV

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Nuclear Science and Techniques 2013年第5期24卷 82-88页

作者： FRANCALANZA L ABBONDANNO U AMORINI F BARLINI S BINI M BOUGAULT R BRUNO M CARDELLA G CASINI G AGOSTINO M D' De FILIPPO V De SANCTIS J GERACI E GIUSSANI A GRAMEGNA F GUIOT B KRAVCHUK V La GUIDARA E LANZALONE G Le NEINDRE N MAIOLINO C MARINI P MORELLI L OLMI A PAGANO A PAPA M PIANTELLI S PIRRONE S POLITI G POGGI G PORTO F RUSSOTTO P RIZZO F VANNINI G VANNUCCI L infn Laboratori Nazionali del Sud-LNS Catania 95123Italy dipartimento di Fisica Universitàdi Catania I-95129Italy infn sezione di Trieste Trieste I-34127Italy dipartimento di Fisica Universitàdi FirenzeINFN Sezione di Firenze 1-50139Italy LPC Caen IN2P3-CNRS/ENSICAEN and UniversitéF-14050 Caen cedex 5-140France dipartimento di Fisica Universitàdi Bologna and INFN Sezione di Bologna 4-50121Italy infn sezione di Catania I-95129 Italy infn sezione di Firenze I-50139 Italy dipartimento di Fisica Universitàdi Milano and INFN Sezione di Milano1-20126Italy infn Laboratori Nazionali di Legnaro 1-35020 Italy Centro Siciliano di Fisica Nucleare e Struttura della Materia Catania 1-95129Italy UniversitàKore Enna 1-94100Italy

The experimental data concerning the58Ni+48Ca reaction at Elab(Ni)=25A MeV,collected by using the CHIMERA 4π device,have been analyzed in order to investigate the competition among different reaction mechanisms for central collisions in the Fermi energy domain.As a main criterion for centrality selection we have chosen the flow angle(flow) method,making an event-by-event analysis that considers the shape of events,as it is determined by the eigenvectors of the experimental kinetic-energy tensor.For the selected central events(flow >60°) some global variables,good to characterize the pattern of central collisions have been constructed.The main features of the reaction products were explored by using different constraints on some of the relevant observables,like mass and velocity distributions and their correlations.Much emphasis was devoted,for central collisions,to the competition between fusion-evaporation processes with subsequent identification of a heavy residue and a possible multifragmentation mechanism of a well defined(if any) transient nuclear system.Dynamical evolution of the system and pre-equilibrium emission were taken into account by simulating the reactions in the framework of transport theories.different approaches have been envisaged(dynamical stochastic BNV calculations + sequential SIMON code,QMD,CoMD,etc.).Preliminary comparison of the experimental data with BNV calculations shows reasonable agreement with the assumption of sequential multifragmentation emission in the mass region of IMFs close to the heavy residues.Possible deviations from sequential processes were found for those IMFs in the region of masses intermediate between the mass of heavy residues and the mass of light IMFs.Further simulations are in progress.The experimental analysis will be enriched also by information obtained inspecting the IMF-IMF correlation function,in order to elucidated the nature of space-time decay property of the emitting source associated with events having the largest IMF multiplicity.

关键词：多重碎裂中心碰撞蒸发过程 MeV 竞争熔合国际货币基金组织事件分析

KLOE results on scalar and pseudoscalar mesons

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Chinese Physics C 2010年第6期34卷 632-637页

作者： P.Gauzzi Sapienza Università di Roma and infn sezione di Roma P.le A.Moro

The data collected by the KLOE Collaboration at the Frascati φ-factory DAФNE from 2001 to 2006 have been used for extensive studies in meson spectroscopy. The decays of the scalar mesons a0（980） and f0（980） into two pseudoscalar mesons have been exploited to measure the relevant parameters of those resonances. The radiative decays φ →ηγ and η＇γ have been used for the determination of the pseudoscalar mixing angle and to search for a possible gluonium content in the η＇. The dynamics of the η → 3π decay has been studied and the Dalitz Plot parameters have been measured. The large amount of η mesons produced allowed also to study interesting rare η decays.

关键词： e^＋e^- interactions φ-factory scalar mesons pseudoscalar mesons

Two-flavor hybrid stars with the Dyson-Schwinger quark model

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Chinese Physics C 2017年第11期41卷 110-116页

作者：魏金标陈欢 H.-J.Schulze School of Mathematics and Physics China University of Geosciences infn sezione di Catania Dipartimento di FisicaUniversitá di Catania

We study the properties of two-flavor quark matter in the Dyson-Schwinger model and investigate the possible consequences for hybrid neutron stars,with particular regard to the two-solar-mass limit.We find that with some extreme values of the model parameters,the mass fraction of two-flavor quark matter in heavy neutron stars can be as high as 30 percent and the possible energy release during the conversion from nucleonic neutron stars to hybrid stars can reach 1052 erg.

关键词： hybrid stars quark matter equation of state Dyson-Schwinger equations

The HEPD particle detector of the CSES satellite mission for investigating seismo-associated perturbations of the Van Allen belts

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Science China(Technological Sciences) 2018年第5期61卷 643-652页

作者： AMBROSI Giovanni BARTOCCI Simona BASARA Laurent BATTISTON Roberto BURGER William J. CARFORA Luca CASTELLINI Guido CIPOLLONE Piero CONTI Livio CONTIN Andrea DE DONATO Cinzia DE SANTIS Cristian FOLLEGA Francesco M. GUANDALINI Cristina IONICA Maria IUPPA Roberto LAURENTI Giuliano LAZZIZZERA Ignazio LOLLI Mauro MANEA Christian MARCELLI Laura MASCIANTONIO Giuseppe MERGE Matteo OSTERIA Giuseppe PACINI Lorenzo PALMA Francesco PALMONARI Federico PANICO Beatrice PATRIZII Laura PERFETTO Francesco PICOZZA Piergiorgio POZZATO Michele PUEL Matteo RASHEVSKAYA Irina RICCI Ester RICCI Marco RICCIARINI Sergio Bruno SCOTTI Valentina SOTGIU Alessando SPARVOLI Roberta SPATARO Bruno VITALE Vincenzo Istituto Nazionale di Fisica Nucleare (infn) Sezione di Perugia Perugia 06123 Italy Uninettuno University Rome 00186 Italy Istituto Nazionale di Fisica Nucleare (infn) Sezione di Roma Tor Vergata Rome 00133 Italy Istituto Nazionale di Fisica Nucleare (infn) TIFPA Povo (TN) 38123 Italy dipartimento di Fisica Universita di Trento Povo (TN) 38123 Italy dipartimento di Fisica Universita di Roma Tor Vergata Rome 00133 Italy IFAC-CNR Sesto Fiorentino (FI) 50019 Italy dipartimento di Fisica e Astronomia Universita di Bologna Bologna 40127 Italy Istituto Nazionale di Fisica Nucleare (infn) Sezione di Bologna Bologna 40127 Italy Istituto Nazionale di Fisica Nucleare (infn) Sezione di Napoli Naples 80126 Italy Istituto Nazionale di Fisica Nucleare (infn) LNE Frascati (RM) 00044 Italy Agenzia Spaziale Italiana (ASI) SSDC Rome 00133 Italy

CSES(China Seismo-Electromagnetic Satellite) is a mission developed by CNSA(Chinese National Space Administration) and ASI(Italian Space Agency), to investigate the near-Earth electromagnetic, plasma and particle environment, for studying the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. The anthropogenic and electromagnetic noise,as well as the natural non-seismic electromagnetic emissions is mainly due to tropospheric activity. In particular, the mission aims to confirming the existence of possible temporal correlations between the occurrence of earthquakes for medium and strong magnitude and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts with highenergy charged particles from the inner Van Allen belt. In this framework, the high energy particle detector(HEPD) of the CSES mission has been developed by the Italian LIMADOU Collaboration. HEPD is an advanced detector based on a tower of scintillators and a silicon tracker that provides good energy and angular resolution and a wide angular acceptance, for electrons of 3–100 Me V, protons of 30–200 Me V and light nuclei up to the oxygen. CSES satellite has been launched on February 2^(nd), 2018 from the Jiuquan Satellite Launch Center(China).

关键词：卫星发射中心粒子带子空间管理合作开发空间机构轻原子核意大利

γγ interactions with KLOE

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Chinese Physics C 2010年第6期34卷 795-800页

作者： Federico Nguyen infn sezione 'Roma TRE'

Studies of γγ interactions are performed with the KLOE detector, without tagging of the outgoing e^＋e^-. The data sample is from an integrated luminosity of 240 pb^-1. It was collected at the φ-factory DAONE with e^＋e^- beams colliding at √s ≌1 GeV, below the φ resonance peak. We present preliminary results concerning the observation of the γγ→η process and the evidence for γγ→π^0π^0 production at low π^0π^0 invariant masses.

关键词： e^＋e^- collisions pseudoscalar meson width π pair production

Nonlinear diffusion and Transient Osmosis

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Communications in Theoretical Physics 2011年第8期56卷 352-366页

作者： Akira Igarashi Lamberto Rondoni Antonio Botrugno Marco Pizzi dipartimento di Matematica Politecnico di Torino infn Sezione di Torino Kavli Institute for Theoretical Physics China CAS Eltek Group

We investigate both analytically and numerically the concentration dynamics of a solution in two containersconnected by a narrow and short channel,in which diffusion obeys a porous medium equation.We also considerthe variation of the pressure in the containers due to the How of matter in the channel.In particular,we identifya phenomenon,which depends on the transport of matter across nano-porous membranes,which we call 'transientosmosis'.We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-likephenomena,which are not present in the case of ordinary Fickian diffusion.Experimental results suggest one possiblecandidate for transiently osmotic processes.

关键词：非线性扩散反渗透瞬态多孔介质方程纳米多孔膜浓度动态运输问题渗透过程

NANOGrav hints on planet-mass primordial black holes

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Science China(Physics,Mechanics & Astronomy) 2022年第3期65卷 26-32页

作者： Guillem Domenech Shi Pi infn sezione di Padova Padova 1-35131Italy CAS Key'Laboratory of Theoretical Physics.Institute of Theoretical Physics ChinesAcademy of SciencesBeijing 100190China Kavli Institute for the Physics and Mathematics of the Universe(WPI) The University of Tokyo Institutes for Advanced StudyThe University of TokyoKashiwaChiba 277-8583Japan

Recently, the North American Nanohertz Observatory for Gravitational Waves(NANOGrav) claimed the detection of a stochastic common-spectrum process of the pulsar timing array(PTA) time residuals from their 12.5 year data, which might be the first detection of the stochastic background of gravitational waves(GWs). We show that the amplitude and the power index of such waves imply that they could be the secondary GWs induced by the peaked curvature perturbation with a dust-like post inflationary era with-0.091 ≤ w ≤ 0.048. Such stochastic background of GWs naturally predicts substantial existence of planet-mass primordial black holes(PBHs), which can be the lensing objects for the ultrashort-timescale microlensing events observed by the Optical Gravitational Lensing Experiment(OGLE).

关键词： pulsar timing array stochastic gravitational waves the early universe