Cosmic Ray research in Armenia

Cosmic Ray research on Mt. Aragats began in 1934 with the measurements of East-West anisotropy by the group from Leningrad Physical-Technical Institute and Norair Kocharian from Yerevan State University. Stimulated by the results of their experiments, in 1942 Artem and Abraham Alikhanian brothers organized a scientific expedition to Aragats. Since that time physicists were studying Cosmic Ray fluxes on Mt. Aragats with various particle detectors: mass spectrometers, calorimeters, transition radiation detectors, and huge particle detector arrays registering protons and nuclei accelerated in most violent explosions in Galaxy. Latest activities at Mt. Aragats include Space Weather research with networks of particle detectors located in Armenia and abroad, and detectors of Space Education center in Yerevan.     

Non-Classical Diffusion of the Cosmic Rays in the Galaxy: Retrieval of Primary Nuclei Spectra in Sources

Physics of Atomic Nuclei - This study investigates the use of results from new-generation balloon-borne and satellite instruments and earthbound observatories for quantifying primary nuclei spectra...     

Mechanisms of Cosmic Ray Generation

Physics of Atomic Nuclei - The origin of cosmic rays (CR) stays an open-ended question for over a hundred years. However, during the past decade, a wide range of new experimental data and...     

宇宙线μ子的大气契仑柯夫光像

给出理想条件下聚光镜焦平面上单个μ子大气契仑柯夫光像的理论结果．简要地介绍在标定第二代大气契仑柯夫光成像望远镜中的应用．     

Variations of Cosmic Ray Muons during Thunderstorms

Journal of Experimental and Theoretical Physics - This article briefly reviews the results of an experiment initiated by A.E. Chudakov. The first results were obtained in pioneering works under his...     

Recent Results in Cosmic Ray Physics and Their Interpretation

The last decade has been dense with new developments in the search for the sources of Galactic cosmic rays. Some of these developments have confirmed the tight connection between cosmic rays and supernovae in our Galaxy, through the detection of gamma rays and the observation of thin non-thermal X-ray rims in supernova remnants. Some others, such as the detection of features in the spectra of some chemicals, opened new questions on the propagation of cosmic rays in the Galaxy and on details of the acceleration process. Here, I will summarize some of these developments and their implications for our understanding of the origin of cosmic rays. I will also discuss some new avenues that are being pursued in testing the supernova origin of Galactic cosmic rays.     

Cosmic Ray Nuclei: Results from AMS-02

Physics of Atomic Nuclei - AMS is a multi-purpose high-energy particle detector designed to perform high precision direct cosmic ray measurements onboard of the International Space Station. AMS can...     

羊八井宇宙线实验的现状和未来

概述了羊八井地理位置的物理优势和一期实验的显示性及其在日益激烈的国际竞争中面临的挑战和选择,提出了一个以RPC“地毯”、契仑可夫成像望远镜群和多成分复合阵列为手段,以亚甚高能天文、宇宙反质子流测量、太阳活动短期变化的监测研究及膝区物理的突破性攻关为目标的羊八井将来计划.     

闪烁光纤量能器单元模型的宇宙线测试

介绍闪烁光纤量能器单元模型宇宙线测试采用的简易实验装置和测量步骤,以及实验数据的分析处理方法.对来自意大利KLOE的铅–光纤量能器单元模型进行了宇宙线测试,对实验数据进行了分析和修正,给出了该单元模型的时间分辨(252ps)和位置分辨(4.1cm)等参数.     

BESⅢ RPC宇宙线测试系统

北京谱仪(BESⅢ)采用阻性板室(Resistive Plate Chambers)作为其muon探测器, 总使用面积达1200m². 为保证探测器的质量, 每一块阻性板室都要求通过宇宙线测试. 宇宙线测试系统使用3个流光管室作为其触发和寻迹系统, 其空间分辨可达2—3mm, 覆盖面积约4m², 测试系统可同时测量8块RPCs. 最后, 还报道了RPC的初次测试结果.     

Electromagnetic Interactions of High Energy Cosmic Ray Muons

This paper investigates the electromagnetic interactions of muons. The various processes such as knock-on electron-, bremsstrahlung-, direct electron pair production, and nuclear interactions are described in detail. The energy range concerned extends from 10⁹ eV up to 10¹⁵ eV for primary muons and from 10⁸ eV up to 10¹⁴ eV for energy transfers to the secondaries. On the one hand the measurement of muon interactions represents a test of quantum electrodynamics. On the other hand the high energies available in cosmic rays would possibly lead to the measurement of new processes or the detection of new particles. One hopes to find in the high energy domain the answer to the question why the muon exists at all and if there are properties (apart from differences in mass, lifetime, and lepton number) which distinguish it from a mere heavy electron. The different experimental techniques are described and the various experimental results on muon interactions are presented and compared with relevant QED-theories. Observed deviations between theory and experiment and anomalies in muon interactions are critically investigated and discussed in the light of experimental difficulties and interpretation problems. In general, agreement between theory and experiment is found, i.e. QED-theories describe the results adequately. However, some experiments claim to have detected anomalies in muon physics in the cosmic ray beam. But the hypotheses on new processes and new particles in the high energy range do not withstand a critical analysis. It is concluded that the observed deviations can be understood in the framework of conventional theories.     

宇宙线高能族事例中的共线现象

通过对甘巴拉山K0—K7乳胶室所观测到的部分族事例与运用COSMOS,CORSIKA程序产生的模拟族事例进行了可分辨能量中心(EDC)的共线性的分析,结果表明:在实验族事例中,共线事例产生的份额随族的总观测能的增高而上升;而传统的模拟计算不能解释共线现象这一特征.文中还对族事例中γ线与强子的判别标准进行了讨论.     

Gamma Ray Astronomy and the Origin of Cosmic Rays

The classical production processes for high energy gamma radiation in the interstellar medium are discussed and confronted with recent satellite observations. It is shown that gamma ray data in their present form do not provide definite conclusions on the origin of cosmic rays. Some current ideas on the nature of gamma ray point sources are presented.     

北京谱仪上宇宙线μ样本的选择

通过对北京谱仪(BES)所记录到的宇宙线事例的挑选和校正重建,得到了BES上数量很大、动量分布宽广的高纯度的μ样本.所得样本已经用于Ds物理研究.     

EAS Phenomenology and Cosmic Ray Spectrum Ground Based Measurements

Primary cosmic ray energy spectrum around and above 1 PeV is of great interest due to its non-power-law behavior (“knee”) in PeV region found many years ago using the indirect EAS (Extensive Air Shower) method. The method is based on secondary particles measuring on Earth’s surface under a thick atmosphere. Traditionally, people use detectors sensitive to ionization produced mostly by secondary electromagnetic component and therefore any found changes in EAS size spectrum correspond to secondary components, which have to be recalculated to primary spectrum. Recently some new “knees” were claimed by high altitude experiments: at ∼45 TeV for all-particle spectrum (HAWC), for primary protons and helium: at ∼400 TeV (Tibet ASγ) and at ∼700 TeV (ARGO-YBJ) thus widening the “knee” region from ∼0.045 to 5 PeV. The natural explanation of such a strange spectrum behavior in a wide energy range could be found in the EAS phenomenological approach to the knee problem.

     

MRPC宇宙线批量测试方法探讨

通过分析33个多气隙电阻板室(MRPC)的宇宙线测试结果, 得到了雪崩信号比例和 平均幅度与时间分辨的关系, 计算得出了MRPC的分辨时间随测试事例数的变化 趋势. 据此提出了~MRPC~的宇宙线批量测试方法.     

Cosmic Ray Electrons and Protons,and Their Antiparticles

Cosmic rays are a sample of solar, galactic, and extragalactic matter. Their origin, acceleration mechanisms, and subsequent propagation toward Earth have intrigued scientists since their discovery. These issues can be studied via analysis of the energy spectra and composition of cosmic rays. Protons are the most abundant component of the cosmic radiation, and many experiments have been dedicated to the accurate measurement of their spectra. Complementary information is provided by electrons, which comprise about 1 % of the cosmic radiation. Because of their low mass, electrons experience severe energy losses through synchrotron emission in the galactic magnetic field and inverse Compton scattering of radiation fields. Electrons therefore provide information on the local galactic environment that is not accessible from the study of the cosmic ray nuclei. Antiparticles, namely antiprotons and positrons, are produced in the interaction between cosmic ray nuclei and the interstellar matter. They are therefore intimately linked to the propagation mechanisms of the parent nuclei. Novel sources of primary cosmic ray antiparticles of either astrophysical (e.g., positrons from pulsars) or exotic origin (e.g., annihilation of dark matter particles) may exist. The nature of dark matter is one of the most prominent open questions in science today. An observation of positrons from pulsars would open a new observation window on these sources. Several experiments equipped with state-of-the art detector systems have recently presented results on the energy spectra of electrons, protons, and their antiparticles with a significant improvement in statistics and better control of systematics. The status of the field will be reviewed, with a focus on these recent scientific results.     

小型宇宙射线探测仪的模拟和测量

介绍了一款小型宇宙射线探测仪。该仪器具有宇宙射线科普演示功能,主要用于实时测量μ子射线并显示计数,以及长时间尺度下（年）稳定地对不同角度的次级宇宙线通量进行监控记录。简要地展示了探测器的硬件构造和探测效率的模拟计算。探测仪单个探测器的探测效率为93.1%,两个探测器符合测量的探测效率为86.6%。根据探测器的计数率以及模拟计算的探测效率,估计了次级宇宙射线垂直地面方向的通量,为J=29±3 m-2 sr-1 s-1。另外,利用该宇宙射线探测仪,测量了兰州市区的次级宇宙射线的天顶角分布。其结果很好地满足I（θ）=IH+I₀ cosα θ经验公式,其中的角度依赖参数α=2.42±0.52。A small cosmic ray device is introduced in this paper.It has the demonstration function for popularization of science,and can be used mainly to display the μ counts in a real-time measurement,and to monitor the secondary cosmic ray flux at different angles in a very long time scale (years).We briefly show the hardware of the device and the detecting efficiency calculation by simulation.The detecting efficiency for one detector of the device is 93.1%,and the detecting efficiency is 86.6% for the coincidence measurement of two detectors.Based on the count rate by the detector and the simulated efficiency,the secondary cosmic ray flux perpendicular to the ground surface is measured,which is J=29±3 m-2sr-1 s-1.Moreover,with an application of the device,we measured the angular distribution of the secondary cosmic ray rate in Lanzhou City.The resulting angular distribution agrees well with the empirical formula as I(θ)=IH+I₀ cosα θ,in which the parameter for the angle-dependence is α=2.42±0.53.     

Diagnostics for Electromagnetic Conditions in the Heliosphere by Cosmic Ray Effects

Physics of Atomic Nuclei - We review some results of diagnostics for the electromagnetic characteristics of the heliosphere and of the Earth magnetosphere within the model for cosmic ray modulation...