天文宇宙

正西藏ASγ实验发现超高能宇宙线加速候选天体中国科学院高能物理研究所、中国科学院国家天文台等国内12个合作单位及日本东京大学宇宙线研究所等16个日方合作单位联合,开展西藏中日合作ASγ实验。相关成果发表于Nature Astronomy。西藏中日合作ASγ实验位于海拔4300米的西藏羊八井,始建于1989年。2014年,中日合作ASγ实验团队在原有的宇宙线表面阵列的地下增设了创新型的地下缪子水切伦科夫探测器(4500平方米)。合作团队利用我国西藏羊八井ASγ实验阵列,在国际上首次发现距地球2600光年的超新星遗迹SNRG106.3+2.7发射出超过100Te V(100万亿电子伏特)的伽马射线。此次重要发现是中日合作双方30年持之以恒的创新结果。     

中日羊八井宇宙线合作实验十年

西藏羊八井优越的自然环境为超高能γ天文观测提供了极好的物理条件。羊八井海拔430 0米 ,有良好的交通、能源和社会生活设施 ,空气透明度好 ,是理想的空气簇射高山站址 ,可以用最少的人力和辅助设备实现高质量的长期连续观测。1　项目背景中日羊八井宇宙线合作实验是中日合作西藏甘巴拉山乳胶室实验的发展和继续。由中国科学院高能物理研究所和日本东京大学宇宙线研究所牵头的乳胶室实验合作项目开始于1 980年 ,在我国山东大学、郑州大学、云南大学、重庆建工学院和日本神奈川大学、横滨国立大学、琦玉大学、宇都宫大学、弘前大学学者的参…     

高海拔宇宙线观测站对地方科教及经济社会的影响

高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)项目是中国科学家在国际宇宙线研究领域提出的重大前沿项目,也是中国在西南地区布局的又一重大科技基础设施。LHAASO项目的实施将最终建成具有国际先进水平的宇宙线研究中心,与世界其他3个宇宙线观测站(位于阿根廷的极高能宇宙线观测站、位于南极的中微子天文观测站、待建的甚高能伽玛天文观测站)形成优势互补,对宇宙线起源这一世纪之谜发起冲击,并推动粒子物理学、天文学、宇宙学领域的相关科学研究产生突破性进展。同时,项目的建设运行也将对设施所在地的科学研究、学科发展、人才培养有重要影响,提高地区科学普及水平,并带动相关经济文化发展。文章将针对重大科技基础设施对地方的科技教育及经济社会影响进行初步分析。     

超高能中微子望远镜样机研制成功并获第一批宇宙线事例

经过历时50多天紧张的调试,由中国科学院高能所研制的超高能中微子望远镜(CRTNT)第二台样机在西藏羊八井投入试运行,并于2007年5月观测期间成功与中意合作ARGO全覆盖地面探测器实现了联合观测,获得第一批宇宙线事例,标志着用于超高能中微子探测的宇宙线大气契伦科夫及荧光望远镜研制的成功。     

云南大学助力国家重大科技基础设施建设

<正>2023年5月10日,中科院高能物理研究所主持的国家重大科技基础设施高海拔宇宙线观测站（LHAASO）顺利通过国家验收。云南大学作为主要建设单位之一,完成了三大阵列之一的广角切伦科夫望远镜（WFCTA）阵列核心部件硅光电倍增管成像探头(相机)的研制和生产,为LHAASO项目取得重大科学发现做出了贡献。宇宙线是来自宇宙空间的高能带电粒子,从1912年发现至今已逾百年,其起源仍然是未解之谜。瞄准这一世纪难题,中科院高能所联合国内多家单位开展了多年预研,并申报了LHAASO项目。     

天文宇宙

正高海拔宇宙线观测站发现首批"拍电子伏加速器"和迄今最高能量光子中国科学院高能物理研究所牵头的LHAASO国际合作组完成国家重大科技基础设施"高海拔宇宙线观测站(LHAASO)"在银河系内发现大量超高能宇宙加速器,并记录到能量达1.4拍电子伏的伽马光子(拍=千万亿),这是人类观测到的最高能量光子,突破了人类对银河系粒子加速的传统认知,开启了"超高能伽马天文学"时代。相关成果发表于Nature。LHAASO尚在建设中,这次报道的成果是基于已经建成的1/2规模探测装置在2020年内11个月的观测数据。LHAASO是以宇宙线观测研究为核心的国家重大科技基础设施,位于四川省稻城县海拔4410米的海子山,可以全方位、多变量地测量宇宙线。     

激波扩散粒子加速理论

正自从1912年奥地利物理学家赫斯通过热气球实验第一次发展宇宙线粒子以来,人类对于宇宙线的探索就从未停止。尤其是关于高能宇宙线的起源和加速机制至今仍是宇宙线科学的未解之谜,本文就宇宙线加速机制中的激波扩散粒子加速理论展开叙述,说明带电粒子是如何在激波中加速的。     

宇宙天文

<正>西藏ASgamma实验发现迄今最高能量的宇宙伽玛射线中国科学院高能物理研究所和日本东京大学宇宙线研究所共同主持的西藏羊八井ASgamma实验发现迄今为止最高能量的宇宙伽玛射线。研究成果发表于Physical Review Letters。这些宇宙伽玛射线来自蟹状星云方向,能量高达450TeV(4.5×10^14电子伏特),比此前国际上正式发表的75TeV的最高能量高出5倍以上。这标志着超高能伽玛射线天文观测进入到100TeV以     

中日宇宙线观测研究成果举世瞩目

宇宙线和超高能天体物理是当代基础科学的重要前沿学科。我国和日本在西藏进行的宇宙线合作研究,是当前我国宇宙线研究的重要组成部分。由于在高海拔的地面可以观测到更多的宇宙线高能粒子,宇宙线研究最好能在数千米高山上进行,而日本没有４０００米以上的高山。中日两国的合作研究酝酿于１９７８年,正式合作从１９８０年开始。实验基地设在拉萨附近的曲水县甘巴拉山（海拔５５００米）上,探测手段是由铅板和Ｘ光片组成的量能器,主要记录超高能宇宙线粒子在大气中产生的空气簇射的轴心附近的高能粒子束,进而研究粒子核作用特性和原初…     

树立科学发展观 深化科技创新

西藏大学宇宙线开放实验室是西藏自治区重点实验室之一，它依托于西藏大学和羊八井宇宙线观测站，通过多年的建设，在实验设备建设、科研工作和人才培养等各方面取得了很大的进展和许多重要成果。     

Relativistic solar cosmic rays

Solar and galactic cosmic rays are of profound astrophysical interest. One facet of contemporary cosmic ray research utilizes these energetic particles as space probes for studying the characteristics of the solar-controlled interplanetary medium, the heliosphere, which is essentially the extension of the solar corona to a considerable distance beyond the orbit of earth. Solar cosmic ray observations in particular contribute to our understanding of the earth's environs, the interplanetary medium, and the sun itself. Appropriately deployed ground-based cosmic ray detectors utilize the earth as a spacedraft for carrying out experiments that are far beyond the capacity of artificial satellites. In interpreting the observations, however, the effects of the geomagnetic field and of the atmosphere must be taken into account by appropriate analytical procedures. Theoretical models account for many of the characteristics of the observed modulations and anisotropies, which manifest themselves as temporal or spatial intensity variations. Analysis of the measurements in terms of various models provides an understanding of the physical mechanisms, as well as the determination of the relevant parameters. Properties of solar cosmic rays that have been investigated include spectra, angular distributions, transport mechanisms and the acceleration to relativistic energies.     

Cosmic rays and particle physics at extremely high energies

Cosmic ray extensive air shower observations can give clues about the properties of high-energy particle interactions above 10¹⁵eV, in addition to giving information about the primary cosmic ray spectrum at these energies. A brief review of recent high energy accelerator data and its theoretical interpretation is given to explain the necessity for obtaining information from cosmic rays about hadronic interactions beyond machine energies. In particular, it is shown that recent measurements of the energy dependence of total cross-sections and of production cross-sections suggest some sort of threshold behavior in the 1000 GeV region. Studies at higher energies are required to understand the nature of this behavior. The use of air shower data for this purpose is illustrated by comparing shower size us depth measurements with the expectations of various models of strong interactions.     

Standards for gas service

The method of analyzing the results of cosmic ray deflection experiments, developed in a previous paper, is here extended to the case where the region of uniform deflecting field is of the same width as that of the counters. In this form it is applicable to the electrostatic deflection experiment of Lenz, and to the electrostatic and magnetic experiments of W. F. G. Swann and the writer. The magnetic experiments of Curtiss and of Mott-Smith are reexamined in the light of the energy distribution recently published by Anderson and Nedderineyer. The latter's result is found to be not inconsistent with the assumption that the induction B gives the correct force; the result of the former requires the addition of low energy rays to the distribution.     

MPS／CAS Partner Group on Radio Astronomy

The Partner Group does research on cosmic magnetic fields using radio astronomy methods. Magnetic fields are found in every astronomical object: the Earth, the Sun, planets, stars, pulsars, the Milky Way, nearby galaxies and in distant radio galaxies. The role of the magnetic fields in the cosmic universe has not been well investigated, mainly because of the difficulties of their observation. The Partner Group has executed several successful observational projects using the 100m radio telescope in Effelsberg, the Very Large Array in the USA and the Australia Telescope National Facilities to collect polarization data tracing the magnetic fields in the Milky Way. The group further plans to install a 6cm receiver system in a 25m radio telescope in Urumqi next summer to make polarization observations that give an unambiguous picture of magnetic field structures emerging from the disk of the Milky Way.     

Yangbajain Cosmic Ray Observatory——The world＇s largest experimental base on high elevation

Cosmic rays are flows of high-energy particles coming from the deep of the universe as material samples voluntarily making their way to the Earth from an extra-terrestrial origin. They are involved with some key, unsolved and long-standing puzzles on the cosmic history, evolution of celestial bodies,     

2001年11月24日特大磁暴前银河宇宙线短时间尺度功率谱分析

采用北京宇宙线超中子堆 5min的数据,利用快速傅里叶变换计算宇宙线的功率谱方法,分析了 2 0 0 1年 1 1月 2 4日特大磁暴前银河宇宙线短时间尺度(t<1h)的功率谱。计算结果表明,在 2 0 0 1年 1 1月 1 8日到 2 0日之间,银河宇宙线的功率谱没有特别突出的特征。在 2 0 0 1年 1 1月 2 3日CME抛出之后到达磁层前的一段时间,银河宇宙线的 2 2.61 5 4min的周期非常显著,而其他短时间周期的特征变得很不明显,几乎变为噪声水平。     

The selection of channels when seeking information: Cost/benefit vs least-effort

Two models of selecting information sources are to be found in the literature. The first, the Cost/Benefit model, proposes that information seekers select information sources on the basis of expected benefits and expected costs of using an information source. Many proponents of this model also feel that expected benefits are the most important consideration for the information seeker. The second model, the Least-Effort model, maintains that information seekers select information sources on the basis of minimizing the effort or cost in obtaining information, while even sacrificing the quality of the information to be obtained. The present study proposes that information seekers place different weights on costs and benefits. In a survey of 968 Forest Service professionals, it was found that perceived costs were twice as important as benefits in choosing information sources.     

Radiations from radioactive rhodium (105)

The characteristic radiations of the 36-hr. rhodium (105) have been investigated with the use of conventional absorption and coincidence methods. The beta rays were found to have a maximum energy of 0.55 Mev., and the gamma rays a quantum energy of ∼0.3 Mev. The beta-gamma coincidence rate of Rh¹⁰⁵ indicated that less than 8 per cent of the beta rays are coupled with the gamma ray.     

γ射线在不同物质中衰减规律的蒙特卡罗模拟

本文根据γ射线与物质相互作用机理,建立基于蒙特卡罗方法的粒子输运数学模型。根据窄束γ射线在物质中的衰减规律公式,通过蒙特卡罗方法模拟计算得到不同能量γ射线对于不同材料的衰减系数。并对γ射线在几种物质中的能量衰减变化进行模拟。结果显示用蒙特卡罗方法模拟与理论完全吻合。