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[新闻] [100731] LHCf completes its first run

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发表于 2010-8-1 09:32:14 | 显示全部楼层 |阅读模式
http://cdsweb.cern.ch/record/1281664

LHCf, one of the three smaller experiments at the LHC, has completed its first run. The detectors were removed last week and the analysis of data is continuing. The first results will be ready by the end of the year.


icon-LHCf_1_image.JPG

One of the two LHCf detectors during the removal operations inside the LHC tunnel.

LHCf is made up of two independent detectors located in the tunnel 140 m either side of the ATLAS collision point. The experiment studies the secondary particles created during the head-on collisions in the LHC because they are similar to those created in a cosmic ray shower produced when a cosmic particle hits the Earth’s atmosphere. The focus of the experiment is to compare the various shower models used to estimate the primary energy of ultra-high-energy cosmic rays. The energy of proton-proton collisions at the LHC will be equivalent to a cosmic ray of 1017eV hitting the atmosphere, very close to the highest energies observed in the sky. “We have now completed the first phase of our research programme”, says Oscar Adriani, LHCf Deputy Spokesperson. “The experiment has been designed to work with high-energy particles but at a low luminosity. The LHC is now increasing the luminosity, which can cause problems for our detectors. At the same time, we have now collected enough data at 450 GeV and 3.5 TeV per beam”.

icon-LHCf_2_image.JPG

The detectors that LHCf used for this first run were mainly plastic scintillators. The collaboration will now work on replacing them with more radiation-resistant crystal scintillators, to be ready by 2013 when the LHC will run at 7 TeV per beam. The collaboration also plans to change the position of its silicon detectors to improve the performance of the experiment in measuring the energy of the interacting particles. “It was an advantage for us to be able to collect data at lower energies as this will allow us to compare the theoretical models also at these intermediate energy regions. The UA7 experiment carried out at the SPS accelerator in the 1980s already provided information for 450 GeV energy collisions. LHCf will be the first to provide results at 3.5 TeV and beyond”, confirms Adriani. The results of the data analysis at 450 GeV will be available by the end of the year, while data at 3.5 TeV will be analysed in 2011.
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发表于 2010-8-6 01:14:03 | 显示全部楼层
翻译一下啊,E文不好
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发表于 2010-8-6 06:44:27 | 显示全部楼层
本帖最后由 cnchina 于 2010-8-6 07:59 编辑

通篇较长,第一段翻译如下。

LHCf, one of the three smaller experiments at the LHC, has completed its first run. The detectors were removed last week and the analysis of data is continuing. The first results will be ready by the end of the year.

在LHC运行的三项小型实验中的一项,LHCf,已经首先完成。检测器上周已经移除,现正在继续解析数据。初步结果将在今年年底揭晓。
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发表于 2010-8-6 07:59:01 | 显示全部楼层

图:两个LHCf检测器之一在LHC隧道中正被移除。

LHCf由两个独立的检测器组成,它们放置于隧道中ATLAS碰撞点的两侧各140米处。这个实验研究在LHC中正面碰撞时产生的二级粒子,因为它们十分类似于宇宙射线簇射中宇宙粒子撞击地球大气所产生的。这个实验的目标在于比较用于估算高能宇宙射线初始能量的不同簇射模型。质子对质子的碰撞产生的能量在LHC相当于一束1017eV的宇宙射线撞击大气,非常接近人们观察到在空中的最大能量。“我们已经完成了研究项目的第一期,”LHCf负责发言人奥斯卡阿德里安尼(Oscar Adriani)说,“实验原设计工作于较低光度的高能粒子。LHC现在正在加强光度,或可对我们的检测器造成问题。同时,我们也已经在450GeV和3.5TeV粒子束中获取了足够的信息。
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发表于 2010-8-6 08:12:42 | 显示全部楼层

LHCf第一次运行所用的检测器主要是塑料闪烁计数器。合作单位现正制作更抗辐射的晶体闪烁计数器,将在2013年LHC运行于每束7TeV之前准备完毕。合作单位也计划改变硅检测器的位置,以增强在测量互相影响的粒子的实验性能。“能够在低能量时获取数据对我们而言是一项优势,这使我们在中间的能量区域也能够对理论模型作出比较。SPS加速器在1980年代所做的UA7实验已经提供了450GeV能量的撞击信息。LHCf将首先提供3.5TeV及以上的结果。”阿德里安尼确认道。450GeV的分析数据将在今年年底前揭晓,而3.5TeV在2011年接受分析。
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发表于 2010-8-6 15:54:33 | 显示全部楼层
这两天曾经接到过几个任务,10秒以内占绝大多数
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