共查询到20条相似文献,搜索用时 15 毫秒
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Mieczyslaw Witold Krasny 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2005,540(2-3):222-234
A method of delivering a small energy spread electron beam to the LHC interaction points is proposed. In this method, heavy ions are used as carriers of projectile electrons. Acceleration, storage and collision-stability aspects of such a hybrid beam is discussed and a new beam-cooling method is presented. This discussion is followed by a proposal of the Parasitic Ion–Electron collider at LHC (PIE@LHC). The PIE@LHC provides an opportunity, for the present LHC detectors, to enlarge the scope of their research program by including the program of electron–proton and electron–nucleus collisions with minor machine and detector investments. 相似文献
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J.M. Jimenez 《Vacuum》2009,84(1):2-7
With the successful circulation of beams in the Large Hadron Collider (LHC), its vacuum system becomes the world's largest vacuum system under operation. This system is composed of 54 km of ultra high vacuum (UHV) for the two circulating beams and about 50 km of insulation vacuum around the cryogenic magnets and the liquid helium transfer lines (QRL). The LHC complex is completed by 7 km of high vacuum transfer lines for the injection of beams from the SPS and their dumping.Over the 54 km of UHV beam vacuum, 48 km are at cryogenic temperature (1.9 K), the remaining 6 km are at ambient temperature and use extensively non-evaporable getter (NEG) coatings, a technology that was born and industrialised at CERN.The cryogenic insulation vacuum systems, less demanding technically, impress by their size and volume: 50 km and 15,000 m3. Once cooled at 1.9 K, the cryopumping allows pressure in the 10−4 Pa range to be attained. 相似文献
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A. Jeff A. BoccardiE. Bravin A.S. FisherT. Lefevre A. RabillerF. Roncarolo C.P. Welsch 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,659(1):549-556
The Large Hadron Collider (LHC) at CERN is the world's largest particle accelerator. It is designed to accelerate and collide protons or heavy ions up to the center-of-mass energies of 14 TeV.Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, in particular to check the injection quality and to measure the proportion of charge outside the nominally filled bunches during the physics periods. In order to study this so-called ghost charge at levels very much smaller than the main bunches, a longitudinal profile measurement with a very high dynamic range is needed.A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions.A prototype was installed during the 2010 LHC run and was able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved.First measurements with the LDM are presented here along with an analysis of its performance and an outlook for future upgrades. 相似文献
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The large hadron collider will be the world next generation accelerator to be operational in 2007 at CERN. The UHV requirements force the installation of ion pumps in the experimental areas of ATLAS. Due to the unacceptable particle background that standards ion pumps may generate, a reduction in the amount of material constitutive of the pump body is required. Hence, a stainless steel 0.8 mm thick body annular triode ion pump has been designed. A pumping speed of ∼20 l/s at 10−9 mbar is provided by 15 pumping elements. Finite elements analysis and destructive tests have been performed in its design. Final vacuum tests results are shown. 相似文献
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Fernando Menezes de Almeida Filho Mounir K. El Debs Ana Lúcia H. C. El Debs 《Materials and Structures》2008,41(6):1073-1089
This paper analyzes the bond behavior of an innovative construction material, self-compacting concrete (SCC), in comparison
to vibrated concrete (VC), using pull-out and beam tests according to the Rilem procedures. The main analyzed parameters were
the concrete compressive strength, the steel bar diameter, the concrete type and the test adequacy to provide a value for
bond strength. Also, a comparison between Code provisions and empirical equations was done. According to the results, SCC
and VC specimens presented similar behavior. The equations results showed a satisfactory approach compared to the experimental
ones, but as expected Code provisions were very conservative. Based on the obtained results, it could be concluded that the
same parameters adopted for VC can be extended for SCC. 相似文献
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Gregg K. Hobbs 《Quality and Reliability Engineering International》1987,3(3):157-162
Development of stress screens is discussed including selection of stimuli appropriate to the defect types sought, selection of screen levels and then finally proof of screen tests. 相似文献
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Eva Schlick-Hasper Marcel Neitsch Thomas Goedecke 《Packaging Technology and Science》2020,33(7):273-286
The Dangerous Goods Regulations currently do not include limit leakage rates or sensitivity requirements for industrial leak testing procedures that are equivalent to the bubble test, which is the prescribed test method for design type testing of dangerous goods packagings. During series production of such packagings, various methods are used, which often do not meet the requirements of the bubble test with regard to important criteria. Sensitivity, flow direction, pressure level and automatability are particularly important factors when selecting a suitable industrial leak testing method. The following methods are in principle both suitable and equally effective as the bubble test: pressure rise test (vacuum chamber), ultrasonic bubble leak detection and gas detection methods (pressure technique by accumulation and vacuum chamber technique). To ensure a uniform test level during design type testing and production line leak testing and therefore a comparable safety level as required by the Dangerous Goods Regulations, it is necessary to include a more precise specification in these regulations. This requires, on the one hand, information about the sensitivity of the bubble test and, on the other hand, the inclusion of a list of suitable, equally effective industrial test methods with their specific boundary conditions. 相似文献
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The outgassing rate of the collimators in the Large Hadron Collider (LHC) at CERN has an important role for the life-time of the Non-Evaporable Getter (NEG), and an accurate analysis allows the definition of future activities, like NEG vacuum activation. For these reasons, both, total outgassing rate and gas composition of a secondary collimator have been measured in the laboratory. The outgassing rate decreases by about two orders of magnitude by after bake-out and moreover, repeated bake-out further reduced the outgassing rate. The gas transmission through the NEG coated beam pipes and the resulting pressure distributions near the collimator were also measured in a dedicated setup. It is found that the main gas component after just 2 m of NEG coated beam pipe is CH4 due to the extreme pumping speed of NEG for the other gases. Large amount of outgassing for H2 and carbon related molecules are released when moving the collimator jaws. It is found that the NEG is very effective even in such case with large gas load. 相似文献
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超声波技术在检测真空系统泄漏中的应用 总被引:1,自引:0,他引:1
基于电厂真空系统泄漏是一种常见故障,因此研究一种简便、快捷、准确的检测方法是必要的.运用超声波技术研究了检测真空系统泄漏的新方法.实践表明,该方法是可行的.所给出的应用超声波技术检测真空系统泄漏的原理和检测方法是有效的. 相似文献
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Peltier current leads (PCLs) for cryogenic systems are investigated in regard to temperature dependence of thermoelectric materials. Due to the Peltier effect on the thermoelectric parts of the current lead, PCLs act as heat pumps. It is expected that PCLs will reduce the amount of heat leak from the room temperature side to the low temperature side of a cryogenic system. Six (three each for p and n type) hot-pressed BiTe samples for PCLs are selected to estimate PCL performance. Our experimental results and analyses indicate that PCLs show a capacity in the order of several hundred Amperes and as much as 20-30% reductions of heat leak. 相似文献
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以我国批量生产真空粉末绝热容器的实际情况为例,并通过数据计算分析,认为对真空粉末绝热容器可以用静态升压法考核夹层总气载,再结合分子筛的吸附作用来满足容器使用寿命的要求。目前,这种方法广泛地运用于真空粉末绝热容器制造业。 相似文献
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四极质谱计在真空检漏中的应用 总被引:2,自引:3,他引:2
介绍了使用四极质谱计进行真空检漏的原理和方法,分别对超高和极高真空系统做了检漏实验研究,并取到了满意的结果。四极质谱计检漏有检漏仪检漏无法比拟的优点,适合在真空工程中推广应用。 相似文献
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安钢制氧厂球罐区氧气管道泄漏,影响了正常供氧并威胁安全生产。文章详细介绍了氧气管道泄漏的应对措施以及检修过程中的停送气方案、施工方案和安全措施,彻底消除了泄漏隐患。 相似文献