共查询到20条相似文献,搜索用时 93 毫秒
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一、前言摄谱法发射光谱分析中摄谱曝光的计时一般用秒表,但人为差错较多;用电动时间继电器计时,精度低,而且故障多。采用微机可编程序计时控制摄谱中的预燃、曝光、移板等步骤,经过调试试验,并投产运行,效果非常好,各步骤控制定时准确,故障少。实践证明,用微机可编程序控制摄谱过程是完全准确可靠的,值得推广应用。 相似文献
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本文详细研究了La0.67Sr0.33Mn0.90Fe0.10O3多晶样品的磁电阻和电子自旋共振谱的特性,发现由于Fe离子的掺入,体系的转变温度明显降低,而且磁电阻的峰位偏离了电阻的峰位,另外在高温处磁电阻又出现了另一峰,这些都是由于铁离子改变屯体系的磁性相互作用以及电子可以在Fe离子eg↑态和Mn离子eg↑态之间跃迁而导致的结果,电子自旋共振实验进一步证实了铁离子的在体系中的作用。 相似文献
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在氢气放电源打靶的实验中,测到了系列能量恒定不变的低能X射线新谱线,这些新谱线的能量分别为(1.70±0.10) keV, (2.25±0.07) keV,(2.56±0.08) keV,(3.25±0.10) keV和(3.62±0.11) keV,与Si,Ta,S,Cl,K和Ca等元素的特征X射线能量相近,但靶中所含的杂质或来自放电室的杂质元素可能会产生这些能量的X射线谱峰,证实新谱线是否由这些元素的特征X射线干扰所致显得尤为重要。分析了本实验系统中各种杂质的可能来源,论证了放电室端杂质对新谱线的影响,及靶材料中体杂质和面杂质对新谱线的影响;用X射线光电子能谱仪对靶做了表面分析。研究结果表明:杂质元素的特征X射线不会对氢气放电源打靶产生的新谱线有影响。这些新谱线的性质有待进一步的实验研究。 相似文献
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Sarika Bhide V. M. Datar Satyajit Jena S. D. Kalmani N. K. Mondal G. K. Padmashree B. Satyanarayana R. R. Shinde P. Verma 《Pramana》2007,69(6):1015-1023
We are currently developing and studying the performance of glass RPC prototypes, under the INO detector R&D programme. While
we were successful in building and characterising a large number of chambers using local glass, these have met with severe
aging problems after a few months of continuous operation. We have then built a couple of RPCs using a Japanese glass. We
report in this paper on our long term stability tests of these RPCs. We also present some of our recent results on tracking
of cosmic ray muons in a stack of glass RPCs.
India-based Neutrino Observatory Collaboration 相似文献
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Plastic scintillator-based hodoscope for the characterization of large-area resistive plate chambers
A scintillator-based hodoscope is fully operational at Nuclear Physics Division, Bhabha Atomic Research Centre (NPD-BARC). It was used for characterizing the resistive plate chambers (RPCs) assembled for the RE4 upgrade for the compact muon solenoid (CMS) experiment, installed during the long shut-down (LS1) using cosmic muons. It has now been employed for R & D related to gas mixtures and glass RPCs for the India-based neutrino observatory (INO) and muon tomography studies. The hodoscope is equipped with gas flow lines, LV, HV and VME-based DAQ with multihit TDCs. CERN-based software was adapted, implemented and along with the cosmic trigger, was used to evaluate the functional parameters for the RPCs, such as efficiency, cluster size etc. 相似文献
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The influence of phosphate glass electrode in the configuration of resistive plate chamber has been studied using GEANT3.21
Monte Carlo code. Bakelite electrodes were replaced by phosphate glass electrodes, as these glass materials have low bulk
resistivity, are portable and easy to handle. These types of RPCs in their compact form of all materials are suitable for
high rate background environment. We find that these new types of RPCs give little higher response to γ-rays and e+/e− particles, both for single-and double gap RPCs. The results of simulation are discussed.
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J. C. Hill 《Czechoslovak Journal of Physics》2005,55(12):1655-1658
The PHENIX forward upgrade adds nosecone calorimeters and level-1 trigger (LVL-1) detectors to the muon forward spectrometers.
The muon detector will trigger on high pT muons from W decay and reject background. This will enable study of quark and anti-quark polarizations in the proton. The
upgrade will add momentum and timing information to the present muon trigger. Signals from 3 Resistive Plate Chambers (RPCs)
will provide momentum and timing information for the LVL-1 trigger. Each RPC carries a plane with coarse structure to establish
a space point for timing and one with radial cathode strips for azimuthal resolution. Timing resolution of ≈ 2 ns rejects
beam-related backgrounds and tracking from RPCs minimizes muons from hadron decays. RPC information is sent by optical. bers
to LVL-1 trigger processors. A discussion of physics measurements possible, layout of the upgrade and details of RPC design
and tests are given below.
for the PHENIX collaboration
Presented in the Poster Session “Future Experiments and Facilities” at the 18th International Conference “Quark Matter 2005”,
Budapest, Hungary, 4–9 August 2005. 相似文献
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MA Lie-Hua WANG Yi-Fang ZHANG Jia-Wen Logan Lebanowski Viktor p XU Guang-Hua CHEN Jin XIE Yu-Guang HAN Ji-Feng ZHANG Qing-Min QIAN Sen NING Zhe 《中国物理C(英文版)》2010,34(8)
This study uses Daya Bay RPCs operating in streamer mode to investigate gas mixtures of at least 50% argon,at most 6% isobutane,and with small amounts of SF6.Isobutane is reduced to 2% without degradation of performance,and SF6 reduces the noise rate and current,as well as the signal size.This study provides quantitative relationships between basic RPC operating parameters and various gas compositions. 相似文献
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P. Abreu S. Andringa P. Assis A. Blanco V. Barbosa Martins P. Brogueira N. Carolino L. Cazon M. Cerda G. Cernicchiaro R. Colalillo R. Conceição O. Cunha R. M. de Almeida V. de Souza F. Diogo C. Dobrigkeit J. Espadanal C. Espirito-Santo M. Ferreira P. Ferreira P. Fonte U. Giaccari P. Gonçalves F. Guarino O. C. Lippmann L. Lopes R. Luz D. Maurizio F. Marujo P. Mazur L. Mendes A. Pereira Mario Pimenta R. R. Prado J. R̆ídký R. Sarmento C. Scarso R. Shellard J. Souza B. Tomé P. Trávníc̆ek J. Vícha H. Wolters E. Zas 《The European Physical Journal C - Particles and Fields》2018,78(4):333
A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers. 相似文献
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HAN Ji-Feng ZHANG Jia-Wen CHEN Jin ZHANG Qing-Min LIU Qian XIE Yu-Guang QIAN Sen MA Lie-Hua 《中国物理C(英文版)》2008,32(5)
The installation of the BESⅢ RPC system has been completed.Cosmic ray test results show that they perform very well in streamer mode and meet the BESⅢ requirements.We have tested several RPCs in the avalanche mode with the addition of extra SF6 in the gas mixture.We find an efficiency plateau that reaches~95%.and a time resolution of 1.8 ns.This demonstrates that the BESⅢ-type RPC can work in the avalanche mode as well. 相似文献
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T. A. Vasiliev V. P. Ladygin A. I. Malakhov 《Physics of Particles and Nuclei Letters》2011,8(10):1090-1092
Transverse momentum spectra of π± and the π+/π−—ratios are obtained for the Au + Au central collisions at the energies of 6, 8 and 10 AGeV. The particles identification
has been done using the time-of-flight information from RPCs. The pions with large values of the transverse momentum can provide
the information of the coexistence phase even in the energy domain of SIS100. 相似文献
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《Radiation measurements》2007,42(9):1545-1551
Resistive plate chambers (RPCs) have been chosen as a part of the muon trigger detectors in the CMS experiment. They are used both in the endcaps and in the barrel regions, and they have to work in an extreme radiation background. Test of glass-RPC detectors have been performed in order to investigate their performance in such situations. In the present work, the simulation response of glass-RPCs exposed to positrons/electrons is evaluated. As expected a lower sensitivity of glass-RPC with respect to the bakelite-RPC has been observed since the glass density is higher and therefore a lower fraction of electrons can reach the gas gap. The obtained results were applied to CMS/RPC endcap and barrel regions, and their respective sensitivities to those particles are reported together with hit rates. 相似文献