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Neutron beam monitor based on a boron-coated GEM 总被引:1,自引:0,他引:1
A new thermal neutron beam monitor with a Gas Electron Multiplier (GEM) is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm GEM foils. Enriched boron-10 is coated on one surface of the aluminum cathode plate as the neutron convertor. 96 channel pads with an area of 8 mm×8 mm each are used for fast signal readout. In order to study the basic characteristics of a boron-coated GEM, several irradiation tests were carried out with α source 239Pu and neutron source 241Am(Be). The signal induced by the neutron source has a high signal-to-noise ratio. A clear image obtained from α source 239Pu is presented, which shows that the neutron beam monitor based on a boron-coated GEM has a good two-dimensional imaging ability. 相似文献
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1引言在振动设计中,往往需要修改一个系统的数学模型的物理参数,这在数学上可以归结为矩阵的逆特征值问题或广义逆特征值问题(见[1]).例如,下面给出振动系统中刚度矩阵与质量矩阵的校正问题.设ω1,ω2,…,ωm(m≤n)是m个自然频率,φ1,φ2,…,φm是相应的振型,令Ω2=diag(ω12,ω22,…,ωm2),φ=(φ1,φ2,…,φm).设K为待校正的刚度矩阵,M为待校正的质量矩阵,它们满足下列条件(1.1)特征方程Kφ=MφΩ2, 相似文献
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