微通道板离子壁垒膜及其对入射离子的阻止作用

给出了三代微光像管中微通道板离子壁垒膜对入射正离子阻止作用的描述,引进了核阻止本领、电子阻止本领和平均射程的概念。结合Tomas-Fermi屏蔽势进行了分析讨论和Monte-Carlo模拟计算,给出Al₂O₃和SiO₂薄膜对不同能量垂直入射时的核、电子阻止的定量结果。得出了Al₂O₃薄膜阻止本领比SiO₂阻止本领高的结论。证实了选用Al₂O₃离子壁垒膜的科学性和可行性。

MCP Ion Barrier Film and Its Stopping Function on Incident Ions

The microchannel plate (MCP) ion barrier film's stopping function on incident positive ions in the third generation low-level-light imaging tube was introduced. The concepts of nuclear stopping power, electronic stopping power and average range were also introduced, the micrographs of unfilmed MCP and MCPs filmed with different thicknesses were shown. Using Tomas-Fermi shielding potential, we analyze and discuss this problem and a Monte-Carlo simulation was peromed. Analytical expressions and corresponding nuclear and electronic stopping power curves have been shown. Quantitative results were given, reflecting the stopping function of Al_2O_3 and SiO_2 films when nucleus and electrons impinge perpendicularly with different energies. Table 1~3 show the corresponding technical data. The conclusion is that the stopping power of Al_2O_3 film is stronger than that of SiO_2, and the selection of Al_2O_3 ion barrier film is reasonable and feasible. After the theoretical analysis and experimental simulation, the conclusions are brought forward as follows:The stopping function of ion barrier film on the incident ions can be described by two concepts of nuclear stopping power and electronic stopping power. When the thickness of the films is constant, the range of the ions with the same energy in Al_2O_3 films is two to three times as short as that in SiO_2 films. It is indicated that the capability of the stopping function of Al_2O_3 films is higher than that of SiO_2 films. From the calculated results of the stopping function of the films on the ions, it is obviously concluded that the capability of nuclear stopping function on the ions is higher than that of electron, which is in agreement with LSS theory. When 9999 oxygen ions with the energies of 100, 300, 500 eV are perpendicularly incident to the Al_2O_3 film with 5 nm thickness, no transmitting ions are observed. While in the same conditions, 34 and 629 oxygen ions with the energies of 300 eV and 500 eV, respectively, can pass through the SiO_2 films with 5 nm thickness, i.e. the maximal transmittance is 6%. In brief, the capability of the stopping function of Al_2O_3 films is higher than that of SiO_2 films, resulting from that Al_2O_3 films are high density and the fiber rigidity of Al_2O_3 films is close to that of corundum; while SiO_2 is atom crystal, and the rigidity of SiO_2 films is equivalent to that of crystal and inferior to that of Al_2O_3.