Development of compact and efficient positive ion sources of surface ionization type

开发紧凑高效的表面电离型正离子源

• 批准号: 10650311
• 负责人: KAWANO Hiroyuki
• 金额: $ 0.64万
• 依托单位: Ehime University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650311/
• 关键词: Positive ion source; surface ionization; Optimum temerature range; Work function; refractory metal surfaces; Alkali halide beams; Alkali halide films; Temperature-programmed desorption spectra; 耐熱金属表面

To develop compact and efficient positive ion sources for salts such as alkali halides (MX), two types of 〔A〕 molecular beam incidence upon a heated metal filament surce (S【similar or equal】0.005cmィイD12ィエD1) and 〔B〕 sample solution coating on a base metal plate (S【similar or equal】0.03cmィイD12ィエD1) were designed and manufactured, and also the current (IィイD1+ィエD1) of ion (MィイD1+ィエD1) due to surface ionization (thermal emission) was measured a function of surface temperature (T), residual gas pressure (P), etc. Thoretical analysis of the data thus achieved yields the following resuits and conclusions.〔A〕Sample beam incidence type(1)Among the seven metals (Nb, Mo, Ta, W, Re, Ir, Pt) studied in this work, Re is the best as a positive ion emitter. (2)When Re is kept at T【similar or equal】1100-1300K at P 【similar or equal】1μTorr, the ionization efficiency (βィイD1+ィエD1) of MX becomes 〜100% because its work function (φィイD1+ィエD1) is increased up to 〜7.5 eV mainly by residual gas adsorption. (3)βィ … More イD1+ィエD1【similar or equal】 100% holds with those thirty elements whose ionozation enegy is less than 6.5eV. (4)The current density (IィイD1+ィエD1/S=eNβィイD1+ィエD1) attains 10ィイD1-5ィエD1A/cmィイD12ィエD1 when the beam intensity (N) is 10ィイD114ィエD1molecules/cmィイD12ィエD1 sec.〔B〕Sample solution coating type(1)When the sample layers (θ【similar or equal】0.1〜10ィイD13ィエD1 molecular layers) of MX is heated up to 〜1300K, neutral molecular evapolation occurs mainly below melting point ? Of MX. (2)Above Tm, however, emission of MィイD1+ィエD1 becomes stronger. (3)MィイD1+ィエD1 is emitled from those active spots on the layers or the base metal (Pt). (4)Work function (φィイD1+ィエD1) of the spots is as high as 〜6-8 eV. (5)Usually, the ionization efficiency (βィイD1+ィエD1) is 10ィイD1-3ィエD1-10ィイD1-4ィエD1, but it increases up to 〜10ィイD1-2ィエD1 as θ decreases to less than unity. (6)When a thin layer (θ【less than or similar】10 molecular layers) is heated around Tm, IィイD1+ィエD1/S becomes 10ィイD1-7ィエD1-10ィイD1-9ィエD1 A/cmィイD12ィエD1.(7)This type is applicable even to such a trace amount as 10ィイD1-11ィエD1 mole of MX.These results have already been published in international journals. Less

为了开发紧凑高效的碱金属卤化物(MX)等盐类正离子源，设计并制作了两种类型的(A)分子束入射到加热的金属丝源(S[等同]0.005 cmィイD12ィエD1)和(B)样品溶液涂覆在贱金属板(S[等同]0.03 cmィイD12ィエD1)上，并测量了由于表面电离(热发射)而产生的离子(Mィイd1+ィエd1)的电流(Iィイd1+ィエd1)，对数据进行理论分析，得到以下结果和结论：(A)样品束入射类型(1)在所研究的七种金属(Nb、Mo、Ta、W、Re、Ir、Pt)中，Re是最好的正离子发射体。(2)当Re保持在1100-1300K，P[相似或等于]1μTorr时，MX的电离效率(βィイD_1+ィエD_1)变为~100%，因为它的功函数(φィイD_1+ィエD_1)主要通过残留气体吸附而增加到~7.5 eV。(3)βィ…对于电离能小于6.5 eV的30种元素，イD_1+ィエD_1[相似或相等]的比例为100%。(4)当束流强度(N)为10ィエD114ィエD1/cmィイD12ィエD 1秒时，电流密度(IィイD 1+ィエD 1/S=ENィイD 1+ィエD 1)达到10ィイD 1-5ィエD 1/cmィイD12ィエD 1.(B)样品溶液镀膜型(1)当MX的样品层(θ[相似或相等]0.1~10ィイD13ィエD 1分子层)加热到~1300K时，中性分子蒸发主要发生在熔点以下？MX.(2)在Tm以上，Mィイd1+ィエd1的发射变强。(3)Mィイd1+ィエd1从层或母材(Pt)上的有源点发射。(4)光斑的功函数(φィイD_1+ィエD_1)高达6-8 eV。(5)通常情况下，电离效率(βィイd1+ィエd1)为10ィイd1-3ィエd1-10ィイd1-4ィエd1，但当ィイ降到1以下时，电离效率增加到~10ィエd1-2θd1。(6)当在Tm周围加热一层薄层(θ[少于或类似]10个分子层)时，Iィイd1+ィエd1/S变成10ィイd1-7ィエd1-10ィイd1-9ィエd1 A/cmィイD12ィエd1。(7)即使是10ィイd1-11ィエd1摩尔的MX，这种类型也适用。较少

项目成果

H. Kawano, Y. Zhu, H. Mine, M. Moriyama and M. Tanigawa: "Selection of the substrate metal best for thermal positive ionization"Rev.Sci.Instrum.. (in press). (2000)

H. Kawano、Y. Zhu、H. Mine、M. Moriyama 和 M. Tanikawa：“选择最适合热正电离的基底金属”Rev.Sci.Instrum..（出版中）。

H. Kawano, K.Ohgami, S. Matsui and Y. Zhu: "Optimum temperature range for positive ion production from metal halide molecules incident upon heated metal catalysts"Appl.Surf.Sci.. 144. 404-408 (1999)

H. Kawano、K.Ohgami、S. Matsui 和 Y. Zhu：“在加热的金属催化剂上发生金属卤化物分子产生正离子的最佳温度范围”Appl.Surf.Sci.. 144. 404-408 (1999)

H.Kawano: "Optimum temperature range for positive ion production from metal halide molecules incident upon heated metal catalysts"Appl.Surf.Sci.. 144/145. 404-408 (1999)

H.Kawano：“在加热的金属催化剂上从金属卤化物分子产生正离子的最佳温度范围”Appl.Surf.Sci.. 144/145。

H.Kawano: "Work function of refracbory metals and its dependence upon working conditions"Appl.Surf.Sci.. 146. 105-108 (1999)

H.Kawano：“难熔金属的功函数及其对工作条件的依赖性”Appl.Surf.Sci.. 146. 105-108 (1999)

H.Kawano: "Work function of refractory metals and its dependence upon working conditions"Applied Surface Science. 146. 105-108 (1999)

H.Kawano：“难熔金属的功函数及其对工作条件的依赖性”应用表面科学。