Development of Metallic Targets with Highly Durability by means of a Hot Spot Deposition

我们发现，在直流弧光放电过程中，阴极表面的等离子体热斑发射出的碳粒子由大尺寸(0.5微米)的团簇粒子组成。传统热蒸发法制备的碳颗粒由0.002um的细小颗粒组成，我们利用这一现象研制出了非常薄的金属复合箔。在直流弧光放电中，阳极由碳棒组成，高密度热等离子体的阴极由待蒸发的金属棒组成。我们用热等离子体点蒸发的方法成功地制备了5-20mug/cm~2的自支撑镀铝碳、钛碳、铁碳和碲碳箔，并用东京工业大学范德格拉夫加速器上3.2 MeV、-3µA的Ne~+离子束测量了这种方法制备的铝碳箔的寿命。实验结果表明，该方法制备的铝碳、钛碳、铁碳和碲碳箔具有较高的寿命。结果表明，用该热点蒸发法制备的金属化合物箔具有很高的强流重离子束轰击寿命。这种新的蒸发方法不仅可用于制备寿命长的碳剥离箔，而且还可用于制备非常薄的、自支撑的金属化合物靶箔(5mug/cm2~20mug/cm2)。

We found that the carbon particles emitted from a hot plasma spot of the cathode surface during DC arc discharge compose of cluster particles of large size (0.5mum). The carbon particles by a conventional thermal evaporation compose of fine particles (0.002mum).We applied this phenomena to develop very thin metallic compound foils. Here, in the DC arc discharge, the anode is composed of the carbon rod and the cathode to make the high density hot plasma is composed of the metallic rod to be evaporated.We could be successfully prepared Aluminized Carbon, Titanium Carbon, Iron Carbon and Hafnium Carbon Foils of self-supporting with 5-20mug/cm^2 by means of the hot plasma spot evaporation, and we measured the lifetimes of the foils made by the present method using Ne^+ ion beam with 3.2 MeV and -3muA current intensity from the Van de Graaff Accelerator at the Tokyo Institute of Technology.From the experiment, we found the metallic compound foils made by the presented hot spot evaporation have a very high durability for heavy ion beam bombardment with high beam current.This new evaporation method is confirmed to be useful for preparation not only carbon stripper foils with long lived lifetime but also metallic compound target foils with very thin and self-supporting(5mug/cm^2 to 20mug/cm^2).