Modification of Tungsten Surface Irradiated by Hydrogen and Helium Plasma

(氢等离子体辐照)在表面温度小于950K、注量大于3×10^~(-1)的低能量(~lt；100 eV)、高通量(~(21&gt；m^&lt；-2&gt；S^&lt；-1)氢等离子体辐照下，钨表面能明显观察到气泡的形成。在较高的辐照剂量下，最大氢泡尺寸可达300微米。清晰地得到了气泡形成与样品温度的关系。当表面温度高于950K时，在不同的入射通量下，钨表面没有观察到起泡。这些结果表明，低温下低能粒子辐照形成如此大的氢泡也会对聚变装置和反应堆中的氢气保持产生很大的影响。(氦等离子体辐照)钨(W)样品被低能量(~lt；65 eV)和高通量(~gt；10^&lt；23&gt；m^&lt；-2&gt；S^&lt；-1&gt；)氦等离子体辐照，以研究入射离子能量对氦泡形成的依赖关系。实验结果表明，气泡形成存在入射离子能量阈值。15 eV附近的阈值能量可能与He离子进入W表面的表面电势有关。

(Hydrogen Plasma Irradiation)Blister formation is clearly observed on tungsten surface under a low energy (<100 eV) and high flux(>l0^<21> m^<-2> s^<-1>) hydrogen plasma irradiation at the surface temperature less than 950 K and the fluence higher than 3 x 10^<24> m^<-2>. The size of maximum hydrogen blisters is up to 300micron at higher fluence irradiation. The dependence of blister formation on sample temperature is clearly obtained. When the surface temperature is higher than 950 K no blisters are observed on tungsten surface at various incident fluence. These results indicate that such large hydrogen blister formation due to low energy particles irradiation at low temperature can also make a great effect on the hydrogen retention in fusion devices and reactors.(Helium Plasma Irradiation)Tungsten (W) specimens were irradiated by low energy (<65 eV) and high flux (>10^<23> m^<-2> s^<-1>) helium plasma to investigate the incident ion energy dependence of helium bubble formation. Experimental results indicate the existence of the incident ion energy threshold for the bubble formation. The threshold energy around 15 eV could associate with the surface potential for He ions entering to the W surface.