Study of Superconductor Thin Film Growth and the manifestation Mechanism Using Super-Excited Atomic Oxygen (O^<****>) Beam

1996年，我们对去年研制的亚稳束源进行了改进，在差动真空室中建立了机械斩波器，对亚稳束流进行脉冲处理。我们还在斩波器下游50 cm处安装了光电倍增管(Ceratron)，以斩波器的门信号为触发，对信号进行积分，获得亚稳态光束的飞行时间(TOF)谱。获得的飞行时间谱表明，He光束的速度平均值为3000 m/S，而O^lt；**&gt；光束的分布在速度平均值为2000和500m/S处有两个峰值，此外，我们还观察到了O^lt；**&gt；TOF光谱的精细结构。这表明，O^&lt；**&gt；束由几个能量不同的O^&lt；**&gt；‘S组成，用TOF方法有可能将一个不同能量的O^&lt；**&gt；原子分开。这一结果还需要用激光等技术进行进一步的研究。我们尝试通过一个差分室和一个超高压室将亚稳态束源连接起来，以生产超导薄膜。我们注意到，在流动的O^&lt；**&gt；梁上维持特高压是困难的。因此，我们将涡轮分子泵与超高压室连接起来。此外，我们还证明了从氮气或二氧化碳气体中可以产生与上述技术不同的激发能的N^&lt；**&gt；或O^&lt；**&gt；，并且亚稳态光束的最佳条件正在研究中。

In 1996 we modified the metastable beam source made in last year, built mechanical chopper in differential vacuum chamber to pulse the metastable beam. We also built photomultiplier (ceratron) at 50 cm downstream of the chopper, to obtain time-of-flight (TOF) spectrum of the metastable beam by integrating the signal, with the gate signal of the chopper as trigger. The obtained TOF spectra showed that the velocity avarage of He^<**> beam is 3000 m/s, whereas the distribution of O^<**> beam has two peak at the velocity avarage of 2000 and 500 m/s. In addition, we observed fine structures of the O^<**> TOF spectrum. This indicates that the O^<**> beam consists of several O^<**>'s each of which has different energy, and there is a possibility to devide an O^<**> atoms with different energy by TOF method. This result needs further investigation with laser technique etc.We have tried to connect the metastable beam source via a differential chamber with an UHV chamber for the production of superconductive thin film. We noticed that it is difficult to maintain UHV on flowing the O^<**> beam. Hence, we connect a turbo molecular pump with the UHV chamber.Furthermore, we have demonstrated that N^<**> or O^<**> with different excitation energy from that by the above technique can be produced from nitrogen or carbon dioxide gas, and the best condition of the metastable beams are on investigation.