Higurashi Y, Ohnishi J, Ozeki K, Kidera M, Nakagawa T
RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan.
Rev Sci Instrum. 2014 Feb;85(2):02A953. doi: 10.1063/1.4848976.
Over the past two years, we have tried to improve the performance of the RIKEN superconducting electron cyclotron resonance ion source using several methods. For the production of U vapor, we chose the sputtering method because it is possible to install a large amount of material inside the plasma chamber and thus achieve long-term operation without a break, although it is assumed that the beam intensity is weaker than in the oven technique. We also used an aluminum chamber instead of a stainless steel one. Using these methods, we successfully produced ∼180 eμA of U(35+) and ∼230 eμA of U(33+) at the injected radio frequency (RF) power of ∼4 kW (28 GHz). Very recently, to further increase the beam intensity of U(35+), we have started to develop a high temperature oven and have successfully produced a highly charged U ion beam. In this contribution, we report on the beam intensity of highly charged U ions as a function of various parameters (RF power and sputtering voltage) and discuss the effects of these parameters on the beam stability in detail.
在过去两年里，我们尝试了多种方法来提高理化学研究所超导电子回旋共振离子源的性能。对于铀蒸汽的产生，我们选择了溅射法，因为尽管预计束流强度比炉技术中的弱，但在等离子体腔室内可以装入大量材料，从而实现不间断的长期运行。我们还使用了铝腔而不是不锈钢腔。使用这些方法，在约4千瓦（28吉赫兹）的注入射频（RF）功率下，我们成功产生了约180电子微安的U(35+)和约230电子微安的U(33+)。最近，为了进一步提高U(35+)的束流强度，我们开始研发高温炉，并成功产生了高电荷态的铀离子束。在本论文中，我们报告了高电荷态铀离子的束流强度与各种参数（射频功率和溅射电压）的函数关系，并详细讨论了这些参数对束流稳定性的影响。
