Jain S K, Jain Akhilesh, Hannurkar P R, Kotaiah S
Accelerator Programme, Raja Ramanna Centre for Advanced Technology, Indore 452-013, India.
Rev Sci Instrum. 2007 May;78(5):053301. doi: 10.1063/1.2735629.
Electron cyclotron resonance (ECR) plasma source at 50 keV, 30 mA proton current has been designed, fabricated, and assembled. Its plasma study has been done. Plasma chamber was excited with 350 W of microwave power at 2450 MHz, along with nitrogen and hydrogen gases. Microwave power was fed to the plasma chamber through waveguide. Plasma density and electron temperature were studied under various operating conditions, such as magnetic field, gas pressure, and transversal distance. Langmuir probe was used for plasma characterization using current-voltage variation. The nitrogen plasma density calculated was approximately 4.5 x 10(11) cm(-3), and electron temperatures of 3-10 eV (cold) and 45-85 eV (hot) were obtained. The total ion beam current of 2.5 mA was extracted, with two-electrode extraction geometry, at 15 keV beam energy. The optimization of the source is under progress to extract 30 mA proton beam current at 50 keV beam energy, using three-electrode extraction geometry. This source will be used as an injector to continuous wave radio frequency quadrupole, a part of 100 MeV proton linac. The required root-mean-square normalized beam emittance is less than 0.2pi mm mrad. This article presents the study of plasma parameters, first beam results, and status of ECR proton source.
设计、制造并组装了50keV、30mA质子流的电子回旋共振(ECR)等离子体源,并对其等离子体进行了研究。等离子体腔室由2450MHz的350W微波功率激发,同时通入氮气和氢气。微波功率通过波导馈入等离子体腔室。在各种运行条件下,如磁场、气压和横向距离,研究了等离子体密度和电子温度。使用朗缪尔探针通过电流-电压变化对等离子体进行表征。计算得到的氮等离子体密度约为4.5×10¹¹cm⁻³,获得了3 - 10eV(冷)和45 - 85eV(热)的电子温度。在15keV束流能量下,采用双电极引出结构引出了2.5mA的总离子束流。目前正在对该源进行优化,以采用三电极引出结构在50keV束流能量下引出30mA质子束流。该源将用作连续波射频四极杆的注入器,后者是100MeV质子直线加速器的一部分。所需的均方根归一化束发射度小于0.2πmm·mrad。本文介绍了等离子体参数研究、首次束流结果以及ECR质子源的现状。