Practical 2.45-GHz microwave-driven Cs-free H− ion source developed at Peking University Project supported by the National Natural Science Foundation of China (Grant Nos. 11775007 and 11575013). |
(color online) Different ECR magnetic field intensities by adding layer(s) of 0.3-mm pure iron (0 position is the microwave window; the magnetic field was measured by means of gaussmeter). |