Ion source for ADS applications

The high power proton accelerators are being developed worldwide for ADS applications. The energy of the proton/deuteron required for this purpose is ∼ GeV. The beam power requirements will depend upon the amount of nuclear power to be generated, the fissile material to be bred and the quantity of waste to be transmuted. Therefore, depending upon the task to be performed, requirement of beam power could vary anywhere from a few tens of MW to a few hundred of MW. To produce such powerful beams, one not only needs a source but a reliable and an efficient one. Generally, the intensities of these source lie in the range of 10 mA to 100 mA with energies varying anywhere from 50 keV to 100 keV. Their normalized emittances are found to be in the range of 0.15 to 0.2 π mm-mrad. Most of the ion source based accelerators built so far, have been used for research in basic sciences. These sources generally deliver low current beam but with high quality. Their currents are generally in the range of tens of nano-amperes to hundred micro- amperes. Although, for industrial applications like ion implantation, ion milling, ion cluster deposition etc. high current ion sources of a few mA have been built but they do not have good beam quality. ADS systems need ion sources with high beam current as well as high beam quality. Many types of high current ion sources have been built over the last two decades and are operational at various labs around the world. To name a few, Penning, Duoplasmatron, multicusp, ECR etc. are some of them. Out of these the microwave based ECR ion source is best suited for ADS accelerator as it was found to be highly efficient, stable, reproducible, and can be operated for long hours. A high current electron cyclotron resonance (ECR) proton ion source at 50 keV, 50 mA has been designed and developed for the low energy high intensity proton accelerator LEHIPA. The ion source has been operated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. The total hydrogen beam current of 42 mA has been extracted at 40 keV of beam energy using three extraction electrodes. The characterization of the ion beam from the source is under progress. A five electrode ion source is under development. The details of design, fabrication and operation of the ion source will be presented. (author)