Topic(题目):Mysteries and Challenges of Negative Ion Sources
Speaker (报告人)：Vadim Dudnikov, Muons, Inc. Batavia, IL 60510, USA
High current, high brightness, high duty cycle negative ion sources are an essential component of many high power particle accelerators. This talk gives an overview of the recent development of negative ion sources.
Volume, surface plasma and charge exchange negative ion production processes are considered shortly. Compact surface plasma sources (CSPS) such as cesiated magnetron, semiplanotron and Penning SPS are discussed along with Large Volume SPS including RF inductively coupled SPS with internal and external antennas. Efficient generation of polarized negative ion is considered. The major challenges facing accelerator facilities are detailed. Beam current, source lifetime and reliability are the most pressing. The features of several SPS are discussed along with their development programs. Improving H- generation efficiency in the RF SPS with a saddle antenna is considered. The uncertainties and unknowns common to these sources are discussed. The dynamics of cesium surface coverage and the causes of source variability are still unknown. Minimizing beam emittance is essential to maximizing the transport of high current beams; space charge effects are very important. The basic physics of negative ion production is still not well understood, theoretical and experimental programs continue to improve this, but there are still many mysteries and magic to be solved.
V. Dudnikov, R. P. Johnson, S. Murray, T. Pennisi, C. Piller, M. Santana, M. Stockli, and R. Welton, “Surface plasma source with saddle antenna radio frequency plasma generator”, Review of Scientific Instruments 83, 02A712 (2012); http://dx.doi.org/10.1063/1.3672111
Vadim Dudnikov. “Forty years of surface plasma source development”, Review of Scientific Instruments 83, 02A708 (2012); http://dx.doi.org/10.1063/1.3670600
V. Dudnikov and R. P. Johnson, “Cesiation in highly efficient surface plasma sources” Phys. Rev. ST Accel. Beams 14, 054801, http://journals.aps.org/prstab/abstract/10.1103/PhysRevSTAB.14.054801