ECR plasma source for heavy ion beam charge neutralization

Highly ionized plasmas are being considered as a medium for charge neutralizing heavy ion beams in order to focus beyond the space-charge limit. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length {approx} 0.1-2 m would be suitable for achieving a high level of charge neutralization. An ECR source has been built at the Princeton Plasma Physics Laboratory (PPPL) to support a joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization with plasma. The ECR source operates at 13.6 MHz and with solenoid magnetic fields of 1-10 gauss. The goal is to operate the source at pressures {approx} 10{sup -6} Torr at full ionization. The initial operation of the source has been at pressures of 10{sup -4}-10{sup -1} Torr. Electron densities in the range of 10{sup 8}-10{sup 11} cm{sup -3} have been achieved. Low-pressure operation is important to reduce ion beam ionization. A cusp magnetic field has been installed to improve radial confinement and reduce the field strength on the beam axis. In addition, axial confinement is believed to be important to achieve lower-pressure operation. To further improve breakdown at low pressure, a weak electron source will be placed near the end of the ECR source

Preventing Abuse by Controlling Shareholders

Abstract: This paper is a comment on Ronald Gilson and Alan Schwarz “Constraints on Private Benefits of Control: Ex Ante Control Mechanisms versus Ex Post Transaction Review”. Together with that paper it will appear in the Journal of Institutional and Theoretical Economics 169 (1) in 2013, in a special issue devoted to Behavioral Theory of Institutions. I argue that the arguments of Gilson and Schwarz are convincing, but that the underlying assumptions may be stronger than the authors suggest. In particular, the G&S paper adopts a US shareholder perspective on corporate governance and is based on standard rationality assumptions. In this comment, I discuss whether and to what extent the recommendations are relevant in the EU context and whether the paper’s conclusions are robust when insights from behavioral economics are included.