Study on the maximum stable output of a novel s-band micro-pulse electron gun

Abstract

A novel S-Band Micro-Pulse electron Gun (MPG) which works at the left crossover point energy EcI on the Secondary Electron Yield (SEY) curve was proposed. The working principles of the MPG were presented. The maximum output beam current limited by space charge effects and beam loading effects was investigated by theoretical analysis. The result shows that the maximum beam current is decided by the parameters of the MPG such as resonant frequency, cavity length, shunt impedance and the secondary emission property of the cathode and grid, having nothing to do with the power flowed into the cavity. The low shunt impedance and the low slope of the SEY curve can help increasing the maximum beam current. According to the principles, a MPG with the frequency of 2.856 GHz has been designed and constructed. The steady working state was achieved by using oxygen free copper and molybdenum grid with different transmission coefficient. It was found a good agreement between the analysis and the experiments.

Biocatalytic Heteroaromatic Amide Formation in Water Enabled by a Catalytic Tetrad and Two Access Tunnels

“…Although various methods for amide formation have been described, − amide synthesis has been voted as a top challenge to be addressed to reduce the number/amount of reagents and the waste which results from, e.g., stoichiometric equivalents of activation reagents needed. − Considering selected APIs with amide functionality (Scheme a), a sterically demanding heteroaromatic group is attached to the carbonyl of the amide functionality, including, for example, pyridine, as in lazabemide or malabemide, , pyrazine in bortezomib, benzofurane (befuraline), , or isoxazole (leflunomide) …”