Metal-to-metal-switches for large currents

Existing metal contact switches, originally developed mainly for nuclear fusion research experiments, are reviewed. Their properties are discussed with respect to an application in large capacitor banks for linear mass accelerators. Comparing the different fast metal-to-metal switches developed so far, it can be concluded that nearly all types reviewed can be used as make-switches in capacitor banks for linear mass accelerators. With respect to current carrying capability (up to megaAmpere) and voltage (up to some 10 kV) they all meet the requirements for single shots. Compared to gas-discharge switches, their resistance in closed position is one to two orders of magnitude smaller and their inductance is also small. Their switching times and their jitter are sufficient. On the other hand, all switches use solid dielectrics in the form of thin sheets which are inserted between fixed electrodes and which have to be renewed each shot. The switches developed up to now are not suitable to be integrated in large capacitor banks which are split into numerous modules. Furthermore, they are not qualified for high repetition rates