Title: Cylindrical Post-Magnetron sputtering for High Rate Niobium deposition
Author: Cristian Pira
Abstract: The use of Nb/Cu cavity at CERN for the LEP and at the INFN-LNL for Alpi Linac has demonstrated the possibility to use this technology for particles accelerators to substitute the more expensive technology of niobium bulk cavity. The limit of the Nb/Cu cavity is the Q-slope, which decreases the Q factor at high accelerating fields. The accelerators community supposes that it’s possible to eliminate, or to decrease, the problem of Q-slope with high pure films of sputtered niobium. One way to obtain pure films is to decrease the number of impurities enclosed in the growing film.
It’s possible to reduce the number of impurities when the sputtering rate process increases.
We study the possibility to enhance the plasma density in order to increase the sputtering rate and then reduce the impurities in the niobium sputtered film and finally obtain high pure films.
In order to enhance the plasma density we sputter the niobium target with high currents to heat it and get to thermoionic emission. This sputtering method is called high rate sputtering.
First results of Niobium coatings will be presented.