Estimation of the ion-stimulated desorption coefficient in the vacuum chamber of the U-70 proton synchrotron

Abstract

We propose a method for estimating the coefficient of ion-stimulated desorption in the vacuum chamber of the U-70 proton synchrotron by measuring the pressure difference for the main components of the residual gas in the chamber with and without a beam. The solutions to the equations describing the variation of hydrogen and nitrogen pressures are considered. The order of magnitude of the ion-stimulated desorption coefficient is determined for an accelerated carbon ion beam. The critical values of the coefficient are indicated. The experimental results are confirmed using various computational methods as well as by the graphs plotted in accordance with current measurements for magnetic-discharge (ion) pumps. The possible role of argon in desorption is considered.