Observation of Bethe-Bloch ionization using the booster ion profile monitor

The booster ion profile monitor (BIPM) was recently (April 1998) used in a test to study the feasibility of collecting the electrons instead of the more traditional ions. These electrons and ions are created by the ionization of the residual gas in the beam pipe by the proton beam. As a consistency check, the proton beam current is compared to the integrated area of the measured profile through the acceleration cycle. It was found necessary to include the effect of the proton beam energy upon ionization by means of the Bethe-Bloch equation in order to have satisfactory agreement.