Upgrade of the beam profile ionization monitor for the KOMBAS fragment separator

The results from upgrade of an ionization beam profile monitor (IBPM) are presented. The IBPM consists of a conventional capacitor that extracts the ionization products of the residual gas and analyzing capacitors. The main objective of this upgrade was to create a device with uniform spatial resolution. For this purpose, an additional difference of potentials, the ramping of which allows the beam cross section to be scanned, is applied between the capacitors of the monitor, while the electric fields in the capacitors themselves remain constant. Two IBPMs have been developed as a result of the facility’s upgrade: an IBPM for on-line monitoring of the vertical and horizontal beam current distributions in the beam line in an area of 8 × 8 cm2 with a uniform 1-mm resolution, and an IBMP for detailed beam profile monitoring with a uniform resolution of 1 × 1 mm2 over the scanning region. It was established experimentally that the proposed scanning technique provides good results in beam profile measurements when the ion component of the ionized residual gas is extracted; for the electron component, the result is much worse.