Design of a Nozzle-Skimmer System for a Low Perturbation Ionization Beam Profile Monitor

Growing interest in the development of low energy projectiles, in particular heavy ions and antiprotons, calls for new beam instrumentation to be developed to match the strict requirements on ultra-high vacuum and low beam perturbation. When it comes to transverse profile monitoring, a convenient solution for simultaneous determination of both transverse profiles is found in a neutral supersonic gas-jet target shaped into a thin curtain and the two-dimensional imaging of the gas ions created by impacting projectiles. The resolution and vacuum efficiency of this monitor is directly linked to the characteristics of the gas-jet curtain. In this contribution we describe the design of a nozzleskimmer system to be used for the creation of the jet curtain in the first prototype of such monitor, together with the geometry and extraction field shape of the experimental chamber which will house the experiment. Using numerical fluid dynamics simulations, we present the effects resulting directly from changes in the geometry of the nozzle-skimmer system on the characteristics of the jet curtain