Abstract: A method for positioning a movable object in a sample chamber of a particle beam microscope is carried out with the aid of a flexible particle beam barrier. The particle beam microscope comprises at least one particle beam column for producing a beam of charged particles, and a sample chamber, a detector for detecting interaction signals and a control and evaluation unit. In the method, initially an object is provided in the sample chamber. Next, a barrier region is defined, which is subsequently scanned with the beam of charged particles. The interaction signals produced during the scan are detected. The object is moved towards the barrier region, wherein the detected interaction signals are monitored and signal changes are registered, with the result that it is possible to detect when the object moves into the barrier region or leaves the barrier region.