Abstract: The present disclosure provides a charged particle source arrangement for a charged particle beam device. The charged particle source arrangement includes: a first vacuum region and a second vacuum region; a charged particle source in the first vacuum region, wherein the charged particle source is configured to generate a primary charged particle beam; and a membrane configured to provide a gas barrier between the first vacuum region and the second vacuum region, and wherein the membrane is configured to let at least a portion of the primary charged particle beam pass through the membrane, wherein a first vacuum generation device is connectable to the first vacuum region and a second vacuum generation device is connectable to the second vacuum region.