A ConFlat iris diaphragm device for direct beam control and alignment inside a vacuum chamber

We describe an easy-to-assemble and robust design of a ConFlat (CF) iris diaphragm device installed in a vacuum environment with its aperture size directly adjustable by users outside the vacuum. This design involves commercially available vacuum equipment, 3D-printed but vacuum-compatible components and a minimal need of professional machining to be straightforwardly taken advantage by a wide range of research groups. The iris diaphragm is centered in a 4.5 in. o.d. double-sided CF flange with user-customizable mounting orientation to allow a maximum range of aperture opening from 0.5 mm to 15 mm in diameter. Installation of this device does not require an additional pump for differential pumping across the iris diaphragm. The functionality of this device is examined at a pressure of ∼7 ×10−9 Torr to provide continuous control on the cross section of a light beam passed through the aperture.