The CaliBall™ is used to calibrate interferometer transmission spheres by using the Random Ball Test (RBT). The Random Ball Test was used with some success in the past but the materials that the balls were made from limited the measurement accuracy. The CaliBall™ has overcome the accuracy dilemma since it is made from silicon nitride. The 25mm balls are grade 5 (round to better than 125nm), have a surface finish of ~1.3nm rms, are opaque and 11% reflective. Virtually indestructible, Caliball™ is a practical solution that can be used repeatedly in a calibration environment for years without degradation.
The CaliBall™ is supplied with a three ball kinematic mount potted in a substantial steel base that is cut away on one side so f/0.7 transmission spheres can be calibrated. The CaliBall™ with 4" Bayonet Mount is well-suited for horizontal interferometer setups and does not require an additional x-y-z mounting configuration. Each CaliBall™ is shipped with a Certificate showing roundness and finish, complete instructions for use and a clean room compatible storage case.