Device for optical calibration of rotary analytical instrument

A calibration disk for a rotary analytical device comprising:

• a body with a main portion with a top surface, a bottom surface and a central rotational axis, and a cylindrical extrusion extending upward from the top surface of the body and having an axis coincident with the central axis, the main portion substantially surrounds the cylindrical extrusion and includes a flat planar portion that extends radially outward from the cylindrical extrusion, the planar portion lying along a plane that is orthogonal to the central rotational axis, the cylindrical extrusion having a top surface and a sidewall surrounding an open interior cavity, a central opening is formed in the top surface of the cylindrical extrusion providing access to the interior cavity, the central opening configured to engage with a spindle of the rotary analytical device and orient the body at a rotational position relative to the spindle;
• a plurality of attenuation zones formed in the body and spaced around the cylindrical extrusion, at least some of the attenuation zones including at least one aperture extending through the body from the top surface to the bottom surface, the apertures being located at a common radial position about the central axis, the apertures having a radial width and an circumferential length extending in the circumferential direction about the central axis, and wherein at least two of the apertures have a different radial width or axial length on the bottom surface from one another, at least one of the attenuation zones is a reference zone that includes a continuously flat top surface and does not include an aperture, and wherein the apertures are all positioned at a radial distance from the center of rotation that corresponds to the radial location of the centers of the LEDS and photoelectric transducers of the analytical device from the spindle.