Abstract: The input polarizer and the output polarizer of a spectrofluorometer are each mechanically identical except for the optical elements, and are constructed as modules which plug into a spectrofluorometer base. Each of the polarizer modules includes a polarizing filter that is rotatable and a self-contained motor drive for rotating the polarizing filter. Each of the motor drives comprises an electric motor mounted on the respective module, a pulley mounted on the respective module and rotatable with actuation of the electric motor, a loop coupling the pulley to the polarizing filter for rotation of the filter with rotation of the pulley, and means for enabling the filter to rotate exactly 90.degree. in opposite directions.

Abstract: A method and means facilitating alignment of a focusing mirror in an optical spectrometer to maximize resolution and performance capability. More particularly, in an optical spectrometer having a monochromator with entrance and exit ports and a grating, an improved method and means for aligning a focusing mirror so that an optical beam can be easily and accurately focused on the entrance or exit ports of the monochromator or on its grating.

Abstract: A high pressure xenon arc illuminator bulb having a sapphire window generates a broad band of ultraviolet, visible and infrared radiation extending from about 180 nanometers to about 2000 nanometers.The emitted radiation in the range from about 180 to about 200 nanometers, in passing through the oxygen in the air, causes the molecules of oxygen in the form O.sub.2 to recombine to produce ozone, O.sub.3. Ozone is toxic.In the invention, a lens barrel, which holds a sapphire condensing lens, is joined to the xenon arc illuminator bulb with a lighttight and also hermetic connection. Thus, the condensing lens is optically rigid with the illuminator bulb and the ozone formed within the lens barrel is not released to the ambient environment, even though its local concentration within the lens barrel becomes high. Furthermore, the ozone confined within the lens barrel acts as an absorption filter for all of the wavelengths in the 180 to 200 nanometer band which are capable of producing ozone.

Abstract: A rotary sample changer for a spectrofluorometer has a revolving turret base which can be indexed and which carries an interchangeable sample carrier. Different sample carriers accommodate test cells, test tubes and cuvettes of different sizes and shapes.The revolving turret base and the interchangeable rotary sample carriers are constructed of material having good thermal conductivity and rotate on a large stationary hollow axle which is thermostated by thermally controlled internal fluid circulation to act as a heat source or sink to the samples. Thus, the sample carriers can readily be interchanged without disturbing the plumbing by which the thermostatic fluid is circulated.The revolving turret base is detented at the stations to which it is indexed without kinematic ambiguity and without application of any cocking force. Two spring biased ball detents, symmetrically spaced 180.degree. about the axis of rotation, are provided.