Knowledge Bank

A versatile infrared recording spectrometer constructed in accordance with the building-block philosophy is described. It consists of a Model 13 source unit, a Model 83 monochromator, a standard wavedrive, a slit servo, a Model 13 amplifier, a modified Leeds and Northrup recorder, and associated controls. The Model 13 source unit may be used either as a double-beam or single-beam instrument. Double-beam operation is based on the Halford-Savitzky system in which the beam is split into space-separated reference and sample beams modulated by a chopper so that their respective signals are in quadrature. A stabilized Nernst glower is utilized as the source. Provision is made for reversing the direction of the light beams so that samples may be analyzed in monochromatic light. The slit servo may be operated to maintain $I\circ$ constant, to follow a predetermined schedule set by a tapped potentiometer, or to follow a manual setting. Schedules for various materials are readily made by means of a plug-in unit. The amplifier, also constructed in accordance with the building-block philosophy, may be operated so as to record ratio, direct function, or difference. Performance data will be presented.