Beamcon III, a linearity measurement instrument for optical detectors

Abstract

The design and operation of Beamcon III, the latest linearity measurement instrument using the beam addition method in the detector metrology program at the National Institute of Standards and Technology, is described. The primary improvements in this instrument are the reduction of stray radiation to extremely low levels by using three well-baffled chambers, a larger dynamic range, and an additional source entrance port. A polynomial response function is determined from the data obtained by this instrument using a least-squares method. The linearity of a silicon photodiode-amplifier detector system was determined to be within 0.054 % (2sigma estimate) over nine decades of signal.