RMS Noise from the Olis RSM 1000 Spectrophotometer

The worse-case scenario RMS noise levels are plotted here using four different optical band-passes with the most common pair of gratings¹.

All readings were made in a dual beam mode with an empty chamber (air vs air).

RMS noise was calculated as a straight line fit to 1000 points in 500 microseconds. No signal averaging, digital or analog filtering of the PMT signal or raw data were done.

Lamp used was a 75 watt Xenon arc. To obtain useful data below 210 nm, we change to a UV-optimized ozone producing 150 watt lamp, which provides useful light to 170 nm and below².

Detectors used were standard UV-Vis photomultiplier tubes. NIR photodetectors are also available, with a useful range of approximately 400-1700 nm³.