Optical null double beam spectrometer

{
  "id": "MLC-T-CHM-008272",
  "term": "Optical null double beam spectrometer",
  "field": "Chemistry",
  "definition": "An instrument that measures the ratio of two radiant powers by adjusting a calibrated attenuator in the reference beam to achieve equal radiant power in both the sample and reference beams. This adjustment is made until a null condition is detected, indicating balanced optical signals. The attenuator's position directly correlates to the transmittance or absorbance of the sample.",
  "synonyms": [
    "NTI double beam spectrometer",
    "null-balance double beam spectrometer"
  ],
  "subject": "Analytical Chemistry",
  "see_also": [
    "wavenumber in vacuum"
  ],
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 758 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/optical-null-double-beam-spectrometer/"
}