White cell

{
  "id": "MLC-T-MET-010847",
  "term": "White cell",
  "field": "Meteorology and atmospheric science",
  "definition": "An optical device used in atmospheric spectroscopy for measuring the concentration of trace gases by passing a light beam through a long path contained within a small volume. It consists of a set of three spherical, concave mirrors that reflect the beam back and forth multiple times before it reaches a detector. This long effective path length, which can extend to kilometers, greatly increases the instrument's sensitivity for detecting gases with weak absorption features in the atmosphere.",
  "url": "https://mlchart.com/terminology/meteorology/white-cell/"
}