Device for the continuous measurement of the amount of a constituent of a gaseous atmosphere, said constituent released by the gaseous atmosphere and absorbed by metallic work pieces arranged within said gaseous atmosphere during a thermo-chemical treatment of said metallic work pieces in a thermo-chemical reactor, the device comprising:
- a holder for a probe whose longitudinal extension exceeds its width, said holder comprises at least one abutment supporting the probe, said abutment located within the gaseous atmosphere of said thermo-chemical reactor, such that the probe is exposed to the constituent,
- a longitudinal measurement system located outside of said thermo-chemical reactor to measure the longitudinal change of the probe over time in the longitudinal direction during the thermal-chemical treatment of the work pieces;
- and
- a computer unit in communication with the measurement system.