Spectroscope for obtaining a mass spectrum by deflecting ions into a thin slit and measuring the ion current with an electrometer WordNet 3.0 & Open English WordNet

A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Wikipedia

Instrument used to measure the spectral components of light as a function of its part in the electromagnetic spectrum Wikidata

A device used in mass spectrometry to discover the mass spectrum of a given substance. Wiktionary

An optical instrument for measuring the absorption of light by chemical substances; typically it will plot a graph of absorption versus wavelength or frequency, and the patterns produced are used to identify the substances present, and their internal structure. Wiktionary

Instrument for measuring the absorption of light by chemical substances. Wiktionary (translation)