[en] Operation and performance of an apparatus for studying the decay dynamics relevant to core–hole decay processes in atoms and molecules excited by energetic electrons using an energy analysed electron–ion coincidence technique are described in some detail. The setup consists of a time- and position sensitive double-field linear TOF mass spectrometer coupled with a dual MCP detector and a single-pass CMA to select the energy of detected electrons. Details of different components involved in the setup are presented and discussed. To demonstrate the performance and capability of the apparatus, presented here are some typical results extracted from the TOF argon ion-mass spectra observed in coincidence with 18-energy selected electrons emitted from interaction of a continuous beam of 3.5 keV electrons with a dilute gaseous target of argon atoms. Specifically, the variation of relative correlation probability for the final ion-charge states Ar¹⁺ to Ar⁴⁺ produced in the considered collision reactions as a function of energy of emitted electrons is determined and discussed