The TITAN source generates wide-aperture beams of gas and metal ions of different materials. This is achieved because of two types of cold-cathode arc discharges, which operate simultaneously in the discharge system of the source. For metal ions to be obtained, use is made of the vacuum arc initiated between an ion-forming cathode and a hollow anode. To produce gas ions, a constricted low-pressure arc discharge is initiated with the same hollow anode. The constitution of ion beams generated by the TITAN source has been investigated using a homemade time-of-flight spectrometer. This paper describes the design of the latter and the principle of its operation, and discusses the physical peculiarities of the spectrometer operation, which affect the ion beam constitution.