A vacuum ultraviolet spectrometer equipped with a charge coupled device and an open multichannel plate has been used to analyze the temperature of carbon and oxygen ions in the NOVA-UNICAMP tokamak. The detection system was optimized and aligned to minimize the instrumental broadening. Also, higher order diffractions of the emissions were analyzed, resulting in lower experimental errors. The ion temperature was monitored during the tokamak discharge, presenting values between 30 and 70 eV. (c) 2007 American Institute of Physics.786