A new hollow cathode tube argon-iron design was developed to be used in laser atomic spectroscopy experiments, were high sensibility is required. This tube was employed in order to allow laser absorption and opto galvanic signal measurements. The tube also included fused-quartz Brewster angle windows aligned with the optical axis in each ending of the tube. Therefore, in this configuration a minimum laser intensity losses through the windows can be attained for the appropriate light polarization. The opto galvanic signal detection was accomplished using a tunable dye laser resonant with tlhe Ar, 3p54p(3S1) ? 3p54d(3Do1) transition, that corresponds to 591.2 nm in air. It was also possible to determine the gas temperature by measuring the Doppler fine broadening and the results were compared to those obtained from a theoretical model for gas heat condution. To measure the temperature of the cathodic external surface a thermocouple was used inside the tube. The analysis of results showed that a high signal to noise ratio can be obtained with this tube configuration, that permits experimental invetigation of eletronic transitions presenting low light absortion cross sections.
