An INP‑16/350 xenon flash tube based on reinforced electrode assemblies was developed. As compared to the similar serially produced lamp INP‑16/580, the new lamp has the same dimensions but reduced discharge gap and reduced filling gas pressure. A stable quasi-arc operating mode of the lamp was reached with duration of radiation pulses of up to ten seconds when forcing power supply. The amplitude on time dependences of the lamp’s radiant exitance are formed by means of computer control of the temporal shape of the thyristor rectifier current pulses. For studying of the thermal overloads of the lamps, the methodology and IR-range optical pyrometry means were designed both, for the quartz bulb and for the electrode. The dependence of the latter’s temperature on energy deposition was studied using two custom-made radiometers. The load and radiation characteristics of the new lamp and the said analogue were compared. The new lamp is capable to operate rather reliably with high-power supply and energy deposition overload of up to 100 times in the single second-long flash mode with natural air cooling.