The supersonic nozzles lower temperature to 170-180 K better for the small signal gain coefficient. But at this temperature, the CO<sub>2</sub> buffer gas may become liquid state. A chemical oxygen-iodine laser (COIL) employing CO<sub>2</sub> as buffer gas and no-flake-nozzle was studied. Some mathematical simulation in three-dimensional computation fluid dynamics was adopted first to validate its usability. New nozzles gave the temperature higher than 400 K and considerable small signal gain coefficient. In the same conditions as simulation, experiments gave a 23% of chemical efficiency and 2.5 kW of output power. And it have got rid of “black area”, which was familiar in the supersonic COIL both in simulation and experimental results.
A traditional pressure recovery system is the major obstacle to mobile chemical oxygen-iodine laser (COIL) for its huge volume. A cryosorption vacuum pump was used as the pressure recovery system for different buffer gases. It made COIL become a flexible, quiet and pressure-tight. Experiments were carried out on a verti- COIL, which was designed for N<sub>2</sub> and energized by a square-pipe jet singlet oxygen generator (JSOG). The output power with CO<sub>2</sub> was 27.3% lower than that with N<sub>2</sub>, but the zeolite bed showed an adsorption capacity threefold higher for CO<sub>2</sub> than for N<sub>2</sub> in the continuous operation. The great volume efficiency interested researchers.
A dual-components absorption method based on absorption spectroscopy was described in the paper. It can easily eliminate the influence of the serious contamination and aerosol scattering on IFR measurement by utilizing the absorptions of iodine vapor and chlorine on two different wavelengths respectively. According to the character that there is no other gaseous product in the reaction besides iodine vapor, IFR in real time can be obtained by the connections of the pressure and the flow rate among chlorine remainder, iodine vapor, and the buffer gas. We used this method to measure IFR for the first time at the exit of a chemical iodine generator. The average of IFR is coincident with that calculated by chemical weighting mass.