Small-signal gain and iodine dissociation in a supersonic chemical oxygen-iodine laser with transonic injection of iodine

Measurements of the gain and temperature in the resonator of a supersonic c hemical oxygen-iodine laser (COIL) with transonic injection of I-2, using d iode laser-based diagnostics, are reported. For conditions corresponding to the maximum chemical efficiency of this type of COIL (11.7 mmole/s of chlo rine, no primary buffer gas, and 1.36 mmole/s of the secondary N-2), the ga in is a nonmonotonous function of the iodine flow rate. Maximum gain of 0.3 4%/cm is achieved for an iodine flow rate of 0.27 mmole/s. An analytical me thod is developed which enables the use of these dependencies for calculati on of the iodine dissociation fraction F and the number N of O-2((1)Delta) molecules lost in the region of iodine dissociation per I-2 molecule. It is found that F is a nonmonotonous function of the iodine flow rate, its maxi mum value being small (0.55). (C) 1999 American Institute of Physics. [S000 3-6951(99)01821-5].