A stereoselective process for the industrial synthesis of compounds of formula : . The apparatus additionally reduces the temperature increase and stabilizes the temperature of the sample upon irradiation with an optical source of excitation. The closed volume can be inflated via an inflation tube, and a reference pattern can be disposed within the closed volume along with a measurement assembly. The power input shaft extends from a first end portion of the body and a power cord extends from within the body adjacent a second end portion of the body.