[en] A silicon detector developed for gamma ray spectrometry (intended for measurement in the mixed neutron gamma fields, e.g. in reactor physics) was tested for the photon energy interval up to 10 MeV. The responses of this spectrometric system were simulated using a Monte Carlo method (MCNPX code), and the response matrix was calculated. Unfolding techniques for reconstructing incident photon spectra were tested, and a method based on the Scofield-Gold iterative solution of the corresponding matrix equation was applied. The applicability of such an approach to spectrometry data processing and spectral analysis is demonstrated, an example of the results is presented, and possible future improvements and optimizations are discussed.