We report measurements on CuGaSe2 solar cells and absorbers prepared by rapid thermal processing of stacked elemental layers deposited by evaporation, in situ conductivity measurements are presented as a method of absorber characterization. I-V-curves, spectral response and EBIC measurements are performed, A selenium deficiency in the absorber is one of the first obstacles that this formation process needs to overcome. A second selenisation step is of some help but better process parameters need to be found. The main limitations of the cells are the small open circuit voltage (<600 mV) and fill factor (<0.55). Spectral Response measurements reveal a poor performance in the long wavelength region.