Emulsion chamber response and PCR mass composition according to the PAMIR data

The response of the X-ray emulsion chamber (XREC) is analyzed. The code GEANT 3.21 has been adopted for simulating the measurement procedure in the PAMIR XREC experiment. The contribution of below threshold gamma-quanta, the mutual influence of neighboring electromagnetic cascades in gamma-families, identification against a background by Raleigh's criterion are taken into account. Our earlier publications overestimated the family energy by about (10÷20)% and the real family angular distribution is less steeper than the measured one. Consequently, the gamma-family intensity should be reduced by 1.10÷1.15 times. It means, that the Pamir experiment estimate of the PCR proton fraction in the energy region slowly decreases from 25% to 20%.