For a given area, the values of Ke and Ic will be constant along with Reo. Since we measure Rt, the only unknown are Kj and Ij. The value of Kj can be determined once the ambient gamma spectrum is known. Data from the manufacturer indicates an error of as much as 6 to 10% could result if energy corrections are not made to the gross readings. The RSS-1ll1ls used in this study were calibrated at the factory using radium sources whose calibration is traceable to the National Bureau of Standards. Cali- bration of the instruments were also checked by EML (formerly HASL) prior to field use. Energy Dependence Corrections In the 1977 surveys, BNL used a sodium iodide detector, whose output was coupled to a multichannel analyzer. The purpose was to enable the BNL team to acquire spectra of the terrestrial background radiation at one meter above the surface, This was done at the same height and in the same areas where the RSS-111 measurements were taken. Consequently, energy dependence factors could be cal- culated by examining the environmental gamma scan for the energies of those nuclides most predominant in the terrestrial environment. The equipment used to accomplish this part of the work was a computing Gamma Spectrometer, Model LEA 74-008 #11 built by Lawrence Livermore Laboratory (2). The system uses a Harshaw 5.08 cm diameter x 5.08 cm thick Nal(T1) detector. scintillation The spectrometer can be operated from AC power or on internal batteries. Spectra are visually displayed on a CRT, and transferred to magnetic tape for storage. Using the math package with the system, each spectrum was examined in 100 KeV increments, and folded into the RSS-111 energy response curve to determine the energy dependence factors. The range of factors needed to compensate the RSS-111 response due to energy