[en] An experimental method for determination of the heat capacity of a spherical assembly containing an ⁶⁰Co isotope source of gamma-radiation is described. The experimental equipment for determination of the emanation in the assembly by a calorimetric method is developed and produced. In order to decrease the measurement error, a material with weak absorption of β-radiation is used for the equipment. The equipment has been calibrated by means of a spherical heating element with the diameter equal to that of the assembly, the heat from the leads and the heat losses of the element being reduced to minimum. The error of the heat flux measurement has been not greater than 9%