CRITERIA OF CHOICE FOR A DIFFERENTIAL SCA NNING CALORIMETER FOR THE STUDY OF CHEMICAL-KINETICS AND THE SOURCE-TERM IN THE HEAT-EQUATION

The most important limitations of DSC use in kinetics or in experiment al study of heat sources comes from errors in heat flux measurements i n isothermal conditions. The 3 precision indicators which are proposed in this work are: the time constant K of entrance into the isotherm, the heat flux noise B and the heat flux drift D. They characterize res pectively the dynamics of heating, the short wave oscillations and the long waves ones. Common values for standard devices are: K = 1.5-15 s , B = 0.5-5 muW, D = 7-70 nW/s. A noise reduction is possible by regul ation, but it leads to an increase of time constant.