Reading and co-workers introduced a new technique a few years ago called Modulated Differential Scanning Calorimetry or MDSC.
Here the first part of a theoretical analysis for this technique is given. A simple mathematical model for modulated differential
scanning calorimetry in the form of an ordinary differential equation is derived. The model is analysed to find the effect
of a kinetic event in the form of a chemical reaction. Some possible sources of error are discussed. A more sophisticated
version of the model allowing for spatial variation in a calorimeter is developed and it is seen how it can be reduced to
the earlier model. Some preliminary work on a phase change is also presented.
A spectrometer for direct positronium annihilation measurements (lifetime as well as energy distribution of annihilation photons) has been built, based on an existing energy spectrometer1 presented by our group. A time branch has been added which allowed us to measure the o-Ps lifetime. We found the decay rate to be 7.0458±0.0279 s–1.