2. Non-Adiabatic Scanning Calorimeter for Controlled Fast Cooling and Heating

This chapter describes a power-compensated differential fast scanning calorimeter, which allows heat capacity determination of nanogram samples on both controlled heating and cooling in the range from 100 to 10,000,000 K/s. A submikron SiN_x membrane sensor was developed together with Xensor Integration as a basis of the calorimeter. Minimizing addenda heat capacity and aiming particularly on fast cooling, the active measuring area of the sensor was embedded into the central part of the membrane and has dimensions down to 5 × 5 μm². The differential power-compensated temperature control scheme was designed for precise temperature control and heat capacity determination. Software programmable temperature scans allow transitions from controlled heating and cooling up to 5 MK/s to isotherm with over/undershoot less than 1 K and within 2 ms. Though the absolute values of sample temperature and heat capacity determination is still complicated due to the free-standing sample configuration, they can be measured with reproducibility ±1 K and 1 pJ/K sensitivity, respectively.