An automated high precision calorimeter for the temperature range 200K-400K - Part 1: Design and performance

A fully automated calorimeter has been designed and tested over the temperature range 200K-400K. The system may be used for measurements with an absolute accuracy of 0·2% of samples of approximate mass 50g and thermal capacity 15 JK<SUP>-1</SUP>. The temperature of the sample is determined by a quartz crystal thermometer of resolution 100 μK which is not in direct thermal contact with the sample. The performance of the system is illustrated by results obtained on high purity copper, distilled water and K<SUB>2</SUB>PbCu(NO<SUB>2</SUB>)<SUB>6</SUB> which exhibits very sharp first order phase transitions at about 273·4K and 281·8K