Never before has it been possible to reach a specific mass below the previously known zero point from thermodynamics of -237.15 degrees Celsius. An international team of scientists has managed to cool down a 400 kilogram block of copper close to this limit.
The CUORE cryostat is the only one of its kind, not only in terms of its dimensions and size, the cooling capacity to extreme temperatures, but also for the materials chosen and the construction technology, such as the use of ancient Roman lead to absorb radioactivity. CUORE was designed to conduct research at temperatures close to 10 millikelvins – that is, ten-thousandths of a degree above absolute zero. Tellurium dioxide crystals are used as a balometer for this performance. These can measure tiny temperature fluctuations, for this experiment the scaling was realized by 1000 tellurium dioxide crystals.
For this new record, a total weight of almost two tons had to be cooled down. The scientists managed to keep the massive blog consistently cold for a period of 15 days. At this temperature, the atoms of the test material stand still. Conversely, the activity of the atoms behaves when exposed to heat. In previous experiments, the atoms were brought to a standstill by stopping the laser for a short time; this was not possible due to the mass of the copper.