Cryogenics in the FMT

At low temperatures, thermal excitations are suppressed, and matter tends to occupy the lowest energy state. The response of such cold material to external stimuli reveals its spectrum of elementary excitations, which determines the processes operating within it. An example is superconductivity – the conduction of current without any heat dissipation. Superconductors can be explored to subject matter to extraordinarily large magnetic fields, leading to the discovery of surprising phenomena, such as the Quantum Hall Effect.

 

To achieve low temperatures, a refrigerant is necessary. Helium is an ideal refrigerant because it is chemically inert, has a low boiling point, and is the only element that remains liquid as the temperature approaches absolute zero at atmospheric pressure. However, helium is expensive. Despite being one of the most abundant elements in the Universe, second only to hydrogen, Earth's helium reserves are dwindling over time. Due to its low density, helium gas rises in the atmosphere and escapes into cosmic space. Meanwhile, the global demand for liquid helium is continuously increasing, driving its price even higher.

 

Aware of the extraordinary potential of low-temperature research, in 1961, Mário Schenberg established the first helium liquefaction plant in Brazil, known as the Cryogenics Workshop, housed in the Department of Materials Physics and Mechanics (DFMT). This heritage needs to be preserved and modernized.

 

The Cryogenics Workshop liquefies helium for research laboratories at the DFMT, other Departments of the Institute of Physics, and other institutions. Helium gas generated in the laboratories is returned to Cryogenics, where it is liquefied again. In this cycle, a fraction of helium is lost. To make helium use viable, it is imperative to minimize the lost fraction. Cryogenics is responsible for implementing procedures to reduce recycling losses.

 

To optimize sector-related processes, the cryogenics team has been implementing changes. A significant innovation, both conceptually and operationally, is the registration of the cryogenics in USP-multi, USP's multi-user facility platform. The sector's internal regulations, as well as the management team and the user committee, were approved by the IFUSP Congregation at its November 2024 meeting. The CTA of IFUSP also approved an agreement with the company White Martins, which should bring sustainability to the sector. In the medium term, adjustments in the sector are expected to boost cryogenic research at USP and reduce the loss of inputs in the recycling process.