Scientists at Fermilab, a US Department of Energy (DOE) national laboratory, have for the first time recorded tracks of charged particles using a small time-projection chamber filled with liquid argon (LAr).
The liquid argon-consuming time-projection chamber (TPC) is a promising technology for the study of high energy physics, and could perhaps allow for the construction of large, cost-effective detectors for future neutrino experiments.
Ultimately, scientists at Fermilab hope to build large neutrino detectors to reveal the role that neutrinos play in the Universe – similar to the way in which scientists at Switzerland-based CERN are attempting to understand the physics and ‘building blocks of matter’ behind the Universe itself.
The development of the liquid argon technology at Fermilab could provide the means to develop electronics and test materials for a huge liquid argon detector in future – according to Cold Facts, the magazine of the Cryogenic Society of America Inc.
A complex process takes place inside the chambers or cryogenic stations. Electrons knocked loose by charged particles travelling through the liquid argon drift along an electric field, towards three wire planes at the top of the chamber which record the signals received.
One of the major challenges met was to remove any impurities in the liquid argon, such as oxygen, that would absorb the electrons before they reached the wire planes. Liquid argon in the two cryogenic test stations was required to be kept at a temperature of 87 Kelvin, which was achieved through cryostats provided by a company in Georgia.