2024-02-22 15:30:00
Chinese researchers want to track down invisible particles 2,400 meters below the earth’s surface.
Deep, deep underground, Chinese researchers are trying to uncover the secrets of Dark matter to come on track. The invisible substance makes 80 percent of the matter in our universe, but has so far only been proven indirectly. With the China Jinping Underground Laboratory II (CJPL-II) that should change.
2,400 meters below the earth’s surface
Construction of the China Jinping Underground Laboratory began in 2010, followed in 2014 by the construction of the CJPL-II expansion, which was completed in December last year. 2,400 meters below the earth’s surface It should be possible to detect dark matter there without the results being distorted by cosmic radiation. 330,000 cubic meters of material were excavated for this purpose.
There is also a similar laboratory in Europe: 1,400 meters below the Italian one Gran-Sasso-Massiv There are also researchers there looking for individual particles of dark matter. There are already signs of dark matter there, but the particles have not yet been directly detected.
➤ Read more: How researchers search for dark matter in space and deep in the mountains
Dark matter hardly interacts with other matter. When a particle hits the Earth, it simply passes through the planet. There, 2,400 meters inside the planet, the dark matter detectors Astrophysical Xenon Experiment (PandaX) and the China Dark Matter Experiment (CDEX) register the particles.
The CJPL laboratory in Mt.
© Creative Commons
PandaX uses the noble gas xenon in liquid form. When the dark matter particles collide with the xenon atoms, they are created Flashes of lightthat sensors can detect. CDEX, on the other hand, uses a germanium detector in which electrical signals are generated when the particles hit it.
Search for the WIMPs
The researchers are looking for so-called WIMPs (weakly interacting massive particles) – hypothetical particles that could make up dark matter. Although these WIMPs do not react with other parts, in rare cases it may happen that a WIMP directly hits an atomic nucleus – such as a xenon nucleus. This can then be registered by sensors.
However, these particle detectors are so sensitive that any kind of radiation – too cosmic background radiation – can trigger them. That’s why they’re located deep underground in thick metal boxes. The CJPL-II laboratory is also intended to clarify the question of whether dark matter really consists of WIMP particles, or rather of other, not yet discovered, subatomic particles.
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