The construction of the LUX-ZEPLIN (LZ) new site began earlier this month in a mine in South Dakota and soon it will be ready to host the world’s most sensitive dark matter detector. The experiment hopes to finally confirm the existence of the elusive particles that are believed to make up dark matter.
The experiment is being built inside the Davis Cavern at Sanford Underground Research Facility (SURF) and it is expected to be completed by 2020. This is an upgrade of LUX, the previous dark matter detector at SURF. But LZ will dwarf its predecessor. The new detector is 30 times larger and 100 times more sensitive.
To construct such an impressive experiment below more than 1.5 kilometers (0.9 miles) of rock, the entire facility is being renovated. Walls are being knocked down, rooms are being enlarged, and the team is modifying the water tank at the center of the experiment and building a new work deck above it.
"This project is important to LZ and to getting it done in a timely fashion is required to keep our project scientifically competitive," said Jeff Cherwinka, LZ chief engineer, in a statement. "The help we've received from SURF is instrumental in helping make our project a success and it is going very well so far."
The work is being carried out by architects and engineers with the LEO A DAILY firm and it presents many challenges. For example, there’s currently another experiment in the mine that requires an extremely clean environment, so the renovation plans had to take that into account.
“The level of coordination and flexibility required, in a tight underground space, with parameters constantly evolving, and with extraordinarily stringent safety and cleanliness requirements, made this one of the most challenging and exhilarating projects we’ve ever done,” said Steven Andersen of LEO A DALY.
The LZ detector uses 9 tonnes (10 tons) of liquid xenon, a noble gas that is liquid at -108.1°C (-162.6°F). It is kept in a cryostat equipped with light-magnifying tubes that hope to capture a collision between the xenon nuclei and dark matter particles. The underground location was chosen because it shields the detector from cosmic rays that could lead to false positives.
The experiment is being led by a global team of 220 scientists from 38 institutions. And it is not the only experiment of its kind. Similar approaches are happening in China and Italy.