LUX-ZEPLIN takes Dark Matter Detection to a new Level

UAlbany post-doctoral fellow Alvine Kamaha (center, green sweater) is joined by other members of the LUX-ZEPLIN research project as the final dark matter detector is installed at the Sanford Underground Research Facility in South Dakota. (Photo used by permission from SURF)

ALBANY, N.Y. (Nov. 21, 2019) -- As a team of specialists at the Sanford Underground Research Facility in South Dakota (SURF) recently moved the LUX-ZEPLIN’s (LZ) main component into place, it marked the final step required to bring the largest direct-detection dark matter experiment ever conceived online.

The LZ Project is a global collaboration, consisting of 250 scientists and engineers from 37 institutions in the U.S., U.K., Portugal, Russia, and Korea. UAlbany’s research efforts are led by assistant professors of Physics Cecilia Levy and Matthew Szydagis.

With this new step, Levy and Szydagis are keen to put the new LZ detector into action, as it’s 100 times more sensitive than its predecessor, the LUX project.

Post-doctoral fellow Alvine Kamaha, installing the teflon reflector on the photosensor array of the LUX-ZEPLIN's new dark matter detector. (Photo by SURF used by permission)

The effort to bring the new device online was no small task. After over a year of assembly work, it saw, in late October, the highly sensitive main component — known as the time projection chamber — carefully lowered 4,850 feet down a shaft formerly used in gold-mining operations.

The time projection chamber will eventually be filled with about 10 tons of liquid xenon – a rare element that is found in only trace amounts in the atmosphere — which will be chilled to minus 148 degrees Fahrenheit. Levy, Szydagis and other scientists are hopeful that the new device can be calibrated to detect dark matter particles as they interact with the heavy xenon atoms in the chamber.

“This is such an exciting time for us. We have been working tirelessly to get the detector perfectly assembled, meeting all the necessary requirements to ensure success. This has been a daunting task, but we are finally to the point of turning on, take data, and hopefully find dark matter.” said Levy, who each year sends students to South Dakota to gain hands-on experience working on the LUX-ZEPLIN.

During the past two years, Levy's post doctoral fellow, Alvine Kamaha, was on hand to help complete the installation of the latest equipment.

"Alvine was an essential part of the assembly of LZ. She was there from beginning to end: one of the first people on-site when we started the assembly over 1.5 years ago, consistently present throughout the assembly, and finally, on-site for the deployment underground," said Levy. "Very few people can actually say that they worked on every single part of the detector assembly, and Alvine is one of them."

LZ is designed to hunt for theorized weakly interacting massive particles, or WIMPs for short. While dark matter is believed to account for about 24 percent of the universe, as of now it has only been indirectly observed through its gravitational effects on normal matter and light.

LZ hopes to change all that, considering it’s 100 times more sensitive than LUX, its predecessor, which operated in the same underground space. Devices such as time projection chambers are required to be placed deep underground as the depth serves to shield the detector from much of the steady bombardment of particles that are present at the Earth’s surface.

“There is a limitation to the current dark matter technology, in that it cannot go past the neutrino floor, an irreducible neutrino background that limits the detector’s sensitivity,” said Levy.

To get around this, the dark matter group led by Levy and Szydagis is trying to develop new, smarter dark matter detectors which could differentiate between dark matter and neutrinos based on their incoming direction.

“Students in my group are and will continue to be involved at all stages of LZ, simulations, building, commissioning, maintenance and data analysis, giving them a unique opportunity to see the many development stages of a successful and large-scale experiment,” said Levy.

Her students are expected to travel regularly to the SURF laboratory to get hands-on experience on LZ. They are also expected to work in her lab at UAlbany on detector research and development.

UAlbany Post-Doc Helps Oversee the Final Move

Just as she was involved in all phases of the assembly, Kamaha was on hand in South Dakota as the time projection chamber was lowered into place.

At UAlbany, she keeps a close eye on LZ’s cleanliness by modelling dust and radon deposition on the over 47,000 parts of the detector, to ensure that LZ can reach its target sensitivity once turned on. She also develops and maintains an information repository system, to help track all the components of the detector and their cleanliness levels.

In addition, she performs various data analyses for the collaboration, and helps mentor Levy’s students. In South Dakota, her job is to assist with installation and ensures compliance with cleanliness protocols and procedures — without which the experiment would be unable to attain its goal of becoming the world’s most sensitive dark matter experiment. She has now been given even more responsibilities within LZ by becoming the calibration coordinator of the experiment, a position partly funded by the Department of Energy.

“I love traveling to South Dakota for first hand opportunity to work on the detector assembly/installation but also for the beautiful scenery and the wildlife over there,” said Kamaha, who is originally from Cameroon and earned her PhD from Queens University in Kingston, Ontario.

Kamaha enjoys the similarities her current University shares Queens, as well as the commonalities between the cities of Albany and Kingston.

“I enjoy the campus feel, the beautiful water fountains and the many opportunities available for staff at UAlbany,” she said, which made her move to the Capital Region feel just like home.

Other team members working with Levy or Szydagis include graduate students Nishat Parveen, Greg Rischbieter, and Greg Blockinger. Together, they form UAlbany's dark matter group.

The goal for the LZ project is to be up and running in 2020.

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