UK researchers have begun designing a new device to detect the elusive dark matter particles thought to make up more than 85% of the content of the Universe.
A preliminary award of £8 million from the UKRI Infrastructure Fund will support a consortium of UK universities, led by Imperial College London, to work with the Science and Technology Facilities Council (STFC) Boulby Underground Laboratory over the next three-and-a-half years.
As part of the world-leading Xenon Lux-Zeplin Darwin (XLZD) Consortium for dark matter research, the team will develop initial plans and design components for the world’s largest and most advanced dark matter detector. Once completed, this international experiment could be hosted at the UK’s deep underground science facility at Boulby mine in the North East of England.
One of the primary aims of the international XLZD Consortium is to build a definitive experiment to detect dark matter and explore its properties and origin.
The detector will consist of a large underground “thermos flask” containing up to 100T of liquid xenon, which scientists believe will react subtly with dark matter as it passes through the Earth. Tiny, but detectable, flashes of light will be generated as evidence of the presence of dark matter particles and recorded for scientists to analyse.
The experiment has the potential to change our understanding of physics in the same way that CERN’s Large Hadron Collider did when it detected the Higgs Boson particle in 2012. The XLZD observatory will explore the fundamental laws of physics but also acts as a telescope for the nature and composition of our universe, searching for dark matter particles and new neutrino physics.
Professor Sean Paling, Director and Senior Scientist at STFC’s Boulby Underground Laboratory said:
“To discover, or even be able to rule out the existence of dark matter, will be an enormous leap for science and transform our understanding of the cosmos.
“We are now closer than ever to achieving this and as long as we can come together as an international community, invest in the right instruments, and remain focussed on our search, there are potential big breakthroughs just around the corner.
“The XLZD experiment is the clear next step for dark matter research and will also be an important instrument for understanding wider fundamental questions about the content of our universe. I’m delighted that Boulby, Imperial, and all contributing UK institutions are playing this key role in making it a reality.”
The preliminary funding from the UKRI Infrastructure Fund will be instrumental in devising initial plans for how best to host and run the experiment in the near future and developing essential components required for constructing the detector.
UK project leader Professor Henrique Araújo, from Imperial College London, welcomed the news:
“Several underground laboratories around the world are bidding to host our experiment; this is fantastic “discovery science”, using the leading technology which we helped pioneer in the UK – and this development project is critical to position the UK to host. We must now show that this is viable!”
The Particle Physics Department and Technology Department constitute a fundamental role within this preliminary design phase. The manufacturing of the detectors accompanying infrastructure within Boulby Underground laboratory has many challenges associated. STFC’s Technology Department will help understand and prepare for these engineering challenges. A variety of subsystems will be sourced from many different collaborators, the integration of these subsystems that form XLZD’s infrastructure will be coordinated by Technology Department. This contribution will ensure safe and efficient subterranean construction for this project.
Joe O’Dell, Technology Department’s Senior Engineering Manager and Lead XLZD engineer, elaborates on this stating:
'Achieving this goal requires us to overcome the many and varied engineering challenges of building and integrating a multitude of large and sophisticated systems deep underground, with extreme requirements that restrict the choice of materials and processes that can be used'.
More information regarding their contributions read Technology Department 's press release.
The particle physics department has been bestowed with many, varied responsibilities. The massive scale of this project necessitates effective communication and properly established planning amongst the national and international collaborators. PPD will help to coordinate this preconstruction phase; Dr Christopher Townsley, Head of the Particle Physics Department Project Office Division, stated "The Particle Physics Department Project Office is providing national and international co-ordination and expert project management, including state-of-the-art scheduling and management data analytics, risk management and project control." Work will begin to create an intricate plan ensuring the construction phase adheres to a strict budget with realistic costs.
PPD will also apply their extensive experience with the LUX-ZEPLIN project to this next generation detector, being eager to improve upon their world leading sensitivity for WIMP candidates. Prior to the LUX-ZEPLIN project, PPD conducted an extensive material searching campaign, selecting commercially available ultra radiopure titanium to be used in the manufacture of the cryostat and other components. This experience will be used to conduct the material search program for the XLZD cryostat and components. A unique and improved radon emanation facility will help fulfil the stringent requirements.
Dr Maurits van der Grinten, a senior researcher in PPD stated ‘This facility offers high sensitivity, unique in its ability to do so at cryogenic temperatures thus is more akin to the conditions within the detector. This will provide measurements of greater accuracy, aiding us in our material search. Having only recently become operational, the assessment of the materials that could be used for the designs is already underway.’
This depicts the detector for the Cold Radon Emanation Facility (CREF). This photograph was taken from within its dedicated clean room facility.
The detector is connected to the emanation chamber depicted here on the right. They can operate at a wide range of temperatures, able to go as low as 80K. The 500-litre chamber can fit 200 litres in volume permitting the testing of large material samples.
A succinct recollection of past projects and an excellent summary of this news was provided by Prof Pawel Majewski, the Dark Matter & Rare Event Studies Group Leader at STFC/RAL, who stated
‘History has come full circle. After almost 25 years, when the ZEPLIN programme, a pioneering initiative in the UK's dark matter research, was launched at the Boulby Underground Laboratory, the UK's dark matter hunters are back, embarking on a new quest with the worldwide XENON-LUX-ZEPLIN-DARWIN (XLZD) experiment and exploration for its possible location at Boulby. This ultimate observatory using liquid xenon is poised to answer fundamental questions about our universe and open up new horizons in our understanding of dark matter and beyond.
ZEPLIN-I was deployed in 2000 and led by the Rutherford Appleton Laboratory. It was one of the first detectors in the world to use liquid xenon for dark matter searches. The follow-on ZEPLIN-II was the first world's dark matter experiment using xenon double-phase technology, while ZEPLIN-III, the most sensitive of them all, led by Imperial College, concluded the programme at Boulby.
Today, researchers from the Particle Physics Department and their colleagues from the Technology Department, who are providing a preliminary design of major parts of the experiment and making the case for XLZD to be hosted at Boulby, are proud to be part of this new endeavour. Being part of this future cutting-edge experiment is a testament to our commitment to scientific advancement and dark matter searches.’
Although it remains to be decided exactly where the experiment will be located, this foundational work by UK universities and Boulby Underground Laboratory will be crucial in deciding how best to build the experiment for success. If the project is hosted at Boulby, this will be amongst the largest and most significant UK-based science projects in over 50 years, attracting international scientists to the North East region'.
The project team comprises colleagues from the institutions University College London, Birmingham University, Bristol University, Edinburgh University, Imperial College London, King’s College London, Liverpool University, Oxford University, Queen Mary University, Royal Holloway University, Sheffield University, Sussex University and teams from STFC’s Daresbury and Rutherford Appleton Laboratories.
This internationally collaborative effort highlights the UK's strong commitment to advancing scientific research and its capability to contribute significantly to common worldwide scientific endeavours.
