Underground Facilities

1. The Boulby Underground Laboratory for Dark Matter Research JIF Facility -1 10 Stub 2 Stub 2a,3 Muon Flux 10-3 Neutron Production ‘H’ Area ZEPLIN-MAX Soudan Kamioka DRIFT 1,10 10-5 Gran Sasso Boulby Neutron Production (g-1s-1) Mont Blanc JIF Area Frejus Muon Flux (cm-2 s-1) ZEPLIN-II 10-7 Sudbury ZEPLIN-III 10-9 10-11 10-13 Depth (mwe) 0 1000 2000 3000 4000 5000 6000 7000 8000 Dark Matter Studies at Boulby Mine The UK Dark Matter Collaboration along with international collaborators are conducting a range of experiments deep in Boulby mine to try to detect and identify the source of the missing mass in the universe. Underground transportation ZEPLIN Three world renowned dark matter experiments are currently underway at Boulby: NAIAD, ZEPLIN and DRIFT. The approach of each experiment is different but the aim is the same: to verify or refute the existence of WIMPS (weakly interacting massive particles) - the strongest and most widely accepted dark matter candidate. NAIAD Boulby mine is a unique and challenging environment in which to carry out sensitive dark matter experiments. Success requires careful planning, design and teamwork. Since dark matter studies began in 1988 there have been great changes in the working environment in Boulby. Now the facility ranks amongst the best dark matter and underground science facilities in the world. DRIFT Boulby Mine Surface Facilities Many of the surface facilities required for dark matter research at Boulby are supplied by Cleveland Potash Ltd. This includes emergency medical support and facilities, chemical laboratory and clean room facilities and surface transportation. Lamps Medical Centre Boulby mine is a working potash mine situated on the North East coast of England, a few miles north of the town of Whitby in the North York Moors. The mine is run by Cleveland Potash Limited (CPL) and at between 850m & 1350m deep it is the deepest mine in Great Britain. Fork-Lift Chemical lab In 2000 Joint Infrastructure Fund (JIF) funding was secured to build a new purpose-built surface facility at Boulby, Now complete, the ‘John Barton building’ provides space for storage and staging of underground experiments, office and laboratory space, computing and mechanical workshop facilities and washing and cooking facilities for staff and visitors. Map of excavations There is a huge underground network of caverns and roadways at Boulby. Since mining began at Boulby in 1968 over 1000 kms of tunnels have been excavated and using remotely controlled ‘heliminers’ around 50 kms of new tunnels are cut each year. Excavations currently stretch approximately 5kms south and 8 kms north - beyond the coast and under the North Sea. The John Barton surface building Staithes - near Boulby Underground Facilities Background Radiation The underground research facilities have evolved since dark matter studies began at Boulby. There are now 3 main research areas, each approximately 1km from the mine shaft, giving a total floor area of >1500m2. All of the laboratories have telephone and internet connection to the outside world and all are fully stocked with the tools and instrumentation required to run and maintain the experiments they house. The ambient temperature in the mine is commonly 30˚C or higher - so air conditioning is used to keep working temperatures to a tolerable working level. A deep underground site is essential for Dark Matter detection experiments as the large amount of overhead material acts as a shield to highly penetrating ‘cosmic ray’ particles which would otherwise dominate and obscure results . At 1100m below ground at Boulby mine the cosmic ray muon flux is a factor of ~106 times smaller than at sea level - which ranks Boulby alongside just a handle of world-class underground research sites around the world. Dark Matter research areas The new JIF area Geology The Boulby facility has the further advantage that the potash and rock-salt layer in which caverns and roadways are excavated has relatively low levels of Uranium & Thorium. These are commonly occurring elements which result in the production of radioactive radon gas and the emission of neutron and gamma background radiation. The reduction or elimination of all sources of background radiation is an important requirement in all dark matter detection experiments. All of the research areas consist of wooden framed structures built within specially excavated caverns in the rock salt. The largest and most recent area is the >1000m2 ‘JIF area’ supported by the Joint Infrastructure Fund. Recently completed and waiting to be filled, the JIF area will house the next generation of dark matter detectors planned by the UK Dark Matter Collaboration. Summary of Backgrounds