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The BHUC is a unique, multidisciplinary research facility located at the Ross Campus of the 4850’ level of SURF with ~4300 meter water equivalent shielding from cosmic rays.

4850’, 7400’ levels of SURF	BHUC Campus Cavern

The facility is comprised of two separate cleanroom spaces and an outside staging area for research and development activities. The 200 sq. ft. class 10,000 cleanroom houses lab benches and the 600 sq.ft. class 1,000 cleanroom space is partially occupied with low background counters.

The BHUC has available standard power outlets within the cleanroom and the work area, access to a ‘star’ ground within the cleanroom, standard internet connections (ethernet and wifi), N2 gas distribution and an automated liquid nitrogen (LN2) system. Below is a proposed configuration of the counting cleanroom. Currently, only about half of this cleanroom is utilized.

BHUC Counting Clean Room

Four 180 L dewars outside the cleanroom supply each counting station with liquid nitrogen via vacuum-jacketed piping that runs along three walls of the cleanroom and out into the work area. These liquid nitrogen dewars also supply gaseous nitrogen via their boil-off which is in turn is also supplied to each counting station as radon purge gas by stainless steel tubing running along the walls.

There are currently three single-crystal low background counting stations in the BHUC: Morgan, Maeve, and Mordred. BHSU manages these detectors on behalf of LBNL. Each of these current counting stations are HPGe detectors surrounded by lead and copper shielding and purged with low activity N2 gas.

BHUC Crystal Counting Stations

Pictured above are the current single-crystal counting stations in the BHUC counting room. From left to right are Mordred, SOLO (now above-ground), Maeve, Morgan HPGe detectors inside their shielding castles. The rack of electronics to the right provides the DAQ and networking for all four detectors. Along the walls of the clean room can be seen the LN2 and N2 lines.

In addition to the three traditional, single, HPGe crystal detectors, the Twins is a dual detector low background counting station in development. Access to a dual-crystal system in development by LLNL is also possible.

Twins Detector installed at the BHUC	Top view of schematic showing two crystals in one shield

Here are the current HPG's underground at BHUC.

Resources

BHUC Tour

BHUC SURF Webpage

Deep Thoughts Video

Academic Minute

BHUC Publications

Background determination for the LUX-ZEPLIN dark matter experiment, [LZ Collaboration], Phys. Rev. D 108, 012010 (2023).

Counting Facilities at the Black Hills Underground Campus, D. Tiedt, B. Mount, A. Rodriguez, AIP Conf. Proc. 2908, 020003 (2023).

Supporting Capabilties for Underground Facilities, A. Kamaha, B.J. Mount, R.W. Schnee, Snowmass UF4 Topical Group Report

The LUX-ZEPLIN (LZ) Radioactivity and Cleanliness Control Programs, [LZ Collaboration], Phys. J. C, 80, 1044 (2020).

Black Hills State University Underground Campus, J. Mount et al., Appl Radiat Isot., 126, 130 (2017).

Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches, [LZ Collaboration], Astropart. Phys. 96, 1 (2017).

Student Opportunities

The BHSU Underground Campus will be a unique research environment for students, both at the undergraduate and graduate levels. Through BHSU faculty members across many disciplines with active research projects in the underground campus, students will be given access to valuable underground experiences that would not be possible without the BHSU Underground Campus.