enable researchers to efficiently share that infrastructure and support.1 The requirements include access to adequate space, power, ventilation, and ready ingress and egress. Safety is of utmost concern, because most of the proposed experiments have measurable safety risks, especially given that they may be conducted a mile or more underground. Because it is expensive to excavate and support underground space, almost all underground experiments would need laboratory space on the surface for assembling and maintaining apparatus as well as developing future work. There is typically also a need to set aside underground laboratory space for low radioactivity studies to reduce background signals. In addition, technical personnel are needed to maintain, operate, and manage the infrastructure. Much of this infrastructure and its associated staff could be shared by co-located experiments. The economies of scale could reduce construction and operating costs, although the extent of savings would need to be quantified by comparing alternate sites. The existence of a central location for underground physics research would also allow carrying out other science experiments.
Integration of infrastructure for co-located experiments would need to be accompanied by at least limited coordination. For example, an integrated safety program would be needed to ensure that all experimenters are safe from risks of their own and other experiments. The location of any given experiment at a site would also need to consider possible interference of other experiments during construction or operations.
While infrastructure could also be shared for some experiments by locating them here or abroad, this section considers the impact of a national facility. The mere co-location of experiments would give to the research communities some, but not all, of the advantages of a more integrated program, as described in the next section. Co-location alone would also not have such a broad impact on education and the public as would a national research facility similar to the proposed DUSEL program.2
1 The term co-location is used to refer to two or more experiments located at a single site. For instance, the three main physics experiments could be co-located in the Homestake mine, or a dark matter experiment could be co-located with existing experiments at an existing laboratory. The proposed DUSEL program co-locates all of the experiments and foresees a more integrated program that includes additional aspects of a national laboratory, including a surface campus, a large user community, mechanisms for developing a future program, and an education/outreach facility.
2 The committee notes that while the DUSEL program was developed with the expectation that the proposed experiments would be placed at the Homestake mine in Lead, South Dakota, the committee’s conclusions on the advantages of co-locating experiments are not limited to that site and should still prevail, regardless of the site chosen. The balance of advantages and disadvantages of a site, including safety issues, will depend on the specifics of the site and experiments proposed to be installed at that site.