The role of underwater cultural heritage on dark matter searches: Ancient lead, a dual perspective

New generations of dark matter detection experiments require extreme low levels of background radiation in order to verify complex particle physics theories. Ancient lead ingots from shipwrecks provide the necessary shielding material to perform these experiments due to their low intrinsic radioactivity, difficult to achieve by modern materials or commercial means. This situation generates a debate between two different perspectives: The preservation of cultural heritage or its use in scientific fundamental research. In this Article we present the scientific implications of the use of salvaged Ancient lead for dark matter searches as well as the consideration on underwater cultural heritage management. We finally highlight the three main dilemmas on the issue and articulate their analysis using the three main cultural heritage mainstays: (1) benefit of the humankind, (2) scientific interest and (3) commercial exploitation of the underwater cultural heritage. We conclude that the use of Ancient lead in dark matter experiments does not contravene the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage, the foremost international legal reference for the protection of underwater cultural heritage. However, to prevent the uncontrolled utilization of the non-renewable Ancient lead we recommend the use of alternative shielding materials such as tungsten and a case-by-case benchmark against commercial ultra-low-alpha lead.