Lawrence Livermore National Laboratory



AIT-WATCHMAN

AIT (Advanced Instrumentation Testbed)-WATCHMAN (WATer CHerenkov Monitor for AntiNeutrinos) is a collaborative United States–United Kingdom effort to pursue a research and development program based on a multi-purpose neutrino detection platform. The overall vision of AIT-WATCHMAN is to take advantage of synergies between pure and applied neutrino research by studying neutrinos emitted by reactors, the Earth, the Sun, and the distant stars—aiming for nuclear security and fundamental science applications.

Location

The existing Boulby Underground Laboratory at Boulby mine, which is expected to be the site of the Advanced Instrumentation Testbed project. The site already hosts a range of deep underground science studies from astrophysics (the search for dark matter in the universe) to studies of geology, geophysics, climate, the environment, and life in extreme in environments on earth and beyond.

Once constructed, the first part of AIT-WATCHMAN—AIT—will consist of a large underground cavern and associated laboratory space. The AIT will permit deployment of numerous advanced technologies that are relevant for remote reactor monitoring and detection, including water-based liquid scintillators, fast photo-sensors, light concentrators, and others.

AIT-WATCHMAN will operate 1.1 kilometers underground at the site of the Boulby Underground Laboratory—an existing U.K. government-funded deep underground science facility operating in a working potash, polyhalite, and salt mine (Boulby Mine) located on the northeast coast of England—and about 25 kilometers away from the Hartlepool nuclear power station. The Hartlepool station emits large numbers of antineutrinos, providing AIT-WATCHMAN with a convenient and free source for the exploration and development of antineutrino detection capabilities.

The great depth of AIT-WATCHMAN means that naturally occurring cosmic ray particles—which continuously bombard the Earth’s surface—are reduced in rate by several orders of magnitude, removing a background that would otherwise interfere with the antineutrino signal of interest from the Hartlepool station.

Research

The immediate goal of the AIT-WATCHMAN project is to detect reactor antineutrinos using a large water-based detector and thereby observe reactor operations at a significant distance from a nuclear reactor complex.

The WATCHMAN detector—the first to be installed at AIT—will consist of approximately 5000 tons of highly purified water. Doping the water with trace amounts of gadolinium, a neutron capture agent, is expected to significantly enhance its sensitivity to antineutrinos. Due to its relatively low cost and attractive scaling properties, demonstration of this water-based detection technique is a key step forward in the long-term goal of building large detectors with greater standoff sensitivity to the existence and operational conditions of nuclear reactors.

WATCHMAN will explore the potential of antineutrino detection systems to monitor man-made nuclear reactors on Earth to assist international efforts to track nuclear-weapons-usable materials, and thereby restrict the growth and spread of nuclear weapons and weapons development around the world.

In addition, WATCHMAN will join the ranks of a handful of large, high-sensitivity astrophysics research detectors built worldwide seeking to detect neutrino emission from nearby exploding stars (supernovae). Observation and analysis of supernova neutrino bursts provides insight into stellar growth and collapse, the formation of elements in the universe with atomic masses greater than that of helium, and the mysterious properties of neutrinos themselves.

Collaboration

The Lawrence Livermore AIT-Watchman team (left to right): Rob Hills, Mark Bergevin, Adam Bernstein, Steven Dazeley, Tomi Akindele, and Nancy Reason.

AIT-WATCHMAN is an international, multi-laboratory and university collaboration for nonproliferation research consisting of:

  • Lawrence Livermore, Lawrence Berkeley, and Brookhaven national laboratories
  • The United Kingdom’s Atomic Weapons Establishment and the Science and Technology Facilities Council’s Boulby Underground Laboratory
  • The University of California (UC), Berkeley; UC Davis; UC Irvine; the University of Hawaii; Iowa State University; Pennsylvania State University; the University of Pennsylvania; the University of Michigan; and the University of Sheffield