Demonstration of Key Elements of a Dual Phase Argon Detection System Suitable for Measurement of Coherent Neutrino-Nucleus Scattering

[摘要] This feasibility study sought to demonstrate several necessary steps in a research program whose ultimate goal is to detect coherent scattering of reactor antineutrinos in dual-phase noble liquid detectors. By constructing and operating a Argon gas-phase drift and scintillation test-bed, the study confirmed important expectations about sensitivity of these detectors, and thereby met the goals set forth in our original proposal. This work has resulted in a successful Lab-Wide LDRD for design and deployment of a coherent scatter detector at a nuclear reactor, and strong interest by DOE Office of Science. In recent years, researchers at LLNL and elsewhere have converged on a design approach for a new generation of very low noise, low background particle detectors known as two-phase noble liquid/noble gas ionization detectors. This versatile class of detector can be used to detect coherent neutrino scattering-an as yet unmeasured prediction of the Standard Model of particle physics. Using the dual phase technology, our group would be the first to verify the existence of this process. Its (non)detection would (refute)validate central tenets of the Standard Model. The existence of this process is also important in astrophysics, where coherent neutrino scattering is assumed to play an important role in energy transport within nascent neutron stars. The potential scientific impact after discovery of coherent neutrino-nuclear scattering is large. This phenomenon is flavor-blind (equal cross-sections of interaction for all three neutrino types), raising the possibility that coherent scatter detectors could be used as total flux monitors in future neutrino oscillation experiments. Such a detector could also be used to measure the flavor-blind neutrino spectrum from the next nearby (d {approx} 10kpc) type Ia supernova explosion. The predicted number of events [integrated over explosion time] for a proposed dual-phase argon coherent neutrino scattering detector is 10000 nuclear recoils/kton, compared to the estimated rate in the Solar Neutrino Observatory (neutral current configuration); 200 deuteron breakup events/kton of D2O, yielding almost a factor 50 improvement in rate. In a more practical vein, these detectors may also be useful for improved cooperative monitoring of nuclear reactors, as required by the Nuclear Nonproliferation Treaty. Recognizing this potential, the International Atomic Energy Agency, which administers the global reactor monitoring regime, has endorsed our research into this technology.

[发布日期] 2007-04-16

[学科分类] 核物理和高能物理

[关键词] ARGON;COHERENT SCATTERING;CROSS SECTIONS;DETECTION;LAWRENCE LIVERMORE NATIONAL LABORATORY;NEUTRINO OSCILLATION;NEUTRINOS;NEUTRON STARS;NON-PROLIFERATION TREATY;RESEARCH PROGRAMS;SCATTERING;SOLAR NEUTRIN