After almost 3 years of preparations, an experiment lead by CNP Members Camillo
Mariani and Omar Benhar and aimed at the determination of the nuclear structure of argon started its run
at the Thomas Jefferson National Laboratory (JLab). By detecting protons knocked out from the argon
nucleus by an electron beam, the measurement will provide complete information on the shell structure of
argon, filling an important gap in our knowledge. The collected data will help the neutrino community to
make more reliable estimates of neutrino-argon cross sections and to model nuclear effects more accurately
in the next generation of neutrino-oscillation experiments, such as the Deep Underground Neutrino
Experiment (DUNE). An improved description of nuclear effects will allow a reduction in the systematic
uncertainties in the measurement of charge-parity symmetry violation in neutrino oscillations and the
search for proton decay, bringing us closer to understanding the matter-antimatter asymmetry of the
Universe and constraining possible extensions of the Standard Model of particle physics.
|The Hall A spectrometer at JLab, which will be used in the Argon Scattering Experiment.|
On February 8th, the Center for Neutrino Physics held a ribbon cutting to introduce
its new Mobile Neutrino Lab. This new state-of-the-art facility
will transport and host the MiniCHANDLER Detector as it is
deployed at the North Anna Nuclear Power plant to demonstrate reactor neutrino detection.
The event was an excellent opportunity to celebrate the great progress in the CHANDLER project and to acknowledge the support of the projects many benefactors, including several organizations within Virginia Tech: The Institute for Critical Technology and Applied Science, The College of Science, The Office of the Vice President for Research and Innovation, The College of Engineering and The Institute for Society, Culture and Environment; as well as the National Science Foundation. The ribbon cutting was preceded by brief remarks for CNP director Jonathan Link and followed by light refreshments, including the world's first (or so we assume) Mobile Neutrino Lab cake.
|Prof. Jonathan Link speaking at the ribbon cutting for the new Mobile Neutrino Lab|
|The Mobile Neutrino Lab in cake and frosting.|
Over the course of the last two weeks, the CHANLER reactor neutrino detector team has
assembled their MiniCHANDLER prototype detector.
This inaugurates the final stage of a two-year R&D program that began
with the MicroCHANDLER prototype and will wrap up with a deployment and test run of MiniCHANDLER at the
North Anna Nuclear Power Plant. MiniCHANDLER is comprised of 320 cubes of wavelength shifting plastic
scintillator cubes and 6 thin sheets of lithium-6 (6Li) loaded zinc sulfide (ZnS) scintillator.
The 6-cm cubes are arraigned in five layers of 8×8 cubes which are separated by the 6Li-loaded
ZnS sheets. The cubes and sheets are well suited for detecting electron antineutrinos from nuclear
reactors, which produce a positron and a neutron when they interact in the plastic cubes. The positron
produces a prompt flash of light in the cube, while the neutron bounces around for a while before
capturing on the 6Li in the sheet producing a delayed flash of light. The correlation between
these two distinct events provides a clean indication of a neutrino interaction. The light from both the
sheets and cubes is transported by total-internal-reflection along the rows and columns of cubes to the
surface of the detector where it is read out by light detectors known as photomultiplier tubes (PMTs).
MiniCHANDLER uses 80 PMTs. This unique method for reading out the light, known as a Raghavan optical
lattice, was invented by the late CNP member Raju Raghavan. It provides precise spatial information for the
neutrino interaction and neutron capture, which will be used to separate the true neutrino events, which
must be close together in both time and space, from the random correlation of unassociated neutron captures
and positron-like events that would otherwise form fake neutrino events.
Upon the successful completion of testing at the power plant the team will prepare to build the full-scale detector consisting of a ton of cubes read out by over 1000 PMTs. This detector could be used to search for neutrino oscillations mediated by a proposed fourth neutrino type, known as a sterile neutrino, and may be useful for monitoring the core of nuclear reactors, perhaps even as a part of a verification program for nuclear non-proliferation.
|The MiniCHANDLER Detector shown with half of its PMTs installed (on the right). The cubes (green) and sheets (white) are visible on the left.|
The Cryogenic Observatory for Rare Events experiment (or CUORE) reached a major
milestone recently, when all 19 of the detector modules (called towers), consisting of 988 TeO2 crystals
and weighing almost 750 kg, were safely installed in the cryostat. Preparations are now underway cool the towers to
their operating temperature of 10 mK, which is a hundredth of a degree above absolute zero. The experiment will
search for neutrinoless double beta decay, a hypothetical but theoretically well motivated process eagerly sought by
particle physicists to deepen our understanding of neutrino masses and possibly discover lepton number violation.
Related processed are key ingredients in theories that attempt to explain the abundance of matter over antimatter in
the Universe. CNP's Professor Thomas O'Donnell led CUORE tower construction and was a key member of the installation
|The full CUORE Tower assembly in the the clean room before installation in the cryostat.|
The proceedings from Heavy Quarks and Leptons 2016 are now available online.
Patrick Huber discusses his recent paper on monitoring Iran's nuclear reactor using neutrinos with WVTF radio.