5 research outputs found
Final Measurement of the U235 Antineutrino Energy Spectrum with the PROSPECT-I Detector at HFIR
This Letter reports one of the most precise measurements to date of the
antineutrino spectrum from a purely U235-fueled reactor, made with the final
dataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By
extracting information from previously unused detector segments, this analysis
effectively doubles the statistics of the previous PROSPECT measurement. The
reconstructed energy spectrum is unfolded into antineutrino energy and compared
with both the Huber-Mueller model and a spectrum from a commercial reactor
burning multiple fuel isotopes. A local excess over the model is observed in
the 5MeV to 7MeV energy region. Comparison of the PROSPECT results with those
from commercial reactors provides new constraints on the origin of this excess,
disfavoring at 2.2 and 3.2 standard deviations the hypotheses that
antineutrinos from U235 are solely responsible and non-contributors to the
excess observed at commercial reactors respectively.Comment: The paper has been updated with an improved parametrization of the
observed antineutrino spectrum excess and extended discussion on its
potential isotopic origi
PROSPECT-II Physics Opportunities
The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, has made
world-leading measurements of reactor antineutrinos at short baselines. In its
first phase, conducted at the High Flux Isotope Reactor (HFIR) at Oak Ridge
National Laboratory, PROSPECT produced some of the strongest limits on eV-scale
sterile neutrinos, made a precision measurement of the reactor antineutrino
spectrum from U, and demonstrated the observation of reactor
antineutrinos in an aboveground detector with good energy resolution and
well-controlled backgrounds. The PROSPECT collaboration is now preparing an
upgraded detector, PROSPECT-II, to probe yet unexplored parameter space for
sterile neutrinos and contribute to a full resolution of the Reactor
Antineutrino Anomaly, a longstanding puzzle in neutrino physics. By pressing
forward on the world's most precise measurement of the U antineutrino
spectrum and measuring the absolute flux of antineutrinos from U,
PROSPECT-II will sharpen a tool with potential value for basic neutrino
science, nuclear data validation, and nuclear security applications. Following
a two-year deployment at HFIR, an additional PROSPECT-II deployment at a low
enriched uranium reactor could make complementary measurements of the neutrino
yield from other fission isotopes. PROSPECT-II provides a unique opportunity to
continue the study of reactor antineutrinos at short baselines, taking
advantage of demonstrated elements of the original PROSPECT design and close
access to a highly enriched uranium reactor core
1ST OBSERVATION OF A SUPERDEFORMED NUCLEUS PRODUCED IN AN ALPHA-XN REACTION CHANNEL
Recent data from the EUROGAM array have revealed the population of the yrast superdeformed (SD) band of192Hg in the α4n exit channel of the16O+184W reaction at 113 MeV beam energy. The nucleus assignment was made on the basis of the SD band transition energies, and the observation of characteristic X-rays and lowlying yrast γ-transition of192Hg in coincidence with the SD band γ-rays. Both the feeding and decay-out patterns of the observed SD band have been found similar to the ones previously measured in the (36S,4n) reaction