51 research outputs found
Calibration strategy of the PROSPECT-II detector with external and intrinsic sources
This paper presents an energy calibration scheme for an upgraded reactor
antineutrino detector for the Precision Reactor Oscillation and Spectrum
Experiment (PROSPECT). The PROSPECT collaboration is preparing an upgraded
detector, PROSPECT-II (P-II), to advance capabilities for the investigation of
fundamental neutrino physics, fission processes and associated reactor neutrino
flux, and nuclear security applications. P-II will expand the statistical power
of the original PROSPECT (P-I) dataset by at least an order of magnitude. The
new design builds upon previous P-I design and focuses on improving the
detector robustness and long-term stability to enable multi-year operation at
one or more sites. The new design optimizes the fiducial volume by elimination
of dead space previously occupied by internal calibration channels, which in
turn necessitates the external deployment. In this paper, we describe a
calibration strategy for P-II. The expected performance of externally deployed
calibration sources is evaluated using P-I data and a well-benchmarked
simulation package by varying detector segmentation configurations in the
analysis. The proposed external calibration scheme delivers a compatible energy
scale model and achieves comparable performance with the inclusion of an
additional AmBe neutron source, in comparison to the previous internal
arrangement. Most importantly, the estimated uncertainty contribution from the
external energy scale calibration model meets the precision requirements of the
P-II experiment.Comment: 19 pages, 10 figure
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
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