B. C. Rasco
A5005183285- Nuclear physics research studies
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Radiation Detection and Scintillator Technologies
- Astronomical and nuclear sciences
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Radiation Therapy and Dosimetry
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Quantum, superfluid, helium dynamics
- Gamma-ray bursts and supernovae
- Radioactive contamination and transfer
- Dark Matter and Cosmic Phenomena
- Advanced Chemical Physics Studies
- Cosmology and Gravitation Theories
- Astro and Planetary Science
- Rare-earth and actinide compounds
- Advanced X-ray and CT Imaging
- Advanced NMR Techniques and Applications
- Spectroscopy and Laser Applications
Oak Ridge National Laboratory
2016-2024
Louisiana State University
2013-2024
University of Tennessee at Knoxville
2016-2023
Joint Institute for Computational Sciences
2016-2021
Argonne National Laboratory
2013-2020
Florida State University
2017
Joint Institute for Nuclear Astrophysics
2013
Michigan State University
2013
Western Michigan University
2013
Comisión Nacional de Energía Atómica
2013
We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs β decays, which are the most important contributors to high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three decays contribute 43% flux near 5.5 MeV emitted by This is particularly interesting due features recently observed several experiments including Daya Bay, Double Chooz, RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory means proton-induced fission...
Excited-state spectroscopy from the first Facility for Rare Isotope Beams (FRIB) experiment is reported. A 24(2)-$\mu$s isomer was observed with FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV $\gamma$ rays in coincidence $^{32}\textrm{Na}$ nuclei. This only known microsecond ($1{\text{ }\mu\text{s}}\leq T_{1/2} < 1\text{ ms}$) region. nucleus at heart $N=20$ island shape inversion crossroads spherical shell-model, deformed ab initio theories. It can be represented...
The excitation functions for quasielastic scattering of ^{22}Ne+^{248}Cm, ^{26}Mg+^{248}Cm, and ^{48}Ca+^{238}U are measured using a gas-filled recoil ion separator. barrier distributions extracted these systems compared with coupled-channel calculations. results indicate that the distribution is affected dominantly by deformation actinide target nuclei, but also vibrational or rotational excitations projectile as well neutron transfer processes before capture. From comparison between...
The quasielastic barrier distribution of 51V+248Cm was extracted by measuring the excitation function backscattering using a gas-filled recoil ion separator, GARIS-III. obtained is well explained coupled-channels calculation, indicating significant effect rotational deformed 248Cm. From measured average Coulomb height and deformation parameters 248Cm, side-collision energy leading to compact configuration colliding nuclei obtained. relation between side collision evaporation-residue cross...
Abstract Effort has been expended to assess the relative merits of undertaking further decay-data measurements main fission-product contributors decay heat neutron-irradiated fissionable fuel and related actinides by means Total Absorption Gamma-ray Spectroscopy (TAGS - sometimes abbreviated TAS) Discrete (DGS). This review carried out following similar work performed under auspices OECD/WPEC-Subgroup 25 (2005–2007) International Atomic Energy Agency (2009, 2014), various highly relevant...
We report the results of a β-decay study fission products ^{86}Br, ^{89}Kr, ^{89}Rb, ^{90gs}Rb, ^{90m}Rb, ^{90}Kr, ^{92}Rb, ^{139}Xe, and ^{142}Cs performed with Modular Total Absorption Spectrometer (MTAS) on-line mass-separated ion beams. These radioactivities were assessed by Nuclear Energy Agency as having high priority for decay heat analysis during nuclear fuel cycle. observe substantial increase in β feeding to excited states all daughter isotopes comparison earlier data. This...
The conceptual design of the BRIKEN neutron detector at radioactive ion beam factory (RIBF) RIKEN Nishina Center is reported. setup a complex system aimed detecting heavy-ion implants, β particles, γ rays and β-delayed neutrons. whole includes Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors up to 166 3He-filled counters embedded in high-density polyethylene moderator. quite due large number different types 3He-tubes involved additional constraints introduced by...
Theoretical models of β-delayed neutron emission are used as crucial inputs in r-process calculations. Benchmarking the predictions these is a challenge due to lack currently available experimental data. In this work probabilities 33 nuclides important mass regions south and south-west 132Sn presented, 16 for first time. The measurements were performed at RIKEN using Advanced Implantation Detector Array (AIDA) BRIKEN detector array. P1n values presented constrain theoretical region,...
New half-lives for exotic isotopes approaching the neutron drip-line in vicinity of N∼28 Z=12-15 were measured at Facility Rare Isotope Beams (FRIB) with FRIB decay station initiator. The first experimental results are compared to latest quasiparticle random phase approximation and shell-model calculations. Overall, consistent available theoretical descriptions suggest a well-developed region deformation below ^{48}Ca N=28 isotones. erosion Z=14 subshell closure Si is experimentally...
The first complete measurement of the β-decay strength distribution Cl281745 was performed at Facility for Rare Isotope Beams (FRIB) with FRIB Decay Station Initiator during second experiment. involved detection neutrons and γ rays in two focal planes a single experiment time. This enabled an analytical consistency extracting over large range excitation energies, including neutron unbound states. We observe rapid increase above separation energy Ar271845. interpreted to be caused by...
The β-delayed neutron emission of ^{83,84}Ga isotopes was studied using the time-of-flight technique. measured energy spectra showed from states at excitation energies high above separation and previously not observed in β decay midmass nuclei. large strength deduced intense is a signature Gamow-Teller transformation. This observation interpreted as evidence for allowed to ^{78}Ni core-excited ^{83,84}Ge favored by shell effects. We developed model calculations proton fpg_{9/2} extended...
Precise antineutrino measurements are very sensitive to proper background characterization. We present an improved measurement of the ^{13}C(α,n)^{16}O reaction cross section which constitutes significant for large ν[over ¯] detectors. greatly improve precision and accuracy by utilizing a setup that is neutron energies while making excited state transitions via secondary γ-ray detection. Our results shows 54% reduction in contributions from ^{16}O(3^{-},6.13 MeV) used KamLAND analysis.
Abstract The β -delayed neutron-emission probabilities of 28 exotic neutron-rich isotopes Pm, Sm, Eu, and Gd were measured for the first time at RIKEN Nishina Center using Advanced Implantation Detector Array (AIDA) BRIKEN neutron detector array. existing -decay half-life ( T 1/2 ) database was significantly increased toward more isotopes, uncertainties previously values decreased. new data not only constrain theoretical predictions half-lives probabilities, but also allow probing mechanisms...
Background: An assessment done under the auspices of Nuclear Energy Agency in 2007 suggested that $\ensuremath{\beta}$ decays abundant fission products nuclear reactors may be incomplete. Many nuclei are potentially affected by so called pandemonium effect and their $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ decay heat should restudied using total absorption technique. The $^{137}\mathrm{I}$ $^{137}\mathrm{Xe}$ were assigned highest priority for restudy due to large...
The $\ensuremath{\beta}$-delayed one- and two-neutron emission probabilities (${P}_{1n}$ ${P}_{2n}$) of 20 neutron-rich nuclei with $N\ensuremath{\ge}82$ have been measured at the RIBF facility RIKEN Nishina Center. ${P}_{1n}$ $^{130,131}\mathrm{Ag}$, $^{133,134}\mathrm{Cd}$, $^{135,136}\mathrm{In}$, $^{138,139}\mathrm{Sn}$ were determined for first time, stringent upper limits placed on ${P}_{2n}$ nearly all cases. ($\ensuremath{\beta}2n$) was unambiguously identified in $^{133}\mathrm{Cd}$...
Precise determination of ground-state feeding in the $\ensuremath{\beta}$ decay fission products is an important but challenging component modeling reactor antineutrino flux and heat. The Modular Total Absorption Spectrometer (MTAS) a versatile NaI(Tl) detector array that determines true $\ensuremath{\beta}$-decay pattern free from pandemonium effect, including precise intensities. In this paper, we report MTAS results intensities $^{88}\mathrm{Rb}$ $^{88}\mathrm{Kr}$, with large cumulative...
GODDESS is a coupling of the charged-particle detection system ORRUBA to gamma-ray detector array Gammasphere. This has been developed in order facilitate high-resolution measurement direct reactions normal and inverse kinematics with stable radioactive beams. commissioned using beam 134Xe at 10 MeV/A, campaign measurements. The demonstrates capabilities under conditions, provides first data on single-neutron states 135Xe, including previously unobserved based orbitals above N=82 shell closure.
An ambitious program to measure decay properties, primarily β-delayed neutron emission probabilities and half-lives, for a significant number of nuclei near or on the path rapid capture process, has been launched at RIKEN Nishina Center.We give here an overview status project.