Postdoctoral Research Staff
Nuclear Data and Theory Group
Lawrence Livermore National Laboratory
I develop theory and codes to improve our understanding of nuclear physics as it relates to astrophysics and nuclear technologies, two fields which test our understanding of matter in neutron-rich environments.
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ORC ID: 0000-0003-3643-9640
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Ph.D. Computational Science, 2024
“Shell Model
Methods, Statistical Nuclear Reactions, and Beta-delayed Neutron
Emission”
University of California, Irvine
San Diego State University joint doctoral
program
M.S. Physics, 2018
“Efficient
Modeling of Nuclei Through Coupling of Proton and Neutron
Wavefunctions”
San Diego State University
B.A. Physics, 2016
University of California, Berkeley
Postdoctoral Research Staff, 2024 – present
Nuclear Data and Theory Group, Lawrence Livermore National Laboratory
(LLNL)
Weapon
Physics and Design ACT Scholar, 2022 – 2024
Nuclear Data and Theory Group, LLNL
New predictive capability for reaction and decay properties of fission
fragments
Glenn T. Seaborg Institute (GTSI) Graduate Intern, Summer 2021
Nuclear Data and Theory Group, LLNL
High Energy Density Physics Graduate Intern, Summer 2018, 2019, and
2020
Nuclear Data and Theory Group, LLNL
Graduate Teaching Associate, 2016 – 2020
Department of Physics, San Diego State University - Co-authored the
department manual
for Physics 182A/195L laboratory courses
I am the primary developer of these codes:
COMMCAS Python [LLNL-TR-2011377] [Not yet
public]
Uncertainty quantification and statistical inference framework for
nuclear physics models - Monte-Carlo, Importance Sampling, MCMC, forward
propagation methods - Provides generic model wrapper with user-friendly
abstractions of model inputs/outputs, experimental data, unknown sources
of uncertainty, and more
PANASh Fortran [Publication]
[Not yet public]
Shell model code with advanced basis-reduction scheme to compute nuclear
wave functions - Custom Krylov-subspace algorithms (block Lanczos with
on-the-fly matrix elements) - MPI and openMP hybrid parallelization
dmscatter Fortran and Python [Publication] [Repository]
A fast Fortran code for WIMP-nucleus form factors and differential event
rate spectra. Modern Fortran with Python interface. OpenMP parallel.
Wigner Fortran Repository
A library of functions for computing vector-coupling coefficients,
written in modern Fortran.
Radiative strength
functions from the energy-localized Brink-Axel hypothesis
O. Gorton, K. Kravvaris, J. Escher, C. Johnson
[Editor’s
Suggestion] – Physical Review C 113, 044327 (2026) | arXiv:2601.12225
Constraining
capture cross sections using proton inelastic scattering as a surrogate
reaction
A. Thapa, J. Escher, E. Chimanski, O. Gorton, M. Dupuis, E.J. In, S.
Ota, S. Peru, W. Younes
Physics Letters B 876, 140322 (2026) | arXiv:2511.03071
Correlated and
uncorrelated Monte Carlo neutron capture rate variations in weak
r-process simulations
A. Kedia, J. Berryman, J. Garcia, J. Escher, O. Gorton, E. Holmbeck, G.
McLaughlin, C. Pruitt, A. Sieverding, R. Surman
[Editor’s
Suggestion] – Physical Review C 114, 035805 (2026) | arXiv:2602.12428
Towards shell model
interactions with credible uncertainties
O. C. Gorton and K. Kravvaris
Physical Review C 112, 014302 (2025) | arXiv:2503.11889
Weak
entanglement approximation for nuclear structure
O. C. Gorton and C. W. Johnson
Physical Review C 110, 034305 (2024) | arXiv:2406.10120
Proton-neutron
entanglement in the nuclear shell model
C. W. Johnson and O. C. Gorton
Journal of Physics G: Nuclear and Particle Physics 50 (4) 045110
(2023) | arXiv:2210.14338
dmscatter: A fast
program for WIMP-nucleus scattering
O. Gorton, C. Johnson, C. Jiao, J. Nikoleyczik
Computer Physics Communications 284, 108597 (2023) | arXiv:2209.09187
Cross sections
for neutron-induced reactions from surrogate data: Reexamining the
Weisskopf-Ewing approximation for (n,n’) and (n,2n) reactions
O. C. Gorton and J. E. Escher
Physical Review C: Nuclear Physics 107 (4), 044612 (2023) | arXiv:2102.03452
Measurements
of proton capture in the A=100-110 mass region: Constraints of the
111In(gamma,p)/(gamma,n) branching point relevant to the
gamma-process
O. Olivas-Gomez, A. Simon, O. Gorton, J. E. Escher et al.
Physical Review C: Nuclear Physics 102 (5), 055806 (2020)
From credible shell model interactions to neutron-capture
uncertainties
O. Gorton and K. Kravvaris
Submitted to European Physical Journal, Web of Conferences
(2026) | arXiv:2604:09935
A weak
entanglement approximation for nuclear structure: a progress
report
C. Johnson and O. Gorton
Journal of Subatomic Particles and Cosmology, 100061 (2025) |
arXiv:2504.00273
Correcting for
neutron width fluctuations in Hauser-Feshbach gamma branching
ratios
O. Gorton and J. Escher
EPJ Web of Conferences 322, 02004 (2025) | arXiv:2410.01074
Extending the
Dispersive Optical Model to Beta-unstable Systems
C. Pruitt, S. S. Perrotta, J. Escher, O. Gorton
EPJ Web of Conferences 322, 05001 (2025)
Towards
next-generation optical potentials for nuclear reactions and structure
calculations
S. S. Perrotta, C. Priutt, O. Gorton, and J. Escher
Nuclear Physics A 1057, 123037 (2025) | arXiv:2410.19269
A Problem in
the Statistical Description of Beta-Delayed Neutron Emission
O. Gorton, C. Johnson, and J. Escher
EPJ Web of Conferences 284, 03013 (2023) | arXiv:2210.05904
Improving
nuclear data evaluations with predictive reaction theory and indirect
measurements
J. Escher, K. Bergstrom, E. Chimanski, O. Gorton, E. J. In, M. Kruse, S.
Peru, C. Pruitt, R. Rahman, E. Shinkle, A. Thapa, W. Younes
EPJ Web of Conferences 284, 03012 (2023) | arXiv:2304:10034
Neutron
capture cross sections from surrogate reaction data and theory:
connecting the pieces with a Markov-Chain Monte Carlo approach
O. Gorton and J. E. Escher
Springer Proceedings in Physics, vol 254, pages 229-231 (2021)
| arXiv:1905:03055
From new measurements to new data libraries: The LLNL nuclear data
pipeline at work
M. Anastasiou, B. Beck, R. Casperson, M.-A. Descalle, J. Escher, O.
Gorton, K. Kravvaris, C. Mattoon, M. Mendenhall, W. Ormand, G. Potel
Aguilar, S. Quaglioni, A. Sieverding, L. Snyder, I. Thompson, and K.
Wendt
Internal working document
COMMCAS: Computational Model Monte Carlo Sampler
O. Gorton, J. Escher, S. Perrotta, C. Pruitt, A. Thapa, V. Kruse, E.
Shinkle, M. Paik, and H. Frye
LLNL-TR-2011377-DRAFT
Evaluations for
neutron-induced activation cross sections for Y and Zr
isotopes
A. Sieverding, R. Hoffman, O. Gorton, and W. Ormand
LLNL-TR-2011750
Computational Workflows for
Uncertainty-Quantified Nuclear Reactions
J. Berryman, C. Pruitt, J. Escher, O. Gorton, E. M. Holmbeck, K.
Kravvaris, A. Sieverding, et al.
LLNL-TR-2015691
Final Technical Report: New predictive capability for reaction and
decay properties of fission fragments (ACT University Program)
O. Gorton, H. Frye, C. Johnson, and J. Escher
LLNL-MI-2003179 (Internal report avilable upon request)
Statistical
properties from the shell model and reduced-order fitting
schemes
FRIB-TA Topical Program: Statistical Nuclear Properties in the AI/ML
Era: Advances, Challenges, and Synergies for FRIB Science (East Lansing,
Michigan, July 2026)
Radiative
strength functions from the energy-localized Brink-Axel
hypothesis
10th Workshop on Level Densities and Gamma Strengths (Oslo, Norway, May
2026)
Initial
analysis of charged-particle reactions as a mix diagnostic for
high-yield NIF implosions
Joint high-energy-density seminar work-in-progress presentation (LLNL,
October 2026)
Nuclear
theory for astrophysics and nuclear technologies
PLS Directorate Postdoctoral Seminar (LLNL, February 2026)
Radiative
strength functions from the energy-localized Brink-Axel
hypothesis
8th International Conference on Collective Motion in Nuclei under
Extreme Conditions (Tallahassee, December 2025)
Shell
model for astrophysics and nuclear technologies
16th Nuclear Data for Science and Technology Conference (Madrid, June
2025)
Is
the USDB interaction unique?
APS Global Physics Summit (Anaheim, March 2025)
A weak
entanglement approximation for nuclear structure
Shell Model Symposium: Celebrating 75 Years of the Nuclear Shell Model
and Maria Goeppert-Mayer (Argonne National Lab., July 2024)
Missing
gammas: beta-delayed neutron emission of Rb-94
APS April 2024 Meeting (Sacramento, April 2024)
Gamma-ray
strength functions using approximate shell model calculations
T3 “Taking the Temperature” Workshop on Statistical Nuclear Physics for
Astrophysics and Applications (Ohio University, August 2023)
Nuclear
Shell Model to the Rescue: Efforts to Resolve a Mystery in Beta Delayed
Neutron Emission
APS Division of Nuclear Physics Fall 2022 Meeting (New Orleans, October
2022)
Crisis in
Beta-Delayed Neutron Emission: Shell Model to the Rescue
Nuclear Data Conference (Sacramento – virtual, July 2022)
DMFortFactor: A
Fast and Accessible for Computing WIMP-Nucleus-Scattering
Event-Rates
DNP21 APS Conference (Boston – virtual, October 2021)
Better
MCMC for Nuclear Data using emcee and B-DJINN
LLNL Summer Slam (Livermore, August 2021)
Nuclear
Physics for WIMPs
SDSU SIAM Student Chapter Summer Colloquium Series, (San Diego, July
2021)
Cross
subsections for neutron reactions from surrogate measurements:
Revisiting the Weisskopf-Ewing approximation
DNP20 APS Conference (New Orleans – virtual, October 2020)
Can we
get rid of the theorists?
LLNL Summer Slam (Livermore, August 2020)
Big
Picture and Background for Nuclear-Electronic Orbital (NEO) Approach:
Calculating Mixed Nucleon-Electron Wave Functions
Seminar for the Furche Group, Chemistry Department, UC Irvine (Irvine,
March 2020)
Indirect
measurements of nuclear cross subsections: tempering experimental
results with theory
Seminar for HEDP Intern Exit Talk (Livermore, September 2019)
A Markov
Chain Monte Carlo Tool for Hauser-Feshbach Codes
Seminar for HEDP Intern Exit Talk (Livermore, August 2018)
Nuclear
theory for astrophysics and nuclear technologies
[Received Nuclear and Chemical Sciences Division Spot Award for an
excellent poster presentation]
Poster at LLNL 2026 Institutional Postdoc Poster Symposium (Livermore,
June 2026)
Width
Fluctuation Correction Factor for Beta-delayed Neutron
Emission
Poster at the 7th international workshop on Compound-Nuclear Reactions
and Related Topics (Vienna, July 2024)
Proton
and Neutron Approximate Shell Model: Factorization-based Importance
Truncation
Poster at Nuclear Structure Conference (Berkeley, June 2022)
Sensitivity
Study of the Surrogate Method
Poster at LLNL Student Poster Symposium (Livermore, August 2019)
Temperature
and Entropy in the Nuclear Shell Model
Poster at SDSU ACCESS event (San Diego, April 2019)
Proton
Neutron Interacting Shell Model: Order of Magnitude Reduction for Medium
Mass Nuclei
Poster at SDSU annual research symposium (San Diego, March 2019)
Neutron
capture cross subsections from surrogate reaction data and theory:
connecting the pieces with a Markov-Chain Monte Carlo approach
Poster at Compound Nuclear Reactions conference CNR18 (Berkeley, September
2018)