18 Feb

Investigating Fission Dynamics within Time-Dependent Density Functional Theory Extended to Superfluid Systems

18 February 2025 - 11:00 AM
1200 FRIB Laboratory and Online via Zoom
Los Alamos National Laboratory

Ibrahim Abdurrahman

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Despite being discovered over 86 years ago, fission still lacks a complete microscopic description, making it one of the oldest problems in quantum many-body theory. For comparison, superconductivity was discovered in 1911 and described microscopically in 1957 by the BCS theory. Fission is particularly difficult to treat theoretically in a unified manner as it contains many qualitatively distinct processes, each of which occurs at vastly different timescales, from the entrance channel (such as neutron absorption) to the splitting of a deformed nucleus into two fragments to the subsequent emission of radiation (typically gamma rays and neutrons). In 2016, the first simulation of the most rapid and highly non-equilibrium stage of fission, the evolution of the compound nucleus from the outer saddle point to scission to the formation of two fully separated fission fragments (FFs), was achieved for realistic initial conditions. This was done in the framework of the time-dependent superfluid local density approximation (TDSLDA) or equivalently time-dependent density functional theory extended to superfluid systems. Since the first study concerning 240Pu, TDSLDA has been applied extensively to compound systems 236U, 240Pu, and 252Cf (spontaneous fission), and recently to odd systems 239U, 241Pu, and 238Np. During this talk I will summarize the results of such investigations, covering the following topics: the role of pairing correlations during fission, the properties of the FF spins and their correlations, complexity and entanglement, the dynamics of the neck rupture and emission of scission neutrons, the differences between odd and even-even fission dynamics, and the energy dependence of fission observables.
19 Feb

A new approach to measuring neutrino mass

19 February 2025 - 3:30 PM
1300 FRIB Laboratory and Online via Zoom
University of Washington

Elise Novitski

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Of all the fundamental fermion masses, those of the neutrinos alone remain unmeasured. From their unknown origin to their effects on the evolution of the universe, neutrino masses are of interest across cosmology, nuclear physics, and particle physics. Neutrino oscillation experiments have set a non-zero lower limit on the mass scale, in contradiction to the original Standard Model prediction. To measure neutrino mass precisely and directly one must turn to beta decay and search for a telltale distortion in the spectrum. I will describe a new technique called Cyclotron Radiation Emission Spectroscopy (CRES), in which beta decay of tritium occurs in a magnetic field and each electron's ~1 fW of cyclotron radiation is directly detected. Electron energies are then determined via a relativistic relationship between energy and frequency. I will present the first CRES-based mass limits from the Project 8 experiment, which demonstrate the promise of this technique for surmounting the systematic and statistical barriers that currently limit the precision of direct neutrino mass measurements. I will also describe the next steps on the path to sensitivity to a mass of 40 meV/c^2, covering the entire inverted ordering of neutrino masses.

21 Feb

EIC RF Systems: A Good RF Challenge to Have

21 February 2025 - 3:00 PM
1200 FRIB Laboratory and Online via Zoom
Brookhaven National Laboratory

Zack Conway

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The Electron Ion Collider Project will upgrade the Brookhaven National Laboratory Relativistic Heavy Ion Collider complex to collide highly polarized (>70%) electrons and ions, from deuterons to the heaviest stable nuclei, with center-of-mass energies spanning 20 to 100 GeV at luminosities of 1033-1034 cm-2 s-1.  To achieve these goals a set of 4 unique superconducting radio frequency systems are required for beam acceleration, storage, and crabbing.  This seminar will briefly review the EIC as it relates to the radio-frequency systems, and then focus on the high-intensity beam interactions with the superconducting radio-frequency (SRF) systems.  Examples will include the 800 kW 2.0 K SRF cryomodules necessary for storing up to 2.5 A electron beams with ~ 10 MW of continuous power loss, 25 mrad crossing angle crab cavities, and the state-of-the-art damping required for all of the superconducting cavities.

04 Mar

Extending the reach of nuclear ab initio approaches with tensor factorization

04 March 2025 - 11:00 AM
1200 FRIB Laboratory and Online via Zoom
Centre DAM-Île de France

Lars Zurek

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Nuclear ab initio calculations are commonly limited by the computational cost of handling very large tensors, especially when breaking rotational symmetry. Applying a singular value decomposition to nucleon-nucleon and three-nucleon potentials obtained from chiral effective field theory reveals that such interactions possess low-rank structure. Exploiting these low-rank properties could allow to extend the reach of ab initio approaches to heavy open-shell nuclei. However, this is a nontrivial task as it requires reformulation of the computational method used to solve the many-body Schrödinger equation. I will present our ongoing work on employing tensor factorization techniques in Bogoliubov many-body perturbation theory, which uses modern linear algebra algorithms and avoids to construct large many-body tensors in the first place.
07 Mar

TBD

07 March 2025 - 3:00 PM
1200 FRIB Laboratory and Online via Zoom
Fermilab

Jacopo Bernardini

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TBD
10 Mar

Neutron stars as unique probes of nuclear physics

10 March 2025 - 12:00 PM
1200 FRIB Laboratory and Online via Zoom
IRAP, University of Toulouse

Sebastien Guillot

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More than 50 years after the discovery of neutrons stars, their interior composition and structure remains unknown. Because the extreme densities and matter asymmetry in neutron star interiors are out of reach for Earth laboratories, the equation of state of bulk nuclear matter is unknown, with important implication for astrophysics and nuclear physics. Thankfully, measurements of neutron stars masses and radii are direct probes of the interior of these compact objects. In the past two decades, X-ray observatories have provided some measurements of neutron star radii and therefore some constraints on the dense matter equation of state. But recently, the results from the NICER Observatory have provided the most promising, robust and precise constraints. I will review some of the key results from the NICER mission (including the most recent measurements) and give an overview of other existing measurements of masses and radii, as well as present their impact on our knowledge of dense nuclear matter. Finally, I will detail future prospects to constrain the equation of state of dense nuclear matter with upcoming X-ray observatories.
11 May

Nuclear Science Summer School

11 May 2025 - 8:30 AM
1221A and 1221B FRIB Laboratory
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The Nuclear Science Summer School (NS3) is a summer school that introduces undergraduate student participants to the fields of nuclear science and nuclear astrophysics. NS3 is hosted by FRIB on the campus of Michigan State University (MSU). The school will offer lectures and activities covering selected nuclear science and astrophysics topics.
20 Jul

Physics of Atomic Nuclei (PAN)

20 July 2025 - 8:00 AM
1221A and 1221B FRIB Laboratory
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PAN introduces participants to the fundamentals of the extremely small domain of atomic nuclei and its connection to the extremely large domain of astrophysics and cosmology.

The PAN @ Michigan State Experience

  • Learn about research in one of the top rare-isotope laboratories in the world.
  • Get introduced to the fascinating fields of astrophysics, precision measurement, and nuclear science.
  • Perform your own nuclear physics experiments.
  • Meet researchers who are exploring a wide array of questions.
  • Discover the surprising array of career opportunities in science.
  • Experience the atmosphere of college life.
  • Participants in the 2024 program get free room and board on campus (if required).

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