Dr
Richard J. deBoer
(University of Notre Dame)
23/05/2018, 16:30
poster
Nearly all stable nuclei reactions have at least a single measurement, and many that are critically important for the modeling of energy generation and nucleosynthesis have been studied several times. This wealth of data is both a blessing and a curse. On the one hand, by combining the results of many different measurements, which have been made in independent ways, one can hope that...
Panagiotis Gastis
(Central Michigan University)
23/05/2018, 16:30
poster
Neutrino driven winds (NDW) in core-collapse supernovae (CCSN) constitute an important astrophysical environment for nucleosynthesis, especially for the formation of elements beyond iron. If the right proton-rich conditions are found in the wind, nuclei with atomic numbers up to Z~50 can be produced via the so called neutrino-p (vp-) process. The strength of vp-process depends on a few key...
Mr
Thomas Chapman
(Central Michigan University)
23/05/2018, 16:30
poster
Current astrophysical models of the r-process suffer from uncertainties in nuclear data for rare neutron rich isotopes. As these properties are found experimentally, the models will become better constrained. The goal of our project is to test the impact of new experimental data in r-process models. Our project will utilize SkyNet, a nuclear reaction network developed by Lippuner and Roberts...
Dr
Benoit Cote
(Michigan State University / University of Victoria)
23/05/2018, 16:30
poster
Neutron star mergers (NSMs) are popular candidates for being the dominant r-process site in the universe. Several arguments such as nucleosynthesis calculations, the recent gravitational wave detection GW170817 and its associated multi-wavelength electromagnetic emission, and galactic chemical evolution studies that require NSM rates similar to what is established by LIGO/Virgo, all point...
Mr
Luis Morales
(University of Notre Dame)
23/05/2018, 16:30
poster
At the University of Notre Dame the St. George recoil mass separator will be used to study $(\alpha,\gamma)$ reactions of astrophysical interest. The particle identification system developed for the St. George recoil mass separator at the University of Notre Dame, in collaboration with Indiana University South Bend, utilizes time-of-flight and total kinetic energy to separate reaction products...
Mr
Anirudh Chiti
(MIT)
23/05/2018, 16:30
poster
Ultra-faint dwarf galaxies are some of the oldest systems (~13 Gyr) in the Milky Way halo. By extension, the study of the metal content (or "metallicity") of their stars can place strong constraints on models of early chemical enrichment. However, spectroscopy, the primary observational technique to study the chemical content of stars, only permits the chemical characterization of at best...
Mr
Devin Whitten
(University of Notre Dame)
23/05/2018, 16:30
poster
The relative age and density distributions of the Milky Way Inner and Outer Halo are mapped using samples of blue horizontal branch (BHB) stars selected from the first data releases of Pan-STARRS, GALEX, and the Dark Energy Survey. We see evidence of deep substructures at unprecedented depths, and explore the chronographic structure of the Large Magellanic Cloud. We present our results for the...
Dr
Mikhail Beznogov
(Institute of Astronomy of National Autonomous University of Mexico)
23/05/2018, 16:30
poster
The neutron star in HESS J1731-347 is the hottest know isolated neutron star for its age (excluding magnetars). It is cooling mainly due to neutrino emission from its core, and this emission has to be inefficient because of the high observed temperature. This fact allows us to put constraints on other hypothetical cooling processes like axion emission in n-n bremsstrahlung processes and...
Dr
Farrukh Fattoyev
(Indiana University)
23/05/2018, 16:30
poster
Some neutron stars are known to rotate rapidly. Initially slowly rotating neutron stars in accreting binary systems may increase their rotational frequency as materials falling from their binary companion transfer their angular momentum. However, most of the observed rapidly rotating neutron stars spin only at about half of the Keplerian break-up frequency. In this work, we argue that this...
Ms
Kristyn Brandenburg
(Ohio University)
23/05/2018, 16:30
poster
The astrophysical site of the nucleosynthesis of the elements from roughly zinc to tin (30$<$Z$<$50) is still unknown. The $\alpha$-process within the neutron-rich neutrino driven winds of core collapse supernovae (CCSN) is a proposed mechanism for the creation of these elements. However, a significant source of uncertainty exists in elemental abundance yields from astrophysics model...
Mr
Orlando Olivas-Gomez
(Universtiy of Notre Dame)
23/05/2018, 16:30
poster
The High Efficiency Total Absorption Spectrometer (HECTOR) is a NaI(Tl) 4π summing detector designed to measure radiative capture cross sections relevant for astrophysical processes. In order to extract cross sections from experiments, the summing efficiency of the detector needs to be well understood. To determine efficiency, experimental yields are typically compared to Geant4 simulations if...
Prof.
Myoung-Jae Lee
(Hanyang University), Prof.
Young-Dae Jung
(Hanyang University)
23/05/2018, 16:30
poster
The quantum shielding effects on the nuclear fusion reaction process are investigated in quantum plasmas. The closed expression of the classical turning point for the Gamow penetration factor in quantum plasmas is obtained by the Lambert W-function. The closed expressions of the Gamow penetration factor and the cross section for the nuclear fusion reaction in quantum plasmas are obtained as...
Kevin Macon
(University of Notre Dame)
23/05/2018, 16:30
poster
The $^{17}\mathrm{O}(\alpha,n)$ reaction recycles neutrons for the most efficient neutron absorber ($^{16}\mathrm{O}(n,\gamma)^{17}\mathrm{O}$) during both the core He-burning and shell C-burning phases of the weak s-process. In order to improve uncertainties in the reaction rate, we are performing $(a,n)$ and ($a,n'\gamma$) cross section measurements at the 5U accelerator of the Notre Dame...
Mr
Shiv Subedi
(Ohio University)
23/05/2018, 16:30
poster
Recent observational advances have enabled high resolution mapping of ${^{44}}$Ti in core-collapse supernova (CCSN) remnants. Comparisons between observations and 3D models provide stringent constraints on the CCSN mechanism. However, recent work has identified several uncertain nuclear reaction rates that influence ${^{44}}$Ti production in model calculations. We use MESA (Modules for...
Mr
Craig Reingold
(University of Notre Dame)
23/05/2018, 16:30
poster
Radiative capture and photodisintegration reactions involving neutrons are of particular importance to various nuclear astrophysics applications. For example, all the elements above iron are produced through processes that involve neutrons. In case of s- and r- processes, neutron capture reactions play a role, while for the initial stages of the p-process are driven by ($\gamma$,n)...
Dr
Rana Ezzeddine
(MIT)
23/05/2018, 16:30
poster
Elements heavier than hydrogen and helium were first produced in the universe within the
first stars. After a few million years, these presumably massive stars exploded as the first supernovae, ejecting the newly forged elements. Theoretical investigations have long indicated that such supernovae would explode in an asymmetric fashion, but insufficient observational evidence has prevented...
Dr
Micha Kilburn
(University of Notre Dame)
23/05/2018, 16:30
poster
A poster highlighting JINA-CEE's efforts for equity and inclusion in all center activities as well as targeted outreach programs to broaden participation in physics.
Rekam Giri
(Ohio University, Athens, OH, USA)
23/05/2018, 16:30
poster
The $^{12}$C($\alpha,\gamma$)$^{16}$O reaction is one of the most important nuclear reactions in astrophysics, as it determines the C/O ratio at the end of the helium burning in red giant stars. This ratio has significant effects for the subsequent stellar evolution and supernova explosions. We have used the DRAGON recoil separator for the measurements of the $^{12}$C($\alpha,\gamma$)$^{16}$O...
Mr
Samuel Henderson
(University of Notre Dame)
23/05/2018, 16:30
poster
Ab-initio methods have been successful in describing the structure of light nuclei using realistic nucleon-nucleon interactions, but more experimental data is needed for light unstable nuclei. Recent no-core configuration interaction calculations have made predictions for the ratio of E2 transition strengths for the first excited state transition in $^7Be$ and $^7Li$. Additional calculations...
Mr
Zac Johnston
(Monash Centre for Astrophysics, Monash University)
23/05/2018, 16:30
poster
Multizone simulations have been used to successfully model various observed features of thermonuclear X-ray bursts on neutron stars (NS), including recurrence times, burst energies, and lightcurve profiles. Although previous multizone studies have explored the dependence of burst properties on system parameters, and compared individual models with observations, no large-scale parameter...
Kyungyuk Chae
(Sungkyunkwan University)
23/05/2018, 16:30
poster
Because of the astrophysical importance of measuring numerous (alpha,p) reactions for explosive nucleosynthesis, we have developed a new approach using heavy ion beams incident on a windowless helium gas target and have measured the 4He(19F,1H)22Ne reaction as a first demonstration. 19F beams were produced at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory...
Cathleen Fry
(MSU/NSCL)
23/05/2018, 16:30
poster
Sulfur isotopic ratios have the potential to aid in the classification of presolar grains. Incomplete knowledge of the $^{34}$S($p,\gamma$)$^{35}$Cl and $^{34g,m}$Cl($p,\gamma$)$^{35}$Ar reaction rates leads to uncertainties in the production of $^{34}$S in oxygen-neon classical nova models. Many proton resonances relevant for classical nova temperatures have a negative parity. In order to...
Maxime Brodeur
(Notre Dame)
23/05/2018, 16:30
poster
The production of exotic nuclei at the vicinity of the N = 126 peak of the rapid-neutron capture process as for a long time pose a challenge. A new facility currently under construction at Argonne National Laboratory aims at undertaking the challenge by producing these difficult nuclei via deep-inelastic reactions. The facility will first include a large-volume gas cell to collect and...
Sebastian Aguilar
(University of Notre Dame)
23/05/2018, 16:30
poster
Overcoming the mass A = 5 and A = 8 gaps are important for understanding nucleosynthesis processes. This typically requires a 3-body reaction, which are the bottlenecks for light element formation. The $^{8}$Li($\alpha$,n)$^{11}$B reaction is potentially important for light-element nucleosynthesis as it provides an alternate pathway for overcoming the A = 5 and A = 8 mass gaps. Measurements...
Mr
Adrian Valverde
(University of Notre Dame)
23/05/2018, 16:30
poster
The doubly-magic nucleus $^{56}$Ni is one of the most important rp-process waiting points. While we now know that it is not the endpoint of the rp-process, the flow around this nucleus is not well understood. The mass of $^{56}$Cu is critical for constraining the reaction rates of the $^{55}$Ni(p,$\gamma$)$^{56}$Cu(p,$\gamma$)$^{57}$Zn($\beta^+$)$^{57}$Cu bypass around the $^{56}$Ni waiting...
Benjamin Loseth
(NSCL, Michigan State University)
23/05/2018, 16:30
poster
We propose a new method for measuring the rate of rare nuclear reactions by capturing the heavier atomic products in a noble gas solid.
Once embedded in the transparent noble gas matrix, the products are selectively identified via laser fluorescence spectroscopy
and individually counted via optical imaging to determine the reaction rate. Single atom sensitivity is feasible due to the noble...
Dr
Duncan Galloway
(Monash Centre for Astrophysics, Monash University)
23/05/2018, 16:30
poster
Observationally, the wide variety of thermonuclear (type-I) bursts from accreting neutron stars present a challenge to modellers. Several aspects of the phenomenology are contrary to the predictions of even the most sophisticated numerical models, including irregular bursting behaviour, a decreasing burst rate with accretion rate (for some sources), and bursts recurring after an insufficiently...
Ms
Aalayah Spencer
(NSCL/MSU)
23/05/2018, 16:30
poster
Recoil separators are used to directly measure the reaction rates of proton and alpha capture reactions that take place in stellar explosions (e.g., X-Ray Bursts, Novae, etc.). Studying these processes are crucial to understanding the mechanisms behind those explosions and the nucleosynthesis at those sites. The recoil separator SECAR is currently under construction at the National...
alfredo estrade
(CMU)
23/05/2018, 16:30
poster
We performed X-ray bursts simulations with the ONEZONE single-zone model to evaluate the impact of nuclear reaction rates on the model’s results. We vary individual proton and alpha capture rates in a large nuclear reaction network, and asses their effect on the nucleosynthesis and the lightcurve of the simulated bursts. Our work is an extension of the sensitivity study of Cyburt et al [1] to...
Mr
Christopher Seymour
(University of Notre Dame)
23/05/2018, 16:30
poster
A probe of the angular and energy acceptance capabilities of the St George recoil separator is being carried out at the Nuclear Science Laboratory of Notre Dame. St George will be used to measure ($\alpha$, $\gamma$) reaction cross sections in inverse kinematics at low energies and over a large energy range. S-factor extrapolations, which are used to calculate the reaction rate at stellar...
Dr
Andrea Richard
(National Superconducting Cyclotron Laboratory)
23/05/2018, 16:30
poster
The “Island of Inversion,” centered on 32Mg, is a region where a narrowed N=20 shell gap and collective np-nh excitations result in nuclei that exhibit deformation in their ground states. Despite years of theoretical and experimental efforts, a complete picture of the deformation in this region has not been achieved and the level schemes remain largely incomplete for many of these nuclei....
Mr
Bryant Vande Kolk
(University of Notre Dame)
23/05/2018, 16:30
poster
Laboratory measurements where an accelerator impinges on a solid target of neutral charge differ intrinsically from reactions that take place in an ionized stellar plasma environment.
Particularly relevant for nuclear astrophysics at stellar energies, electron screening effects lower the Coulomb barrier and thus enhance measured thermonuclear reaction rates. The $^{10}$B(p,$\alpha$)$^7$Be...
Mr
Matthew Hall
(University of Notre Dame)
23/05/2018, 16:30
poster
A direct way to test nova explosion models would be to observe gamma rays created in the $^{18}$F, is believed to be the main source of observable 511 keV gamma rays. The main destruction mechanism of $^{18}$F is thought to be the $^{18}$F(p,$\alpha$)$^{15}$O reaction. Uncertainties in the reaction rate are attributed to uncertainties in the energies, spins, and parities of the nuclear levels...
Mr
Honggeun Kim
(Massachusetts Institute of Technology)
23/05/2018, 16:30
poster
Rapid (r-) neutron capture process(es) are responsible for the production of elements heavier than Fe in the Universe. About 5% of old, metal-poor stars are known to have a strong enhancement in r-process elements. One of the best examples is HE 1523-0901, an old, metal-poor giant star with enhanced r-process elements ([r/Fe] = 1.8). In this study, we examine a new high-resolution (R~85,000),...
Mr
Matthew Caplan
(Indiana University)
23/05/2018, 16:30
poster
In the oceans of accreting neutron stars, hydrogen and helium burns to a produce a mixture of nuclei with a large range of atomic numbers. These mixtures continually freeze out to form new crust, however, recent work suggests that the crust cannot accommodate the entire mixture, and only a limited number of crust compositions can form. I will discuss recent work using molecular dynamics...
Ms
Brianna Douglas
(Texas A&M University Commerce)
23/05/2018, 16:30
poster
Neutron stars are one of the most exotic objects in the universe. They are complex due to their extremely high densities. Trying to find the equation of state (EOS) exceeding nuclear saturation density is one of the many quests of nuclear physics and astrophysics. One way to constrain the EOS is to learn more about the cooling processes of neutron stars over time. Stars cool from one of two...
Mr
Dwaipayan Ray
(University of Manitoba)
23/05/2018, 16:30
poster
The origin of chemical elements heavier than $^{56}$Fe is still not clearly understood.
The rapid neutron capture process (*r* process) is presumed to be responsible for more than half of these elements on the neutron rich side of the chart of nuclides.
However, the site and exact conditions for the *r* process is still not accurately known.
Making and verifying these *r*-process...
Lauren Balliet
(Texas A&M University - Commerce)
23/05/2018, 16:30
poster
**The Depth of a Neutron Star Crust**
Lauren Balliet and Brianna Douglas
Department of Physics and Astronomy Texas A&M University - Commerce
Dr. William Newton
Department of Physics and Astronomy Texas A&M University - Commerce
(Dated: February 28, 2018)
Neutron stars are a valuable asset to modern nuclear astrophysics in that they provide a unique environment to study...
Dr
Pavel Denisenkov
(University of Victoria)
23/05/2018, 16:30
poster
I will present the results of our new study of (n,$\gamma$) reaction rate uncertainties of unstable isotopes near the magic neutron number $N=82$ on the i-process nucleosynthesis. Like in our previous work, in which we studied the impact of (n,$\gamma$) reaction rate uncertainties of unstable isotopes near $N=50$ on the i-process nucleosynthesis in the He-flash white dwarfs, we use Monte Carlo...
Erika Holmbeck
(University of Notre Dame)
23/05/2018, 16:30
poster
There exist some 30 very metal-poor stars discovered over the course of the past quarter-century that are highly enhanced with heavy elements, recording signatures of r-process events early in the Galactic history. These "r-II stars" offer observational evidence of nearly pure r-process events. With a goal of identifying 100 new r-II stars, the R-Process Alliance has completed its pilot...
Ilka Petermann
(Arizona State University)
23/05/2018, 16:30
poster
Following the convective core burning of hydrogen and helium in
massive stars the next phase, core carbon burning, can proceed either
convectively or radiatively. Under certain thermodynamic conditions core carbon-burning
generates enough energy for the energy released to be transported by
convection. Otherwise, the nuclear energy generated is too small
relative to thermal neutrino...
Dan Bardayan
(University of Notre Dame)
23/05/2018, 16:30
poster
Light-ion transfer reactions have been used for many years to study the structure of exotic nuclei. Recently there has been a renaissance of such studies to the application of nuclear astrophysics. In particular, knowledge of the structure of proton-rich exotic nuclei can be used to estimate the astrophysical rates of proton-induced reactions in explosive hydrogen burning. Such studies...
Mr
Michael Ross
(Texas A&M University-Commerce)
23/05/2018, 16:30
poster
Neutron stars in binary star systems accrete matter from their neighboring star, causing their surface temperature to rise. When accretion stops, the neutron star cools. Using cooling data on neutron stars MXB1659-29 and KS1731-260 and the codes MESA and dStar, this research modeled neutron star cooling by varying attributes including radius, mass, density, pressure, core temperature, and...
Doug Soltesz
(Ohio University)
23/05/2018, 16:30
poster
The reaction rate of the $^{59}$Cu(p,$\gamma$)$^{60}$Zn has been identified to have a significant impact on the light curve of X-ray bursts, controlling the reaction flow out of the Ni-Cu cycle impacting the late-time light curve. The $^{58}$Ni($^{3}$He,n)$^{60}$Zn indirect measurement can be used to study the $^{59}$Cu(p,$\gamma$)$^{60}$Zn reaction. We are using the neutron evaporation...
Mr
Tamas Budner
(Michigan State University)
23/05/2018, 16:30
poster
A micro pattern gas amplification detector was built at NSCL to measure low-energy, β-delayed protons and α-particles for constraining thermonuclear reactions rates relevant to explosive astrophysical environments, such as classical novae and type I X-ray bursts. The first experiment using the Proton Detector is scheduled to run in May 2018. Here, I present work from the past year leading up...