Bulletin of the American Physical Society
2021 Fall Meeting of the APS Division of Nuclear Physics
Volume 66, Number 8
Monday–Thursday, October 11–14, 2021; Virtual; Eastern Daylight Time
Session JD: Nuclear Astrophysics IV |
Hide Abstracts |
Chair: Harrison Sims, Rutgers University, New Brunswick Room: The Loft |
Wednesday, October 13, 2021 9:30AM - 9:42AM |
JD.00001: Study of the 37Cl(a,n)40K reaction to constrain the reaction rate of destruction of 40K in stars. Nikolaos Dimitrakopoulos, Georgios Perdikakis, Pelagia Tsintari, Carl R Brune, Thomas Massey, Zachary P Meisel, Alexander Voinov, David C Ingram, Yenuel Jones-Alberty, Shiv K Subedi, Justin Warren, Kristyn H Brandenburg, Nisha Singh, Lauren P Ulbrich 40K is thought to be one of the main isotopes responsible for the radiogenic heating of the mantle in an Earth-like exoplanet. The radiogenic heat keeps the mantle and the outer core, that mainly consists of molten iron and nickel, in a state of turbulent convection. This motion is generating magnetic field, which is essential for developing a habitable environment [1]. In addition, it contributes to the formation of plate tectonics, which play a key role in the volcanic activity and eventually the carbon cycle of a planet. The abundance of 40K in these planets depends on the composition of the interstellar medium from which they were formed. Thus, nuclear reactions that determine the amount of 40K during stellar evolution are crucial. In this study, we constrain the reaction rate of 40K(n,a)37Cl, one of the two major destruction paths of 40K in stellar nucleosynthesis by measuring the reverse reaction 37Cl(a,n)40K and applying the principle of detailed balance to the reaction rate as it has been done in the past for the other reaction responsible for the destruction of 40K (40K(n,p)40Ar reaction) [2]. We performed differential cross-section measurements on the 37Cl(a,n1γ)40K, 37Cl (a,n2 γ) 40K and 37Cl (a,n3 γ) 40K reactions, for six different center of mass energies in the range between 5.1 and 5.4 MeV. The experiment took place at the Edwards Accelerator Laboratory at Ohio University. The gamma rays from the reactions mentioned above were detected by two LaBr3 scintillators. Using the swinger facility to change the angle of the beam on target with respect to the detection system, we were able to obtain the differential cross-section for six different angles between 20 and 120° in the lab system. Here, we present some preliminary results of this ongoing analysis. |
Wednesday, October 13, 2021 9:42AM - 9:54AM |
JD.00002: Constraining the Astrophysical P Process: Cross Section Measurement of the 84Kr(p, γ)85Rb Reaction in Inverse Kinematics Alicia R Palmisano, Artemis Spyrou, Sean N Liddick, Andrea L Richard, Mallory K Smith, Stephanie Lyons, Alexander C Dombos, Paul A Deyoung, Caley Harris One of the biggest questions in nuclear astrophysics is understanding where the elements come from and how they are made. This work focuses on a nucleosynthesis process, namely the p process, which is a series of photodisintegration reactions responsible for producing the stable isotopes on the proton rich side of stability. These nuclei, known as the p nuclei, cannot be made through the well-known neutron-capture processes. Currently scientists rely heavily on theory to provide the relevant reaction rates in astrophysical p-process models to predict the final p-nuclei abundances and more experimental data is needed. The present work reports on an experiment performed with the Summing Sodium Iodide (NaI) (SuN) detector at the National Superconducting Cyclotron Facility (NSCL) at Michigan State University (MSU) using the ReAccelerator (ReA) facility to measure the 84Kr(p, γ)85Rb reaction cross section in inverse kinematics for the first time. This reaction is a branching point in the p-process reaction network important in the production of the p-nucleus, 78Kr. A new hydrogen gas target was designed and fabricated and a new analysis technique for background subtraction and efficiency calculations of the detector were developed. The experimental cross section is compared to standard statistical model calculations using the NON-SMOKER and TALYS codes. |
Wednesday, October 13, 2021 9:54AM - 10:06AM |
JD.00003: A possible origin of the anomaly of the silicon isotopes relative abundance in 67P/Churyumov–Gerasimenko Lina Quintieri, Anthony Palladino, Elettra L Piacentino, Antonio Gioiosa, Vincenzo Testa, Fausto Fasano, Livio Conti, Giovanni M Piacentino Cometary objects, such as 67P/Churyumov–Gerasimenko, are thought to have formed or been altered during the protosolar nebula phase of our solar system. In Particular, cometary cores are thought to have formed via accretion of grains and dusts with olivine { (Mg2+, Fe2+)2SiO4} and pyroxene {XY(Si,Al)2O6 ) where X,Y = metal ions} being the most common constituent. The recent vidence for depletion of heavy silicon isotopes at comet 67P/Churyumov–Gerasimenko in comparison with solar standard, is an anomaly that deserves to be investigated. |
Wednesday, October 13, 2021 10:06AM - 10:18AM |
JD.00004: Time-of-Flight Mass Measurement of Exotic Nuclei Near N=28 Shell Closure Around Sulfur Chowdhury Irin Sultana, Kailong Wang, Alfredo Estradé, Michael A Famiano, A. M. Amthor, Nikolaos Dimitrakopoulos, Tom Ginter, Rahul Jain, Zachary P Meisel, Wolfgang Mittig, Jorge Pereira, Nabin Rijal, A.M. Rogers, E. Rubino, S. Samaranayake, Hendrik Schatz, Oleg B Tarasov, P. Tsintari Nuclear masses of neutron-rich nuclides are important for understanding the processes occurring in the crust of accreting neutron stars and the evolution of nuclear shell closures towards the neutron drip-line. The time-of-flight (TOF) magnetic-rigidity (B$\rho$) technique offers access to these short-lived exotic nuclei. In the recent TOF-B$\rho$ experiment at the National Superconducting Cyclotron Laboratory (NSCL), the projectile fragmentation of $\rm ^{48}{Ca}$ was used to produce the isotopes of interest below argon near the $\rm ^{46}{S}$ region. We measured the nuclear masses of $\rm ^{42}{Si}$, $\rm ^{44}{P}$, and $\rm ^{46}{S}$ which have not been determined experimentally so far. The mass of $\rm ^{46}{S}$ will help to measure the strength of the shell gap at the N=28 and the mass of $\rm ^{42}{Si}$ will allow the determination of the electron capture Q-value for the $\rm ^{42}{P}(EC)^{42}{Si}$ reaction. The current status of the data analysis and the preliminary results of this experiment will be discussed. |
Wednesday, October 13, 2021 10:18AM - 10:30AM |
JD.00005: Measurement of decay properties of the neutron-rich Se to Y isotopes Neerajan Nepal, Alejandro Algora, Alfredo Estrade, Shunji Nishimura, Jorge Agramunt, Deuksoon Ahn, Carlo Bruno, Roger Caballero-Folch, Tom Davinson, Iris Dillmann, Alexandra Fijalkowska, Naoki Fukuda, Shintaro Go, Robert Grzywacz, Tadaaki Isobe, Shigeru Kubono, Jiajian Liu, Giuseppe Lorusso, Keishi Matsui, Anabel Morales, S.E.A. Orrigo, Vi H. Phong, Bertis C Rasco, Krzysztof Rykaczewski, Hiroyoshi Sakurai, Yohei Shimizu, Dan Stracener, Toshiyuki Sumikama, Hiroshi Suzuki, Jose L Tain, Hiroyuki Takeda, Ariel Tarifeno-Saldivia, Alvaro Tolosa-Delgado, Marzena Wolinska-Cichocka, Jin Wu, Rin Yokoyama β-decay half-lives (T1/2) and β-delayed neutron emission probabilities (Pxn) are two essential ingredients of nucleosynthesis calculations for the rapid neutron capture process (r-process). Using the state-of-the-art instrumentation β-delayed neutron detector at RIKEN (BRIKEN) in the Radioactive Ion Beam Factory (RIBF) at the RIKEN laboratory in Japan, we did an experiment to measure the decay properties of neutron-rich isotopes of Se to Y around mass A = 100. The half-lives and β-delayed neutron emission probabilities of thirty-four isotopes measured in this experiment will be presented. In addition, implications of the new measured values for r-process models and nuclear structure based on the decay properties will be discussed. |
Wednesday, October 13, 2021 10:30AM - 10:42AM |
JD.00006: Measurements of 92Mo(p,γ)93Tc and 94Mo(p,γ)95Tc cross sections for γ-process modeling Rebeka Kelmar, Anna Simon, Jane O'Reilly, Alexander C Dombos, Orlando Gomez, John P McDonaugh, Miriam Matney, Jessica Koros, August Gula, Edward J Stech, Khachatur Manukyan, Daniel Robertson When modeling the p-nuclei abundances through the γ-process a consistent underproduction of the lighter p-nuclei, molybdenum and ruthenium, has been observed. Additionally, past measurements of the 92Mo(p,γ)93Tc cross section showed the possibility of resonance structures within the energy range relevant to the γ-process, which deviate from the smooth cross sections predicted in Hauser-Feschbach based models used in the modelling. In order to investigate this we measured both the 92Mo(p,γ)93Tc and the 94Mo(p,γ)95Tc cross sections at the University of Notre Dame’s Nuclear Science Laboratory. The High EfficienCy TOtal absorption spectrometeR (HECTOR) was used as well as the 5U 5 MV single-ended accelerator to measure the cross sections over the range Ep = 1.4–4.4 MeV. Various structures were observed in the 92Mo(p,γ)93Tc cross section and preliminary results for both measurements will be discussed. |
Wednesday, October 13, 2021 10:42AM - 10:54AM |
JD.00007: Constraining the 76,77Zn neutron capture reactions via the β-Oslo method Erin C Good, Hannah C. C Berg, Katherine L Childers, Alexander C Dombos, Caley Harris, Rebecca Lewis, Sean N Liddick, Stephanie Lyons, Alicia Palmisano, Debra Richman, Mallory K Smith, Artemis Spyrou, Antonius W Torode, Remco G Zegers, Adriana Sweet, Darren L Bleuel, Nicholas D Scielzo, Benjamin P Crider, Anna Simon Neutron capture reactions far from stability are important to a number of astrophysical nucleosynthesis processes, such as the r- and i-processes. These processes are responsible for the creation of the majority of the neutron-rich heavy elements, but they are not yet fully understood. This is because of incomplete nuclear data in this region due to the difficulty in creating both neutron and exotic radioactive ion beams. The β-Oslo method uses β decay to populate highly excited nuclear states in the compound nucleus of interest and is used to extract the nuclear level densities (NLD) and gamma-ray strength functions (γSF) from the decay of these states. These experimentally-determined properties reduce uncertainties in theoretical neutron capture rates. I will specifically discuss the β decay of 76,77Cu and the implementation of the β-Oslo method to reduce uncertainties in the current 76,77Zn(n,γ) reaction rates. These particular reactions are both in the mass region important for the weak r-process. |
Wednesday, October 13, 2021 10:54AM - 11:06AM |
JD.00008: Measurement of capture reaction cross-section of (p, γ), (p, n) and (p, α) reactions on 196Hg at astrophysically relevant energies Khushi Bhatt, Michael A Famiano, Shivi Saxena, Ramakrishna Guda, Asghar Kayani, Hayden Karrick, Mark Siegel, Shiva Agarwal, Luke Bessler, Trevor Wendt, Christopher Desmon, Claire George, Eric Helgemo The p-nuclei (proton-rich nuclei) are among the rarest of all the known stable nuclei. The astrophysical processes responsible for the synthesis of p-nuclei are not fully understood despite the efforts made since late 1950s. Of the 35 known p-nuclei, the heaviest is 196Hg. The synthesis of 196Hg is studied through the method of activation using (p, γ), (p, n) and (p, α) reactions. A mono-energetic beam of proton is incident on a homogeneously thin, solid HgS (mercury sulfide) target of ~10 mg/cm2 thickness and capture reaction cross-sections are measured for each reactions mentioned above. The specific kind of mercury target required has been developed through utilizing a casting method. The production methods as well as the experimental method resulting in a self-calibrating activation experiment are described. |
Wednesday, October 13, 2021 11:06AM - 11:18AM |
JD.00009: Nuclear properties of the 72,74Co isotopes via β decay Hannah C. C Berg, Katherine L Childers, Alexander C Dombos, Erin C Good, Caley Harris, Rebecca Lewis, Sean N Liddick, Stephanie Lyons, Alicia Palmisano, Debra Richman, Mallory K Smith, Artemis Spyrou, Antonius W Torode, Remco G Zegers, Adriana Sweet, Darren L Bleuel, Nicholas D Scielzo, Benjamin P Crider, Anna Simon, Ann-Cecilie Larsen It is known that the majority of the heavy elements (Z >26) are formed in neutron capture processes, and the rapid neutron capture (r-) process is responsible for producing half. To fully understand heavy nucleosynthesis through the r process, accurate knowledge of nuclear properties is needed. Frequently, nuclear input is not well constrained, and in lieu of data, extrapolations and theoretical models have to be used. Predictions can diverge over orders of magnitude for basic properties far from stability. One of the most important inputs to the r process is β-decay properties. Theory relies on data to constrain their models and make more reliable predictions for experimentally inaccessible nuclei. Measuring β-decay strength functions is a sensitive benchmark to such theoretical mod-els. This talk will feature preliminary results on neutron-rich Co isotopes, including β-decay strengths, energy levels, level densities and γ-strength functions. The measurements were done at the National Superconducting Cyclotron Laboratory using the SuN detector. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700