SNAQ January 2022

Wednesday 12 Jan 2022, 14:45 → 18:30 Europe/Brussels

online (virtual)

Rosario Gianluca Pizzone (Laboratori Nazionali del Sud, Italy), Aurora Tumino (Kore University of Enna, Italy), Konrad Schmidt (Helmholtz-Zentrum Dresden-Rossendorf, Germany)

ChETEC-INFRA SNAQs [snacks] Schools on Nuclear Astrophysics Questions

Question in January 2022: What is the link between radioactive nuclei and astrophysics?

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Update: Below, all talks are available as PDF for download.

Update: Congratulation to the 3 winners of our SNAQs Scientific Talk Award in recogrecognition and appreciation for giving a scientic talk at the January 2022 edition of SNAQs:

• Kelsey Lund (North Carolina State University)
• Jacobus Swartz (Centre d'Etudes Nucleaires de Bordeaux Gradignan, France)
•  Heinrich Wilsenach (Justus-Liebig-Universität Gießen)

And thanks to all other applicants who submitted an abstract.

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This is the 9th edition of a monthly, virtual school format discussing questions related to nuclear astrophysics.

 

Previous events:

SNAQ Febrauary 2021 SNAQ March 2021 SNAQ April 2021 SNAQ May 2021

SNAQ June 2021 SNAQ October 2021 SNAQ November 2021 SNAQ December 2021

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A new event of SNAQs is organized always on the 2nd Wednesday in each month with a break in summer. SNAQs last about 3.5 hours, including breaks, with lectures and scientific talks around a given question in nuclear astrophysics. Lectures are held by senior researchers and scientific talks preferably by young researchers, as master and PhD students. Further, SNAQs put a special focus on the interaction between participants to allow young scientists networking even if traveling to schools, workshops and conferences is not an option.

SNAQs join the community of schools related to nuclear astrophysics that partner with ChETEC-INFRA:

• Carpathian Summer School of Physics (well established)
• European Summer School on Experimental Nuclear Astrophysics (well established)
• Intercontinental School on Nuclear Astrophysics (new)
• International school on nuclear physics, neutron physics and applications (well established)
• Nuclear Physics in Astrophysics School (new)
• Rußbach School on Nuclear Astrophysics (well established)
• School on observations and spectroscopic tools (new)

The aim of this community is to give all students and young researchers the same, multidisciplinary knowledge about nuclear astrophysics. SNAQs will support this idea and strengthen the community of schools by providing a frequent lecture series to train and educate the next generation of scientist with knowledge across the three types of infrastructures used by nuclear astrophysicists:

• astronuclear laboratories supplying reaction data,
• supercomputer facilities performing stellar structure and nucleosynthesis computations, and
• telescopes and mass spectrometers collecting elemental and isotopic abundance data.

Those infrastructures are networked by ChETEC-INFRA, Chemical Elements as Tracers of the Evolution of the Cosmos - INFRAstructures for Nuclear Astrophysics, a new European starting community of 32 partner institutions.

We are looking forward to meet you at the 9th SNAQ.

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SNAQ January 2022 organizers

SNAQs organizing committee

Gianluca Pizzone (Laboratori Nazionali del Sud, Italy) Aurora Tumino (Kore University of Enna, Italy)

Rosanna Depalo (Università degli Studi di Milano, Italy) Camilla Juul Hansen (TU Darmstadt, Germany) Marcel Heine (Hubert Curien Pluridisciplinary Institute, France) Ann-Cecilie Larsen (University of Oslo, Norway) Andreas Korn (Uppsala University, Sweden) Arūnas Kučinskas (Vilnius University, Lithuania) Sara Palmerini (University of Perugia, Italy) Gianluca Pizzone (Laboratori Nazionali del Sud, Italy) Konrad Schmidt (Helmholtz-Zentrum Dresden-Rossendorf, Germany) Olivier Sorlin (Grand Accélérateur National d'Ions Lourds, France) Livius Trache (Horia Hulubei National Institute for Physics & Nuclear Engineering, Romania) Aurora Tumino (Kore University of Enna, Italy)

Guidelines for participants of SNAQs Please, … … rename yourself in the Zoom sessions to match your registration name and institution – this will serve as your “nametag”. … mute your microphone during talks. … use the public chat only for questions related to the lecture; for discussions, please use the private chat. … write your questions in the chat – due to the high number of participants, a moderator will read a selection of questions but can choose a limited number only. … use breakout rooms to talk and chat to each other in smaller groups. Breakout rooms will be available during coffee breaks and participants can choose rooms freely. … behave professionally and respectfully. … follow ethical standards as professional integrity and honesty. … foster a welcoming and inclusive work environment.

14:45 → 15:00 Zoom room available

15:00 → 15:05 Welcome and Introduction

Speaker: Konrad Schmidt (Helmholtz-Zentrum Dresden-Rossendorf, Germany)

SNAQ_2022_01_1_Konrad_Schmidt.pdf

15:05 → 15:10 European Summer School on Experimental Nuclear Astrophysics

Introduction of the biannual school and invitation for the 11th edition June 12 to 19, 2022

Speaker: Rosario Gianluca Pizzone (Laboratori Nazionali del Sud, Italy)

15:10 → 15:55 Techniques to constrain r-process reaction rates

Speaker: Artemis Spyrou (Michigan State University, USA)

SNAQ_2022_01_3_Artemis_Spyrou.pdf

15:55 → 16:05 Moderated questions

Speaker: Aurora Tumino (Kore University of Enna, Italy)

16:05 → 16:50 Astrophysics and unstable nuclei: Indirect method for radioactive ion beam experiments

Speaker: Giuseppe Gabriele Rapisarda (University of Catania, Italy)

SNAQ_2022_01_4_Giuseppe_Gabriele_Rapisarda.pdf

16:50 → 17:00 Moderated questions

Speaker: Olivier Sorlin (Grand Accélérateur National d'Ions Lourds, France)

17:00 → 17:20 Coffee break and breakout session

Breakout rooms are available to (1) very briefly introduce yourself, (2) talk about the lectures, (3) clarify lecture items, and (4) phrase questions for the round table discussion.

Afterwards, questions can be written in the chat of the main Zoom room. Please tag questions related to lecture 1 with L1 and questions related to lecture 2 with L2. Moderators can only choose a limited number of questions to be discussed at the round table discussion.

This session also povides the opportunity to establish contacts that can be continued using the private chat. Networking is an important tool not only in science.

17:20 → 17:32 Actinide-dating stars: Nuclear uncertainties in cosmic age

Nuclear cosmochronometry is the process of using known radioactive decays and astronomical spectra as a method of determining the ages of stars on cosmic timescales. Particularly useful are measurements of the long-lived isotopes of the actinides Thorium and Uranium, which are produced via the rapid neutron capture process (r-process). The production of these actinides in r-process simulations is sensitive to the nucleosynthetic conditions in which their production occurs. Beta decay rates are an important component in r-process calculations as they set the timescale on which the r-process occurs and play a role in determining the extent to which heavy nuclei are populated. In this talk, I will discuss theoretical uncertainty in astrophysical conditions for the r-process as well as currently unmeasured beta decay rates and how these uncertainties propagate into age predictions for a selection of r-process enhanced, metal-poor stars.

Speaker: Kelsey Lund (North Carolina State University)

SNAQ_2022_01_5_Kelsey_Lund.pdf

17:32 → 17:35 Moderated questions

Speaker: Sara Palmerini (University of Perugia, Italy)

17:35 → 17:47 Determining neutron-induced reaction cross sections through surrogate reactions at storage rings

Investigating the interactions of neutrons with unstable nuclei is crucial to our understanding of nuclear astrophysics as it sheds light on the stellar nucleosynthesis of heavy elements. Obtaining accurate cross section data for neutron-induced reactions on these nuclei presents major experimental challenges since both beam and target are radioactive. The NECTAR (NuclEar reaCTions At storage Rings) project aims to solve this problem by using the surrogate-reaction method, where one may indirectly infer the neutron-induced cross sections of short-lived nuclei, in inverse kinematics. A heavy, radioactive nucleus in the beam is to interact with a light, stable nucleus in the target to produce the compound nucleus formed in the neutron-induced reaction of interest via an alternative or surrogate reaction such as transfer or inelastic scattering. This compound nucleus may decay by fission, neutron or gamma-ray emission, and the probabilities for these modes of decay are to be measured as a function of the excitation energy of the compound nucleus. This information is used to constrain model parameters and to inform more accurate predictions of neutron-induced reaction cross sections. The heavy-ion storage rings at GSI/FAIR in Germany present an ideal laboratory for the development of the surrogate reaction method, which still suffers from various target-related issues. The sustained high beam quality, along with the use of an ultra-thin gas-jet target, makes it possible to measure excitation energies and decay probabilities with an unrivalled accuracy. A first Proof-of-Principle experiment is to be performed during the first half of 2022 at the ESR storage ring facility. The 208Pb(p,p’) reaction will be investigated in inverse kinematics with an incident beam of 208Pb at 30 AMeV. Target residues will be measured with a detector telescope inside the reaction chamber, in coincidence with beam residues using double sided silicon strip detectors downstream after a dipole magnet, thus providing decay probabilities for both neutron and gamma-ray emission. After this first pilot experiment, the NECTAR detection setup will be supplemented with fission fragment detectors, thus enabling for fission, neutron and gamma-ray emission probabilities to be measured simultaneously for the first time at this facility. This presentation will focus on the concept and technical development of NECTAR, as well as the preparation for these experiments at the storage rings of GSI/FAIR. This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC-Advanced grant NECTAR, grant agreement No 884715).

Speaker: Jacobus Swartz (Centre d'Etudes Nucleaires de Bordeaux Gradignan, France)

SNAQ_2022_01_6_Jacobus_Swartz.pdf

17:47 → 17:50 Moderated questions

Speaker: Sara Palmerini (University of Perugia, Italy)

17:50 → 18:02 Triple radio-frequency quadrupole trap system for measuring neutron capture cross sections of short-lived isotopes

One of the current limitations of predicting the nuclear astrophysics r-process abundance is the lack of experimental data on neutron-capture cross-sections of radioactive neutron-rich isotopes. These cross-sections are also invaluable for nuclear reactions and nuclear structure in general. Their measurement is currently considered impossible due to the instability of the targets and projectile. We propose a method to overcome this limitation. We plan to select and store fission fragments in a radio frequency system (coined ‘NG-Trap’), which will form a trapped ‘cloud target’ that will consequently be irradiated by an intense neutron beam. The reacted ions will be mass-selected, identified and counted using a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS), thus extracting (n,γ) cross sections. This talk will mainly focus on the NG-Trap system that will be developed for the Soreq Applied Research Accelerator Facility (SARAF), currently under construction in Yavne, Israel. We will further present an existing triple radio-frequency quadrupole system, which is presently being set up at Tel-Aviv University for research and development of the cloud target concept, and preliminary estimations of event rates for numerous radioactive target isotopes.

Speaker: Heinrich Wilsenach (Justus-Liebig-Universität Gießen)

SNAQ_2022_7_Heinrich_Wilsenach.pdf

18:02 → 18:05 Moderated questions

Speaker: Sara Palmerini (University of Perugia, Italy)

18:05 → 18:25 Round table discussion

Questions that were compiled in the chat during and after lectures and the breakout session will be answered and discussed.