Scientific Workshop on nu-Ball2 2024 - Reports from the last campaign and prospects for future experiments

3 juil. 2024, 14:00 → 5 juil. 2024, 13:00 Europe/Paris

University of Milan

Giorgia Pasqualato (IJCLab Orsay), Magda Zielinska (CEA Saclay), Simone Bottoni (University of Milano and INFN), Stephan Oberstedt

nu-Ball2 workshop 2024

The next nu-Ball2 hybrid gamma ray spectrometer workshop will be held in-person on the 3-5 of July and hosted by the University of Milano and INFN sez. Milano and sponsored by CAEN S.p.A.

The main aims of the workshop are as follows: 

• To present and discuss progress with data analysis and emerging results from experiments in the recent nu-Ball2 campaign with FATIMA, PARIS+DSSD, at the ALTO facility in 2022 and 2023.
• To learn about complimentary parallel activities at various facilities. 
• To discuss perspectives and potential future experiments and experimental campaigns.

Following previously successful workshops/meetings in JRC-Geel (2018), University of Köln (2019), University of Warsaw (2019) and online (2021), the goal is to present progress on analysis and results and share knowledge. This in-person workshop will reunite collaborators one year after the conclusion of the experimental campaign. There will be time allotted for discussions on data analysis techniques and problem-solving.

To enhance the workshop's content, experts will present and discuss relevant complementary activities at other facilities (AGATA@LNL, FIPPS@ILL, EXOGAM@NFS/GANIL, GRIFFIN@TRIUMF). Finally, there will be presentations and discussions on potential future experiments and campaigns, addressing key questions such as: 

• Future hybrid gamma-ray spectrometers.
• Future spectroscopy of nuclear fission and fast neutron-induced reactions.
• Future experimental campaigns at ALTO and other facilities.

The active participation of postdoctoral fellows and PhD students is strongly encouraged.

There is no registration fee for the workshop, which will start with the afternoon session on the 3rd and conclude after the morning session on the 5th. Please note that lunches and the social dinner scheduled for the 4th are not financially supported.

 

The Organizing Committee:

• Giorgia Pasqualato, IJCLab (France)
• Jonathan Wilson, IJCLab (France)
• Simone Bottoni, INFN-Milano (Italy)
• Silvia Leoni, INFN-Milano (Italy)

 

 

mercredi 3 juillet

14:00 → 14:30 Welcome and registration

14:30 → 17:50 Introduction to the workshop, presentation of detectors and devices

The different detectors used during the campaign (the HPGE clovers and coaxial, the DSSD, the FATIMA and the PARIS array) as well as the LICORNE neutron source and the FASTER acquisition system will be introduced in this section.

14:30 Introduction to the workshop

Presentation of the goals of the workshop and the program. Summary of the performed experiments and devices used during the campaign. Comparison with the previous campaign nuBall1.

Orateur: Giorgia Pasqualato (IJCLab Orsay)

14:40 The nuBall2 project (remote)

NuBall2 experiment was installed at the ALTO facility at IJCLab, Orsay, France. It took data between April 2022 and May 2023. This presentation will give an overview of the life of the detectors between their reception up until all the NuBall2 equipment was removed from the beamline. It will be a good opportunity to list the different equipment that were able to run within NuBall2 as well as the different experiments that were carried out.

Orateur: Dr Gabriel Charles (IJCLab)

15:05 FASTER New features and prospects

FASTER is a new digital modular acquisition system developed at LPC, this contribution will focus on the new features of the current version FASTERV2 and on the main characteristics and the initial results of the new version FASTERV3.

Orateur: David Etasse (LPC Caen)

15:30 The LICORNE inverse kinematic neutron source: Development and perspectives

The LICORNE directional neutron source has been developed and improved over the last ten years at the ALTO facility of IJC Lab. In particular the spectroscopy of neutron-induced reactions has been facilitated with these developments, leading to coupling with the nu-Ball1 and nu-Ball2 spectrometers and several successful experiments/publications. In this presentation I will review the neutron source developments and examine the future potential.

Orateur: Dr Jonathan Wilson (IJC Lab, Orsay, France)

15:55 Coffee Break

16:25 FATIMA: a versatile tool for nuclear physics studies

In this talk I will introduce the fast-timing measurement method. Following, I will give some examples of measurements done with FATIMA over the years. I will also show some lifetime measurements, which is the main reason for the conception of such array, as well as some other results obtained for astrophysical purposes.

Orateur: Dr Sorin Pascu

16:50 PARIS array - status of the project and performance in the nuBall3 campaign

I plan to present the idea behind the PARIS project, its status and outlook. In addition I try to summarize the performance of the PARIS wall geometry used in the nuBall2 campaign.

Orateur: Adam Maj (IFJ PAN)

17:15 The Warsaw SiLCA array - status and perspectives

The SiLCA reaction chamber was designed and developed at the HIL Warsaw to place a DSSD array in the backward scattering angles primarily for the Coulomb excitation studies, with the possibility of using it in different reactions, and with a future perspective of adding more detectors at other angles. It was first commissioned with the Nuball2+PARIS array in December 2022. In the period of January-July 2023 the Warsaw DSSD array was used in a series of experiments. After the campaign, it was shipped to Warsaw and after maintenance, upgrade, and bench-tests, it is ready to be used in the in-beam experiments at HIL Warsaw. In this talk, I will present the past, present, and perspectives of the SiLCA DSSD array.

Orateur: Dr Kasia Hadynska-Klek (Heavy Ion Laboratory University of Warsaw)

18:00 → 19:30 Welcome cocktail

jeudi 4 juillet

09:00 → 10:30 Reports on the experiments - FIRST SESSION (exp. N-SI-120)

09:00 Spectroscopy of neutron-rich fission fragments produced in the 238U(n,f) reaction

Presentation of the N-SI-120 experiment

Orateur: Sorin Pascu

09:10 nuBall2 fission campaign: fast-timing calibration and first results

The applicability of the fast-timing technique within the ν-Ball2 fission campaign during 2022 is discussed. First, a time-walk calibration and time alignment of the LaBr3(Ce) detectors was performed. Then, in order to verify the fast-timing technique, known lifetimes of low-lying excited states in the ps regime are measured using the centroid-shift method. The strongly produced fission fragments 134,136Te served as benchmark cases and new preliminary results are presented.

Orateur: Julia Fischer

09:30 Lifetime measurement of neutron rich Xe isotopes using the fast timing technique (remote)

Using the fast timing technique, the lifetimes of the first yrast states of the fission isotopes 140Xe and 142Xe were determined within the NuBall2 campaign.

Orateur: Andi Messingschlager

09:50 Improvement of the 238U level scheme thanks to γ-spectroscopy

Orateur: Carole Chatel

10:10 Angular momentum removal by neutrons in fission fragments

Orateur: Dorthea Gjestvang

10:30 → 11:00 Coffee Break

11:00 → 12:30 Reports on the experiments - SECOND SESSION

11:00 Current status of the 12C+182W fusion-fission studies analysis

Orateur: Krzysztof Miernik

11:30 High precision spectroscopy of fission shape isomers with Nu-Ball2 : Exploring the gamma back-decay

Orateur: Corentin Hiver (IJCLab)

12:00 Characterization of the de-excitation path of fission fragments during the spontaneous fission of 252Cf

The experiment N-SI-125 aimed at characterizing the de-excitation path of fission fragments during the spontaneous fission of 252Cf by correlating measurement of prompt neutron and gammas and the fission fragment kinematics. For N-SI-125, an ionization chamber containing a 252Cf source was coupled to nu-Ball2 (PARIS geometry) enabling the reconstruction of the kinematics properties of the fission products. The preliminary results from the ongoing data analysis (trace analysis, calibrations, event reconstruction, …) will be presented.

Orateur: Brigitte Pertille-Ritter (IJCLab, Orsay (France))

12:30 → 14:30 Lunch

14:30 → 15:30 Reports on the experiments - THIRD SESSION

14:30 Evidence for enhanced collectivity in 58Fe examined through Coulomb excitation

Orateur: Giorgia Pasqualato (IJCLab Orsay)

15:00 Coulomb excitation of 60Ni at the IJC Lab with the Nuball2+SiLCA DSSD setup

Orateur: Dr Kasia Hadynska-Klek (Heavy Ion Laboratory University of Warsaw)

15:30 → 16:00 Coffee Break

16:00 → 17:00 Reports on the experiments - FOURTH SESSION

16:00 Links between 80Sr compound nucleus’ shape and its residue’s deformation studied with the GDR

Orateur: Michał Ciemała (IFJ PAN Kraków, Polska)

16:30 Investigation of high spin structures in 44Ti and 42Ca via discrete and continuum gamma spectroscopy (to confirm)

Orateur: Magdalena Matejska-Minda (Institute of Nuclear Physics, PAN, Cracow)

17:00 → 18:00 Discussion

19:45 → 21:45 Social dinner

vendredi 5 juillet

09:00 → 13:00 Presentation of parallel complementary activities in other facilities, perspectives for the future experiments and campaigns

09:00 AGATA physics campaign at LNL

My intention is to discuss the general picture of physics cases addressed with AGATA at LNL, with one or two examples presented in more detail, as well as provide information on available ancillary detectors, as well as perspectives of studies in the second part of the campaign involving AGATA at zero degrees.

Orateur: Magda Zielinska (CEA Saclay)

09:25 Nuclear structure after slow neutron reactions at ILL

Thermal neutron induced reactions are used at the Institut Laue-Langevin (ILL, Grenoble) with the high-resolution gamma-ray spectroscopy setup FIPPS (Fission Product Prompt gamma-ray Spectrometer). After a general introduction about the nuclear physics activities at ILL, recent results obtained in different experiments at FIPPS will be reported, including those using the innovative technique of fission tagging for the measurement of lifetimes of medium-high spin states in neutron-rich nuclei. The future perspectives for the coupling of the existing FIPPS setup to a fission-fragment identification system will also be outlined.

Orateur: Caterina Michelagnoli (ILL)

09:50 First EXOGAM campaign at NFS

The EXOGAM array was installed at the NFS beam line at GANIL; Ni and Pb target have been bombarded by fast neutrons up to 40 MeV and the prompt spectroscopy was performed in the vicinity of 58Ni and 208Pb. The detailed gamma-gamma analysis will investigate which part of the level scheme in the recoil is populated in the fast neutron induced reaction. Preliminary results in 57Ni and 57Co will be presented.

Orateur: Emmanuel Clement (CNRS GANIL)

10:15 The GRIFFIN Spectrometer at TRIUMF: Its Capabilities and Science Highlights

In the presentation, I will focus on what we can do with the GRIFFIN spectrometer, it's potential for investigating nuclear structure, and some highlights of work that we have done with it showing examples of studies near stability with very high beam rates, and far from stability and very weak beams.

Orateur: Paul Garrett (University of Guelph)

10:40 Coffee Break

11:05 Spectroscopy of shape isomers: status and perspectives

A survey of decay properties of excited 0+ states in regions of the nuclear chart well known for shape coexistence phenomena has been recently performed. The aim is to identify examples of extreme shape coexistence, namely, coexisting deformed and spherical (or close-to-spherical) nuclear states, with wave functions well separated in the Potential Energy Surface (PES) with coordinates in the deformation space. The Hindrance Factor (HF) of the E2 transitions de-exciting 0+ states is a primary quantity which is used to differentiate between types of shape coexistence. It is found that a limited number of 0+ excitations (in the Ni, Sr, Zr and Cd regions) exhibit large HF values (>10), few of them being associated with a clear separation of coexisting wave functions, while in most cases the decay is not hindered, due to the mixing between different configurations.

Orateur: Silvia Leoni (University of Milano and INFFN Milano)

11:30 Perspective about spontaneous fission studies

Orateur: Matthieu Lebois (IJCLab/Univ. Paris-SAclay)

11:55 Nuclear Fission – interesting questions after 85 years

Since the discovery of nuclear fission, more than 85 years ago, many properties of this complex process could be unraveled. A variety of experimental data, obtained with increasingly complex instrument setups, like e.g., nu-Ball and nu-Ball2, have shaped and improved our understanding of fission, with impact on both nuclear modelling and nuclear applications. A few of the still open questions will be addressed and possible experiments discussed, which may help to provide satisfactory answers.

Orateur: Stephan Oberstedt

12:20 Future possibilities for gamma-ray spectroscopy of fission in direct kinematics

The gamma ray spectroscopy of nuclear fission provides a very useful tool to study both the nuclear structure of neutron-rich nuclei and the fission process itself. Spectroscopy in direct kinematics allows the fission fragments to stop in 1-2 ps and hence allows spectroscopic study with the intrinsic resolution of Germanium without Doppler broadening. In this presentation I will focus on ideas for future experiments on fission spectroscopy and potential future projects at ALTO and other facilities such as EXOGAM@NFS and AGATA@Legnaro.

Orateur: Dr Jonathan Wilson (IJC Lab, Orsay, France)