Nuclear Spectroscopy Group

The Nuclear Spectroscopy Group utilises in-beam gamma-ray and electron as well as decay-spectroscopic methods to shed more light on the microscopic structure of the nucleus through the studies of exotic nuclei, mainly along the proton drip line and in the region of heavy elements. These methodologies in conjunction with heavy-ion beams form the backbone for experimental studies of the Nuclear Spectroscopy Group.

Overview

Core fields of research

Basic natural phenomena and mathematical thinking

Research areas

Nuclear and accelerator based physics

Faculty

Faculty of Mathematics and Science

Department

Department of Physics

Research group description

In atomic nuclei, the interplay of three fundamental forces (electromagnetic, strong and weak) between strongly interacting individual fermions generates an effective nucleon-nucleon interaction. As a result, nuclei present us with one of Nature's most intricate examples of the interplay between single-particle motion, collectivity and pairing in a quantum many-body system. A theoretical microscopic description of the nucleus is extremely difficult due to the relatively large number of nucleons, and additional experimental data are needed to validate and develop better nuclear models. The Nuclear Spectroscopy Group utilises in-beam gamma-ray and electron as well as decay-spectroscopic methods to shed more light on the microscopic structure of the nucleus through the studies of exotic nuclei, mainly along the proton drip line and in the region of heavy elements. These methodologies in conjunction with heavy-ion beams form the backbone for experimental studies of the Nuclear Spectroscopy Group.

Shape coexistence in neutron-deficient Hg, Pb, and Po nuclei near the N=104 midshell is considered well established, yet direct spectroscopic evidence remains limited. A key objective of the JYFL experimental programme has been to shed light on these phenomena using complementary in-beam spectroscopic techniques. Notably, the JUROGAM arrays enabled the first direct observation of a prolate structure in the beyond-midshell nucleus ¹⁸⁵Pb and an oblate non-yrast band in the midshell nucleus ¹⁸⁶Pb. The persistence of shape coexistence near the proton dripline was explored in ¹⁸⁰Pb, where prompt γ-rays from proton-unbound states were observed. It is noteworthy that, apart from the excited 0⁺ state in ¹⁸⁴Pb, excited states in Pb isotopes with N≤104 midshell have only been measured at JYFL. Collectivity has also been investigated in ^186,188,190Pb through plunger lifetime measurements. More recently, combined in-beam γ-ray and electron spectroscopy with the SAGE spectrometer led to a reassignment of the shapes of excited 0⁺ states in ¹⁸⁶Pb and the first direct measurement of three different deformations in atomic nucleus.

Experiments performed at JYFL have also led the way in in-beam spectroscopy of very heavy nuclei in the region of ²⁵⁴No. Systematic studies of the rotational bands and high-K structures in these nuclei have led to a wealth of information concerning the underlying shell structure and single-particle states around the Z=100 and N=152 deformed shell gaps. A major milestone was the in-beam study of ²⁴⁶Fm, the nucleus with the lowest production cross-section (~10 nb) investigated to date, conducted at JYFL. This was followed by a landmark experiment on the Z=104nucleus ²⁵⁶Rf, the heaviest nucleus studied in-beam so far and a key gateway to the superheavy element region. Subsequent studies of ²⁵¹Md, ²⁵³No, and ²⁵⁵Lr were conducted using the SAGE spectrometer.

The spectroscopy of N≈Z nuclei has long been of interest due to the wide range of unique phenomena observed in this region of the nuclear chart. These nuclei are also directly relevant to nucleosynthesis, particularly through their role in the rapid proton capture (rp) process via (p,γ) reactions. A distinctive feature of N≈Z nuclei is the potential for neutron–proton (np) pairing. While nucleon pairing is well understood away from the N=Z line, near this line both isovector (T=1) and isoscalar (T=0) np-pairing modes become increasingly significant. A longstanding question remains: how do these different pairing modes manifest in nuclear structure?

To address this, we have exploited the RBT technique to exotic, proton-rich, medium-mass nuclei, whose excited states are still poorly known. Since 2005, several successful RBT experiments have been conducted on nuclei near the N=Z line, including ⁷⁸Rb, ⁷⁸Y, ⁶⁶As, ^70,71Kr, and ⁶⁶Se. These studies have enabled systematic investigations of Coulomb Energy Differences and Triplet Energy Differences in this mass region.

The integration of MARA, JUROGAM 3, JYTube, and advanced focal-plane detectors represents a flagship setup for advancing these studies. Notably, the introduction of the APPA device has enabled lifetime measurements of N≈Z nuclei, providing crucial data to constrain observables such as spectroscopic quadrupole moments (Q_s) obtained from Coulomb excitation experiments at radioactive ion beam facilities.

Current

Members

Research group

Group leaders

Janne Pakarinen

Senior Researcher

Members

Paul Greenlees

Professor, Head of Department

Staff Scientist (teachresea)

Panu Ruotsalainen

Senior Lecturer

Kalle Auranen

Academy Research Fellow

Joonas Ojala

Postdoctoral Researcher

External members

Rauno Julin

Professor Emeritus

University of Jyväskylä

Matti Leino

Professor Emeritus

University of Jyväskylä

Publications

Publication

2023

Spectroscopy along flerovium decay chains. III : Details on experiment, analysis, 282Cn, and spontaneous fission branches

Physical Review C.

Såmark-Roth, A.

Cox, D. M.

Rudolph, D.

Sarmiento, L. G.

Albertsson, M.

Carlsson, B. G.

Egido, J. L.

Golubev, P.

Heery, J.

Yakushev, A.

Åberg, S.

Albers, H. M.

Block, M.

Brand, H.

Calverley, T.

Cantemir, R.

Clark, R. M.

Düllmann, Ch. E.

Eberth, J.

Fahlander, C.

Forsberg, U.

Gates, J. M.

Giacoppo, F.

Götz, M.

Götz, S.

Herzberg, R.-D.

Hrabar, Y.

Jäger, E.

Judson, D.

Khuyagbaatar, J.

Kindler, B.

Kojouharov, I.

Kratz, J. V.

Krier, J.

Kurz, N.

Lens, L.

Ljungberg, J.

Lommel, B.

Louko, J.

Meyer, C.-C.

Mistry, A.

Mokry, C.

Papadakis, P.

Parr, E.

Pore, J. L.

Ragnarsson, I.

Runke, J.

Schädel, M.

Schaffner, H.

Schausten, B.

Shaughnessy, D. A.

Thörle-Pospiech, P.

Trautmann, N.

Uusitalo, J.

Publication

2023

Technical note : Simulation of lung counting applications using Geant4

Physica Medica.

Jutila, Henri

Greenlees, Paul

Torvela, Tiina

Muikku, Maarit

Publication

2023

The spectroscopic quadrupole moment of the 21+ state of 12C : A benchmark of theoretical models

Physics Letters B.

Saiz-Lomas, J.

Petri, M.

Lee, I. Y.

Syndikus, I.

Heil, S.

Allmond, J. M.

Gaffney, L. P.

Pakarinen, J.

Badran, H.

Calverley, T.

Cox, D. M.

Forsberg, U.

Grahn, T.

Greenlees, P.

Hadyńska-Klȩk, K.

Hilton, J.

Jenkinson, M.

Julin, R.

Konki, J.

Macchiavelli, A. O.

Mathy, M.

Ojala, J.

Papadakis, P.

Partanen, J.

Rahkila, P.

Ruotsalainen, P.

Sandzelius, M.

Sarén, J.

Stolze, S.

Uusitalo, J.

Wadsworth, R.

Publication

2023

VADER : A novel decay station for actinide spectroscopy

Nuclear Instruments and Methods in Physics Research. Section B : Beam Interactions with Materials and Atoms.

Raggio, A.

Pohjalainen, I.

Rey-Herme, E.

Beliuskina, O.

Bequet, J.

Block, M.

Eronen, T.

Illana, A.

Jaries, A.

Kankainen, A.

Kumar, D.

Moore, I. D.

Mougeot, M.

Plaza, A. M.

Reponen, M.

Sarén, J.

Sulignano, B.

Stryjczyk, M.

Thisse, D.

Vandebrouck, M.

Warbinek, J.

Publication

2023

β-delayed neutron spectroscopy of 133In

Physical Review C.

Xu, Z. Y.

Madurga, M.

Grzywacz, R.

King, T. T.

Algora, A.

Andreyev, A. N.

Benito, J.

Berry, T.

Borge, M. J. G.

Costache, C.

De Witte, H.

Fijalkowska, A.

Fraile, L. M.

Fynbo, H. O. U.

Gottardo, A.

Halverson, C.

Harkness-Brennan, L. J.

Heideman, J.

Huyse, M.

Illana, A.

Janiak, Ł.

Judson, D. S.

Korgul, A.

Kurtukian-Nieto, T.

Lazarus, I.

Lică, R.

Lozeva, R.

Marginean, N.

Marginean, R.

Mazzocchi, C.

Mihai, C.

Mihai, R. E.

Morales, A. I.

Page, R. D.

Pakarinen, J.

Piersa-Siłkowska, M.

Podolyák, Zs.

Sarriguren, P.

Singh, M.

Sotty, Ch.

Stepaniuk, M.

Tengblad, O.

Turturica, A.

Van Duppen, P.

Vedia, V.

Viñals, S.

Warr, N.

Yokoyama, R.

Yuan, C. X.

Publication

2022

AWAGS : A single ASIC to identify fast ions from protons to uranium

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.

Wieczorek, P.

Flemming, H.

Kurz, N.

Löchner, S.

Nociforo, C.

Schmidt, C.J.

Simon, H.

Voss, B.

Winkler, M.

García, F.

Grahn, Tuomas

Luoma, Minna

Rocco, E.

Publication

2022

Candidate revolving chiral doublet bands in 119Cs

European Physical Journal A.

Zheng, K. K.

Petrache, C. M.

Zhang, Z. H.

Astier, A.

Lv, B. F.

Greenlees, P. T.

Grahn, T.

Julin, R.

Juutinen, S.

Luoma, M.

Ojala, J.

Pakarinen, J.

Partanen, J.

Rahkila, P.

Ruotsalainen, P.

Sandzelius, M.

Sarén, J.

Tann, H.

Uusitalo, J.

Zimba, G.

Cederwall, B.

Aktas, Ö.

Ertoprak, A.

Zhang, W.

Guo, S.

Liu, M. L.

Zhou, X. H.

Kuti, I.

Nyakó, B. M.

Sohler, D.

Timár, J.

Andreoiu, C.

Doncel, M.

Joss, D. T.

Page, R. D.

Publication

2022

Coulomb excitation of 222Rn

Physical Review C.

Spagnoletti, P.

Butler, P. A.

Gaffney, L. P.

Abrahams, K.

Bowry, M.

Cederkäll, J.

Chupp, T.

de Angelis, G.

De Witte, H.

Garrett, P. E.

Goldkuhle, A.

Henrich, C.

Illana, A.

Johnston, K.

Joss, D. T.

Keatings, J. M.

Kelly, N. A.

Komorowska, M.

Konki, J.

Kröll, T.

Lozano, M.

Singh, B. S. Nara

O'Donnell, D.

Ojala, J.

Page, R. D.

Pedersen, L. G.

Raison, C.

Reiter, P.

Rodriguez, J. A.

Rosiak, D.

Rothe, S.

Scheck, M.

Seidlitz, M.

Shneidman, T. M.

Siebeck, B.

Sinclair, J.

Smith, J. F.

Stryjczyk, M.

Van Duppen, P.

Viñals, S.

Virtanen, V.

Wrzosek-Lipska, K.

Warr, N.

Zielińska, M.

Publication

2022

Coulomb excitation of the |Tz|=1/2, A=23 mirror pair

Physical Review C.

Henderson, J.

Hackman, G.

Ruotsalainen, P.

Holt, J. D.

Stroberg, S. R.

Andreoiu, C.

Ball, G. C.

Bernier, N.

Bowry, M.

Caballero-Folch, R.

Cruz, S.

Diaz, Varela A.

Evitts, L. J.

Frederick, R.

Garnsworthy, A. B.

Holl, M.

Lassen, J.

Measures, J.

Olaizola, B.

O'Sullivan, E.

Paetkau, O.

Park, J.

Smallcombe, J.

Svensson, C. E.

Whitmore, K.

Wu, C. Y.

Publication

2022

Decay studies in the A∼225 Po-Fr region from the DESPEC campaign at GSI in 2021

Il Nuovo Cimento C.

Polettini, M.

Pellumaj, J.

Benzoni, G.

Zhang, G.

Mengoni, D.

Vidal, R. M. P.

Genna, D.

Bracco, A.

Aggez, G.

Al Aqueel, M.

Alayed, B.

Albers, H. M.

Algora, A.

Alhomaidhi, S.

Appleton, C.

Arici, T.

Armstrong, M.

Arnswald, K.

Balogh, M.

Banerjee, A.

Blazhev, A.

Bottoni, S.

Boutachkov, P.

Bruce, A.

Bruno, C.

Camera, F.

Cederwall, B.

Chishti, M. M. R.

Cox, D. M.

Crespi, F. C. L.

Das, B.

Davinson, T.

De Angelis, G.

Dickel, T.

Doncel, M.

Donthi, R.

Ertoprak, A.

Escudeiro, R.

Esmaylzadeh, A.

Fraile, L. M.

Gaffney, L.

Gamba, E. R.

Gerl, J.

Gottardo, A.

Ha, J.

Haettner, E.

Hall, O.

Heggen, H.

Hrabar, Y.

Hubbard, N.

Jazrawi, S.

John, P. R.

Jolie, J.

Jones, C.

Joss, D.

Judson, D.

Kahl, D.

Karayonchev, V.

Kazantseva, E.

Kern, R.

Knafla, L.

Kojouharov, I.

Korgul, A.

Korten, W.

Koseoglou, P.

Kosir, G.

Kostyleva, D.

Kurtukian-Nieto, T.

Kurz, N.

Kuzminchuk, N.

Labiche, M.

Lenzi, S.

Leoni, S.

Lozeva, R.

Mertzimekis, T. J.

Mikolajczuk, M.

Million, B.

Mistry, A. K.

Morales, A.

Mukha, I.

Murias, J. R.

Napoli, D.

NaraSingh, B. S.

O'Donnell, D.

Orrigo, S. E. A.

Page, R.

Pelonis, S.

Petrovic, J.

Pietralla, N.

Pietri, S.

Pigliapoco, S.

Podolyak, Z.

Porzio, C.

Arnes, B. Q.

Recchia, F.

Regan, P. H.

Reiter, P.

Rezynkina, K.

Roy, P.

Rudigier, M.

Ruotsalainen, P.

Sahin, E.

Sarmiento, L. G.

Satrazani, M. M.

Schaffner, H.

Scheidenberger, C.

Sexton, L.

Sharma, A.

Smallcombe, J.

Sood, A.

Vasileiou, P.

Vesic, J.

Vilhena, J.

Waring, L.

Weick, H.

Werner, V.

Wiederhold, J.

Wieland, O.

Wimmer, K.

Wollersheim, H. J.

Woods, P.

Yaneva, A.

Zanon, I.

Zhao, J.

Zidarova, R.

Ziliani, S.

Zimba, G.

Zyriliou, A.

Publication

2022

Decay studies of new isomeric states in 255No

Physical Review C.

Bronis, A.

Heßberger, F. P.

Antalic, S.

Andel, B.

Ackermann, D.

Heinz, S.

Hofmann, S.

Khuyagbaatar, J.

Kindler, B.

Kojouharov, I.

Kuusiniemi, P.

Leino, M.

Lommel, B.

Mann, R.

Nishio, K.

Popeko, A. G.

Streicher, B.

Sulignano, B.

Uusitalo, J.

Venhart, M.

Yeremin, A. V.

Publication

2022

Estimating mean lifetime from partially observed events in nuclear physics

Journal of the Royal Statistical Society Series C: Applied Statistics.

Karvanen, Juha

Niilo‐Rämä, Mikko

Sarén, Jan

Kärkkäinen, Salme

Nuclear Spectroscopy Group

Research group description

Research on the structural properties of heavy nuclei

Synthesis of new isotopes and decay spectroscopy near the proton dripline

Nuclear structure studies near and at the N~Z line

Research group

Group leaders

Members

External members

Rauno Julin

Matti Leino

Publications