Exotic nuclei and beams (IGISOL)

The exotic nuclei and beams group studies properties of nuclei employing a novel combination of ion manipulation techniques, mass spectrometry, laser and decay spectroscopy at the IGISOL facility. The research conducted in the group furthers our understanding of nuclear structure and provides essential data for nuclear astrophysics, neutrino physics, fundamental interactions as well as for applications.

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

The exotic nuclei and beams group exploits the universal ion guide production method at the IGISOL facility to explore short-lived exotic nuclei. In addition, our research takes place also at other laboratories, such as the ISOLDE facility in CERN, and Helmholzzentrum GSI, the location of the future radioactive beam facility FAIR. These international activities are done in close collaboration with HIP, the Helsinki Institute of Physics.

The research is strongly supported by the Research Council of Finland (RCF), with several research projects ongoing. Dr. Mikael Reponen is leading the experimental part of the "Nuclear properties at the N=Z line (NUANZ)" project 2025-2029. While NUANZ focuses on laser spectroscopy, Academy research fellow Zhuang Ge's project "Mass measurements of exotic N=Z nuclei (up to 100Sn) and the vicinity for nuclear physics and nuclear astrophysics studies" (2023-2027) provides information on masses. Prof. Anu Kankainen is leading "Heavy Exotic Nuclei for Nuclear Astrophysics" (2023-2027) RCF project. In 2026, she will start her academy professorship project "Nuclei – the Structure and Origin of Matter" (2026-2031). She also leads a research team in the new RCF Centre of Excellence (CoE) in Neutron-Star Physics (2026-2033).

We also benefit from the Euratom Research and Training Programme (EURATOM) which funds the "Addressing PRiorities of Evaluated Nuclear Data in Europe" (APRENDE) project (2024-2028).

Selected publications

IGISOL Portrait - three decades of research. The "IGISOL Portrait - three decades of research" is a collection of articles describing the research conducted using the ion guide technique at IGISOL.

Ion traps in nuclear physics—Recent results and achievements. T. Eronen, A. Kankainen, and J. Äystö, Progress in Particle and Nuclear Physics 91, 259-293 (2016). [Open Access: JYX]

Laser spectroscopy for nuclear structure physics. P. Campbell, I.D. Moore and M.R. Pearson, Progress in Particle and Nuclear Physics 86, 127-180 (2016) [Open Access: JYX]

Research

Nuclear Astrophysics

Almost all chemical elements have been created via nuclear reactions in stars. The multimessenger observations, the gravitational wave event GW170817 and its electromagnetic counterparts, gave the first direct evidence that elements heavier than iron are created via the rapid neutron capture process (the r process) in a merger of two neutron stars. New fascinating observations are anticipated in coming years. In order to understand and model the r process in detail, precise data on the properties of neutron-rich nuclei, such as their masses, are required. These can be obtained with the JYFLTRAP Penning trap. Recently commissioned PI-ICR technique provides new opportunities for mass measurements of exotic nuclei at JYFLTRAP.

The properties of exotic nuclei and their reactions play also a key role in novae, type I x-ray bursts, and in the core collapse of supernovae. Our aim is to provide crucial and more reliable nuclear physics inputs for modeling these astronomical events and related nucleosynthesis. The experimental programme is mainly carried out at the IGISOL facility, and is complemented by experiments at other international radioactive ion beam facilities.

A. Kankainen et al., Physics Letters B 813, 136033 (2021). [Open Access: JYX]
Decay of the key 92-keV resonance in the 25Mg(p,γ) reaction to the ground and isomeric states of the cosmic γ-ray emitter 26Al
D.A. Nesterenko et al., Physics Letters B 808, 135642 (2020). [Open Access: JYX]
Three beta-decaying states in 128In and 130In resolved for the first time using Penning-trap techniques
L. Canete et al., Physical Review C 101, 041304(R) (2020). [Open Access: JYX]
Precision mass measurements of 67Fe and 69,70Co: Nuclear structure toward N = 40 and impact on r-process reaction rates
M. Vilén et al., Physical Review C 101, 034312 (2020). [Open Access:JYX]
Exploring the mass surface near the rare-earth abundance peak via precision mass measurements at JYFLTRA
A. Kankainen et al., Hyperfine Interactions 241, 43 (2020). [Open Access: JYX]
Recent experiments at the JYFLTRAP Penning trap
O. Kirsebom et al., Physical Review Letters 123, 262701 (2019). [Open Access: JYX]
Discovery of an Exceptionally Strong β-Decay Transition of ²⁰F and Implications for the Fate of Intermediate-Mass Stars. Editor's Suggestion with a Physics Viewpoint.
C.J. Horowitz et al., Journal of Physics G: Nuclear and Particle Physics 46, 083001 (2019). [Open Access: arXiv]
r-process nucleosynthesis : connecting rare-isotope beam facilities with the cosmos
D. Kahl et al., Physics Letters B 797, 134803 (2019). [Open Access]
Single-particle shell strengths near the doubly magic nucleus ⁵⁶Ni and the ⁵⁶Ni(p,γ)⁵⁷Cu reaction rate in explosive astrophysical burning
M. Vilen, A. Kankainen et al., Physical Review C 100, 054333 (2019). [Open Access: JYX]
High-precision mass measurements and production of neutron-deficient isotopes using heavy-ion beams at IGISOL
C.V. Hampton et al., Proceedings in Physics 219, 367-372 (2019). [Open Access: JYX or arXiv]
Women Scientists Who Made Nuclear Astrophysics
L. Canete, PhD thesis, University of Jyväskylä (2019).
High precision mass measurements for nuclear astrophysics
M. Vilen, PhD thesis, University of Jyväskylä (2019).
Mass measurements and production of ions at IGISOL for the astrophysical r- and rp-processes
M. Vilen, J. M. Kelly, A. Kankainen, M. Brodeur et al., Physical Review Letters 120, 262701 (2018). [Open Access: JYX]
Precision Mass Measurements on Neutron-Rich Rare-Earth Isotopes at JYFLTRAP: Reduced Neutron Pairing and Implications for r-Process Calculations
A. Kankainen, P.J. Woods et al., Physics Letters B 769, 549 (2017). [Open Access]
Measurement of key resonance states for the ³⁰P(p,γ)³¹S reaction rate, and the production of intermediate-mass elements in nova explosions
A. Kankainen, L. Canete et al., Physical Review C 93, 041304(R) (2016). [Open Access: JYX]
Mass of astrophysically relevant ³¹Cl and the breakdown of the isobaric multiplet mass equation

Weak interaction studies

Weak interaction is one of the four known fundamental interactions of nature. It is, for example, responsible for nuclear beta decay process, where proton is transformed to neutron or vice versa in the nucleus of an atom. At the same time also a positron and a neutrino (or electron and an anti-neutrino) is emitted. The energy released in the decay is distributed between the three particles -- each time in differently, underlying the challenges in studying beta decay.

The amount of energy released in the decay (also known as the Q-value) is one of the key quantities in these studies. Recently, through advances in atomic mass spectrometry, the most precise way of measuring a Q-value is through a mass difference measurement of the decay-parent and daughters. The energy is obtained using the mass-energy equivalence formula E=mc², where E is the decay energy, m the mass difference and c the speed of light.

Enhancing Decay Spectroscopy with Purified Beams

In the realm of decay spectroscopy, the presence of radiation from contaminant isotopes with high production yields often poses a challenge. At IGISOL, we address this challenge through various purification methods. Initially, a 55-degree dipole magnet is employed for preliminary mass separation. Subsequently, the JYFLTRAP Penning trap, and soon the MR-TOF (Multi-Reflection Time-Of-Flight) mass spectrometer, are utilized to selectively isolate the desired isotope or even its specific isomeric state for in-depth decay studies.

Our research is fostered by collaborative efforts with international research groups. These partnerships provide invaluable support in terms of both manpower and resources. To leverage the ultra-pure beams available at IGISOL, we have deployed a range of advanced detection setups. Notable among these are the BELEN beta-delayed neutron detector, the Decay Total Absorption Spectrometer (DTAS), the TAsca Small Image mode Spectroscopy setup (TASISpec), and the beta-gamma coincidence setup (its HPGe detector array in a four-pack configuration is depicted in the accompanying photo). The latter comprises six germanium detectors, financed under the project "Multidetector Spectrometer of Low-Energy Gamma Photons" by J. Kurpeta, A. Płochocki, T. Rza̧ca-Urban, and W. Urban, and supported by the Polish Ministry of Science and Higher Education in 2013 (decision no. 6341/IA/115/2013). Furthermore, a new beta coincidence detector for the beta-gamma coincidence setup has been constructed with assistance from the National Centre for Nuclear Research in Poland.

Scientists from University of Jyväskyla, National Centre for Nuclear Research and University of Warsaw made an agreement to construct a beam line suitable to connect the MR-TOF facility to the beta-gamma spectroscopy setup. The beam line is under construction. When completed, the exotic nuclei of much shorter half-lives will be available to studies.

In a significant milestone, the Modular Neutron Spectrometer (MONSTER) designed for the FAIR facility was successfully commissioned with ⁸⁵As at IGISOL in March 2019, as detailed in our press release. The future holds promising prospects for MONSTER experiments at IGISOL.

Betagamma detector setup for posttrap spectroscopy at IGISOL.

V. Guadilla et al., Phys. Rev. Lett. 122, 042502 (2019). [Open Access: JYX] Large Impact of the Decay of Niobium Isomers on the Reactor Antineutrino Summation Calculations
V. Guadilla et al., Phys. Rev. C 100, 044305 (2019). [Open Access: JYX]
Total absorption γ-ray spectroscopy of the β-delayed neutron emitters ¹³⁷I and ⁹⁵Rb.
J. Kurpeta et al., Phys. Rev. C 100, 034316 (2019). [Open Access: JYX]
First β-decay scheme of ¹⁰⁷Nb : New insight into the low-energy levels of ¹⁰⁷Mo.
Ch. Lorenz et al., Phys. Rev. C 99, 044310 (2019). [Open Access: JYX]
β decay of ¹²⁷Cd and excited states in ¹²⁷In
J. Wisniewski et al., Phys. Rev. C 100, 054331 (2019). [Open Access: JYX]
Excited states in ⁸⁷Br populated in β decay of ⁸⁷Se

Fission studies

Charged particle induced fission has since 1980's utilised at IGISOL to produce neutron rich nuclei for spectroscopy. Since the ions extracted from the ion guide are primary fission products, and ions of any element can be extracted within tens of milliseconds, the technique is suitable for fission product yield distribution measurements, allowing studies of the fission process itself. Identification of the fission products on the basis of their mass with JYFLTRAP further enhances the FY measurements. In addition to charged particle induced fission, neutron induced fission can be studied utilising a recently build neutron converter.

V. Rakopoulos et al., Physical Review C 99, 014617 (2019). [Open Access: JYX].
Isomeric fission yield ratios for odd-mass Cd and In isotopes using the phase-imaging ion-cyclotron-resonance technique
A. Mattera et al. European Physical Journal A 54, 33 (2018). [Open Access: JYX].
Production of Sn and Sb isotopes in high-energy neutron-induced fission of ^natU
V. Rakopoulos et al., Physical Review C 98, 024612 (2018). [Open Access: JYX].
First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments
H. Penttilä, et al., Eur. Phys. J. A 48,43 (2012). [Open Access: link] Fission yield studies at the IGISOL facility
D. Gorelov, et al., Nuclear Instruments and Methods B 376, 46 - 51 (2016). [Open Access: JYX]
Developments for neutron-induced fission at IGISOL–4
A. Mattera, et al., Eur. Phys. J. A 53, 173. (2017). [Open Access: JYX]
A neutron source for IGISOL-JYFLTRAP: Design and characterisation

Optical spectroscopy

The structure and properties of atomic nuclei can be measured using many different techniques. One important class of techniques uses lasers to probe the energy levels of the electrons which are bound to the nucleus, in order to access the electromagnetic nuclear moments, the nuclear spin, and the changes in the size of the nucleus. These observables provide unique insight into the configuration of atomic nuclei, the purity of their wavefunctions, their shape and deformation and their nuclear sizes. Thus, they are exceptionally potent tests for nuclear models.

Optical spectroscopy techniques yield very precise values for these nuclear observables and can be applied even to short-lived isotopes produced with relatively low production rates. At the IGISOL laboratory, we currently have three experimental laser spectroscopy stations which offer a different compromise between experimental efficiency and resolution.

In addition to these spectroscopy experiments, we also house two experiments which rely on lasers to manipulate the properties of atoms or ions placed inside of traps. The aim of these projects is to look for physics beyond the standard model through precision beta-decay studies (MORA), and to realize the first experimental demonstration of gamma-ray coherent emission by means of super-radiance in a Bose-Einstein condensate of 135mCs isomers (GAMMALAS).

The collinear laser spectroscopy technique provides high resolution measurements of the nuclear size and electromagnetic moments. This method relies on the excitation of electrons of an isotope from the energy levels of a low-lying hyperfine manifold to those of an excited state using continuous wave lasers, followed by detection of the subsequent de-excitation. This is achieved by counting the fluorescence emitted by the atoms, using a photomultiplier tube. The energy difference between the hyperfine levels is sensitive to the nuclear properties and thus allows for their precise measurement. The high experimental resolution is achieved by performing the experiment in a collinear geometry, meaning that the ion beam and the laser beam are propagating along the same axis. Because the ion beam is accelerated to a high velocity (beam energy of 30 keV), Doppler broadening effects are thus suppressed.

The measured nuclear properties can be used to test our understanding of the nuclear many-body problem. As the nuclear magnetic moment probes the single particle nature of the nucleus while the quadrupole moment is related to the collective behavior, these properties combined provide crucial information about the complex interactions between the protons and neutrons inside the atomic nucleus. In addition to the electromagnetic moments, the changes in the nuclear charge radius of the radioactive isotopes with respect to the stable isotope can also be extracted from the laser spectroscopy measurements. This gives access to the variation of the nuclear charge distribution along an isotopic chain and provides information on both the bulk properties of nuclear matter and the details of nucleon-nucleon interactions.

Operating at the intersection of nuclear and atomic physics, this technique can also be used for the measurement of the atomic properties such as the hyperfine parameters or the atomic field and mass shift constants.

The RAPTOR project - RIS And Purification Traps for Optimised spectRoscopy

The RAPTOR project was initiated to provide a more efficient variant of collinear laser spectroscopy, though with a trade-off some in terms of the high precision of that method. The beamline is currently (2021) under commissioning; first results are expected in the coming months.

The RAPTOR beamline is designed to accept ion beams with a variable beam energy between 1 and 10 keV. This means that the Doppler broadening is suppressed less as compared to standard collinear laser spectroscopy, but gives the device a small footprint and provides longer interaction times between the atoms and the lasers. Rather than monitoring the excitation of the atoms via the detection of their spontaneous decay, instead a step-wise laser ionization process is used. Thus, more efficient charged-particle detection can be employed. The device is thus particularly well suited to the study of isotopes produced at very low rates and/or with very short lifetimes, but where the highest precision is not required to extract nuclear information.

The fact that atoms are laser ionized inside the RAPTOR beamline means they can then be further manipulated, for example to perform an additional purification. The lab has therefore also developed the capability of injecting ions from the RAPTOR beamline directly into the double-Penning trap mass spectrometer. Thus, ultra-low background hyperfine spectra can be obtained, free from any contribution of isobaric beam contamination.

The long interaction times offered by the use of slower beams also makes it possible to perform laser-radiofrequency double resonance spectroscopy, which offers superior precision on hyperfine constants of the atomic ground state, but provides no information on the excited atomic states. Thus, it is an ideal tool to measure higher-order nuclear moments or hyperfine anomalies, but is not sensitive to changes in the nuclear charge radius.

This project was funded by the Marie Skłodowska-Curie grant agreement No 844829.

IGISOL facility

The IGISOL (Ion Guide Isotope Separation On-Line) mass separator is the heart of the research infrastructure of the Exotic Nuclei and Beams -group. The facility is located in the newer part of the JYFL Accelerator Laboratory built around 10 years ago. IGISOL produces a broad range of low-energy (30 keV) radioactive and stable ion beams for studies of atomic nuclei and their properties.

Ion guides

The radioactive ions are produced with different kinds of techniques at the IGISOL (Ion Guide Isotope Separator On-Line) facility. We do active research and development work related to the ion guide method, gas cells and related production techniques.

The IGISOL method is fast, sub-ms technique for producing low-energy radioactive ion beams. It was developed in Jyväskylä in early 1980s. The IGISOL technique is chemically insensitive, and thus makes it possible to produce radioactive beams of all elements, including refractory elements usually difficult to produce at ISOL facilities. The basic idea, stopping of ions in gas with a swift extraction of radioactive ion beams, has been adopted in many major accelerator facilities worldwide over the years.

For example the following ion guides or ion sources have been used or developed at IGISOL:

Light-ion ion guide for fusion-evaporation reactions with p or d beams
Heavy-ion ion guide HIGISOL for heavy ion fusion-evaporation reactions
Fission ion guide for proton- or deuteron-induced fission
Fission ion guide designed for neutron-induced fission
Ion guide for multinucleon-transfer reactions
Hot cavity laser ion source
Off-line ion source station for stable ion beams

References to main publications describing the technique
The IGISOL technique—three decades of developments
Hyperfine Interactions 223, 17 (2014). [Open Access: link ]
I. D. Moore, P. Dendooven, J. Ärje
Production of neutron deficient rare isotope beams at IGISOL; on-line and off-line studies
Nuclear Instruments and Methods in Physics Research B 222 (2004) 632
J. Huikari et al.
Development and applications of the IGISOL technique
Nuclear Physics A 693 (2001) 477–494
J. Äystö
An inductively heated hot cavity catcher laser ion source
Review of Scientific Instruments 86, 123501 (2015)
M. Reponen et al.
Developments for neutron-induced fission at IGISOL-4
Nuclear Instruments and Methods in Physics Research B 376, 46 (2016).
[Open Access: JYX]
D. Gorelov et al.
Simulations of the fission-product stopping efficiency in IGISOL
European Physical Journal A 51, 59 (2015). [Open Access: JYX]
A. Al-Adili et al.
A new off-line ion source facility at IGISOL
Nuclear Instruments and Methods in Physics Research Section A 263, 382-383 (2020).
[Open Access: arXiv]
M. Vilen et al.

Radio-Frequency Quadrupole (RFQ) Cooler and Buncher

The RFQ cooler and buncher cools the ions and converts the continuous radioactive ion beam into narrow ion bunches. The ejected bunches are further used in different kinds of ion trapping and laser spectroscopy experiments. The RFQ cooler and buncher was developed and commissioned at IGISOL already in early 2000s. Details can be found from:

V. Virtanen et al., Nucl. Instrum. Meth. Phys. Res. A 1072 (2025) 170186
Miniaturised cooler-buncher for reduction of longitudinal emittance at IGISOL
A. Nieminen et al., Nucl. Instrum. Meth. Phys. Res. A 469 (2001) 244
Beam cooler for low-energy radioactive ions
A. Nieminen et al., Phys. Rev. Lett. 88 (2002) 094801
On-Line Ion Cooling and Bunching for Collinear Laser Spectroscopy

A new cooler-buncher for NUSTAR at FAIR has also been designed, constructed and commissioned at IGISOL:

A. Jaries et al., Nucl. Instrum. Meth. Phys. Res. A 1073 (2025) 170273
HIBISCUS: A new ion beam radio-frequency quadrupole cooler-buncher for high-precision experiments with exotic radioactive ions

JYFLTRAP Double Penning Trap Mass Spectrometer

JYFLTRAP is a cylindrical double Penning trap mass spectrometer at IGISOL. It is located inside a 7 T superconducting solenoid.

Details of the trap and used measurement methods can be found from:

JYFLTRAP: a Penning trap for precision mass spectroscopy and isobaric purification
T. Eronen et al., European Physical Journal A 48, 46 (2012). [Open Access: JYX].

Phase-Imaging Ion-Cyclotron-Resonance technique at the JYFLTRAP double Penning trap mass spectrometer
D.A. Nesterenko et al., European Physical Journal A 54, 154 (2018). [Open Access: JYX]

Study of radial motion phase advance during motion excitations in a Penning trap and accuracy of JYFLTRAP mass spectrometer
D.A. Nesterenko et al., European Physical Journal A 57, 302 (2021). Open Access.

Multi-Reflection Time-of-Flight Mass Spectrometer (MR-ToF-MS)

The Multi-Reflection Time-of-Flight Mass Spectrometer (MR-ToF-MS) at IGISOL consists of six electrode pairs that form a nearly energy-isochronous potential and a pulsed drift-tube, which traps the ions between the electrodes. With the MR-ToF-MS, mass-resolving powers of around 150 000 within 20 ms have been demonstrated. In addition to atomic mass measurements of short-lived exotic nuclides, the MR-ToF-MS can be used as a fast mass separator for various other experiments at IGISOL and as an ion counter for laser spectroscopy and yield measurements.

High-resolution multi-reflection time-of-flight mass spectrometer for exotic nuclei at IGISOL
V.A. Virtanen, T. Eronen, A. Kankainen, O. Beliuskina, Z. Ge, R.P. de Groote, A. Jokinen, M. Mougeot, A. de Roubin, J. Ruotsalainen, J. Sarén, and A. Takkinen
arXiv:2508.10048 [physics.ins-det]

Mass separation and atomic mass measurements of exotic radioactive nuclides with a multi-reflection time-of-flight mass spectrometer at the ion-guide isotope separator on-line facility
Ville Virtanen, PhD thesis, University of Jyväskylä (2025).
https://urn.fi/URN:ISBN:978-952-86-1036-6

Current

Projects

Members

Research group

Group leaders

Ari Jokinen

Professor

Members

Staff scientist, Title of Docent

Zhuang Ge

Academy Research Fellow

Simon Rausch

Postdoctoral Researcher

Brian Kootte

Postdoctoral Researcher

Wirunchana Rattanasakuldilok

Doctoral Researcher

Ville Virtanen

Postdoctoral Researcher

Luis Motilla Martinez

Doctoral Researcher

External members

Saikumar Chinthakayala

Doctoral researcher

University of Jyväskylä & University of Caen

Publications

Publication

2019

First β-decay scheme of 107Nb : New insight into the low-energy levels of 107Mo

Physical Review C.

Kurpeta, J.

Płochocki, A.

Urban, W.

Abramuk, A.

Canete, L.

Eronen, T.

Fijałkowska, A

Geldhof, S.

Gotowicka, K.

Jokinen, A.

Kankainen, A.

Moore, I. D.

Nesterenko, D.

Penttilä, H.

Pohjalainen, I.

Pomorski, M.

Reponen, M.

Rinta-Antila, S.

de Roubin, A.

Rząca-Urban, T.

Vilén, M.

Wiśniewski, J.

Publication

2019

High-precision mass measurements and production of neutron-deficient isotopes using heavy-ion beams at IGISOL

Physical Review C.

Vilén, M.

Kankainen, A.

Baczyk, P.

Canete, L.

Dobaczewski, J.

Eronen, T.

Geldhof, S.

Jokinen, A.

Konieczka, M.

Kostensalo, J.

Moore, I. D.

Nesterenko, D. A.

Penttilä, H.

Pohjalainen, I.

Reponen, M.

Rinta-Antila, S.

de Roubin, A.

Satula, W.

Suhonen, J.

Publication

2019

High-precision measurement of the mass difference between 102Pd and 102Ru

International Journal of Mass Spectrometry.

Nesterenko, Dmitrii

Canete, Laetitia

Eronen, Tommi

Jokinen, Ari

Kankainen, Anu

Novikov, Yu.N.

Rinta-Antila, Sami

de Roubin, Antoine

Vilén, Markus

Publication

2019

Isomeric fission yield ratios for odd-mass Cd and In isotopes using the phase-imaging ion-cyclotron-resonance technique

Physical Review C.

Rakopoulos, V.

Lantz, M.

Pomp, S.

Solders, A.

Al-Adili, A.

Canete, Laetitia

Eronen, Tommi

Jokinen, Ari

Kankainen, Anu

Mattera, A.

Moore, Iain

Nesterenko, Dmitrii

Reponen, Mikael

Rinta-Antila, Sami

de Roubin, Antoine

Vilén, Markus

Österlund, M.

Penttilä, Heikki

Publication

2019

Measurement of the 2+→0+ ground-state transition in the β decay of 20F

Physical Review C.

Kirsebom, O. S.

Hukkanen, M.

Kankainen, A.

Trzaska, W. H.

Strömberg, D. F.

Martínez-Pinedo, G.

Andersen, K.

Bodewits, E.

Brown, B. A.

Canete, L.

Cederkäll, J.

Enqvist, T.

Eronen, T.

Fynbo, H. O. U.

Geldhof, S.

de Groote, R., Jenkins, D. G.

Jokinen, A.

Joshi, P.

Khanam, A.

Kostensalo, J.

Kuusiniemi, P.

Langanke, K.

Moore, I.

Munch, M.

Nesterenko, D. A.

Ovejas, J. D.

Penttilä, H.

Pohjalainen, I.

Reponen, M.

Rinta-Antila, S.

Riisager, K.

de Roubin, A.

Schotanus, P.

Srivastava, P. C.

Suhonen, J.

Swartz, J. A.

Tengblad, O.

Vilen, M.

Vínals, S.

Äystö, J.

Publication

2019

r-process nucleosynthesis : connecting rare-isotope beam facilities with the cosmos

Journal of Physics G: Nuclear and Particle Physics.

Horowitz, C. J.

Arcones, A

Côté, B.

Dillmann, I.

Nazarewicz, W.

Roederer, U. I.

Schatz, H.

Aprahamian, A.

Atanasov, D.

Bauswein, A.

Beers, T., C.

Bliss, J.

Brodeur, M.

Clark, J. A.

Frebel, A.

Foucart, F.

Hansen, C. J.

Just, O.

Kankainen, A

McLaughlin, G. C

Kelly, J. M.

Liddick, S. N.

Lee, D. M.

Lippuner, J.

Martin, D.

Mendoza-Temis, J.

Metzger, B. D.

Mumpower, M. R.

Perdikakis, G.

Pereira, J.

O'Shea, B. W.

Reifarth, R.

Rogers, A. M.

Siegel, D. M.

Spyrou, A.

Surman, R.

Tang, X

Uesaka, T.

Wang, M.

Publication

2019

β decay of 127Cd and excited states in 127In

Physical Review C.

Lorenz, Ch.

Sarmiento, L. G.

Rudolph, D.

Golubev, P.

Eronen, Tommi

Nesterenko, Dmitrii

Kankainen, Anu

Canete, Laetitia

Cox, Daniel

Fernandez, A.

Forsberg, U.

Jungclaus, A.

Kojouharov, I.

Kurz, N.

Lalovic, N.

Partanen, Jari

Reponen, Mikael

Rinta-Antila, Sami

de Roubin, Antoine

Såmark-Roth, A.

Vaquero, V.

Vilén, Markus

Publication

2018

First determination of β-delayed multiple neutron emission beyond A = 100 through direct neutron measurement : The P2n value of 136Sb

Physical Review C.

Caballero-Folch, R.

Dillmann, I.

Agramunt, J.

Taín, J. L.

Algora, A.

Äystö, Juha

Calviño, F.

Canete, Laetitia

Cortès, G.

Domingo-Pardo, C.

Eronen, Tommi

Ganioglu, E.

Gelletly, W.

Gorelov, Dmitry

Guadilla, V.

Hakala, Jani

Jokinen, Ari

Kankainen, Anu

Kolhinen, Veli

Koponen, Jukka

Marta, M.

Mendoza, E.

Montaner-Pizá, A.

Moore, Iain

Nobs, C. R.

Orrigo, S. E. A.

Penttilä, Heikki

Pohjalainen, Ilkka

Reinikainen, Juuso

Riego, A.

Rinta-Antila, Sami

Rubio, B.

Salvador-Castiñeira, P.

Simutkin, Vasily

Tarifeño-Saldivia, A.

Tolosa-Delgado, A.

Voss, Annika

Publication

2018

First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments

Physical Review C.

Rakopoulos, V.

Lantz, M.

Solders, A.

Al-Adili, A.

Mattera, A.

Canete, Laetitia

Eronen, Tommi

Gorelov, Dmitry

Jokinen, Ari

Kankainen, Anu

Kolhinen, Veli

Moore, Iain

Nesterenko, Dmitrii

Penttilä, Heikki

Pohjalainen, Ilkka

Rinta-Antila, Sami

Simutkin, V.

Vilén, Markus

Voss, Annika

Pomp, S.

Publication

2018

Phase-Imaging Ion-Cyclotron-Resonance technique at the JYFLTRAP double Penning trap mass spectrometer

European Physical Journal A.

Nesterenko, Dmitrii

Eronen, Tommi

Kankainen, Anu

Canete, Laetitia

Jokinen, Ari

Moore, Iain

Penttilä, Heikki

Rinta-Antila, Sami

de Roubin, Antoine

Vilén, Markus

Publication

2018

Precision Mass Measurements on Neutron-Rich Rare-Earth Isotopes at JYFLTRAP : Reduced Neutron Pairing and Implications for r-Process Calculations

Physical Review Letters.

Vilén, Markus

Kelly, J. M.

Kankainen, Anu

Brodeur, M.

Aprahamian, A.

Canete, Laetitia

Eronen, Tommi

Jokinen, Ari

Kuta, T.

Moore, Iain

Mumpower, M. R.

Nesterenko, Dmitrii

Penttilä, Heikki

Pohjalainen, Ilkka

Porter, W. S.

Rinta-Antila, Sami

Surman, R.

Voss, Annika

Äystö, Juha

Publication

2018

Production of Sn and Sb isotopes in high-energy neutron-induced fission of natU

European Physical Journal A.

Mattera, A.

Pomp, S.

Lantz, M.

Rakopoulos, V.

Solders, A.

Al-Adili, A.

Penttilä, Heikki

Moore, Iain

Rinta-Antila, Sami

Eronen, Tommi

Kankainen, Anu

Pohjalainen, Ilkka

Gorelov, Dmitry

Canete, Laetitia

Nesterenko, Dmitrii

Vilén, Markus

Äystö, Juha

Publications

Publication

2024

Isospin symmetry breaking in the T=1, A=70 triplet

Physical Review C.

Zimba, G. L.

Ruotsalainen, P.

De Gregorio, G.

de Angelis, G.

Sarén, J.

Uusitalo, J.

Auranen, K.

Briscoe A., D.

Ge, Z.

Grahn, T.

Greenlees, P. T.

Illana, A.

Jenkins, D. G.

Joukainen, H.

Julin, R.

Jutila, H.

Kankainen, A.

Louko, J.

Luoma, M.

Ojala, J.

Pakarinen, J.

Raggio, A.

Rahkila, P.

Romero, J.

Stryjczyk, M.

Tolosa-Delgado, A.

Wadsworth, R.

Zadvornaya, A.

Publication

2024

Long-sought isomer turns out to be the ground state of 76Cu

Physics Letters B.

Canete, L.

Giraud, S.

Kankainen, A.

Bastin, B.

Nowacki, F.

Ascher, P.

Eronen, T.

Girard Alcindor, V.

Jokinen, A.

Khanam, A.

Moore, I. D.

Nesterenko, D.

De Oliveira, F.

Penttilä, H.

Petrone, C.

Pohjalainen, I.

De Roubin, A.

Rubchenya, V.

Vilen, M.

Äystö, J.

Publication

2024

Mass measurements in the 132Sn region with the JYFLTRAP double Penning trap mass spectrometer

Physical Review C.

Beliuskina, O.

Nesterenko, D. A.

Jaries, A.

Stryjczyk, M.

Kankainen, A.

Canete, L.

de Groote, R. P.

Delafosse, C.

Eronen, T.

Ge, Z.

Geldhof, S.

Gins, W.

Hukkanen, M.

Jokinen, A.

Moore, I. D.

Mougeot, M.

Nikas, S.

Penttilä, H.

Pohjalainen, I.

Raggio, A.

Reponen, M.

Rinta-Antila, S.

de Roubin, A.

Ruotsalainen, J.

Vilen, M.

Virtanen, V.

Zadvornaya, A.

Publication

2024

Measurements of binding energies and electromagnetic moments of silver isotopes : A complementary benchmark of density functional theory

Physics Letters B.

de Groote, R. P.

Nesterenko, D. A.

Kankainen, A.

Bissell, M.L.

Beliuskina, O.

Bonnard, J.

Campbell, P.

Canete, L.

Cheal, B.

Delafosse, C.

de Roubin, A.

Devlin, C.S.

Dobaczewski, J.

Eronen, T.

Garcia, Ruiz R. F.

Geldhof, S.

Gins, W.

Hukkanen, M.

Imgram, P.

Mathieson, R.

Koszorús, Á.

Moore, I.D.

Pohjalainen, I.

Reponen, M.

van den Borne, B.

Vilén, M.

Zadvornaya, S.

Publication

2024

Metal-insulator transition effect on Graphene/VO2 heterostructure via temperature-dependent Raman spectroscopy and resistivity measurement

Scientific Reports.

Lerttraikul, Kittitat

Rattanasakuldilok, Wirunchana

Pakornchote, Teerachote

Bovornratanaraks, Thiti

Klanurak, Illias

Taychatanapat, Thiti

Srathongsian, Ladda

Seriwatanachai, Chaowaphat

Kanjanaboos, Pongsakorn

Chatraphorn, Sojiphong

Kittiwatanakul, Salinporn

Publication

2024

Model-independent Approach of the JUNO 8B Solar Neutrino Program

Astrophysical Journal.

JUNO Collaboratorion

Publication

2024

New Evidence for DM-like Anomalies in neutron multiplicity spectra

International Conference on Topics in Astroparticle and Underground Physics. POS Proceedings of Science. Sissa.

Trzaska, Wladyslaw Henryk

Barzilov, Alex

Enqvist, Timo

Jędrzejczak, Karol

Kasztelan, Marcin

Kuusiniemi, Pasi

Loo, Kai

Orzechowski, Jerzy

Słupecki, Maciej

Szabelski, Jacek

Ward, Tom

Publication

2024

Nuclear structure studies by collinear laser spectroscopy

European Physical Journal A.

Koszorús, Á.

de Groote, R. P.

Cheal, B.

Campbell, P.

Moore, I. D.

Publication

2024

Octupole correlations in the N = Z + 2 = 56 110Xe nucleus

Physics Letters B.

Illana, A.

Pérez-Vidal, R.M.

Stramaccioni, D.

Valiente-Dobón, J.J.

Rodriguez, T.R.

Robledo, L.M.

Poves, A.

Auranen, K.

Beliuskina, O.

Delafosse, C.

Eronen, T.

Ge, Z.

Geldhof, S.

Gins, W.

Grahn, T.

Greenlees, P.T.

Joukainen, H.

Julin, R.

Jutila, H.

Kankainen, A.

Leino, M.

Louko, J.

Luoma, M.

Nesterenko, D.

Ojala, J.

Pakarinen, J.

Rahkila, P.

Ruotsalainen, P.

Sandzelius, M.

Sarén, J.

Uusitalo, J.

Zimba, G.L.

Publication

2024

Opportunities for fundamental physics research with radioactive molecules

Reports on Progress in Physics.

Arrowsmith-Kron, Gordon

Athanasakis-Kaklamanakis, Michail

Au, Mia

Ballof, Jochen

Berger, Robert

Borschevsky, Anastasia

Breier, Alexander A

Buchinger, Fritz

Budker, Dmitry

Caldwell, Luke

Charles, Christopher

Dattani, Nike

de Groote, Ruben P

DeMille, David

Dickel, Timo

Dobaczewski, Jacek

Düllmann, Christoph E

Eliav, Ephraim

Engel, Jonathan

Fan, Mingyu

Flambaum, Victor

Flanagan, Kieran T

Gaiser, Alyssa N

Garcia, Ruiz Ronald F

Gaul, Konstantin

Giesen, Thomas F

Ginges, Jacinda S M

Gottberg, Alexander

Gwinner, Gerald

Heinke, Reinhard

Hoekstra, Steven

Holt, Jason D

Hutzler, Nicholas R

Jayich, Andrew

Karthein, Jonas

Leach, Kyle G

Madison, Kirk W

Malbrunot-Ettenauer, Stephan

Miyagi, Takayuki

Moore, Iain D

Moroch, Scott

Navratil, Petr

Nazarewicz, Witold

Neyens, Gerda

Norrgard, Eric B

Nusgart, Nicholas

Pašteka, Lukáš F

N Petrov, Alexander

Plaß, Wolfgang R

Ready, Roy A

Pascal, Reiter Moritz

Reponen, Mikael

Rothe, Sebastian

Safronova, Marianna S

Scheidenerger, Christoph

Shindler, Andrea

Singh, Jaideep T

Skripnikov, Leonid V

Titov, Anatoly V

Udrescu, Silviu-Marian

Wilkins, Shane G

Yang, Xiaofei

Publication

2024

Overview of High-Performance Timing and Position-Sensitive MCP Detectors Utilizing Secondary Electron Emission for Mass Measurements of Exotic Nuclei at Nuclear Physics Facilities

Sensors.

Ge, Zhuang

Publication

2024

Precision mass measurements in the zirconium region pin down the mass surface across the neutron midshell at N = 66

Physics Letters B.

Hukkanen, M.

Ryssens, W.

Ascher, P.

Bender, M.

Eronen, T.

Grévy, S.

Kankainen, A.

Stryjczyk, M.

Beliuskina, O.

Ge, Z.

Geldhof, S.

Gerbaux, M.

Gins, W.

Husson, A.

Nesterenko, D.A.

Raggio, A.

Reponen, M.

Rinta-Antila, S.

Romero, J.

de Roubin, A.

Virtanen, V.

Zadvornaya, A.

News

Open postdoctoral positions in the group!
- Postdoctoral Researcher in Experimental Nuclear Astrophysics (Deadline: 4th Feb 2026)
- Postdoctoral Researcher in Nuclear Astrophysics (Deadline: 4th Feb 2026)
- Postdoctoral Researcher in Experimental Nuclear Physics (Deadline: 4th Feb 2026)
- See also other positions open for the CoE in Neutron-Star Physics at https://neutronstars.fi/jobs/
Anu Kankainen appointed as Academy Professor (22.12.2025)
University of Jyväskylä part of breakthrough: Nuclear magnetism measured in a new way (9.12.2025)
Ion recycling opens the way to research into the heaviest elements (27.11.2025)
Centre of Excellence in Neutron-Star Physics funded by the Research Council of Finland (29.10.2025)
Dissertation: Development of measurement devices led to a breakthrough in the study of exotic nuclei (Virtanen 15.10.2025)
Dissertation: High-precision measurements made in the Accelerator Laboratory reveal the energies of nuclear decays (Ruotsalainen 10.10.2025)
Dissertation: New laser spectroscopy device strengthens nuclear physics research in Jyväskylä (Kujanpää 26.9.2025)
NUANZ project funded by the Research Council of Finland (16.6.2025)
Dissertation: Experimental insights from the mass measurement of neutron-rich rare-earth isotopes (Jaries 5.6.2025)
New silver mass brings us a step closer in our understanding of the antineutrino mass (6.5.2025)
Dissertation: Advancing laser and decay spectroscopy for actinide ion beam production (Raggio 28.3.2025)
A new feature discovered in radioactive lanthanum isotopes (31.1.2025)

Exotic nuclei and beams (IGISOL)

Research group description

Selected publications

Research

Nuclear Astrophysics

Selected publications

Weak interaction studies

Enhancing Decay Spectroscopy with Purified Beams

Selected publications

Fission studies

Selected publications

Optical spectroscopy

Collinear laser spectroscopy

IGISOL facility

Ion guides

Radio-Frequency Quadrupole (RFQ) Cooler and Buncher

JYFLTRAP Double Penning Trap Mass Spectrometer

Multi-Reflection Time-of-Flight Mass Spectrometer (MR-ToF-MS)

Related projects

ERC CoG Project MAIDEN

Heavy Exotic Nuclei for Nuclear Astrophysics

Mass measurements of exotic N=Z nuclei (up to 100Sn) and the vicinity for nuclear physics and nuclear astrophysics studies (MASSPASS)

From neutrino mass ordering to developing liquid scintillators for new applications

Research group

Group leaders

Members

External members

Saikumar Chinthakayala

Publications

Publications

News