Recherche
Guide des thèmes : qu’étudient-ils ?
Ces thèmes se recouvrent : un article peut appartenir à plusieurs. Les nombres concernent cette bibliographie, pas tout le domaine. Un thème sans article conserve une explication sans prétendre à une publication ici. Combinez thème, année, rôle et recherche. La spectrométrie de masse mesure les masses ; la spectroscopie optique mesure les spectres. Topic explanations: English.
Existing research themes
N = Z nuclei / MASSPASS (4)
Precision masses near equal neutron and proton numbers probe shell evolution and astrophysical reaction paths.
Observables usuelles: See the linked research programme and papers.
Afficher les articles (4)Q values for neutrino physics (11)
Decay-energy measurements assess candidates for direct neutrino-mass experiments.
Observables usuelles: See the linked research programme and papers.
Afficher les articles (11)Atomic masses and isotope shifts (1)
Accurate atomic masses support isotope-shift analysis and the separation of mass and nuclear-size effects.
Observables usuelles: See the linked research programme and papers.
Afficher les articles (1)Storage rings, MR-TOF and MCP detectors (7)
Ion manipulation, precision timing and position detection enable rare-isotope mass measurements.
Observables usuelles: See the linked research programme and papers.
Afficher les articles (7)Mass methods and beams
Mass spectrometry and ion-beam applications (71)
Measures and separates ions by mass-to-charge ratio. Precision masses and clean isotope beams support decay-energy, nuclear-structure and astrophysics studies.
Observables usuelles: Atomic masses, Q values, beam purity and emittance.
Afficher les articles (71)Mass-spectrometry innovations in heavy-ion research (27)
Develops Penning traps, MR-TOF instruments, storage rings, timing detectors and ion optics for rare isotopes. Read resolving power, accuracy and efficiency separately: a narrow peak alone does not establish an accurate mass.
Observables usuelles: Resolving power, calibration, timing, transmission and systematic uncertainty.
Afficher les articles (27)Laser spectroscopy and ion sources (4)
Laser spectroscopy uses isotope shifts and hyperfine structure to determine radii, spins and moments. Ion sources create and prepare the required beam; a laser-ablation source is not automatically a laser-spectroscopy measurement.
Observables usuelles: Isotope shifts, hyperfine constants, charge radii, beam yield and purity.
Afficher les articles (4)Nuclear structure
Shape coexistence and nuclear structure (0)
Different intrinsic nuclear shapes can produce low-lying states in the same nucleus. Energies, electromagnetic transitions and radii help distinguish coexistence from a gradual change in deformation; a mass trend alone is not proof.
Observables usuelles: Low-lying 0+ states, E0/E2 strengths, charge radii and configuration mixing.
Afficher les articles (0)Nuclear structure and isotope evolution (25)
Follows how shell structure, pairing and deformation change along isotope or isotone chains. Here isotope evolution means changes with proton or neutron number, rather than motion of isotopes through a material.
Observables usuelles: Separation energies, shell gaps, pairing indicators, radii and isomers.
FRIB nuclear theory · IGISOL research programme ·
Afficher les articles (25)Multi-neutron systems (4)
Investigates correlations and possible resonances in systems made only of neutrons. A short-lived resonance-like structure must be distinguished from a bound nucleus and from final-state interaction effects.
Observables usuelles: Missing-mass spectra, relative energies, widths and reaction-model dependence.
Observation of a correlated free four-neutron system ·
Afficher les articles (4)Dipole resonances and strength distributions (1)
Examines dipole excitations and how their strength is distributed in energy. Electric dipole motion can reveal collective response and weakly bound neutron dynamics; a low-energy peak requires interpretation before being called a distinct resonance.
Observables usuelles: E1 strength, excitation energy, decay channels and polarizability.
Afficher les articles (1)Octupole deformation and correlations (1)
Reflection-asymmetric, often pear-like shapes involve octupole degrees of freedom. Static deformation and octupole vibrations are different possibilities, tested through spectra, parity partners and electric-octupole transition strengths.
Observables usuelles: Parity doublets, E3 strengths, collective bands and deformation indicators.
Octupole collective motion review ·
Afficher les articles (1)Nuclear structure and isospin symmetry (3)
Compares mirror nuclei and isobaric multiplets by exchanging proton and neutron roles. Coulomb effects and other charge-dependent interactions break ideal isospin symmetry, affecting displacement energies and precision weak-decay tests.
Observables usuelles: Multiplet masses, Coulomb displacement energies, IMME coefficients and decay corrections.
FRIB fundamental symmetries · FRIB nuclear theory ·
Afficher les articles (3)Neutron skins and nuclear symmetry energy (0)
The neutron skin is the difference between neutron and proton root-mean-square radii. Its relation to the density dependence of symmetry energy is model-dependent; charge radii alone do not directly measure a neutron skin.
Observables usuelles: Neutron/proton radii, parity-violating scattering, dipole polarizability and equation-of-state constraints.
Afficher les articles (0)Decay and symmetries
Beta decay and fundamental symmetries (2)
Uses decay rates, spectra and angular correlations to test the weak interaction. Searches for time-reversal violation or non-standard couplings need controlled nuclear and detector effects; an ordinary beta-decay measurement is not itself evidence of symmetry violation.
Observables usuelles: Correlation coefficients, Vud, spectral shapes and systematic corrections.
Afficher les articles (2)Neutrino masses and double beta decay (13)
Direct beta or electron-capture endpoints probe the neutrino mass scale through decay kinematics. Double-beta studies also need Q values and nuclear matrix elements; neutrinoless decay, if observed, would test lepton-number conservation. These methods make different assumptions.
Observables usuelles: Q values, endpoint spectra, phase-space factors, matrix elements and backgrounds.
DOE: neutrinoless double beta decay ·
Afficher les articles (13)Nuclear structure and isotope decay (29)
Uses radioactive decay to identify levels, spins, transition strengths and long-lived isomers. Decay energies and branching ratios connect the mass surface to the structure of parent and daughter nuclei.
Observables usuelles: Half-lives, Q values, branching ratios, level schemes and beta strength.
IGISOL research programme · FRIB fundamental symmetries ·
Afficher les articles (29)Nuclear astrophysics
Nucleosynthesis and the chemical evolution of stars (7)
Links nuclear reaction and decay networks to the abundance of elements in stars and ejecta. Masses and lifetimes constrain pathways, while stellar evolution and mixing determine how products reach later generations of stars.
Observables usuelles: Abundances, reaction flows, masses, half-lives and astrophysical conditions.
Afficher les articles (7)Nuclear reactions and nucleosynthesis in novae (0)
Classical novae are thermonuclear outbursts on accreting white dwarfs. Resonances, proton captures and beta decays determine reaction rates and the isotopes ejected; a supernova or Big-Bang study is not automatically a nova study.
Observables usuelles: Resonance energies and strengths, temperature-dependent rates and ejecta yields.
JINA: nuclear astrophysics · IGISOL research programme ·
Afficher les articles (0)Astrophysical reactions and nuclear dynamics (8)
Connects laboratory cross sections and resonances with reaction rates in astrophysical plasmas. Reaction mechanisms, target states and uncertainties matter when translating a beam experiment into a stellar rate.
Observables usuelles: Cross sections, resonance strengths, reaction rates and network sensitivity.
Afficher les articles (8)Heavy nuclei and reactions
Superheavy-element synthesis and decay (0)
Creates the heaviest nuclei in fusion reactions and identifies them through decay chains. Production probabilities compete with fission, and shell effects influence survival. Transfer reactions on heavy targets do not automatically imply superheavy-element synthesis.
Observables usuelles: Evaporation-residue cross sections, alpha-decay chains and fission lifetimes.
GSI superheavy-nucleus research ·
Afficher les articles (0)Fission-fragment dynamics and energy distributions (2)
Studies how a fissioning nucleus divides mass, charge, energy and angular momentum between fragments. Fragment yields and isomer populations constrain the roles of shell structure, excitation and the scission process.
Observables usuelles: Mass/charge yields, total kinetic energy, spin distributions and isomeric ratios.
GSI: shell effects in fission ·
Afficher les articles (2)Detector technologies
Superconducting calorimeters for precision detection (0)
Measures deposited energy as a tiny temperature rise at cryogenic temperatures. Transition-edge sensors use the steep resistance change near a superconducting transition; energy resolution, response time and background must be assessed together.
Observables usuelles: Energy resolution, thermal response, pile-up, calibration and noise.
Afficher les articles (0)Resistive plate chambers in particle detection (0)
Gas detectors with resistive electrodes amplify ionization signals in a strong electric field. They provide fast timing and triggering in particle experiments; they are a different technology from MCP detectors.
Observables usuelles: Efficiency, time resolution, rate capability, gas mixture and ageing.
CMS resistive plate chambers ·
Afficher les articles (0)J’étudie la physique du neutrino, la structure nucléaire et l’astrophysique nucléaire par des mesures de masse de haute précision dans les pièges à ions et les anneaux de stockage. Les références ci-dessous proviennent de la bibliographie commune ; la liste complète est disponible dans Publications .
Les méthodes en images #
Noyaux exotiques N = Z jusqu’à ¹⁰⁰Sn — MASSPASS #
Je dirige ce projet de l’Academy Research Fellowship. Les mesures des noyaux N = Z et de leurs voisins à IGISOL et au RIKEN testent l’évolution des couches vers ¹⁰⁰Sn et fournissent des données pour le processus rp. Présentation du projet
4 références bibliographiques
- , Direct mass measurement of ⁹¹Rh and ⁸⁹Ru and mid-shell trend of the one-proton separation energies for N = Z + 1 nuclei, Phys. Rev. C 114, 034311 (2026)
- , Direct mass measurement of ⁹³Pd and implications for the isomer structures in ⁹⁴Ag, Phys. Rev. Research 7, L042022 (2025)
- , High-precision mass measurements of neutron-deficient silver isotopes probe the robustness of the N = 50 shell closure, Phys. Rev. Lett. 133, 132503 (2024) · arXiv:2401.07976
- , Study of mass-measurement method for N = Z nuclei with isochronous mass spectrometry, Nucl. Phys. Rev. 36, 294 (2019)
Valeurs Q pour déterminer la masse du neutrino #
Les mesures directes d’énergies de désintégration dans un piège de Penning permettent de sélectionner les transitions β⁻ et de capture électronique à très faible valeur Q, et d’écarter les candidats inadaptés aux futures expériences.
11 références bibliographiques
- , Precise determination of electron-capture Q value of ¹¹³Sn decay related to electron neutrino mass measurements, Phys. Rev. C 114, 035501 (2026) · arXiv:2604.03410 — QEC = 1039.25(19) keV
- , High-precision direct decay energy measurements of the electron-capture decay of ⁹⁷Tc, Phys. Rev. C 112, 035501 (2025) · arXiv:2502.04490 — QEC = 324.82(21) keV
- , High-precision measurements of the atomic mass and electron-capture decay Q value of ⁹⁵Tc, Phys. Lett. B 859, 139094 (2024) · arXiv:2406.05273
- , Direct high-precision measurement of the mass difference of ⁷⁷As–⁷⁷Se related to neutrino mass determination, Eur. Phys. J. A 60, 104 (2024) · arXiv:2401.15242
- , β⁻ decay Q-value measurement of ¹³⁶Cs and its implications for neutrino studies, Phys. Rev. C 108, 045502 (2023) · arXiv:2306.04604
- , Direct determination of the atomic mass difference of the pairs ⁷⁶As–⁷⁶Se and ¹⁵⁵Tb–¹⁵⁵Gd rules out ⁷⁶As and ¹⁵⁵Tb as possible candidates for electron (anti)neutrino mass measurements, Phys. Rev. C 106, 015502 (2022) · arXiv:2202.07656
- , High-precision electron-capture Q value measurement of ¹¹¹In for electron-neutrino mass determination, Phys. Lett. B 832, 137226 (2022) · arXiv:2201.12573
- , Observation of an ultralow-Q-value electron-capture channel decaying to ⁷⁵As via a high-precision mass measurement, Phys. Rev. C 106, 015501 (2022) · arXiv:2203.00457
- , High-precision measurement of a low Q value for allowed β⁻ decay of ¹³¹I related to neutrino mass determination, Phys. Lett. B 830, 137135 (2022)
- , ¹⁵⁹Dy electron-capture: a new candidate for neutrino mass determination, Phys. Rev. Lett. 127, 272301 (2021) · arXiv:2106.06626
- , Direct measurement of the mass difference of ⁷²As–⁷²Ge rules out ⁷²As as a promising β-decay candidate to determine the neutrino mass, Phys. Rev. C 103, 065502 (2021) · arXiv:2103.08729
Masses atomiques et déplacements isotopiques #
Les masses précises réduisent l’incertitude de la contribution de masse aux déplacements isotopiques en spectroscopie laser et, par conséquent, des différences de rayons de charge extraites.
1 références bibliographiques
- , High-precision measurement of the atomic mass of ⁸⁴Sr and implications to isotope shift studies, Eur. Phys. J. A 60, 147 (2024) · arXiv:2404.02025
Anneaux de stockage, MR-TOF et détecteurs MCP #
Mon doctorat au Rare-RI Ring du RIKEN portait sur l’identification des ions pour les mesures isochrones et sur les détecteurs à galettes de microcanaux (MCP), sensibles au temps et à la position. Mes travaux concernent aussi les spectromètres MR-TOF d’IGISOL et du FRS Ion Catcher du GSI, ainsi que des concepts de détecteurs pour HIAF.
7 références bibliographiques
- , High-resolution multi-reflection time-of-flight mass spectrometer for exotic nuclei at IGISOL, Nucl. Instrum. Methods A 1088, 171513 (2026)
- , 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 24, 7261 (2024) — review
- , Development of a large-area timing and position-sensitive foil-MCP detector for mass measurements at the Rare-RI Ring in RIKEN, arXiv preprint (2021) · arXiv:2106.08264
- , Development of mirror-type MCP detectors for mass measurements at the Rare-RI Ring, JPS Conf. Proc. 35, 011023 (2021)
- , Scheme of high-resolution identification and selection of secondary ions for mass measurements with the Rare-RI Ring, Hyperfine Interact. 240, 92 (2019)
- , Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass measurements at HIAF, Nucl. Sci. Tech. 30, 152 (2019) · arXiv:2105.14551
- , Timing performance of a mirror-type MCP detector for mass measurements at the Rare RI Ring, RIKEN Accel. Prog. Rep. 51, 152 (2018)
Optique ionique #
Conception de lignes de faisceau, d’anneaux de stockage et de systèmes de piégeage : optique d’injection du Rare-RI Ring, mesures isochrones et simulations SIMION de RFQ, MR-TOF et pièges de Penning.
- Z. Ge, Q. Wang, M. Wang, T. Uesaka, étude d’une méthode de mesure des noyaux N = Z, Nucl. Phys. Rev. 36, 294 (2019) .
- Z. Ge et al., résultats de l’optique d’injection du Rare-RI Ring, RIKEN Accel. Prog. Rep. 49, 180 (2016) .
Structure nucléaire #
- Évolution des couches et nombres magiques loin de la stabilité, jusqu’à ¹⁰⁰Sn.
- Symétrie d’isospin, noyaux miroirs et différences d’énergie coulombienne.
- Énergies de séparation, appariement et états isomériques.
- Énergies des désintégrations rares pour la physique du neutrino.
Astrophysique nucléaire #
- Masses aux points d’attente des processus rp et νp près de N = Z.
- Masses riches en neutrons pour les réseaux du processus r.
- Données nucléaires pour les sursauts X et l’origine des éléments.
Principes physiques #
Piège de Penning. Un ion de charge q et de masse m, soumis à un champ magnétique fort et à un potentiel électrique quadrupolaire, possède trois mouvements propres. La fréquence cyclotron libre vérifie νc = qB/(2πm) ; la comparaison avec un ion de référence élimine le champ magnétique du rapport. À JYFLTRAP, un premier piège purifie les ions et le second effectue la mesure. En TOF-ICR, la résonance correspond à un minimum du temps de vol ; en PI-ICR, la phase radiale accumulée est projetée sur un détecteur sensible à la position.
MR-TOF. Deux miroirs électrostatiques allongent le trajet des ions par réflexions successives. Le pouvoir de résolution R = m/Δm = t/(2Δt) augmente avec le temps de vol. Des ions de référence étalonnent la relation m/q ∝ (t − t0)².
Valeurs Q. Pour une désintégration β⁻ ou une capture électronique, la différence des masses atomiques de l’état initial et final donne l’énergie disponible, Q = [M(parent) − M(fils)]c². Les transitions à très faible Q peuvent améliorer la sensibilité à la masse du neutrino ; les énergies d’excitation doivent être prises en compte pour une transition vers un état excité.
Structure et astrophysique. Les énergies de liaison révèlent fermetures de couches, appariement et effets associés à N = Z. Les valeurs Q de capture contrôlent les points d’attente et les cycles du processus rp ; les énergies de séparation des neutrons influencent le chemin du processus r. Voir aussi le tableau périodique et l’origine des éléments .
CLS · IAEA · NNDC · NIST
Noyaux et lumière : laboratoire de données
Jouer au parcours de spectroscopie .
The family of ion and atom traps — how they work
Animated sketches, not to scale. Red/blue = electrode polarity (switching with the RF where relevant); the coloured trail is one ion or atom.