JYVSKYLN YLIOPISTO 39 th Erice School 2017 ATOMIC

JYVÄSKYLÄN YLIOPISTO 39 th Erice School 2017 ATOMIC MASS MEASUREMENTS OF ULTRALOW Q-VALUE NUCLEI Tommi Eronen University of Jyväskylä

JYVÄSKYLÄN YLIOPISTO OUTLINE n Q-value from atomic mass spectrometry n Nuclei with potential ultralow Q-value n (On-line) Penning trap atomic mass spectroscopy – +PI-ICR technique n Program at JYFLTRAP, Jyväskylä Q-value for a reaction is the amount of energy released by that reaction. 19. 10. 2021

JYVÄSKYLÄN YLIOPISTO Q-value from mass spectroscopy n Tritium beta decay electron spectrum from parent-daughter mass difference

JYVÄSKYLÄN YLIOPISTO Q-values from masses for neutrino studies n Several cases already studied. . – 2νββ, 0νββ – 0νECEC – Search for resonant enhancement n Now: Ordinary (highly forbidden) β and EC decays – Ground-state-to-ground state decays: • Direct neutrino mass probes, e. g. tritium, 163 Ho – Ground-state-to-excited-state decays • Low Q-values of highly forbidden decays

JYVÄSKYLÄN YLIOPISTO Low Q-value n 19. 10. 2021

JYVÄSKYLÄN YLIOPISTO Ultralow Q-value nuclei n Single β- and EC capture decays n Decay with very low Q-value to an excited state n Bigger fraction of the Q-value in neutrino mass n Search for ”slightly positive” Q-value β-/EC parent mass difference excited state Q-value excitation energy Ground state Daughter

JYVÄSKYLÄN YLIOPISTO Required experimental quantities n Parent-daughter decay Q-value – mass difference – From mass spectroscopy n Daughter excited state excitation energy β-/EC parent mass difference excited state Q-value excitation energy Ground state Daughter

JYVÄSKYLÄN YLIOPISTO Candidates Immediate improvement With precise Mass difference measurement Half-lives range from few hours to few days J. Suhonen, Phys. Scr. 89, 054032 (2014).

JYVÄSKYLÄN YLIOPISTO 115 In decay Cattadori et al. Nucl. Phys A 748, 333 (2005) Q-values: JYFLTRAP 350(170) e. V E. Wieslander, J. Suhonen, T. Eronen et al. PRL 103, 122501 (2009) FSU-TRAP 155(24) e. V B. J. Mount, M. Redshav, E. G. Myers, PRL 103, 122502 (2009)

JYVÄSKYLÄN YLIOPISTO Precisions n The goal: Find ”slightly positive Q-value” cases: n Phase 1: Coarse selection – Daughter state excitation energies < 100 e. V – ~100 e. V gs-gs precision with Penning traps (TOF-ICR) n Phase 2: Finer selection – If survived phase 1 – Daughter state excitation energies < 10 e. V – ~10 -50 e. V gs-gs precision with Penning traps (PI-ICR) n Phase 3: Ultimate – Push to e. V-level with non-destructive Penning trap mass measurement techniques – E. g. with PENTATRAP in MPIK, Heidelberg

JYVÄSKYLÄN YLIOPISTO Production of ions of interest n Half-lives few days up to few years – Need (near) on-line production n IGISOL facility at Uni Jyväskylä accelerator lab – K 130 and K 30 cyclotrons n Proton/deuteron induced fusion reactions – E. g. 77 As production: 76 Ge(d, n)77 As @ 7 Me. V

JYVÄSKYLÄN YLIOPISTO IGISOL n IGISOL – Ion Guide Isotope Separator On. Line – ISOL-system for all elements, fast ( ~ms) • Stopping reaction products into (helium) gas • Extraction as ions – no need to reionize – But: relatively low efficiency – Different geometries for • • • Light-ion fusion Fusion evaporation p/d fission n-induced fission Cryogenic

JYVÄSKYLÄN YLIOPISTO Parent and daughter production n For example 77 As -> 77 Se Q-value – Parent: 76 Ge(d, n)77 As @ 7 Me. V – Daughter: stable selenium exists as a contaminant n BOTH available simultaneously

JYVÄSKYLÄN YLIOPISTO IGISOL-4 FACILITY LAYOUT From K 130 cyclotron MCC 30/15 light-ion cyclotron Atom trap 30 ke. V IGISOL-4 target area Decay Spectroscopy station JYFLTRAP, Double Penning Trap • High precision mass measurements • Isobaric/Isomeric purification of RIB Trap assisted spectroscopy 2014 -03 -12 High purity ion samples RFQ cooler/buncher Collinear laser Spectroscopy Post-trap decay spec

JYVÄSKYLÄN YLIOPISTO JYFLTRAP n Buncher n 2 Penning traps – Purification trap – Precision trap 30 ke. V buncher 1 k e. V 30 ke. V Penning traps

JYVÄSKYLÄN YLIOPISTO Penning trap – confining charged particles • Three eigenmotions – Axial nz – Magnetron n– Modified cyclotron n+

JYVÄSKYLÄN YLIOPISTO Free-space cyclotron frequency n Mass measurements through SIDEBAND FREQUENCY: G. Gabrielse, Int. J. Mass. Spec. 279 (2009) 107– 112

JYVÄSKYLÄN YLIOPISTO Q-value from cyclotron frequencies daughter n Frequency ratio – experimental quantity n Q-value (for singly charged ions) parent For same A/q: parent daughter

JYVÄSKYLÄN YLIOPISTO Time-of-flight ion cyclotron resonance (TOF-ICR) method for mass measurements - ”phase 1”

JYVÄSKYLÄN YLIOPISTO Example resonances,

JYVÄSKYLÄN YLIOPISTO Phase imaging ion cyclotron resonance (PI-ICR) method for mass measurements ”phase 2”

JYVÄSKYLÄN YLIOPISTO PI-ICR method n Novel Penning trap mass measurement technique n Developed by Sergey Eliseev, MPIK Heidelberg at SHIPTRAP GSI n Faster by 40 x

JYVÄSKYLÄN YLIOPISTO PI-ICR at JYFLTRAP n Detector installed in June 2017 Trap center

JYVÄSKYLÄN YLIOPISTO PI-ICR scheme for mass measurements

JYVÄSKYLÄN YLIOPISTO PI-ICR results n SHIPTRAP at GSI: 163 Ho-163 Dy Q-value with uncertainty 30 stat + 15 syst e. V – Eliseev et al. , PRL 115, 062501 (2015) n JYFLTRAP test measurement 85 Rb-87 Rb – 52 e. V precision (preliminary, room for improvement) – This is better than 10 -9 ! In general: few ten e. V precision available (few x 10 -10 frequency ratio precision) 19. 10. 2021

JYVÄSKYLÄN YLIOPISTO After Q-value measurement. . n J. Suhonen et al. will be busy for a while – Branching ratio n A potential case will have – Very low Q-value (< 100 e. V) – Reasonable branching ratio n Low background near the endpoint n With very small Q-value atomic effects might interfere with beta decay

JYVÄSKYLÄN YLIOPISTO Final remarks n IGISOL + JYFLTRAP is the ideal facility for low Q- value measurements – Easy production, “cheap” beamtime – Simultaneous availability of parent, daughter (A/q doublet mass measurement) n PI-ICR technique allows to push to ~20 e. V level n 11 days of beamtime approved for 6 cases n Collaboration with J. Suhonen’s group

JYVÄSKYLÄN YLIOPISTO Advertisement n Isomerically clean beams available with unprecedented resolution! n Phase-sensitive cleaning – – For A/q = 100 50 ke. V isomer 45 deg phase difference Need 200 ms 250 ms

http: //research. jyu. fi/igisol JYVÄSKYLÄN YLIOPISTO Acknowledgments EXPERIMENT: L. Canete T. Eronen S. Geldhof A. Jokinen A. Kankainen I. D. Moore D. Nesterenko H. Penttilä I. Pohjolainen A. de Roubin M. Reponen S. Rinta-Antila A. Takkinen M. Vilen J. Äystö THEORY: J. Suhonen M. Haaranen J. Kostensalo J. Kotila P. C. Srivastava (Roorkee, India) Thank you!