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This article discusses the recent research highlights and advancements in direct mass measurements using the FRS-ESR facilities at GSI. Topics covered include nuclear mass measurements, binding energies, deformation, new phenomena, and reaction Q-value. The article also highlights the applications of mass measurements in nuclear physics, nuclear astrophysics, and fundamental interactions.
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Progress on direct mass measurements with the FRS-ESR facilities at GSI Bao-Hua Sun Justus-Liebig-University Giessen Beihang University • Introduction • Recent research highlights • Summary
Motivation of mass measurements Nuclear Mass M(N, Z) = Z·mp + N·mp - B(N, Z)/c2 • Total Binding energies • Separation energy, drip-line • Shell, subshell, pairing, np pairing • Deformation • New phenomena: decay mode, halo nuclei • New isomer, new isotope • Reaction Q-value • Test nuclear model or formula • … • Nuclear physics • Nuclear astrophysics • Others • Paths of nucleosynthesis • Element abundance • … • Fundamental interactions and Standard-Model • Metrology: fundamental constants, Kg .. • …..
GSI Accelerator Facility Today Up to 1000 MeV/u U92+ 2*109 pps SIS 11.4 MeV/u U73+ IonSources FRS UNILAC SHIP 238U4+ ESR Experimental Areas
FRS-ESR facilities —Storage ring mass spectrometry Pereira et al., PRC 75, 14602(2007) • FRagment Separator (FRS) • Experimental Storage Ring (ESR) • SMS --- Electron cooler • Statistic cooling • Schottky pick-up • Primary beams @ 400-1000 MeV/u • Projectile fragmentation and fission • Cocktail beam or mono-isotopic (selectivity) • Highly-charged ions (Rrelativistic energy) • In-Flight separation within ~ 500 ns
FRS-ESR facilities • FRagment Separator (FRS) • Experimental Storage Ring (ESR) B. Franzke, H. Geissel, and G. Münzenberg, H. Wollnik
FRS-ESR facilities • FRagment Separator (FRS) • Experimental Storage Ring (ESR) • SMS --- Electron cooler (dv/v~10-7) • Stochastic cooling pick-up • Schottky pick-up Litvinov 2003, Chen 2008
FRS-ESR facilities • FRagment Separator (FRS) • Experimental Storage Ring (ESR) • SMS --- Electron cooler • Stochastic cooling pick-up • Schottky pick-up • IMS --- Isochronous mode • TOF detector D(m/q)/(m/q)~10% Sun, Knoebel, 2008
Mass surface covered at GSI Large-scale measurements Schottky Mass Spectrometery: Time-resolved, half-live, masses Mass accuracy: 10-30 keV Mass resolving power: 2·106 T1/2 : > 1s Isochronous Mass Spectrometry: First large-scale measurement Mass accuracy: ≈100 keV Mass resolving power: 2·105 T1/2 : ~ 50 s In analysis Masses of more than 1100 Nuclides were measured Results: ~ 350 new masses In addition more than 300 improved mass values Y. Litvinov
Outline • Introduction • Recent research highlights • Summary
Neutron-rich nuclides in the element range of Pt – U Chen, Knoebel
Overview of this experiment • cold-fragmentation • 238U->234Ra • nuclear charge exchange reaction:238Pa, 237Th, 236Ac
New isotope – 224At b- • Single-ion sensitivity • b- decay • life time • Mass determination
Resolved isomer in 133Sb with IMS First large-scale Isochronous mass measurement About 10% in mass-over-charge range: [2.4,2.7] B.Sun et al., NPA2008
Resolved isomer in 133Sb with IMS First large-scale Isochronous mass measurement About 10% in mass-over-charge range: [2.4,2.7] B.Sun et al., NPA2008
RTOF=60 000 Resolved isomer in 133Sb with IMS First large-scale Isochronous mass measurement About 10% in mass-over-charge range: [2.4,2.7] B.Sun et al., NPA2008
17 s isomeric state in 133Sb (neutral atom) New half-live domain for storage-ring experiments Expected half-live of bare isomer: ~ 17 ms, t~991 Genevey et al., EPJA 7, 463 (2000) Sun et al., PLB 688 (2010) 294
Extension of IMS for short-lived isomer investigation “lifetime” in the ring Level scheme In support of the shell-model calculation and also complement to the “missing“ information in g-ray spectroscopy
New resonant Schottky pick-up -- fast and sensitive cavity-like • Working freq. ~ 245 MHz ( h~125) • + separation of Schottky lines: 4 • + less time to resolve lines • Signal to noise ratio: ~50:1 F. Nodeln, et al., NIMA (2011)
New resonant Schottky pick-up Hot Fragments (Iso. Mode)—Broad band Each frame: 320 ms Spectrum of 16 ms Resolving power f/Df~17000
Hot Fragments (Iso. Mode) – Narrow band With this new resonant Schottky pick-up, one could see the momentum dispersion for each particle ..
Outline • Introduction • Recent research highlights • Summary
Summary • Ability: mapping nuclear mass surface, new isotopes • Single-ion sensitivity: np interaction, decay • Resolution: isomeric separation • Time-resolved characteristic: life-time measurement • New resonant Schottky pick-up: short-lived nuclear mass and lifetime measurements
Future -- ILIMA • Isomeric beams, LIfetimes and MAsses: The ILIMA project at FAIR Dr. Yuri Litvinov Tuesday, 11 October 2011, 15:45 - 16:10 • Status of the Storage Ring Design at FAIR Dr. Sergey Litvinov, Tuesday, 11 October 2011 , 17:05 - 17:30
FRS-ESR Mass Collaborations G. Audi, K. Beckert, P. Beller, F. Bosch, D. Boutin, T. Buervenich, L. Chen, I. J. Cullen, B. Fabian, T. Faestermann, B. Franzke, H. Geissel, M. Hausmann, P. Kienle, N. Kuzminchuk,O. Klepper, C. Kozhuharov, R. Knöbel, S.A. Litvinov, Yu.A. Litvinov, Z. Liu, L. Maier, J. Meng, G. Münzenberg, F. Nolden, T. Ohtsubo, A. Ozawa, Z. Patyk, B. Pfeiffer, W.R. Plass, T. Radon, M. Reed, H. Schatz, C. Scheidenberger, J. Stadlmann, M. Steck, B. Sun, S. Typel, D.J. Vieira, P.M. Walker, H. Weick, M. Winkler, H. Wollnik, T. Yamaguchi and FRS-ESR collabration