Masses and beta-decay studies with fast beams
A. Estrad´ e 1
University of Edinburgh
12 nd workshop on β delayed neutron emission measurements at RIKEN
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 1 / 16
Nuclear data for the r-process
BRIKEN:
β-decay half lives.
β-decay delayed neutron emmission probabilities.
MBRIKEN:
BRIKEN + Nuclear masses.
Fission properties, (n,γ ) reaction rates.
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Nuclear data for the r-process
BRIKEN:
β-decay half lives.
β-decay delayed neutron emmission probabilities.
MBRIKEN:
BRIKEN + Nuclear masses.
Fission properties, (n,γ ) reaction rates.
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 2 / 16
Nuclear data for the r-process
BRIKEN:
β-decay half lives.
β-decay delayed neutron emmission probabilities.
MBRIKEN:
BRIKEN + Nuclear masses.
Fission properties, (n,γ ) reaction rates.
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Sensitivity of r-process calculations to nuclear masses
A. Arcones and G. Martinez, PRC , 2011.
see also: S. Brett et al., EPJ A 2012 for sensitivity to single mass values.
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 3 / 16
Extrapolations of nuclear mass models
D. Lunney et al, Rev. Mod. Phys., 2003
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FRDM vs AME2012
-1.
0.
1.
8 8 14 14
28 28
50 50
82 82
126 HRMSD=0.65403 MeVL
BE H FRDM L - BE H AME12 L
Z
N
Courtesy: J. Mendoza Temis
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 5 / 16
HFB21 vs AME2012
-1.
0.
1.
8 8 14 14
28 28
50 50
82 82
126 HRMSD=0.57194 MeVL
BE H HFB21 L - BE H AME12 L
Z
N
Courtesy: J. Mendoza Temis
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Comparison of mass measurement techniques
Exoticity: = log 10
δN
stab.τ
1/2·δN
dripCourtesy: Z. Meisel and S. George.
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 7 / 16
Time-of-flight mass measurements with BigRIPS
B ρ = γv
m q
= γ TOF L
m q
In practice need calibration function:
m
q = f (TOF , Bρ, Z , A)
Calibration with known masses:
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Time-of-flight mass measurements with BigRIPS
Mass resolution: δm m ≤ 3.5 × 10 −4 (beam test Dec. 2012; N. Fukuda, T.
Kubo et al.)
Mass accuracy: need few ×10 −6 . BigRIPS test under analysis.
Setup at NSCL ( M.Matos et al., NIMA 2012 ):
σ
sys.= 5.3 keV/q (i. e. 180 keV for Z=35 )
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 9 / 16
MBRIKEN: Masses + β -decay studies at RIKEN
Reference isotopes: ≈ 20 % of run time less neutron-rich setting (thin target; Nuclear Tecnologies? D. Cano Ott).
Big RIPS setting with wide acceptance in Z, A/Z.
Minimize systematic effects on TOF.
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MBRIKEN: Masses + β -decay studies at RIKEN
Proposal combining TOF masses with β-decay spectroscopy (EURICA) accepted in latest PAC meeting (June 2013).
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 11 / 16
Masses and β -decay properties of r-process nuclei around N=56
A. Estrade, G. Lorusso, V. Werner, et al. (12
thNP-PAC at RIBF) 22 new nuclear masses (red+yellow).
13 new β-decay half-lives (yellow+green).
γ-ray spectroscopy for N=56 Ge/Se isotopes (NP1112-RIBF81).
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Towards the rare earth peak (C. Domingo’s talk)
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 13 / 16
Concluding remarks
Nuclear data for the r-process! Nuclear data for the r-process!
TOF mass measurements under development at RIBF (T. Kubo, M.
Famiano, et al.).
First experiment combining β -decay and TOF mass measurements approved by latest NP-PAC.
Interesting opportunities for symbiosis with BRIKEN (timeline?).
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Thank you for your time
A. Estrad´e Mass measurements and beta-decay studies 2ndBRIKEN workshop 15 / 16
Z. Meisel & NSCL TOF Collaboration
Recent Results in Time-of-Flight Mass Measurement 7/31/2013, Slide 10
Rigidity Correction
M. Matoš et al. NIMA 696, 171 (2012)
Time of Flight
MCP Disp er siv e P os it ion
55 Ti
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