JINA Mass Model School, Argonne, May 14, 2007
Milan MATOŠ
TOF Mass Measurements at the Extremes: An input for astrophysical calculations
JINA Mass Model School, Argonne, May 14, 2007
2
PRINCIPLE OF TOF MASS MEASUREMENTS
vq
mB t
Lv
constB
constL
tconstq
m
usually Br acceptance ± several percent constB
solutions
Br measurement
constL
B
isochronicity
t constant for fixed m/q even if v1 < v2
xB
dispersive mode
start stop
momentumanalysis p=mv L
Br
JINA Mass Model School, Argonne, May 14, 2007
3
ISOCHRONOUS MASS MEASUREMENT IN THE STORAGE RING AT GSI
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
10m
JINA Mass Model School, Argonne, May 14, 2007
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TIME-OF-FLIGHT MEASUREMENT WITH THE STORAGE RING IN THE ISOCHRONOUS MODE
In jectionIn jectionIn jection
tim e [ s]
U [V ]
0 1 2
0
-0.5
tim e [ s]
U [V ]
0 1 2
0
-0.5
JINA Mass Model School, Argonne, May 14, 2007
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MEASURED MASSES OF URANIUM FISSION FRAGMENTS
JINA Mass Model School, Argonne, May 14, 2007
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TOF-B MASS MEASUREMENT AT THE NSCL
6
10m
K500
K1200 A1900
transfer hall
S800TOF startTOF stop
B meas.
JINA Mass Model School, Argonne, May 14, 2007
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0 2 0 4 0
3 0
1 0
2 0
0
Pro
ton n
um
ber
Neutron number
Proton dripline
Neutron dripline
210
10
310
410
51086Kr
RESULTSknown mass
very well known mass s<30keV
JINA Mass Model School, Argonne, May 14, 2007
8
RESULTSknown mass
very well known mass s<30keV
0 2 0 4 0
3 0
1 0
2 0
0
Pro
ton n
um
ber
Neutron number
Proton dripline
Neutron dripline
86Kr
LEBIT
ISOLTRAP
N>1000
JINA Mass Model School, Argonne, May 14, 2007
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VERYPRELIMINARY
VERYPRELIMINARY
PRELIMINARY FIT
2.45 2.50 2.55 2.60-1000
-500
0
500
1000
ME
- M
EA
ME[k
eV]
m/qnew measuredmass value
71 72 73
-1500
-1000
-500
0
500
AME This work FRDM FRLDM HFB HFBCS Duflo-Zuker
ME
- M
EA
ME [
keV
]
A
only statisticaluncertainties!!!
AME extrapolation
Comparison with Mass Models
fit of the reference masses
Niisotopes
m/q = function(TOF, Z)
JINA Mass Model School, Argonne, May 14, 2007
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THANKS
Alfredo Estrade, Hendrik Schatz,Daniel Bazin, Alexandra Gade, Daniel Galaviz,
Giuseppe Lorusso, Mauricio Portillo, Dan Shapira, Andreas Stolz, John Yurkon, Mark Wallace
and many others
NSCL, MSU & JINA & ORNL & LANL & Ohio Univ.
JINA Mass Model School, Argonne, May 14, 2007
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ASTROPHYSICAL MOTIVATION
preceding following
• after enormous interest in explosive processes in stars
• sites still not clear
• last decade rise of the interest in processes:
the explosions
JINA Mass Model School, Argonne, May 14, 2007
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R-PROCESS SEED NUCLEI
Calculations: K. Farouqi, F. Montes et al.
seed/n too high
Only np-, a- process
Area coveredin this experiment
in Neutrino-Driven Wind Modelof Core-Collapsed Supernovae
charge-particlefreeze-out
FRDM mass model used
r-process conditions
need of nuclear physics data
- high temperature ejecta- cooled by adiabatic expansion driven by a neutrino wind
n, p, a
JINA Mass Model School, Argonne, May 14, 2007
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HEATING OF THE ACCRETING NEUTRON STAR CRUST (AFTER RP-PROCESS)
- after matter flow suppressed- ashes of rp-process sink deeper into the crust, me rises with an increasing density
- Haensel & Zdunik: on a single rp-process nuclide two stages electron capture n emission and absorption pycnonuclear fusion r>1012g/cm2
- Schatz, Cumming: superburst: 12C ignition at r ~109g/cm2
not enough heat according to HZ model!
- S. Gupta et al: on realistic rp-ashes mix electron capture into excited states followed by a radiative deexcitation – more heat!
electron Fermi energy
calculated excitation energies
masses needed for reaction thresholds, separation energies and reaction rates FRDM (Möller et al., 1995) used S. Gupta et al. astro-ph/0609828