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

4

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

5

MEASURED MASSES OF URANIUM FISSION FRAGMENTS

JINA Mass Model School, Argonne, May 14, 2007

6

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

7

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

9

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

10

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

11

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

12

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

13

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