PowerPoint PresentationMain sequence star
Big Bang
Accelerating universe
•Red giant stars: 12C(α,γ)16O
ANL
TAMU
ND
• High beam intensities • Good beam qualities
(narrow resonances) • Good targets available • Small energy loss of p or α
• Detection efficiency small for (p,γ) and (α,p)
• Beam intensities lower by 3-6 orders of magnitude
• Beam contaminants • Have to use inverse kinematics • Need for gas targets • Higher energy loss of heavy
ions (narrow resonances) • Increased detection efficiency
for inverse kinematics
Homestake Superkamiokande SNO
8B
Techniques to measure the decay of 8B 8Be 2α
3He beam
6Li
Stop an energetic 8B beam in the middle of a Si detector
8B, 27 MeV
to experiment
35 MeV
bending magnet
Energy calibration?
β+
8B 8Be 2α 20Na 20Ne α + 16O
Experimental Results
E(2+) [keV]
Γ(2+) [keV]
3120±130 1700±130 8B decay PRC33,303
3012±7 1382±19 8B decay This work
E(2+) [keV]
Γ(2+) [keV]
3000±100 1230±200 9Be(d,t)
3120±100 1430±60 9Be(d,t)
3060±300 1370±70 “best value” 2002
8B Neutrino spectrum
Garcia et al.
γ-ray Astronomy 7Be (53 d) 18F (110 m) 22Na (2.6 y)
26Al (7.2 My) 44Ti (60 y)
53Mn (3.7 My) 56Co (77 d)
60Fe (1.5 My)
“galactic cannibalism”
Ne-Na cycle
Chandra
COMPTEL Search for 22Na A. Iyudin et al. Astron. Astrophys. 300,422(1995)
Expected from Nova models (S. Starrfield et al. ApJ391, L71(1992))
•Wrong distance?
•Wrong hydrodynamics?
D=2.3±0.5 kpc
Theoretical estimates for the 21Na(p,γ)22Mg reaction rate: uncertainties up to a factor of 50
For 22Na(p,γ)23Mg the uncertainties are a factor of 100
T9
J. José et al., ApJ 520, 347(1999)
N. Bateman et al., PRC63, 035803(2001)
J. Hardy et al. PRC9, 2654(1974)
J. Nolen et al. NIM 115, 189(1974) ΔE=212 keV
J. Caggiano et al. PRC66, 015804(2002)
22Mg
p(21Na,22Mg)γ, T1/2(21Na)=22.5 s
New experimental uncertainty
Resonance strength
Limits of detectability with INTEGRAL
Theoretical estimates
Mass: ~1.4 M
Radius: ~10 km
Density: ~1014 g/cm
waiting point
(particle unstable)
Sensitivity of X-ray luminosity to masses of several waiting points (60Zn,64Ge,68Se,72Kr)
B. A. Brown et al.
Phys. Rev. C65, 045802 (2002)
Δm ~ 10 keV
CPT at ATLAS
64Ge 68Se
CPT: J. A. Clark et al. (PRL2004) ME=-54232±19 keV ND/ANL: A. Wöhr et al. (NPA2004), ME=-54189±240
Mass of 69Br needs to be extrapolated:
Future possibilities at RIA: 68Se(3He,d)69Br 70Br(d,t)69Br 70Kr(d,3He)69Br
Audi-Wapstra: ME=-54150 ± 300 keV
GANIL: A. S. Lalleman, Hyperf. Int.132,315(2001) ME=-52347 ± 80 keV
GANIL: G. F. Lima et al. PRC 65,044618(2002) ME=-53620 ± 1000 keV
Summary of Mass Measurements:
•Many reaction rates still unknown
100
10
1
10-1
10-2
10-3
T1/2
[s]
Audi-Wapstra
GANIL
The 12C(α,γ)16O Reaction
The determination of the ratio 12C/16O produced in helium burning is a problem of paramount importance in Nuclear Astrophysics.
W. Fowler, Nobel prize lecture 1982
Universe Human Body
Other 0.9%
Need indirect techniques:
•Detector with no β sensitivity
S(E1) from the β-delayed α decay of 16N 16N(β)16O 12C+α
β-delayed α decay of 16N 16O
Eα
16N β decay
direct (α,γ) measurements at higher energies 12C + α elastic scattering phase shifts
Sensitivity of S(E1) to different experiments (R. Azuma et al., Phys. Rev. C50, 1194(1994)
310:1
620:1
310:1
Rotating wheel/cathode
Stepping motor, encoder
Experimental setup for the study of the β-delayed α decay of 16N
(4 high-acceptance gas ionization chambers, practically insensitive to β’s
Rotating wheel, cathode
60Fe T1/2=1.5 My (AMS techniques) K. Knie et al.
Phys. Rev. Lett. 83, 18(1999)
Phys. Rev. Lettt. 93, 171103 (2004).
182Hf T1/2=9 My C. Vockenhuber et al.,
New Astr. Rev. 48, 161(2004)
244Pu T1/2=81 My M. Paul et al. ApJ, 558, L133(2001)
Long-lived radioisotopes
e.g. 60Fe
Known nuclides
Measured nuclides with unknown masses before (80) Measured nuclides with previously known masses
Neutron Number
Proton Number
20 28
C. Scheidenberger et al. To be publ.
Mass measurements at the GSI storage ring
Fission fragments from 252Cf are difficult to obtain by other methods.
-3 -2 -1 0 1 2 3 55
60
65
70
75
80
149Ce2+
s) /
2
Frequency applied - 1214469.23 Hz -3 -2 -1 0 1 2 3
60
65
70
75
80
85
149Pr2+
Measurements on neutron-rich nuclei
limits of known nuclei
130Cd, 129Ag [CERN] (PRL91, 162503(03)) 78Ni [MSU] PRL 94, 112501(05)
Difficult experiments:
Summary: Advances in
Significant reductions in uncertainties for quiescent burning, e.g. 3He(4He,γ), 7Be(p,γ),14N(p,γ),12C(α,γ)..).
New experimental data for explosive stellar nucleo-synthesis, e.g. 21Na(p,γ) [novae], 68Se [X-ray bursts] from radioactive beams.
‘Extreme’ environments (e.g. supernovae) need a next generation facility.
Dark blue: something known (at least a half-life)
Extremely neutron rich nuclei in r-process path
Red: Within reach at RIA 80% of r-process path up to mass 208
Stable nuclei
21Na x102
22Na x103
68Se x105
8B x106
26 neutron-rich isotopes measured up to now
-600
-400
-200
0
200
400
600
800
A (amu)
M ea
su re
d- Ta
bu la
te d*
m as
s (m
( )θcos~ RDEVG −⋅A
ELi=4/7*Eα
Main sequence star T6 ~ 15, M ~1, t ~ 1010 y
White dwarf star T9 ~ 0.1-0.4, M ~1, t ~ days
Neutron star T9 ~ 0.7-2, M ~1, t ~ 10 sec
massive star T9 ~ 1, M ~10, t ~ sec
T9 ~ 0.1, M ~102-105
t < 106 y
Red Giant star; T9 ~ 0.1 –0.2 , M ~1, t ~ 109 y
supermassive starsred giants
p=160 Torr
p=120 Torr
p=80 Torr
p=60 Torr
Φ : 12C + α phase shifts
Stotal=S(E1)*f(S(E2)/S(E1),Φ) C. Brune, Phys. Rev. C64,055803(2001)
anode grid
Study of the 8B b-spectrum
g-ray Astronomy
Gamma Sphere
CPT: J. A. Clark et al. (PRL2004) ME=-54232±19 keVND/ANL: A. Wöhr et al. (NPA2004), ME=-54189±240
Measurements on neutron-rich nuclei