The 18F(p,)15O reaction and
RIB developments
F. de Oliveira Santos
The case of 18F(p,)15O
• 18F an important source of annihilation radiation from Novae
• Annihilation radiation is an observable of gamma-ray observatories
• Observation determined by amount of 18F synthesised by nova
• 18F synthesis depends upon production and destruction rates
• 18F(p,) dominates destruction rate and is the major nuclear uncertainty
J. Gomez-Gomar et al., Mon. Not. R. Astron. Soc. 296, 913 (1998).
M. Hernanz, J. Jose, A. Coc, J. Gomez-Gomar, and J. Isern, Astrophys. J. 526, L97 (1999).
A. Coc, M. Hernanz, J. Jose, and J.-P. Thibaud, Astron. Astrophys. 357, 561 (2000).
A “new” method: Inelastic scattering
19Ne
LLN cyclotron
19Ne6+
+ 1H
p + 19Ne*
Ex & Total
9 AMeV
 8 107 pps
E/E
θ=0°
Target
CH2
3.5 µm
simulation
Experimental setup
19Ne
Target
+ 1H
p + 19Ne*
Beam catcher
Al
250 µm
E/E
θ=0°
19Ne(p,p’)19Ne*
Labe
l
E*(19Ne)exp
E*(19Ne)lit
p’(exp)
p’(lit)
A
7.079 ± 0.005
7.076 ± 0.016
32 ± 8
39 ± 1.6
B
7.203 ± 0.031
7.238 ± 0.006
7.253 ± 0.010
35 ± 12
-
C
7.502 ± 0.030
7.500 ± 0.009
7.531 ± 0.011
17 ± 7
16 ± 16
31 ± 16
D
7.616 ± 0.005
7.608 ± 0.011
21 ± 10
45 ± 16
E
7.863 ± 0.039
-
292 ± 107
-
F
7.974 ± 0.010
7.944 ± 0.015
8.069 ± 0.012
11 ± 8
-
E*(19Ne)
Sp = 6.4 MeV
This state was predicted by
Dufour and Descouvemont NPA 785, 381 (2007)
Predictions are:
E = 7.91 MeV and tot = 296 keV
Inelastic scattering
19Ne
+ 1H
p + 19Ne*
15O+α
18F
+p
S = 3.53 MeV
Sp = 6.41 MeV
J
Beam catcher
Target
Aligned states
E/E
CD - PAD
Ferguson « Angular correlation methods … »
North-Holland Publ. 1965
Pronko et al, NIM98,445 (1972)
Ex : spin 5/2 decaying by α emission
p1+p3+p5 =1
p1 = P(m=+1/2) + P(m=-1/2)
p2 = P(m=+3/2) + P(m=-3/2)
p3 = P(m=+5/2) + P(m=-5/2)
E = 4.594 MeV
Jπ = 5/2
19Ne(p,p’)19Ne*()15O
Kmax= 0
Kmax= 4
Kmax= 2
Kmax= 6
E*(19Ne)exp
Jexp
E*(19Ne)lit
Jlit
4.594 ± 0.020
5/2
4.600
5/2+
4.722 ± 0.010
5/2
4.712
5/2-
5.074 ± 0.015
5/2
5.092
5/2+
5.376 ± 0.021
1/2
5.351
1/2+
5.465 ± 0.011
7/2
5.463
-
5.565 ± 0.026
3/2, 5/2, 7/2
5.539
-
5.832 ± 0.004
5/2
5.832
-
6.015 ± 0.014
7/2
6.013
-
6.136 ± 0.010
3/2
6.149
-
6.304 ± 0.020
7/2
6.288
-
6.449 ± 0.005
3/2
6.419/6.449
-
States above proton threshold
States above proton threshold
New state
1/2+ state was predicted by
Dufour and Descouvemont NPA 785, 381 (2007)
Good agreement
J.C. Dalouzy et al. Physical Review Letters. April 24th 2009
A. Murphy et al
Edinburgh University
stripper
8.4 μm of Al
60 μg/cm² of C
18F9+
18Ne9+
97 % 4 AMeV
3%
+…
SPIRAL
18F4+
18O4+
~ 2nAe
18Ne4+
target
Z spectrometer
degrader
MCP
2 104 pps
DSSSD
CH2
50 µm
Au
6 µm
E ~ 2.3 AMeV
H(18F,p)18F
and
H(18F,)15O
Preliminary results
Thesis work of David Mountford, Edinburgh
• Candidate state observed at
ECM=1.352MeV / 1.452 MeV
• Factor of 2 narrower than
predicted in proton channel
• Factor of 2 broader than
predicted in alpha channel
• Rough agreement in total
width (287keV) with
Dalouzy (292keV) and
prediction (296keV)
• Broad state is required to
fit to data
A
D
A
C
F
B
E
18F(p,α)15O
new
Limited effects of the interferences due to the tail of
the resonance
Large uncertainties due to the unknown signs of interferences.
The signs of the interferences cannot be predicted, neither
measured indirectly.
Lowest point
18F(p,α)15O
(+ + -)
(+ + +)
N. de Séréville et al., Phys. Rev. C79 (2009) 015801
Required beam intensity for a direct measurement
SPIRAL2 beams
From Report N°1 WP7.1 SP2 PP
GANIL,
Soreq NRC,
Weizmann Institute
Day1_SPIRAL2_Phase2
High intensity beams
Production rate of 14O
12C(3He,n)14O
Cross section Measured at Rez (CZ)
(pps/mA)
Taux de production
rate (pps/mAe)
Production
1.E+12
1.E+11
Singh
Nos mesures max
Nos mesures min
Nozaki et al.
1.E+10
1.E+09
0
10
20
30
40
Energie (MeV)
For 1 mA of 3He@35 MeV 35 kW
14O
Production ~ 2 1011 pps
More than 100 times the SPIRAL1
intensity @ 1.5 kW
50
Thank you
•
•
•
University of Edinburgh:
– A. S. Murphy
•
– T. Davinson
– P. J. Woods
•
– D. Mountford
University of York:
– A. M. Laird
– J. R. Brown
•
Orsay:
– N. de Sereville
LPC Caen
– N. L. Achouri
GANIL
– F. de Oliveira
– P. Ujic
– O. Kamalou
ORNL:
– S. Pittman
G. Lhersonneau, A. Pichard,
M.G. Saint-Laurent, F. de
Oliveira Santos
GANIL, Caen, France
M. Hass, T.Y. Hirsh, V. Kumar,
Weizmann Institute of
Science, Rehovot, Israel
D. Berkovits, Y. Nir-El, L.
Weissman
Soreq NRC, Yavne, Israel