1. Study of the resonance states in 27P by using
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Study of the resonance states in 27P by using
elastic scattering of 26Si + p
Young Kwan Kwon
Department of physics, Chung-Ang University,
Republic of Korea

2. 1.809 g-ray image, made by COMpton TELescope
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1.809 g-ray image, made by COMpton TELescope
Estimation of the abundance of 26Al under different stellar sites, i.e., Novae, Supernovae, etc.
: Important for building a model of stellar evolution, or identifying the main origin of the g-sources
26mAl and 26gAl have different paths.
Then, they should be dealt with as different species??

3. Under higher temperature of T > 0.4 GK, they can communicate
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Under higher temperature of T > 0.4 GK, they can communicate
through internal transitions.
(Ward80, Coc00, and Runk01)
Therefore the abundance of 26mAl become s important and
we should know the reaction rate of 26Si (p, g)27P, which
competes with 26Si(b+n)26mAl.
More contributable, the resonance reaction rate needs
the information of the resonances within Gamow window,
such as E i (resonance energy), J (spin).

4. To get the resonance parameters of resonance states in 27P,
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To get the resonance parameters of resonance states in 27P,
• Probe : Elastic scattering with a radioactive ion beam 26Si,
because of its large scattering cross section
• Physical quantity to be measured :
Excitation function of the elastic scattering of 26Si + p
using thick target scan technique
• Tool for analysis :
R-matrix based code SAMMY M6-beta
• Physical quantities to be extracted :
Resonance parameters, such as energy, spin-parity, and
proton decay width for each observed resonance
• Astrophysical Information to be presented :
Reaction rate for resonant capture as a function of temperature

5. Dr. Jung Young Moon’s PhD work
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1st experiment
Date : June ~ June
RI beams at F2 : 25Al (11.1 kcps, 5.1 % purity), 26Si (2.32kcps, 1.1 %)
for full 24Mg beam of 600enA
Dr. Jung Young Moon’s PhD work
2nd experiment
Date : Jan ~ Jan
RI beams at F3 : 25Al (33 kcps, 61.8 % purity), 26Si (12kcps, 23.2 %)
for full 24Mg beam of 1600enA
Miss Hyo Soon Jung’s PhD work

6. Experimental setup in 2003 D1 D2
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Experimental setup in 2003
CRIB (CNS Radioactive Ion Beam RIKEN, Japan
24Mg beam (7.439 MeV/u, ~ 600 emA) + 3He gas (1atm)
3He (24Mg, n)26Si D2 D1
PPAC
Target holder
DE-E 0 deg.
DE-E 17 deg.
PPAC

7. E cm (26Si) = 3.606 MeV on target Beam Intensity = 2 .32 kcps
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Depending on different Br, the fragments are
separated by two dipole magnets.
E cm (26Si) = MeV on target
Beam Intensity = kcps
By using position sensitive
detectors, proton spectra
can be converted to those
in C.M. frame.

8. Experimental setup in 2003 26Si14+ - Energy ~ 3.710MeV/u
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Experimental setup in 2003
26Si14+
- Energy ~ 3.710MeV/u
- Purity ~ 23 %
- Intensity ~ 1.2X104 pps

9. 26Si RIB 3.710MeV/u recoiled protons H2 gas target (30cm, 330torr)
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26Si RIB
3.710MeV/u
recoiled protons
H2 gas target
(30cm, 330torr)
DSSDs at 0o and 15o
for DE-E telescope
PPACs

10. Excitation function from experimental data
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Excitation function from experimental data
The excitation function of 26Si + p can be analyzed by R-matrix theory and Shell model calculation to extract the resonance parameters.

11. Preliminary result Excitation function of 26Si+p In 2003 In 2011 0o
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Excitation function of 26Si+p
In 2003 0o
Preliminary result
In 2011

12. R-matrix analysis for 1st exp’s data
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R-matrix analysis for 1st exp’s data
It was hard to determine a good spin-parity
combination for the observed peaks, because of
large statistical error. So all candidates were taken and
used in determining the important resonance parameters.

13. Comparison with the shell model calculation (OXBASH)
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Comparison with the shell model calculation (OXBASH)
Iliadis et al., NPA 618, 166 (1997) :
~ 0.2 for 1d3/2, 5/2 ~ 0.4 for 2s1/2
Spectroscopic factor Calculation (Oxbash)
- Model space : sdpn
- Interaction : wpn
- Core : 16O(g.s., 0+)

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15. Preliminary result Results for 2nd experiment Ex (keV) Gp (keV)
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Results for 2nd experiment
Ex (keV)
Gp (keV)
Jp(l-wave)
c2/NDAT
(1)
2888
8.3
7/2+
1.55
2897
1.5
3/2+
2974
84.5
1/2+
3310
84.2
3436
106.2
3491
56.3
5/2+
3548
10.2
(2)
2879
4.4
1.98
2960
85.9
3146
1.2
3338
124.4
3504
68.8
3570
248.6
Preliminary result

16. ** 26Si + p  27P radiative capture reaction rate calculation
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26Si + p  27P radiative capture reaction rate calculation
1. Parameters, used in the resonant capture reaction rate calc. **
** Weisskopf width, calculated and based on the transition information of 27Mg
2. Direct capture reaction rate
So = from Caggiano et al. (PRC , 2001)
3. Total capture reaction rate
Resonant capture + Direct capture reaction rate

17. Not including new levels
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Not including new levels
1.2 MeV
1.631 MeV
Including new levels

18. X-ray burst model 1.35Msun 1.25Msun 26Si + p  27P 26Si b-decay
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Competition between 26Si + p  27P and 26Si  26mAl b-decay
solid and dashed line : rXH<sv>/AH = /T1/2 (XH = 0.5, T1/2 = s)
X-ray burst model
1.35Msun
1.25Msun
26Si + p  27P
26Si b-decay
For T > 2GK and r < 10-2 g cm-3 , the newly found states become more significant.

19. 26Si+p resonant elastic scattering has been measured successfully.
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26Si+p resonant elastic scattering has been measured successfully.
- The R-matrix analysis is in progress.
CRIB is one of the best facilities for studying nuclear astrophysics
with low energy RI beams.
- There are number of astrophysically important nuclear reactions
to be studied.
- Future works : alpha transfer reaction -15O(6Li,d)19Ne
(alpha,p) reaction – 26Si(a,p)29P
KoRIA (Korea Rare Isotope Accelerator) in Korea (2018~ (plan))
- KRS (Korea Recoil Spectrometer) for NAP in KoRIA
- Absolutely we need man powers in related fields
- Strong collaboration with CRIB is very helpful for success of KoRIA
: educating people at CRIB, comments or ideas from CRIB etc

20. [Collaborators]