RMatrix Analysis of 15Np,g016O using the program AZURE'

1
R-Matrix Analysis of 15N(p,g0)16O using the
program AZURE.

• P.J. LeBlanc
• April 23rd, 2008
• Sante Fe, NM

2
Outline

• Previous experimental data
• Experimental update of the 15N(p,g0) performed at
  Notre Dame in April 2007
• Using AZURE to analyze the results

3
Experimental Background

• Previous results published by Rolfs in 1974.
• This data was re-analyzed using an early version
  of AZURE by Ed Simpson.
• Results indicated that the interference between
  the resonances was critical in determining S(0).

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New Experiment at Notre Dame
3.5 MV KN VdG accelerator
1 MV JN VdG accelerator
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Experimental Set Up _at_ ND

• Used a Ge Clover Detector set up at 45
• Clover was used in Add-Back mode.
• Targets used were TiN, enriched in 15N, around 8
  keV thick at 430 keV.

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Experimental Results
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AZURE Analysis Set Up

• Need Data files
• (p,g0) obviously, but any other data will help
  constrain the parameters.
• (p,p) (p,a0) data sets are also included
• Nuclear Physics Environment
• Spins and parities of particles involved
• Also energy levels and some initial values for
  the gamma widths.

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Current included Data Sets

• 15N(p,p)15N
• Hagedorn (1957) 160, 125, 90
• Bashkin (1959) 90 , 160.8
• 15N(p,g0)16O
• Notre Dame 2007 Data
• 15N(p,a0)12C
• Schardt (1952) 160
• Redder (1982) 160
• Zyskind (1979) 160

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Nuclear Physics EnvironmentResonance
Transitions 12.442 13.091, 1- States
Elastic scattering
Gamma decay
Alpha decay
1-
1-
1-
E1
12Ca0
0
15Np
15Np
15Np
15Np
S0, l1
16Og
S0-, l1
S0-, l1
S1-, l0,1,2
S1-, l0,1,2
Starting parameters from TUNL
13.091 MeV State
12.442 MeV State
Indicates component not included by setting rwa
0.0. In, general, only the lowest l-value is
allowed
Indicates component excluded by parity
considerations.
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Initial AZURE calculation (p,p)
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Initial AZURE Calculation (p,g0) (p,a0)

• All calculations look very good using just the
  literature values of the experimental partial
  widths.
• Note that no target integration or convolution
  included.
• So what does the fit look like?

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First try for AZURE fit (p,p)
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First try for AZURE fit (p,g0) (p,a0)

• Fits still need a little workbut look promising.
• C2 / point
• (p,p) 1.66
• (p,a0) .98
• (p,g0) 6.27

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Closing Remarks Improving the fit

• Look into the (p,p) data
• Could be a problem with the scan
• Notre Dame (p,p) data available
• Adding the (p,a1) data would help
• Include the recent LUNA (p,g0) data

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Thanks to Dick!

• Little did I know back in 2004 what I was getting
  myself into!!
• But working with the AZURE code under Dicks
  guidance taught me more nuclear physics than I
  could have hoped to learn in any class.