Nuclear Level Density and Gamma Strength from Quasi-Continuum Lifetimes with GRETINA. Leo Kirsch Oslo 5/10/17

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1 Nuclear Level Density and Gamma Strength from Quasi-Continuum Lifetimes with GRETINA Leo Kirsch Oslo 5/10/17

2 Nuclear Level Density and Gamma Strength from Quasi-Continuum Lifetimes with GRETINA 16 MeV proton Fe target 56 Leo Kirsch Oslo 5/10/17

3 Nuclear Level Density and Gamma Strength from Quasi-Continuum Lifetimes with GRETINA -ray det 16 MeV proton Fe target 56 Leo Kirsch Oslo 5/10/17

4 Nuclear Level Density and Gamma Strength from Quasi-Continuum Lifetimes with GRETINA p det -ray det 16 MeV proton Fe target 56 Inside Leo Kirsch Oslo 5/10/17

5 Fe(p,p'g) 56 Gretina gammas E1,θ1,φ1, E2,θ2,φ2,... Phoswich Wall: particles ID, E, θ, φ p 56 Fe ions stop in target Ex, KE, θ, φ from p kinematics

6 Doppler Shift Review: E, observed= E, source(1 + v cos Θ / c) 56 Fe p Recoil, antiparallel Fe 56 p Recoil, parallel

7 Doppler Shift Review: E, observed= E, source(1 + v cos Θ / c) 56 Fe Fe 56 p p Recoil, antiparallel Recoil, parallel 0

8 Doppler Shift Review: E, observed= E, source(1 + v cos Θ / c) Emission Depends on lifetime 56 Fe Fe 56 p p Recoil, antiparallel Recoil, parallel 0 Initial

9 Monte-Carlo DSAM Directly populated events: ΔEp= EL Compare well with ENSDF e- friction and nuclear scatter 30 ΘFe-,0; EFe,0 SRIM Trajectories Simulated Slope F(τ) (kev/%c) 0 meas 0 τ(fs) 150

10 Counts in with E = 2113 Excitation Cuts Indirect QC (p,p) elastic coincidences Indirect discrete Direct Ex(MeV) = Ep,i - Ep,f Sp Sn

11 Counts in with E = 2113 Excitation Cuts Indirect QC (p,p) elastic coincidences Indirect discrete Direct Ex(MeV) = Ep,i - Ep,f Sp Sn 30 direct Slope F(τ) E = τ(fs) 150

12 Counts in with E = 2113 Excitation Cuts Indirect QC (p,p) elastic coincidences Indirect discrete Direct Ex(MeV) = Ep,i - Ep,f Sp Sn 30 direct Slope F(τ) 0 0 τ(fs) discrete 150 E = 2113

13 Counts in with E = 2113 Excitation Cuts Indirect QC (p,p) elastic coincidences Indirect discrete Direct Ex(MeV) = Ep,i - Ep,f Sp Sn 30 tfeed( Ei, Ef ) Slope F(τ) 0 0 τ(fs) direct QC discrete 150 E = 2113

14 Feeding Time Been analyzing strength with gamma spectra: P(E ) Now can analyze strength with lifetimes: ΔE (Θ) tfeed( Ei, Ef )

15 Nuclear Testing Grounds Level Density Models Gamma Strength Functions

16 Simulation E t 9 MeV MeV MeV MeV 2+ g.s fs 31 fs Final product: Feeding time distributions tfeed(ef,jf,πf) 62 fs 87 fs

17 Simulation E t 9 MeV MeV MeV MeV 2+ g.s. 0+ New level energies, contents, widths 7 fs 31 fs Used DICEBOX1 But had trouble extending to different initial E,J,π Suited to do (n,g) Final product: Feeding time distributions tfeed(ef,jf,πf) 62 fs 87 fs F. Bečvář, NIM A 417, 2-3 (1998) 1

18 Simulation E t 9 MeV MeV MeV MeV 2+ g.s. 0+ New level energies, contents, widths 7 fs 31 fs Used DICEBOX1 But had trouble extending to different initial E,J,π Suited to do (n,g) Final product: Feeding time distributions tfeed(ef,jf,πf) 62 fs 87 fs 4500 lines FORTRAN ~ lines C++ / ROOT Annotated well Input energy, spin, parity distribution Same built nucleus energies, contents, widths Output many observables, including time F. Bečvář, NIM A 417, 2-3 (1998) 1

19 Simple Nuclear Parameters: dice.c Initial Excitations: E = Gaussian, 11 +/- 0.2 MeV J = Poisson, mean 2.2 ћ P = Uniform +/Decay: E1 = GLO; M1,E2 = std Lorentzian

20 dice.c Initial Excitations: E = Gaussian, 11 +/- 0.2 MeV J = Poisson, mean 2.2 ћ P = Uniform +/Decay: E1 = GLO; M1,E2 = std Lorentzian Built Discrete From RIPL counts Simple Nuclear Parameters:

21 dice.c Initial Excitations: E = Gaussian, 11 +/- 0.2 MeV J = Poisson, mean 2.2 ћ P = Uniform +/- Built Discrete From RIPL counts Decay: E1 = GLO; M1,E2 = std Lorentzian counts Simple Nuclear Parameters:

22 dice.c Initial Excitations: E = Gaussian, 11 +/- 0.2 MeV J = Poisson, mean 2.2 ћ P = Uniform +/- Built Discrete From RIPL counts Decay: E1 = GLO; M1,E2 = std Lorentzian counts Simple Nuclear Parameters:

E1 = GLO; M1,E2 = std Lorentzian counts 1+2

23 dice.c Initial Excitations: E = Gaussian, 11 +/- 0.2 MeV J = Poisson, mean 2.2 ћ P = Uniform +/- counts Simple Nuclear Parameters: Built Discrete From RIPL Decay: E1 = GLO; M1,E2 = std Lorentzian counts 1+2 step Fit = 0.88 Exp(-t / 1.56) Exp(-t / 17.7) step

24 Starting Energy Lower Ex,i Slower: ρ(ef), Eg3 Higher population: fewer ways to pass MeV 2+ MeV

25 Initial Spin Dist T. Døssig, 6th Workshop on Nuclear Level Density and Gamma Strength, Oslo Still benchmarking and tuning the feeding times Poisson 2.2 ћ Poisson 3.6 ћ

26 Thanks I.Y. Lee, A.O. Macchiavelli, C.M. Campbell, M. Cromaz, R.M. Clark, H.L. Crawford, P. Fallon, M.D. Jones and the rest of the GRETINA team L.A. Bernstein, Karl van Bibber

27 Benchmark In Progress Initial state: 56Fe, 7.0 MeV, 3+ Initial state: 186Re, 6.0 MeV, 1+ Population of low lying levels dice DICEBOX Different random # methods Magnitudes of the same order Porter-Thomas Fluctuations of same order: PT: = 1 Violent dist dice might seem slower but: 1. DICEBOX is saving initial state widths 2. dice presumes widths will need recalc every initial state 3. DICEBOX slows to same speed with this presumption

28 To Do Intricate strength and level density models Odd A nuclei Internal conversion More benchmarking

Order-to-Chaos Transition in Rotational Nuclei

Order-to-Chaos Transition in Rotational Nuclei I.Y. Lee, F.S. Stephens, M.A. Deleplanque, A.O. Macchiavelli, D. Ward, P. Fallon, M. Cormaz, R.M. Clark, M. Descovich, R.M. Diamond, and E. Rodriguez-Vieitez