TUNL Contributions in the US Nuclear Data Program Nuclear Structure Data Evaluation Program J.H. Kelley (USNDP Structure Group Leader), Jim Purcell, and Grace Sheu (H.R. Weller & Kent Leung) We are responsible for nuclear structure evaluation in the A=2-20 mass region Energy Levels of Light Nuclei reviews published in Nuclear Physics A ENSDF files for A=2-20 XUNDL from A=2-20 Web interface for A=3-20 Information

Evaluation Activities Energy Levels of Light Nuclei –Follow style of Fay Ajzenberg-Selove –Broad scope of reactions is included – discussion format. –Adopted levels/gammas, Energy Level Diagrams ENSDF –More rigorous information required –Better documentation of original sources –reaction data sets/decay data sets –Adopted levels/gammas, decay widths, etc.

Adopted Levels  -ray transitions

Present Evaluation Activities Published “Energy Levels of Light Nuclei: A=3” Nucl. Phys. A848 (2010) 1 “Energy Levels of Light Nuclei: A=11” Nucl. Phys. A880 (2012) 88 (ENSDF Updated) Work in progress: –A=12 Evaluation for “Energy Levels” (90%) –Preparing A=12 ENSDF file –Preparing A=3 ENSDF file(Jim Purcell) –Preparing A=2 ENSDF file(K. Leung & H.R. Weller)

Evaluation Activities Updated ENSDF nuclides – 6 B, 14 F, 15 Ne, 18 Mg, 19 Mg Updated ENSDF Reaction Data sets –  : 14 Be, 14 B, 19 N, 20 N –  -n: 12 Be, 13 B, 14 Be, 14 B, 15 B, 16 C, 17 B, 17 C, 17 N, 18 C, 18 N, 19 B, 19 C, 19 N, 20 C, 20 N –  -p: 9 C, 11 Be, 13 O, –  : 9 C, 11 Be, 14 Be, 17 N, 18 N, 20 Na

XUNDL Compilation Activities Experimental Unevaluated Nuclear Data Library –Up-to-date structure data Library –New articles added within 1-2 months – Feedback loop between source and evaluator –Committed to A=2-20 since April 2009 –60-65 data sets/year (5-6/month) –Organized “Workshop on the Future of XUNDL” TUNL May

Why XUNDL makes a difference 17Ne 17 Ne used for device calibration

Other Compilation Activities Compilation of ground state decay &  -decay references and data Compilation of (p,X) and ( ,X) excitation functions TUNL Dissertations- –

Synergistic Experimental Activities HIGS Facility Compton Backscattered Photons Monoenergetic Neutron Sources at TUNL DD, DT, PT, and PLi 147 Nd Absolute 239 Pu Fission Product Yield

HIGS Facility Compton Backscattered Photons TUNL and HIGS

Nuclear Resonance Fluorescence Technique TUNL and HIGS Experimental Observables in NRF HIGS Advantages AXNAXN 1-1-  Excitation energy E x  Spin and parity J,   Decay width  0  Branching ratio  i /  A.P. Tonchev, NIM B (2005)‏ G. Rusev, PRC 79, (2009) In a completely model independent way !  σ el = f(E γ ) (from primary g.s. transitions)  σ inel = f(E γ ) (from secondary transitions)  σ tot = σ el + σ inel = σ abs

High Intensity Gamma-ray Source Nuclear Resonance Fluorescence Levels and Level Parameters DHS/DNDO cargo container interrogation

Spin and Parity Determination TUNL and HIGS N. Pietralla, at al. PRL 88 (2002) ; A. Tonchev, NIM B 241 (2005) 51474

Spin and Parity Determination TUNL and HIGS N. Pietralla, at al. PRL 88 (2002) ; A. Tonchev, NIM B 241 (2005) 51474

NRF from 238 U TUNL and HIGS  Over 105 new excited low-spin states in 238 U were observed at γ-ray beam energies from 2.0 to 5.5 MeV.  80 E1 and 25 M1 states were identified HIGS facility is an ideal source for identifying low-spin states Samantha Hammond Ph.D. Project

NRF from 235 U TUNL and HIGS E  = 1800 keV; ΔE/E = 70 keV m 235U = 3.5 g; t i = 6 h; ϕ γ = 3x10 7 γ/s  13 discrete deexcitations were identified for the first time in the from 1.6 to 3.0 MeV.  This includes 10 to the ground state, two branching transitions to the third excited state at 46.2 keV and one unresolved transition in 235 U.  Unique decay pattern E. Kwan et al., accepted by PRC

DENIS source FN TANDEM 10MV Shielded neutron source area 2 H(d,n) 3 He; Monoenergetic neutrons: 4.0 – 7.7 MeV 3 H(p,n) 3 He; Monoenergetic neutrons: 0.5 – 7.7 MeV Quasi-monoenergetic neutrons 7 Li(p,n) 7 Be; Monoenergetic neutrons: 0.1 – 0.65 MeV 3 H(d,n) 4 He; Monoenergetic neutrons: 14.8 – 20.5 MeV

1.Motivation 1.Energy Dependence of Fission-Product Yields 2.Experimental technique 3.Results 4.Future plans

21 TUNL Duke C. BHATIA M. BHIKE B. FALLIN C. HOWELL W. TORNOW N.C. State Univ. M. GOODEN J. KELLEY LLNL J. BECKER R. HENDERSON J. KENNEALLY R. MACRI C. RYAN S. SHEETS M. STOYER A. TONCHEV LANL C. ARNOLD E. BOND T. BREDEWEG M. FOWLER W. MOODY R. RUNDBERG G. RUSEV D. VIEIRA J. WILHEMY Acknowledgements

 Resolve the long-standing difference between LLNL and LANL with respect to selected fission product data  Joint LANL/LLNL fission product review panel endorsed a possible energy dependence of 239 Pu(n,f) 147 Nd fission product yield with fission neutrons: 4.7%/MeV from 0.2 to 1.9 MeV (M. Chadwick) 3.2%/MeV from 0.2 to 1.9 MeV (I. Thompson)  Mostly low energy data from critical assembly or fast reactors 239 Pu(n,f) 147 Nd M.B. Chadwick et al. Nuclear Data Sheets 111 (2010) 2923; H.D Selby et al. Nuclear Data Sheets 111 (2010) P. Baisden et al, LLNL-TR , 2010; R. Henderson et al. LLNL-TR DRAFT; I. Tompson et al. Nucl. Sci. Eng. 171, 85 (2012) There are no 147 Nd data between 1.9 and 14 MeV  Very scarce experimental data at the MeV-range  Large discrepancy (~20%) at 14 MeV

Scission point % KE Prompt n-emission Prompt  -emission Beta decay, delayed n,  Credit: Encyclopædia Britannica, Inc Saddle point Distance between fragments (cm) time (s)

Pre-actinides ((e.g.W,Au,Pb,Bi) Heavy (Es to Lr) Medium (U to Cf) Asymmetric Symmetric Light (Th, Pa ) Triple humped

 Y i E (A) = fractional yields of mass chain ‘A’ (after  decays) from initial actinide ‘i’ for neutron energy ‘E’.  How does the asymmetry evolve with neutron energy for 235,238 U, 239 Pu? Depends on actinideDepends on neutron energy Goal: Develop high-precision FPY energy dependence from 1 to 15 MeV

2 H gas From VdG accelerator p or d n One thick target ~0.2 g/cm 2 Two thin targets ~10 μg/cm 2 Dual fission chamber n-detector

Fission_counts = m f  σ n,f ε f t f Gamma_counts ( 147 Nd) = m γ  σ n,f FPY I γ ε γ t γ m γ ( m f ) = atoms in the 239 Pu thick (thin) target  = neutron flux (n.cm -2.s -1 ) σ n,f = 239 Pu(n,f) fission cross section (cm 2 ) FPY = fission product yield of 147 Nd per 239 Pu fission I γ = branching ratio of E  ε γ (ε f ) = counter efficiency of  -ray (fission) detection t γ ( t f ) = time factor for irradiation and counting periods of  -ray (fission) (Gamma_count / Fission_count) = (m thick / m thin ) * FPY * C  FPY = (Gamma_count) / Fission_count) * (m thin / m thick ) * C

Relative FPY Ratio (This is what we have promised) 1. Statistical uncertainties of  -ray peak counts (1-2%) 2. Relative HPGe detector efficiency (1-2% including the fit) Absolute FPY energy dependency: 1.Statistical error of  -ray peak counts (1-3%) 2.Absolute detector efficiency (2% including the fit) 3.Branching ratios (0.2 – 8% ( 147 Nd)) 4.Absolute FC efficiency (3% experimentally, 0.5% simulation) 5.Low energy neutrons (<1%) 6.Neutron fluence rate fluctuation (<0.3%) 7.Efficiency conversion ratio between close and standard geometry (<1%) 8.True coincidence summing (<1%) 9.Random coincidence summing (<0.2%) 10. Sample weight (<0.1%) 11. Self-absorption of  -ray ( %)

Region of interest Not desirable events in our measurements

Reactions studied 115 In(n, n') 115m In 197 Au(n, 2n) 196 Au 27 Al(n,  ) 24 Na 235 U (n, f) 133 I and 135 I Room return neutrons ~ 10 5 times smaller than primary flux on target

Neutron and gamma are well separated Break up – Negligible Neutron and gamma are well separated Break up – Negligible

 Design and fabricate three fission chambers: one for 239 Pu, one for 235 U, and one for 238 U  Dedicated thin (~10 μg/cm 2 ) 235,238 U and 239 Pu foils electroplated on 0.5” titanium backing ★  Dedicated thick ( mg/cm 2 ) 235 U (93.27%) 238 U (99.97%) and 239 Pu (98.4%) targets  Fission chamber efficiency confirmed: 100%, confirmed with activation measurements ★ Made by LANL Gas flow in and out FCFC gas cel l

Excellent  / fission separation alpha fission

in cadmium without cadmium 9 MeV / Background neutrons = 150 / 1

Experimental Results

FP/ 99 Mo Present Data Present Data Present Data Present Data Gindler 1 et al. LANL 2 Selby et al. Saclay 3 J. Laurec et al. England 4 et al. LANL 5 LLNL 6 Nethaway 4.6 MeV9 MeV14.5 MeV14.8 MeV4.5 MeV MeV 14.7 MeV 14 MeV 14.8 MeV 87 Kr 91 Sr 92 Sr 97 Zr 105 Ru 131 I 132 Te 133 I 140 Ba 142 La 143 Ce 147 Nd 0.21 ± 5.3% 0.52 ± 2.2% 0.56 ± 4.3% 0.96 ± 3.3% 0.96 ± 3.7% ± 5.2% 1.18 ± 5.0% 0.89 ± 3.8% ± 3.9% 0.37 ± 5.1% 0.22 ± 5.3% 0.48 ± 1.4% 0.51 ± 3.7% 0.89 ± 2.9% 0.85 ± 2.2% 0.93 ± 3.3% 0.76 ± 4.0% 1.03 ± 3.5% 0.82 ± 3.0% 0.80 ± 2.1% 0.64 ± 2.6% 0.34 ± 3.9% 0.22 ± 5.5% 0.52 ± 1.4% 0.52 ± 3.7% 0.97 ± 2.1% 0.86 ± 2.0% 1.03 ± 3.0% 0.80 ± 4.0% 1.09 ± 3.9% 0.84 ± 2.3% 0.85 ± 2.0% 0.64 ± 2.3% 0.35 ± 3.2% 0.21 ± 5.3% 0.53 ± 1.8% 0.52 ± 3.8% 0.86 ± 2.7% ± 4.9% 0.88 ± 3.7% 0.85 ± 2.8% 0.90 ± 3.4% ± 4.6% 0.22 ± 4.5% 0.51 ± 4.8% 0.58 ± 6.4% 0.93 ± 0.6% 0.87 ± 6.0% ± 0.7% 1.11 ± 0.6% 0.88 ± 0.6% 0.79 ± 5.9% 0.65 ± 0.6% ± 4.5% ± 4.2% ± 5.2% 0.34 ± 3.5% ± 3.3% ± 3.5% 0.81 ± 4.5% 0.99 ± 6.2% 0.82 ± 3.1% ± 3.2% 0.31 ± 5.2% ± 7.1 % 0.74 ± 6.0 % 0.97 ± 5.2 % 0.61 ± 7.9 % 0.74 ± 5.7 % 0.74 ± 5.8 % ± 6.3 % 0.86 ± 7.1 % ± 7.1% ± 7.1 % ± 7.1 % 1 J.E.Gindler et al. Phys. Rev. C 27 (1983) H.D.Selby et al. Nucl. Data Sheets 111(2010) J. Laurec et al. Nucl. Data Sheets 111(2010) T.R. England and B.F. Rider, LA-UR M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135– D.R.Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827

FP/ 99 Mo Present Data Present Data Present Data Glendenin et al. 1 ANL Selby et al. 2 LANL Laurec et al. 3 Saclay Maeck mass- spectrometry 4 England et al. 5 Innes et al. 6 LANL Nethaway et al. 7 LLNL 4.6 MeV 9 MeV14.5 MeV3.9 MeV~1.4 MeV14.7 MeV MeV14 MeV 14.8 MeV 238 U 97 Zr 105 Rh 131 I 132 Te 135 Xe 140 Ba 141 Ce 143 Ce 147 Nd 0.86 ± 2.6 % 0.55 ± 3.0 % ± 4.3 % ± 2.9 % ± 3.2 % 0.35 ± 3.5 % 0.85 ± 2.4 % 0.62 ± 3.3 % 0.60 ± 2.7 % 0.74 ± 4.5 % ± 2.8 % ± 3.1 % 0.37 ± 2.8 % 0.97 ± 2.2 % 0.76 ± 3.4 % 0.71 ± 2.2 % 1.18 ± 5.4 % 1.15 ± 3.4 % 0.93 ± 2.5 % 0.88 ± 2.4 % 0.87 ± 2.6 % 0.40 ± 3.5 % 0.94 ± 0.2 % 0.73 ± 0.4 % 0.56 ± 0.2 % 0.82 ± 0.3 % ± 0.5 % ± 0.4 % 0.45 ± 0.4 % ± 3.6 % ± 3.8 % 0.89 ± 3.4 % 0.58 ± 5.0 % 0.70 ± 3.4 % 0.81 ± 4.7 % 0.99 ± 4.8 % 0.79 ± 3.3 % 0.67 ± 3.5 % 0.77 ± 3.2 % 0.34 ± 5.4 % ± 2.4 % ± 1.8 % ± 6.1 % 0.57 ± 14.7 % 0.71 ± 5.6 % 0.82 ± 5.9 % ± 5.9 % 0.75 ± 5.9 % ± 5.6 % 0.88 ± 6.5 % ± 7.2 % ± 7.2 % 0.36 ± 7.0 % 235 U 97 Zr 105 Rh 131 I 132 Te 140 Ba 143 Ce 147 Nd 1.04 ± 4.4 % 0.37 ± 2.5 % ± 4.6 % 0.99 ± 3.6 % 0.93 ± 3.8 % 0.35 ± 4.3 % 1.04 ± 2.4 % 0.39 ± 2.4 % 0.91 ± 3.6 % 1.08 ± 4.2 % 1.05 ± 2.9 % 0.93 ± 3.8 % 0.30 ± 3.0 % 1.02 ± 1.8 % 0.37 ± 1.8 % 0.84 ± 2.4 % 1.10 ± 3.3 % 1.06 ± 2.5 % 0.92 ± 2.6 % 0.38 ± 2.7 % 1.09 ± 0.4 % ± 0.3 % 0.94 ± 0.4 % 1.07 ± 0.4 % 0.86 ± 0.5 % 0.41 ± 0.3 % ± 3.3 % ± 3.4 % 0.98 ± 3.6 % ± 3.3 % 0.81 ± 4.7 % 0.89 ± 3.3 % 0.72 ± 3.3 % 0.30 ± 5.5 % ± 1.4 % ± 1.4 % ± 6.6 % 0.37 ± 6.0 % 0.89 ± 5.8 % 0.81 ± 5.5 % 0.89 ± 5.5 % ± 5.8 % 1 ± 13.9 % ± 10.6 % ± 11.9 % 1 L. E. Glendenin et al. Phys. Rev. C 24 (1981) H. D. Selby et al. Nucl. Data Sheets 111(2010) J. Laurec et al. Nucl. Data Sheets 111(2010) W.J. Maeck et al., ENICO – 1028 (1980). 5 T.R. England and B.F. Rider, LA-UR M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135– D. R. Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827.

1. Our absolute magnitude of the 147 Nd FPY below 2.5 MeV and at 14.5 MeV neutron energies are slightly higher than the predicted values. 2. We can rule out the two low- yield data at 14.8 MeV. 3. The slope of 147 Nd FPY from 4.6 to 14.8 MeV is slightly negative (- 1% / MeV). 4. There is no energy dependence (or it is below our experimental sensitivity) for 140 Ba and 99 Mo fragments. Model calculation ___ Uncertainties ___ J. Lestone. Nuclear Data Sheets 112 (2011) 3120

Summary We start delivering precise (< 2% relative uncertainty) information on FPY ratios obtained at SIX energies in case of 239 Pu and at FOUR energies for 235 U and 238 U We will deliver accurate (4-5% absolute uncertainty) information on the energy dependent fission product yields covering an energy range from 1 < E n < 15 MeV Potential experiments:  Reduce 147 Nd branching ratio uncertainty from the current 8%  High-accuracy measurements in the 0-2 MeV range to clarify 144 Ce and 147 Nd neutron-energy dependence Strong LLNL-LANL-TUNL Collaborative Effort

FragmentE  (keV)'T 1/2 I  % 95 Zr d % Zr h % Rh h % Sb d % I d % I h % Te d 1388 % I h % Xe h 290 % Ba d % Ce d % Ce h % Nd d % 11

Reducing fission-product  -ray branching-ratio uncertainties 147 Ce Q  =3.4 MeV 56.4 s IY: 1.91% 147 Pr Q  =2.7 MeV 13.4 m IY: 0.18% 147 Nd Q  =0.9 MeV d IY: 0.001%    Produce pure sources using mass-separated CARIBU fission-product beam… (  M/M~10 -4 … only need  M/M~10 -2 ) (10 10 atoms after 1 day) …collaborate with TAMU for high-precision  and  -ray spectroscopy At TAMU, they have a unique HPGe detector laboriously calibrated to ~0.2% for efficiency count  decays with low- threshold 4   counter (~100% efficient for  s) N. Scielzo: ER-LDRD proposal