1. EGAF Status 2015 Richard B. Firestone Lawrence Berkeley National Laboratory and the University of California, Berkeley, 94720, USA 21 st Technical Meeting of the NSDD IAEA Headquarters, Vienna, Austria 20-24 April 2015

2. Outline 1.Published results 2013-2015 (9 journal publications) – 23 Na, 39,40,41 K, 152,154 Eu, 156,158 Gd, 180, 182,183,184,186 W, 237 Np, 241 Am, 242 Pu(n,  ) 2.Evaluations in progress – 2 H, 16,17,18 O, 54,56,57,58 Fe, 90 Y, 94 Nb, 140 La, 186 Re(n,  ) 3. 57 Fe photon strength function a)Primary  -ray strengths b)Secondary  -ray strengths c)Comparison to Porter-Thomas distribution 4.Future plans

3. Published Results 2013-2015 Isotope   (b) Atlas*   (b) This work 23 Na0.517(4)0.541(3) 39 K2.1(2)2.28(4) 40 K30(8)90(7) 41 K1.46(3)1.62(3) E  42 K(  -) P  ENSDFP  This work 1524.70.1808(9)0.164(4) New Potassium Nuclear Structure Data Isotope 23 Na 40 K 41 K 42 K # levels below E crit (RIPL) † 415114 # levels below E crit (This work) † 13211617 New J  assignments21328 New levels placed01800 Previous levels removed0100 New  -rays placed 27200 23 Na: R.B. Firestone et al, submitted to Phys. Rev. C 89, 014617 (2014) 39,40,41 K: R.B. Firestone et al, Phys. Rev. C 87, 024605 (2013) *Atlas of Neutron Resonances, S.F. Mughabghab, Elsevier (2006). † E crit is the excitation energy where the level scheme is complete. S n (keV) IsotopeThis workAME 24 Na6959.352(18)6959.42(4) 40 K7799.57(12)7799.62(6) 41 K10095.243(15)10095.37(6) 42 K7533.829(10)7533.80(11)

4. Published Results 2013-2015 Tungsten Thermal (n,  ) Cross Sections Isotope Cross section (b) This workAtlas 182 W(n,  ) 183 W 20.5(14)19.9(3) 182 W(n,  ) 183 W m 0.177(18)--- 183 W(n,  ) 184 W 9.4(4)10.4(2) 183 W(n,  ) 184 W m 0.025(6)--- 184 W(n,  ) 185 W 1.43(10)1.7(1) 184 W(n,  ) 185 W m 0.0062(16)--- 186 W(n,  ) 187 W 33.3(6)38.1(5)* 186 W(n,  ) 187 W m 0.400(16)--- Tungsten Neutron Separation Energy Isotope S n (keV) This WorkAME 183 W6190.88(6)6190.81(5) 184 W7411.11(13)7411.66(25) 185 W5753.74(5)5753.71(30) 187 W5466.62(7)5466.79(5) 182,183,184,186 W: A.M. Hurst, et al, Phys. Rev. C 89, 014606 (2014). 187 W  decay P  (686 keV) This work0.352(9) ENSDF0.332(5) * Based on old ENSDF decay scheme normalization.

5. Published Results 2013-2015 New Tungsten Nuclear Structure Data Isotope 183 W 184 W 185 W 187 W # levels below E crit (RIPL)111283 # levels below E crit (This work)12181140 New J  assignments11316 New levels placed0001 Previous levels removed1100 New  -rays placed 1225 J  of -26.6 eV 184 W bound resonance ENSDF(0,1)  This work11 ENSDF This work

6. Published Results 2013-2015 180 W(n,  ): A. Hurst et al, Nucl. Data Sheets 119, 91, 2014 180 W(0.12% nat) target enriched to 11.35% Reference   (b) Pomerance (1952) <15 0 Kang (2007) 22.6±1.7 Vorona (200*) 36.3±2.4 This work 24.7±0.8 181m W(14.6  s) 6.8±0.9 S n =6686±5 keV AME S n =6668.79±20 keV This work

7. Published Results 2013-2015 Isotope Cross section (b) This workAtlas 152 Eu(n,  ) 153 Eu g 7060(400)5900(200) 152 Eu(n,  ) 153 Eu m1 2345(220)3300(200) 152 Eu(n,  ) 184 Eu g+m1 9405(460)9200(100) 154 Eu(n,  ) 155 Eu m 335(10)310(7) 155 Gd(n,  ) 156 Gd 56,700(2100)60,900(500) 157 Gd(n,  ) 158 Gd 239,000(6000)254,000(815) The discrepancy in the 153 Eu m1 cross section due to decay scheme normalization. 152,154 Eu: Basunia et al, Nucl. Data Sheets 119, 88 (2014). 155,157 Gd: Choi et al, Nucl. Sci. Eng. 177, 219 (2014)

8. Published Results 2013-2015 241 Am: Genreith et al, Nucl. Data Sheets 119, 69 (2014) S n (tentative) This workAME 5534.87(15)5537.64(10)

9. Published Results 2013-2015 237 Np, 242 Pu: Genreith et al, J. Radioanal. Nucl. Chem. 296, 699 (2013). S n (tentative) IsotopeThis workAME 238 Np5039.0(4)5033.9(26) 243 Pu5490.44(5)5488.32(20)

10. 2 H 16,17,18 O(n,  ) Multiple internal standards EGAF Evaluations in Progress

11. 16 O(n,  ) 17 O(n,  ) EGAF Evaluations in Progress Reference   (mb) Jurney (1963) 0.178(25) McDonald (1973) 0.185(26)* Wuest(1977) 0.187(10) This work 0.167(3) *Recalibrated to new standard Reference   (mb) Lone (1978) 0.54(6) This work 0.66(6)

12. EGAF Evaluations in Progress Reference   (mb) Seren (1947) 0.22(4) Blaser (1971) 0.16(1) Ohsaki(2002) 0.156(16) Nagai(2007) 0.153(10) This work (prompt) 0.139(3) This work (Activation) 0.139(5) S n =3955.6(26) keV (AME) S n =3963.18(19) keV (This work) 18 O(n,  ) 2 H(n,  ) Enriched 2 H 17,18 O data   ( 2 H)=0.478(18) mb   ( 2 H)=0.477(17) mb 2 H nat O data   ( 2 H)=0.535(13) mb This discrepancy appears to be repeatable in our measurements and is not yet understood!

13. EGAF Evaluations in Progress Isotope CS composition   (this work)   (Atlas) Lead researcher 90 Y(2  ) 99.75%-1 , 0.25%-0  1.34±0.03 b 1.28±0.02 b Abusaleem (Jordan) 90 Y (7 + ) 7+ 1.9±0.3 mb 1.0±0.2 mb Abusaleem (Jordan) 94 Nb(6  ) 85%-4+, 15%-5+ 1.27±0.08 b 1.15±0.05 b Turkoghu (Ohio State) 140 La(3  ) 0.9%-3 , 99.1% 4  8.5±0.4 b 9.04±0.04 b Ureche (UC Berkeley) 186 Re(1  ) 47.4%-2 , 52.6% 3  84±6 b 112±2 b Lerch (US Army)

14. Level scheme intensity balance 56 Fe(n,  ) A nearly complete (n,  ) decay scheme has been constructed from a Budapest cold neutron measurement on a 56 Fe, target enriched to 99.94%, and  coincidence data from the Rez Reactor, Prague. 449  -rays and 99 levels were placed in this work, including 37 new levels, and 38 previous levels not confirmed. Reference   (b) Pomerance (1952)2.65(8) Shcherbokov (1977)2.57(14) This work2.71(4) Intensity balance through the level scheme is >99% complete.

15. Low-energy photon strength enhancement in 57 Fe 56 Fe( 3 He,  ) Substantial enhancement in the reduced photon strength is seen in 57 Fe below 2 MeV. E. Tavukcu, et al, Proceedings of the Eleventh International Capture Gamma Ray Symposium, Pruhonice, Prague, Czech Republic, 2–6 September 2002. Primary  -ray strength f  definition   =0.9 eV – capture state (CS) width* D 0 =22 keV – level spacing at CS* P  – transition probability per decay of CS E  –  -ray energy *Mughabghab Atlas

16. 57 Fe primary  -ray strength The 57 Fe primary  -ray strength can be investigated microscopically with these data. Increased strength at low energies appears to be M1

17. 57 Fe secondary  -ray strength Photon strengths can also be determined for secondary  -rays from levels with known widths. Here we define individual transition strengths f  ’ =   /E  2l+1 ignoring level spacing. Here f’ BA =f BA D 0 M1 strength greater than E1 or E2 strength

18. 57 Fe  -ray strength level energy dependency No significant dependency of the photon strength on level energy is observed. Notice that the strengths vary over two orders of magnitude at each level.

19. Test of Porter-Thomas photon strength distribution Transition strengths are assumed to follow a P-T distribution (chi square, n=1). Only the 57 Fe E1 are found to follow P-T.

20. Summary 1.Evaluation of (n,  ) data for 16 isotopes published 2013-2015. 2.Evaluation of 12 isotopes in progress. 3.5 S n measurement found to have large discrepancies wrt AME. 4.3 decay scheme normalizations found to be discrepant. 5.Inconsistent cross section measurements for 2 H not yet resolved. 6.Low energy photon strength enhancement in 57 Fe ascribed to M1 transition strength. 7.M1 and E2 transition probabilities were found to be inconsistent with Porter-Thomas distribution.

21. Future EGAF Plans 1.Complete ENSDF format evaluations of (n,  ) nuclei a.Thermal (n,  ) data sets 1)P  and   normalizations 2)Adopted   values plus summary of all measurements 3)Photon strengths 4)Fitted S n values b.ARC, Resonance data c.Adopted Levels, Gammas 1)All relevant datasets 2)Recommended RIPL data d.(n,  ) activation decay data sets 2.(n,n’x) data a.Baghdad (n,n’  ) database b.Data from the literature c.New measurements from FRM-II and LBNL d.P  and   normalizations e.Adopted Levels, Gammas as discussed above