24-Cr- 52 JAEA,ORNL EVAL-Nov09 N.Iwamoto,L.Leal+ DIST-SEP12 20111216 ----JENDL-4.0u1 MATERIAL 2431 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT Update File Distribution Sep.14,2012 JENDL-4.0u1 History 09-11 The resolved resonance parameters were evaluated by L.Leal+. The data above the resolved resonance region were evaluated and compiled by N.Iwamoto. 10-06 MF33 and MF34 were added by N.Iwamoto. 11-12 MF33/MT1 and MF33/MT102 were revised by N.Iwamoto. MF= 1 General information MT=451 Descriptive data and directory MF= 2 Resonance parameters MT=151 Resolved and unresolved resonance parameters The details of the resolved resonance parameters are given below: ================================================================= EVALUATION of the RESONANCE PARAMETERS of Cr-52 in the ENERGY RANGE below 1.43 MeV ================================================================= 24-Cr- 52 ORNL Resonance Evaluation Including Covariance L. C. Leal, H. Derrien, K. Guber, G. Arbanas and D. Wiarda Resolved resonance parameter evaluation for Cr-52 was done with the computer code SAMMY.[ref1] Capture and transmission measurements enriched Cr-52 and natural chromium were performed at the Oak Ridge Electron Linear Accelerator (ORELA) of the Oak Ridge National Laboratory. The neutron transmission and capture data were measured in the energy range from 10 keV to 600 keV. The transmission data were measured at the 80-meter flight-path, whereas the 40-meter flight-path was used for the capture cross section measurements. The determination of the resolved resonance parameters for the chromium isotope below 100 keV relied mainly on the recent ORELA measurements. The ORELA capture cross section data were essential in the evaluation since there are no capture cross section data available in the literature. In addition to the new ORELA measurements, existing high-resolution transmission data for enriched nuclides were also included in the evaluation. Thermal cross section data available in the EXFOR data system were also included in the evaluation. Direct-semidirect (DSD) capture on Cr-52 was computed using the computer code CUPIDO created by F.S. Dietrich (LLNL).[ref2] To obtain the optical potential for this computation, the global optical potential of Koning-Delaroche was manually adjusted to reproduce the experimentally measured scattering radius R'. This method was justified since low-energy phenomena are determined by R'. It was found that the low-energy capture is dominated by electric-dipole (E1) capture of s-wave neutrons. A density form of the E1 operator was used. The spectroscopic factors for the capturing bound states in Cr-53 were taken from L.K. Peker.[ref3] The computed thermal DSD capture is about 0.11 barns. The uncertainty of DSD computation is inherently large, usually about 20-30%. A set of resonance parameter describing the experimental data was obtained. Resonance parameter covariance matrices were also obtained in the SAMMY evaluation process. The Cr-52 evaluation was done in the energy region 10-5 eV 1.43 MeV. Thermal cross section obtained in the present evaluation are compared to the values listed in the Atlas of Neutron Resoances in the following table: Cross Section ORNL Atlas Resonance Res+Direct Capt 0.75+/-0.02 0.86 0.86+/-0.02 Total 3.82+/-0.01 3.93 3.82+/-0.03 Scat 3.07+/-0.07 - 2.96+/-0.02 Uncertainty in the group cross section around the thermal cross section due the covarinace data has been calculated for a energy group between the energies 0.0253 eV and 0.3 eV. The average cross sections for this energy group are listed in the following tale: Cross Section Average Value Capt 0.72+/-0.02 (2.8%) Total 3.79+/-0.11 (2.9%) Scat 3.07+/-0.08 (2.6%) [ref 1] N. M. Larson,"Updated Users' Guide for SAMMY," Oak Ridge National Laboratory report ORNL/TM-9179/R6 (2003) [ref 2] W.E. Parker et al., Phys. Rev. C 52, 252 - 266 (1995) [ref 3] Nuclear Data Sheets 43, 481 (1984), page 531 Thermal cross sections and resonance integrals at 300 K ---------------------------------------------------------- 0.0253 eV res. integ. (*) (barn) (barn) ---------------------------------------------------------- Total 3.9341e+00 Elastic 3.0776e+00 n,gamma 8.5607e-01 4.9403e-01 ---------------------------------------------------------- (*) Integrated from 0.5 eV to 10 MeV. MF= 3 Neutron cross sections MT= 1 Total cross section In the energy range from 1.43 to 6.751 MeV, cross section was adopted from JENDL-3.3. Above 6.751 MeV, cross section was calculated with CCONE code/1/. MT= 2 Elastic scattering cross section Obtained by subtracting non-elastic scattering cross sections from total cross section. MT= 4 (n,n') cross section Sum of partial cross sections in MT= 51-91. MT= 16 (n,2n) cross section Calculated with CCONE code /1/. MT= 22 (n,na) cross section Calculated with CCONE code /1/. MT= 28 (n,np) cross section Calculated with CCONE code /1/. MT= 51, 52 (n,n') cross section Cross sections were evaluated on the basis of experimental data of Mihailescu et al./2/. MT= 53-91 (n,n') cross section Calculated with CCONE code /1/. MT=102 Capture cross section Calculated with CCONE code /1/. MT=103 (n,p) cross section Calculated with CCONE code /1/. MT=104 (n,d) cross section Calculated with CCONE code /1/. MT=105 (n,t) cross section Calculated with CCONE code /1/. MT=106 (n,He3) cross section Calculated with CCONE code /1/. MT=107 (n,a) cross section Calculated with CCONE code /1/. MT=111 (n,2p) cross section Calculated with CCONE code /1/. MT=112 (n,pa) cross section Calculated with CCONE code /1/. MT=115 (n,pd) cross section Calculated with CCONE code /1/. MF= 4 Angular distributions of emitted neutrons MT= 2 Elastic scattering Calculated with CCONE code /1/. MF= 6 Energy-angle distributions of emitted particles MT= 16 (n,2n) reaction Calculated with CCONE code /1/. MT= 22 (n,na) reaction Calculated with CCONE code /1/. MT= 28 (n,np) reaction Calculated with CCONE code /1/. MT= 51-91 (n,n') reaction Calculated with CCONE code /1/. MT=102 Capture reaction Calculated with CCONE code /1/. MF=32 Covariances of resonance parameters MT=151 Covariance data were taken from the ORNL Resonance Evaluation. The details were explained in MF/MT=2/151. MF=33 Covariances of neutron cross sections MT= 1 Total cross section Calculated with KALMAN code /3/. MT= 2 Elastic scattering cross section Obtained in terms of the covariance matrices of the evaluated cross sections. MT= 4 (n,n') cross section Calculated with KALMAN code /3/. MT= 16 (n,2n) cross section Calculated with KALMAN code /3/. MT= 22 (n,na) cross section Calculated with KALMAN code /3/. MT= 28 (n,np) cross section Calculated with KALMAN code /3/. MT= 51-91 (n,n') cross section Calculated with KALMAN code /3/. MT=102 Capture cross section Calculated with KALMAN code /3/. MT=103 (n,p) cross section Calculated with KALMAN code /3/. MT=104 (n,d) cross section Calculated with KALMAN code /3/. MT=105 (n,t) cross section Calculated with KALMAN code /3/. MT=106 (n,He3) cross section Calculated with KALMAN code /3/. MT=107 (n,a) cross section Calculated with KALMAN code /3/. MT=111 (n,2p) cross section Calculated with KALMAN code /3/. MT=112 (n,pa) cross section Calculated with KALMAN code /3/. MT=115 (n,pd) cross section Calculated with KALMAN code /3/. MF=34 Covariances for Angular Distributions MT= 2 Elastic scattering Calculated with KALMAN code /3/. The covariances of P1 components were only evaluated. ***************************************************************** Nuclear Model Calculation with CCONE code /1/ ***************************************************************** Models and parameters used in the CCONE calculation 1) Optical model * optical model potential neutron omp: Kunieda,S. et al./4/ (+) proton omp: Koning,A.J. and Delaroche,J.P./5/ (+) deuteron omp: Lohr,J.M. and Haeberli,W./6/ triton omp: Becchetti Jr.,F.D. and Greenlees,G.W./7/ He3 omp: Becchetti Jr.,F.D. and Greenlees,G.W./7/ alpha omp: McFadden,L. and Satchler,G.R./8/ (+) (+) omp parameters were modified. * DWBA calculation levels: 1,2,18 (see Table 1) 2) Two-component exciton model/9/ * Global parametrization of Koning-Duijvestijn/10/ was used. * Gamma emission channel/11/ was added to simulate direct and semi-direct capture reaction. 3) Hauser-Feshbach statistical model * Width fluctuation correction/12/ was applied. * Neutron, proton, deuteron, triton, He3, alpha and gamma decay channel were taken into account. * Transmission coefficients of neutrons were taken from optical model calculation. * The level scheme of the target is shown in Table 1. * Level density formula of constant temperature and Fermi-gas model were used with shell energy correction/13/. Parameters are shown in Table 2. * Gamma-ray strength function of generalized Lorentzian form /14/,/15/ was used for E1 transition. For M1 and E2 transitions the standard Lorentzian form was adopted. The prameters are shown in Table 3. ------------------------------------------------------------------ Tables ------------------------------------------------------------------ Table 1. Level Scheme of Cr-52 --------------------------------- No. Ex(MeV) J PI, DWBA: beta --------------------------------- 0 0.00000 0 + 1 1.43409 2 + 0.21 2 2.36963 4 + 0.05 3 2.64690 0 + 4 2.76777 4 + 5 2.96479 2 + 6 3.11386 6 + 7 3.16174 2 + 8 3.41532 4 + 9 3.47225 3 + 10 3.61593 5 + 11 3.73960 2 + 12 3.77172 2 + 13 3.94850 2 + 14 4.01551 5 + 15 4.03920 4 + 16 4.10000 3 - 17 4.47000 3 - 18 4.56300 3 - 0.09 19 4.61100 0 + 20 4.62732 4 + 21 4.70200 2 + 22 4.73000 4 + 23 4.74230 2 + 24 4.75032 8 + 25 4.80010 0 + 26 4.80619 6 + 27 4.81570 0 + 28 4.84130 0 + --------------------------------- Table 2. Level density parameters -------------------------------------------------------- Nuclide a* Pair Eshell T E0 Ematch 1/MeV MeV MeV MeV MeV MeV -------------------------------------------------------- Cr- 53 7.8100 1.6483 -1.1345 1.2832 -0.7530 9.9152 Cr- 52 6.6800 3.3282 -1.3204 1.6541 -0.9930 16.2114 Cr- 51 7.8300 1.6803 -1.0884 1.4788 -2.9231 13.9698 V- 52 7.1000 0.0000 -0.6140 1.2996 -2.0622 7.3847 V- 51 6.9100 1.6803 -0.6457 1.5346 -2.3344 12.8214 V- 50 7.0000 0.0000 -0.6353 1.4319 -3.1193 9.4496 Ti- 51 7.6300 1.6803 -0.3127 1.1333 0.1795 7.4616 Ti- 50 7.2500 3.3941 -0.4613 1.2919 1.1007 10.9863 Ti- 49 7.8800 1.7143 0.2445 1.1040 -0.1128 7.6316 Ti- 48 7.0700 3.4641 0.6643 1.4400 -0.8454 13.4405 -------------------------------------------------------- Table 3. Gamma-ray strength function for Cr- 53 -------------------------------------------------------- * E1: ER = 17.80 (MeV) EG = 6.50 (MeV) SIG = 88.00 (mb) * M1: ER = 10.92 (MeV) EG = 4.00 (MeV) SIG = 1.49 (mb) * E2: ER = 16.77 (MeV) EG = 5.47 (MeV) SIG = 1.18 (mb) -------------------------------------------------------- References 1) Iwamoto,O.: J. Nucl. Sci. Technol., 44, 687 (2007). 2) Mihailescu,L.C. et al.: Nucl. Phys. A786, 1 (2007). 3) Kawano,T., Shibata,K.: JAERI-Data/Code 97-037 (1997) in Japanese. 4) Kunieda,S. et al.: J. Nucl. Sci. Technol. 44, 838 (2007). 5) Koning,A.J. and Delaroche,J.P.: Nucl. Phys. A713, 231 (2003) [Global potential]. 6) Lohr,J.M. and Haeberli,W.: Nucl. Phys. A232, 381 (1974). 7) Becchetti Jr.,F.D. and Greenlees,G.W.: Ann. Rept. J.H.Williams Lab., Univ. Minnesota (1969). 8) McFadden,L. and Satchler,G.R.: Nucl. Phys. 84, 177 (1966). 9) Kalbach,C.: Phys. Rev. C33, 818 (1986). 10) Koning,A.J., Duijvestijn,M.C.: Nucl. Phys. A744, 15 (2004). 11) Akkermans,J.M., Gruppelaar,H.: Phys. Lett. 157B, 95 (1985). 12) Moldauer,P.A.: Nucl. Phys. A344, 185 (1980). 13) Mengoni,A. and Nakajima,Y.: J. Nucl. Sci. Technol., 31, 151 (1994). 14) Kopecky,J., Uhl,M.: Phys. Rev. C41, 1941 (1990). 15) Kopecky,J., Uhl,M., Chrien,R.E.: Phys. Rev. C47, 312 (1990).