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).