Ce-136

Reviewed by T. Nakagawa, JAERI, January 2004

**1. Files**

***ENDF/B-VI***: No data are given.

***JENDL-3.3 and JENDL-3.2***:

No data are given..

***JEFF-3.0 and JEF-2.2***:

No data are given.

***CENDL-3***: Evaluation was made by Y.L.Han et al. in 2000.

***BROND-2***: No data are given.

**2. Thermal and resonance region**

***CENDL-3***

No resonance parameters were given.

Cross sections below 100 keV were calculated with a formula of
a+bE+C/sqrt(E).

**[Recommendation/conclusion for the thermal and resonance
region]{.underline}**

***CENDL-3*** is tentatively recommended. However, resonance parameters
in the energy range from 66 to 876 eV were reported by Vertebny et al.
\[Ve70\] This set of parameters should be considered. Since the
resonance parameters are ignored in CENDL-3, the capture resonance
integral is much smaller than recommendation by Mughabghab \[Mu81,
Mu03\].

**3. Fast neutron region**

**(1) Methodology**

***CENDL-3***

Theoretical calculation was performed using the NUNF code. The optical
potential parameters were obtained by fitting to the total and
non-elastic scattering cross sections and angular distributions of
elastic scattering for natural Ce. Direct inelastic was calculated with
DWUCK-4.

Emitted particle distributions are given in MF=6. Gamma-ray production
data are also given.

**(2) Total cross section (MT=1)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt1)Ce136.htm#mt1

**(3) Capture cross section (MT=102)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt102)Ce136.htm#mt102

Maxwell averaged cross sections were measured by Käppeler et al.
\[Ka96\] at kT=25 keV. Comparison of Maxwell averaged cross sections
shows CENDL-3 is smaller than the measured data.

Average cross section (mb) at kT=25 keV

CENDL-3 278

Käppeler et al. 35521

The shape around 4 MeV may be too large.

**(4) Elastic scattering cross section (MT=2)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt2)Ce136.htm#mt2

**(5) Inelastic scattering cross section (MT=4, 51 -- 91)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt4)Ce136.htm#mt4

Discrete levels considered in the evaluations are as follows:

CENDL-3 6 levels up to 1.9785 MeV

The direct inelastic was calculated with DWUCK4 code.

The data of continuum inelastic scattering is zero between threshold
(1.99 MeV) and 4.3 MeV. Therefore, the total inelastic has a dip around
4 MeV.

**(6) (n,2n) reaction cross section (MT=16)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt16)Ce136.htm#mt16

Experimental data are reproduced well.

**(7) (n,p) reaction cross section (MT=103)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt103)Ce136.htm#mt103

The resonance-like structure at 4 MeV seems to be strange.

**(8) (n,) reaction cross section (MT=107)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/](http://www.nndc.bnl.gov/sg21/fp21/htm/Ce136.htm#mt107)Ce136.htm#mt107

The resonance-like structure is seen at 4 MeV.

**(9) Other reactions**

The following reaction cross sections are given:

CENDL-3 (n,3n), (n,n), (n,np), (n,d), (n,t), (n,2p)

**[Recommendation/conclusion for the fast energy region]{.underline}**

***CENDL-3*** is recommended.

**References**

\[Br56\] Brosi A.R. and Ketelle B.H.: *Phys. Rev.*, **103**, 917 (1956).

\[Ka96\] Käppeler et al.: *Phy. Rev.*, **C53**, 1397 (1996).

\[Ke63\] Keish B.: *Phys. Rev.*, **129**, 769 (1963).

\[Mu81\] Mughabghab S.F. et al.: *Neutron Cross Sections, Vol. 1, part
A*, Academic press (1981).

\[Mu03\] Mughabghab S.F.: "Thermal Neutron Capture Cross Sections
Resonance Integrals and g-Factors," *INDC(NDS)*-440 (2002)

\[Ve70\] Vertebny V.P. et al.: *INDC(CCP)*-15/U, p.49 (1970).

Table 1 Summary for Resolved and Unresolved Resonance Region: Ce-136

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Library RRP URP Remarks

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

> CENDL-3 not given not given

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Table 2. Thermal Cross Sections and Resonance Integral: Ce-136

Units: barns

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Library/Experiment Total Elastic Capture Res.Integ.

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

CENDL-3 12.50 5.25 7.25 6.96

Mughabghab et al. \[Mu81\] 7.31.5 5812

Mughabghab et al. \[Mu03\] 6.51.0\* 7712

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

\*) to ground state.

Table 3. Thermal Capture Cross Sections: Ce-136

Units: barns

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

Library/Experiment ground meta ratio (M/G) total

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

CENDL-3 7.25

Mughabghab et al. \[Mu81\] 6.31.5 0.950.25 0.15 7.31.5

Mughabghab et al. \[Mu03\] 6.51.0

Brosi and Ketelle \[Br56\] 6.3 0.1 7.0

Keish \[Ke63\] 0.150.01

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--