WPEC SG 21: Assessment of Neutron Cross-Section Evaluations for the Bulk
of Fission Products

**Pm-149**

Reviewed by Shen Qingbiao CIAE, February, 2003

**1. Files**

***ENDF/B-VI***: Evaluation was made in 1974 for ENDF/B-V. It was
converted to ENDF-B6 format for ENDF/B-VI.

***JENDL-3.2***: The evaluation was made for JENDL-3 in 1990.

***JEF-2.2***: ENDF/B-V was adopted. The charged particle production
cross sections were added from REAC-ECN-4 library in 1989. The data were
compiled in 1992.

***CENDL-3***: Evaluation was performed in 1999. The data were compiled
in 2001.

Figs: <http://www.nndc.bnl.gov/~sirakov/fp/fp21/htm/Pm149.htm#mt1>

**2. Thermal and resonance region**

\(1\) Resolved resonance parameters

***ENDF/B-VI***

No resolved resonance parameters are given.

***JENDL-3.2***

No resolved resonance parameters are given.

***JEF-2.2***

No resolved resonance parameters are given.

***CENDL-3***

No resolved resonance parameters are given.

\(2\) Unresolved resonance parameters

***ENDF/B-VI***

No unresolved resonance parameters are given.

***JENDL-3.2*** (2.6 eV -- 100 keV)

The neutron strength function S0, S1 and S2 were calculated with optical
model code CASTHY. The observed level spacing was determined to
reproduce the capture cross section calculated with CASTHY. The
effective scattering radius was obtained from fitting to the calculated
total cross section at 100 keV. The radiation width GG was based on the
systematics of measured values for neighboring nucleus.

***JEF-2.2***

No unresolved resonance parameters are given.

***CENDL-3*** (2.6 eV -- 100 keV)

JENDL-3.2 was adopted. Small changing was made.

\(3\) Recommendation/conclusion for resonance region

***JENDL-3.2*** (***CENDL-3***) is recommended. No resonance parameters
for ***ENDF/B-VI*** (***JEF-2.2***). No experimental data of thermal
elastic scattering cross section and radiative capture resonance
integrals are available.

**3. Fast neutron region**

\(1\) Methodology

***ENDF/B-VI***

Theoretical calculation was widely used. The optical potential of
Moldauer was adopted. Inelastic scattering was calculated with COMNUC-3
code, and the capture cross section with NCAP codes. No direct inelastic
was considered. No threshold reaction cross sections are given.

Isotropic distributions were given to elastic and continuum inelastic
scattering channels.

The evaporation spectra were given to the continuum inelastic
scattering.

***JENDL-3.2***

The total, elastic and inelastic scattering, and capture cross sections
were calculated with the spherical optical model and statistical model
code CASTHY. The direct inelastic scattering contribution was not
considered. Other reaction cross sections were calculated with a
preequilibrium and multi-step evaporation code PEGASUS. Sum of the
threshold reaction cross sections were considered as a competing
reaction cross sections in the CASTHY calculation.

Angular distributions of elastic and inelastic scattering were
calculated with CASTHY code. Isotropic distributions were assumed to the
other reactions.

The energy distributions were calculated with PEGUSUS code.

***JEF-2.2***

The data were taken from ENDF/B-V. The charged particle production cross
sections were added from REAC REAC-ECN-4 library.

***CENDL-3***

Calculated with SUNF code and DWUCK-4 code. The optical model parameters
were determined with APOM code. The direct inelastic scatterings of some
discrete levels were calculated by DWUCK4 code.

Angular and energy distributions of neutrons were also calculated with
SUNF code.

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

No experimental data are available for Pm149 total cross section. The
curve shapes of the all libraries are reasonable.

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

No experimental data are available for Pm149 capture cross section. The
capture cross section values of ENDF/B-VI (JEF-2.2) seems more large
compared with values of Pm-147.

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

This cross section was obtained as (total cross section) -- (sum of
partial cross sections) in the all

libraries.

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

Excited levels considered in the files.

> ENDF/B-VI 6 levels up to 0.386 MeV
>
> JENDL-3.2 4 levels up to 0.6548 MeV
>
> JEF-2.2 6 levels up to 0.386 MeV
>
> CENDL-3 6 levels up to 0.5379 MeV

No experimental data are available for Pm149 total inelastic scattering
cross section. The direct inelastic scattering was considered in CENDL-3
library only. The curve shape of ENDF/B-VI (JEF-2.2) in high energy
region is wrong since no (n,2n) cross section was considered. The curve
shape in high energy region is decided by (n,2n) cross section.

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

No experimental data are available for Pm149 (n,2n) cross section. The
curve shapes of CENDL-3 and JENDL-3.2 are acceptable. (see Pm-147
review)

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

No experimental data are available for Pm149 (n,p) cross section. The
curve shapes and values of CENDL-3, JENDL-3.2, and JEF-2.2 are closed.

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

No experimental data are available for Pm149 (n,) cross section. The
maximum difference of CENDL-3, JENDL-3.2, and JEF-2.2 is about 2 times.
They are all in the reasonable range compared with the closed nuclei.

\(9\) Other reactions

The following other reaction cross sections are given in the files.

> JENDL-3.2 (n,3n), (n,n), (n,np), (n,nd), (n,nt), (n,d), (n,t)
>
> CENDL-3 (n,3n), (n,n), (n,np), (n,d), (n,t), (n,He-3)
>
> JEF-2.2 (n,d), (n,t), (n,He-3), (n,2p)
>
> ENDF/B-VI No

\(10\) Recommendation/conclusions for fast neutron region

***CENDL-3*** or ***JENDL-3.2*** is recommended. The contribution of the
direct inelastic scattering was considered in ***CENDL-3.***

**References**

\[Ga76\] Gaeggeler H. et al., J, JIN, 38, 205 (1976)

\[Ko65\] Kondurov I. A. et al., J, AE, 19(8), 188(1965)

\[Mo68\] Mowatt R. S. et al., C, 68WASH, 2, 1291(H-13) (1968)

\[Mu84\] Mughabghab S.F. et al.: "Neutron Cross Sections, Vol.1, Part
B," Academic Press (1984).

Table 1. Summary for Resolved and Unresolved Resonance Region: Pm-149

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

Library RRP URP Remarks

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

ENDF/B-VI No RRP No URP

JENDL-3.2 No RRP 2.6 eV-100 keV

JEF-2.2 No RRP No URP

CENDL-3 No RRP 2.6 eV-100 keV taken from JENDL 3.2

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

Table 2. Thermal Cross Sections and Resonance Integral: Pm-149

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

Library/Experiment Total Elastic Capture Res.Integ.

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

ENDF/B-VI 1405.10 5.139 1400.0 800.545

JENDL-3.2 1403.20 3.20 1400.0 570.666

JEF-2.2 1405.14 5.140 1400.0 800.545

CENDL-3.2 1403.20 3.20 1400.0 1516.27

Mughabghab et al. \[Mu84\] 1400300

Gaeggeler H. et al. \[Ga76\] 1630160\*1

Kondurov I. A. et al \[Ko65\] 1700300\*2

Mowatt R. S. et al. \[Mo68\] 1000400\*2

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

\*1) Maxwellian averaged

\*2) Spectrum averaged

**[Attachment 2]{.underline}**

Figs: <http://www.nndc.bnl.gov/~sirakov/fp/fp21/htm/Pm149.htm#mt1>