Ru-99

Reviewed by T. Nakagawa, JAERI, December 2003

**1. Files**

***ENDF/B-VI***: Evaluation was made by Schenter and Schmitoroth in 1974
for ENDF/B-IV. The data of ENDF/B-VI are the same as ENDF/B-IV.

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

The evaluation was made by JNDC FPND working group \[Ka92\] for
JENDL-3.1 in 1990. The resonance parameters were revised for JENDL-3.2
\[Ka01\] The total spin of each resonance was revised for JENDL-3.3.

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

JEFF-3.0 adopted the data of JEF-2.2. The original data of JEF-2.2 was
the same as ENDF/B-V. They replaced the RRP with recommendation of
Mughabghab et al. \[Mu81\], and added charged particle emission cross
sections (MT's = from 103 to 111) from REAC-ECN-4.

***CENDL-3***: The first evaluation was made by Zheng-Jun Zhang and
Xiu-Quan Sun, and the final revision was performed by Zheng-Jun Zhang
and Qing-Biao Shen in 2001.

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

**2. Thermal and resonance region**

***ENDF/B-VI***

Resonance parameters were taken from BNL-325 3rd edition \[Mu73\].
Background cross section was given to the capture to reproduce 5.0 barns
at 0.0253 eV. The upper boundary of RRP is 115.6 eV. No unresolved
resonance parameters are given.

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

Resolved resonance parameters were based on the data of Popov et al.
\[Po79\]. Those of the first two levels were taken from Mughabghab et
al. \[Mu81\]. Total spin J for each resonance was determined on the
basis of the data of Coceva et al. \[Co68\] and a random number method.
J values of JENDL-3.2 and JENDL-3.3 are different from each other. In
JENDL-3.2, unphysical J values are given to several resonances.

In the energy range from 1 to 100 keV, the unresolved resonance
parameters were given. Neutron strength functions were calculated with
CASTHY code (optical model), and level spacing was adjusted at each
energy to the capture cross section calculated with CASTHY code
(statistical model, average capture width =0.195 eV \[Mu81\], D=25
eV\[Mu81\]).

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

Resolved resonance parameters were taken from Mughabghab et al.
\[Mu81\].

***CENDL-3***

Resonance parameters were taken from JENDL-3.2. Unphysical J values are
given to several resonances. The capture width of the first resonance at
10.05 eV was modified to reproduce the capture cross section of 7.1 at
0.0253 eV \[Mu81\].

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

The thermal capture cross section has not been measured well. Available
experimental data of Halperin et al. \[Ha65\] is 4.17 b which is much
smaller than the recommendation of Mughabghab \[Mu81,Mu03\].

***JENDL-3.3*** is recommended. However, if the data of Halperin et al.
is correct, the capture cross section in the thermal region may be too
large.

**3. Fast neutron region**

**(1) Methodology**

***ENDF/B-VI***

Theoretical calculation was performed using the optical potential of
Moldauer and Hauser-Feshbach statistical model. No threshold reaction
cross sections except inelastic scattering were considered.

All angular distributions were assumed to be isotropic. Evaporation
spectra were given to the continuum inelastic scattering.

***JENDL-3.3 and 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 gamma-ray strength function was determined from the
radiation width (0.195 eV \[Mu81\]) and the level spacing (25 eV
\[Mu81\]). Twelve excited levels up to 1.572 MeV were adopted for the
inelastic scattering cross section. No direct process was considered for
the inelastic. The direct/semi-direct capture was calculated from a
simple formula of Benzi and Reffo \[Be69\]

Other reaction cross sections were calculated with the preequilibrium
and multi-step evaporation code PEGASUS. The (n,p) and (n,) reaction
cross sections were normalized to 49.4 mb \[Fo86\] and 12.3 mb \[Fo86\]
at 14.5 MeV. 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 the CASTHY code. Isotropic distributions were assumed to
the other reactions.

The energy distributions were calculated with the PEGASUS code.

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

Same as ENDF/B-VI except for threshold reaction cross sections which
were adopted from REAC-ECN-4 library.

***CENDL-3***

Optical model parameters were adjusted to the total cross section of
natural Ru. The inelastic scattering, and angular and energy
distributions were calculated with SUNF code. DWUCK code was used to
calculate the direct inelastic process.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt1)99.htm#mt1

No experimental data are available. No large discrepancies among
evaluated data.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt102)99.htm#mt102
and Fig. A1.

The capture cross sections above 1 keV are compared in Fig. A1. Comment
of CENDL-3 says the capture cross sections of natural Ru were taken into
consideration. However, CENDL-3 does not reproduce well the natural
data.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt2)99.htm#mt2

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)**

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt4)99.htm#mt4

Discrete levels considered in the evaluations are as follows:

ENDF/B-VI, JEFF-3.0 12 levels up to 0.999 MeV

JENDL-3.3 12 levels up to 1.572 MeV

CENDL-3 9 levels up to 0.7341 MeV

***JENDL-3.3*** ignored several levels above 0.6 MeV. Direct inelastic
was considered in ***CENDL-3***. The shape of ***ENDF/B-VI*** and
**JEFF-3.3** is not adequate because they did not consider the competing
reaction channels in the calculation.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt16)99.htm#mt16

***JENDL-3.3*** and ***CENDL-3*** give the (n,2n) cross section.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt103)99.htm#mt103

***JENDL-3.3***, ***CENDL-3*** and ***JEFF-3.0*** provide this cross
section. They are in large scattering.

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

See Fig:
[http://www.nndc.bnl.gov/sg21/fp21/htm/Ru](http://www.nndc.bnl.gov/sg21/fp21/htm/Ru99.htm#mt107)99.htm#mt107

The same situation as the (n,p) cross section.

**(9) Other reactions**

The following reaction cross sections are given:

ENDF/B-VI no threshold reactions

JENDL-3.3 (n,3n), (n,n), (n,np), (n,nd), (n,d), (n,t), (n,^3^He)

JEFF-3.0 (n,d), (n,t), (n,^3^He), (n,2p)

CENDL-3 (n,3n), (n,n), (n,np), (n,d), (n,t), (n,^3^He)

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

***JENDL-3.3(=JENDL-3.2)*** is recommended. The inelastic scattering
data of JENDL-3.3 should be replaced with ***CENDL-3***.

**References**

\[Be69\] Benzi V. and Reffo G.: *CCDN-NW/*10 (1969).

\[Co68\] Coceva C. et al.: *Nucl. Phys.*, **A117**, 586 (1968).

\[Fo86\] Forrest R.A.: *AERE-R* 12419 (1986).

\[Ha65\] Halperin J. et al.: *ORNL*-3832, p.4 (1965).

\[Ka92\] Kawai M. et al.: *J. Nucl. Sci. Technol.*, **29**, 195 (1992).

\[Ka01\] Kawai M. et al.: *J. Nucl. Sci. Technol.*, **38**, 261 (2001).

\[Mu73\] Mughabghab S.F. and Garber D.I.: "Neutron Cross Sections, Vol.
I," *BNL*-325 3-rd Edition (1973).

\[Mu81\] 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)

\[Po79\] Popov JuP. Et al.: *Yad. Fiz.*, **29**, 561 (1979).

Table 1 Summary for Resolved and Unresolved Resonance Region: Ru-99

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

Library RRP URP Remarks

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

> ENDF/B-VI 115.6 eV, SLBW not given BG given to elastic and capture
>
> JENDL-3.3 1.0 keV, MLBW 1.0 - 100 keV
>
> JEFF-3.0 1.007keV,MLBW not given Same as JEF-2.2
>
> CENDL-3 1.0 keV, MLBW 1.0 - 100 keV Same as JENDL-3.2.

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

Table 2. Thermal Cross Sections and Resonance Integral: Ru-99

Units: barns

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Library/Experiment Total Elastic Capture Res.Integ.

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

ENDF/B-VI 8.511 3.510 5.001 137

JENDL-3.3 10.994 3.686 7.309 171

JEFF-3.0 12.048 4.948 7.100 163

CENDL-3 10.782 3.661 7.121 171

Mughabghab et al. \[Mu81\] 7.11.0 16020

Mughabghab et al. \[Mu03\] 7.11.0 16020

Halperin et al. \[Ha65\] 4.1725% 19510%(0.54 eV)

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

![](media/image1.wmf){width="7.333333333333333in"
height="6.451388888888889in"}

Fig. A1 Ru-99 capture cross section