report of subgroup 7 - nuclear data standards …...report of subgroup 7 nuclear data standards...

Report of Subgroup 7

Nuclear Data Standards

Coordinator: A.D. CarlsonIonizing Radiation Division

National Institute of Standards & Technology

Presented atThe WPEC meeting

Aix-en-Provence, FranceMay 26, 2004

STANDARDS TO BE EVALUATED

Reaction Energy Range

H(n,n) 1 keV to 200 MeV

3He(n,p) thermal to 50 keV

6Li(n,t) thermal to 1 MeV

10B(n,α ) thermal to 1 MeV

10B(n,α1γ) thermal to 1 MeV

197Au(n,γ) thermal, 0.2 to 2.5 MeV

235U(n,f) thermal, 0.15 to 200 MeV

238U(n,f) threshold to 200 MeV

The International Neutron Cross Section Standards Evaluation

• WPEC and CSEWG

• Encourage /motivate new measurements where necessary

• Investigate experimental work to get better information oncorrections and uncertainties

• Mainly interested in the final product, the standards evaluation

• IAEA Coordinated Research Project

• Refines/improves the evaluation process

• Seeks to improve the understanding of the uncertainties

• The focus is on the evaluation process

IAEA CRPon

Improvement of the Standard Cross Sections for Light Elements

Objectives� Improve the methodology for determination of the covariance matrix in R-matrix fits.Upgrade computer codes using this methodology.

� Study the reasons for uncertainty reduction in R-matrix fits.

� Evaluate cross sections and covariance matrices for neutron induced standard reactions forthe light elements,[H(n,n), 3He(n,p), 6Li(n,t), 10B(n,α) and 10B(n,αlγ)]

� Establish the methodology and computer codes for combining the light element with theheavy element evaluations.

Second RCM at NIST

HartmutHofmann

Gerry Hale

AllanCarlson

NancyLarson

VladimirPronyaev

HerbertVonach

JoschHambsch

SergeiBadikov

Soo YoulOh

CRP Work Now Underway (Two RCMs have been held)

�Improvements to the experimental data in the standards database�More than 30 data sets have been added to the standards database since the formation of the CRP. More are expected before the completion of the evaluation.

�R-matrix evaluations �Hale is evaluating the hydrogen scattering cross section below 30 MeV neutron energy using the code EDA. Improvement in the angular distribution was observed compared with recent measurements. Unexpected problems at the 1% level appear in the total cross section near 10 MeV neutron energy that require further investigation.

�The 6Li(n,t) cross section has been evaluated by Hale and Zhenpeng.

However they used somewhat different databases and procedures

�The 10B(n,α1γ), and 10B(n,α) cross sections were evaluated by Zhenpeng.

Indiana University Preliminary H(n,n) Results

CRP Work Now Underway (Two RCMs have been held)

�Improvements to the experimental data in the standards database�More than 30 data sets have been added to the standards database since the formation of the CRP. More are expected before the completion of the evaluation.

�R-matrix evaluations �Hale is evaluating the hydrogen scattering cross section below 30 MeV neutron energy using the code EDA. Improvement in the angular distribution was observed compared with recent measurements. Unexpected problems at the 1% level appear in the total cross section near 10 MeV neutron energy that require further investigation.

�The 6Li(n,t) cross section has been evaluated by Hale and Zhenpeng.

However they used somewhat different databases and procedures

�The 10B(n,α1γ), and 10B(n,α) cross sections were evaluated by Zhenpeng.

CRP Work Now Underway (cont.)

�Microscopic calculations leading to independent determinations of R-matrix poles for light elements nearing final stages

�Refined Resonating Group Model used for 3He(n,p)�Effective NN potentials used for 6Li(n,t)

� Generalized least squares evaluations for the 6Li(n,t), 10B(n,α), 10B(n,α1γ), Au(n,γ), 235U(n,f), and 238U(n,f) standard cross sections.

�GMA Coding improvement by Pronyaev�GMA calculations using 419 sets of data

Neutron energy, MeV1

197 Au

cap

ture

cro

ss s

ectio

n, b

0.05

0.10

0.15

0.20

0.25W.Poenitz, 1987 GMA-4, 2003 K.Harris, 1965 S.Sakamoto, 1991 Shape, W.Poenitz, 1968 S.Joly, 1979 C.LeRegoleur, 1976 E.Fort, 1975 A.Davletshin, 1980 A.Davletshin, 1988 A.Davletshin, 1991 A.Ferguson, 1959 W.Poenitz, 1975 A.Paulsen, 1980 A.Paulsen, 1975 Chen Ying, 1982 T.Ryves, 1971 H.Hussain, 1983 J.Voigner, 1986

Neutron energy, MeV0.01 0.1 1

Rat

io o

f GM

A-4

to P

oeni

tz e

valu

atio

n fo

r 197 Au

(n,g

)

0.97

0.98

0.99

1.00

1.01

1.02

1.03

Neutron energy, MeV0.001 0.01 0.1 1

238 U

cap

ture

cro

ss s

ectio

n, b

0.1

1

10W.Poenitz, 1987 GMA-4, 2003 G.Desaussure, 1978 Yu.Panitkin, 1972 H.Menlove, 1979 Shape, H.Menlove, 1968 C.Rigoleur, 1975 Shape, M.Fricke, 1971 K.Dietze, 1977 T.Belanova, 1966 Yu.Stavisskii, 1966 Shape, T.Ryves, 1973 J.Voigner, 1986 ENDF/B-VI, 1989

Neutron energy, MeV0.1 1

238 U

cap

ture

cro

ss s

ectio

n, b

0.1

W.Poenitz, 1987 GMA-4, 2003 Shape, H.Menlove, 1968 C.Rigoleur, 1975 Shape, M.Fricke, 1971 Shape, T.Ryves, 1973 J.Voigner, 1986 ENDF/B-VI, 1989


Rat

io o

f GM

A-4

to P

oeni

tz e

valu

atio

n

0.90

0.95

1.00

1.05

1.10


235 U

fiss

ion

cros

s se

ctio

n, b

1.10

1.15

1.20

1.25

1.30

1.35

GMA-4, 2003 W.Poenitz, 1987JENDL-3.3, 2001

Neutron energy, MeV1 2 3 4 5

235 U

fiss

ion

cros

s se

ctio

n, b

1.05

1.10

1.15

1.20

1.25

1.30

GMA-4, 2003 W.Poenitz, 1987JENDL-3.3, 2001 LASL evaluation, 2003

Neutron energy, MeV6 8 10 12 14 16 18 20

235 U

fiss

ion

cros

s se

ctio

n, b

1.2

1.4

1.6

1.8

2.0

2.2


Neutron energy, MeV10 100

235 U

fiss

ion

cros

s se

ctio

n, b

1.2

1.4

1.6

1.8

2.0

2.2

GMA-1, 2003JENDL-3.3, 2001 GMA-4, 2003A prior, "old" standardShape, P.Lisowski,1991

Neutron energy, MeV5 10 15 20

238 U

fiss

ion

cros

s se

ctio

n, b

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

GMA-4, 2003 Poenitz1987 Wu Jingxia, 1983 K.Smith, 1975 M.Cance, 1968 TUD/KRI collab., 1991 B.Adams, shape, 1961 K.Yoshida, 1983 V.Pankratov, 1962, shape V.Pankratov, 1964, shape I.Kuks, 1971 M.Mangialajo, 1963, shape C.Uttley, 1956 G.Winkler, 1991

Neutron energy, MeV12 13 14 15 16 17

238 U

fiss

ion

cros

s se

ctio

n, b

0.9

1.0

1.1

1.2

1.3

1.4

GMA-4, 2003 Poenitz1987 Wu Jingxia, 1983 K.Smith, 1975 M.Cance, 1968 TUD/KRI collab., 1991 B.Adams, shape, 1961 K.Yoshida, 1983 V.Pankratov, 1962, shape V.Pankratov, 1964, shape I.Kuks, 1971 M.Mangialajo, 1963, shape C.Uttley, 1956 G.Winkler, 1991


238 U

fiss

ion

cros

s se

ctio

n, b

0.8

1.0

1.2

1.4

1.6

1.8

GMA-4, 2003 Poenitz1987 Wu Jingxia, 1983 K.Smith, 1975 M.Cance, 1968 TUD/KRI collab., 1991 B.Adams, shape, 1961 K.Yoshida, 1983 V.Pankratov, 1962, shape V.Pankratov, 1964, shape I.Kuks, 1971 M.Mangialajo, 1963, shape C.Uttley, 1956 G.Winkler, 1991 V.Eismont, 1996 V.Goldanskiy, 1955 Protons, P.Stevenson, 1958, Protons, H,Steiner, 1956


238 U

to 23

5 U fi

ssio

n cr

oss

sect

ion

ratio

0.5

0.6

0.7

0.8

0.9

1.0

1.1GMA, 2003 ENDF/B-VI, 1987 A.Goverdovskii, 1983 A.Goverdovskii, 1984 J.Behrens, 1977 J.Meadows, 1983 J.Meadows, 1986 P.White, 1967 F.Difilippo, 1978 M.Lamphere, 1956 W.Stein, 1968 P.Lisowski, 1991

GMA-4, 2003 O.Shcherbakov, 2001 Protons, H.Steiner, 1956 GMA-6, 29Oct2003 R.Nolte, Not final, 2003

Neutron energy, MeV0.1 1

239 Pu

fiss

ion

cros

s se

ctio

n, b

1.45

1.50

1.55

1.60

1.65

1.70

1.75GMA-4, 2003 W.Poenitz, 1987JENDL-3.3, 2001

Neutron energy, MeV0.2 0.4 0.6 0.8 1.0

239 Pu

fiss

ion

cros

s se

ctio

n, b

1.45

1.50

1.55

1.60

1.65

1.70

1.75GMA-4, 2003 W.Poenitz, 1987

JENDL-3.3, 2001


239 Pu

fiss

ion

cros

s se

ctio

n, b

1.7

1.8

1.9

2.0GMA-4, 2003 W.Poenitz, 1987JENDL-3.3, 2001 LASL evaluation, 2002

Neutron energy, MeV6 8 10 12 14 16 18 20

239 Pu

fiss

ion

cros

s se

ctio

n, b

1.8

2.0

2.2

2.4

GMA-4, 2003 W.Poenitz, 1987 JENDL-3.3, 2001

Neutron energy, MeV1 10 100

239 Pu

fiss

ion

cros

s se

ctio

n, b

1.4

1.6

1.8

2.0

2.2

2.4

GMA-4, 2003 W.Poenitz, 1987JENDL-3.3, 2001


239 Pu

to 23

5 U fi

ssio

n cr

oss

sect

ion

ratio

1.0

1.1

1.2

1.3

P.Staples et al., 1998O.Shcherbakov et al., 2001 GMA-4, 2003 JENDL-3.3, 2001 P.Lisowski, 1991


� Studies of the effect of Peelle�s Pertinent Puzzle (PPP) and its effect on the standards evaluation

�Effects are most pronounced from use of correlated discrepant data�Noticed early in the activities of the CRP�Seen in model independent LS analyses�Tests using Chiba-Smith method with GMA (GMAP) and logarithmic transformation method with SOK suggest the PPP problem is under control.

E:\Develop\standards\DBUpdate\GMA-GMAP-DLS-Rev02.doc

Fig. 1. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit for 6Li(n,t) reaction.

Neutron energy, MeV0.0001 0.001 0.01 0.1 1

Rat

io

0.990

0.995

1.000

1.005

1.010


Fig. 4. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit for 10B(n,α1) reaction.

Neutron energy, MeV0.0001 0.001 0.01 0.1 1

Rat

io

0.98

0.99

1.00

1.01

1.02


Fig. 6. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit for 197Au(n,γ) reaction.


Rat

io

0.97

0.98

0.99

1.00

1.01

1.02

1.03


Fig. 7. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit of 238U(n,γ).


Rat

io

0.97

0.98

0.99

1.00

1.01

1.02

1.03


Fig. 8. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit of 235U(n,f).

Neutron energy, MeV0.001 0.01 0.1 1 10

Rat

io

0.990

0.995

1.000

1.005

1.010



Neutron energy, MeV20 40 60 80 100 120 140 160 180 200

Rat

io

0.96

0.98

1.00

1.02

1.04


Fig. 10. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit of 239Pu(n,f).

Neutron energy, MeV0.001 0.01 0.1 1 10

Rat

io

0.990

0.995

1.000

1.005

1.010


Fig. 11. Ratio of GMAP fit with using of Chiba-Smith option to exclude PPP to the standard GMA fit of 239Pu(n,f).


Rat

io

0.96

0.98

1.00

1.02

1.04




Rat

io

0.990

0.995

1.000

1.005

1.010




Rat

io

0.96

0.98

1.00

1.02

1.04

-0.04

-0.02

0

0.02

0.04

0.06

0.08

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

(Rat

io to

Prio

r) -

1

Neutron Energy [MeV]

6Li(n,α)

SOKGMA

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100

(Rat

io to

Prio

r) -

1


10B(n,α1)

SOKGMA

-0.05

0

0.05

0.1

0.15

0.2

0.25

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

(Rat

io to

Prio

r) -

1


197Au(n,γ)

SOKGMA

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

(Rat

io to

Prio

r) -

1


238U(n,γ)

SOKGMA

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 102 103

(Rat

io to

Prio

r) -

1


235U(n,f)

SOKGMA

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 102 103

(Rat

io to

Prio

r) -

1


239Pu(n,f)

SOKGMA

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

100 101 102 103

(Rat

io to

Prio

r) -

1


238U(n,f)

SOKGMA

0

1

2

3

4

5

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

Cro

ss S

ectio

n E

rror

s [%

]


6Li(n,α)

SOKGMA

0

1

2

3

4

5

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100

Cro

ss S

ectio

n E

rror

s [%

]


10B(n,α1)

SOKGMA

0

1

2

3

4

5

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

Cro

ss S

ectio

n E

rror

s [%

]


197Au(n,γ)

SOKGMA

0

2

4

6

8

10

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101

Cro

ss S

ectio

n E

rror

s [%

]


238U(n,γ)

SOKGMA

0

1

2

3

4

5

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 102 103

Cro

ss S

ectio

n E

rror

s [%

]


235U(n,f)

SOKGMA

0

1

2

3

4

5

10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101 102 103

Cro

ss S

ectio

n E

rror

s [%

]


239Pu(n,f)

SOKGMA

0

2

4

6

8

10

100 101 102 103

Cro

ss S

ectio

n E

rror

s [%

]


238U(n,f)

SOKGMA


�Combining of R-matrix and generalized least squares evaluations�R-matrix results from the RAC code were used as input to the GMA program to provide a combining of R-matrix and generalized least squares outputs. The R-matrix input was cross section, uncertainty and the correlation matrix.

Neutron Energy, MeV0,001 0,01 0,1 1

Rat

io to

EN

DF/

B-VI

eva

luat

ion

(198

7)

0 ,96

0,98

1,00

1,02

1,04

1,06RAC, Oct2003 GMA, Sep2003 GMA+RAC, Oct2003

Fig.2 Results of fitting of 6Li(n,t) reaction w ith GMA, RAC and in the combining of GMA and RAC fits (GMA+RAC).


10B(

n,α

1) c

ross

sec

tion:

ratio

to th

e EN

DF/

B-VI

0.92

0.94

0.96

0.98

1.00

1.02

1.04

1.06

RAC-3, cross-corr (n,α0)&(n,α1), Feb2004RAC+GMAP, cross-corr (n,a0)&(n,a1), Apr2004GMAP, April 2004


10B(

n,α

) cro

ss s

ectio

n: ra

tio to

the

END

F/B-

VI

0.92

0.94

0.96

0.98

1.00

1.02

1.04

1.06

RACGMAPGMAP-RAC

Neutron energy, MeV

0.01 0.1 1

10B

(n,α

0)/1

0B(n

,α1)

rat

io

0.1

1

F.-J. Hambsch, 2001 ENDF/B-VI, 1987 GMAP+RAC, 2004 RAC, 2004 Weston&Todd, 1991

Neutron energy, MeV

0.01 0.1 1

10B

(n,α

0)/1

0B(n

,α1)

rat

io, r

elat

ive

EN

DF

/B-V

I

0.6

0.8

1.0

1.2

1.4

F.-J. HambschRACGMAPWeston&Todd


�Comparisons of R-matrix and model independent least squares codes for values of the cross sections and covariances produced

�Using the full database, the SOK and GMA calculations agree

�Using 5 6Li(n,t) data sets, (Fort, Fort & Marquette, Friesenhahn, Lamaze and Poenitz & Meadows):

�With R-matrix codes, differences are observed near the 250 keV resonance, for relativistic vs non-calculations�Model independent codes GMA, GLUCS & SOK agree �R-matrix codes give smaller variances than model independent codes�Some comparisons of R-matrix and model independent codes done�Further work on R-matrix code comparisons is planned in Vienna this summer

�EDA R-matrix analyses only use a normalization uncertainty (long energy range correlation) and random uncertainties (short energy range correlation) for each data set. In addition RAC R-matix analyses use medium energy range correlations.

Fig.1a Results of fitting of 6Li(n,t) reaction with GMA, RAC, EDA and in the combining of GMA with R-matrix fits.

Neutron Energy, MeV1e-7 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0

Rat

io to

Poe

nitz

's e

valu

atio

n (1

987)

0.90

0.92

0.94

0.96

0.98

1.00

1.02

1.04

1.06

RAC, 17Oct2003 GMA, Sep2003 GMA+RAC, 17Oct2003 GMA+EDA, 4Nov2003 EDA, 4Nov2003 RAC, 13Oct2003. RAC, 26Jan2004.


�Methods for smoothing evaluated data�6Li(n,t), 10B(n,α) and 10B(n,αlγ) data can be fit with R-matrix�Models may provide insight on defining curves

� Effects of experimental resolution on evaluated results�R-matrix analyses handle resolution effects but model independent codes don�t�Unfolding data used for model independent codes is not appropriate�Folding resolution functions into R-matrix and model independent codes is difficult and would result in broadened cross sections for the evaluation�The simple approach taken is to not include poor resolution data for the model independent codes

AllanCarlson

DonSmith

Ken Hanson

ToshihikoKawano

Patrick Talou

VladimirPronyaev

Sebastian Lemaire

LANL Standards Workshop

LANL April Standards Workshop Activities

�R-matrix discussions

�PPP comparisons

�Estimation of medium energy range correlation components for discrepant data

�Studies and comparisons of LANL, JENDL and the present evaluations for the 235U(n,f) and 239Pu(n,f) cross sections.

�Discussions concerning the 235U(n,f) cross section near 1 MeV�After improvements to databases used in the evaluations to exclude obsolete or redundant data and adding new measurements, the consistency amongst the evaluations is good considering the different methods and procedures being used�Calculations of Godiva yield 0.99971 using the present preliminary 235U(n,f) evaluation�Calculations for Jezebel are underway using the present preliminary 239Pu(n,f) evaluation�Concerns about the database above 20 MeV were discussed


235 U

fiss

ion

cros

s se

ctio

n, b

1.05

1.10

1.15

1.20

1.25

1.30




�PPP comparisons




5 10 15 20Neutron Energy (MeV)

1.5

2

2.5

Cro

ss S

ectio

n (b

arns

)

GLUCS, April’04Lisowski’01Shcherbakov’01Staples’98JENDL-3.3GMA, April’04

239Pu (n,f) Cross Section



�PPP comparisons




E n (MeV)

Goldanski et al., 1955Pankratov et al., 1962Lisowski et al., 1991Nolte et al., 2001

235U(n,f)

Neutron energy, MeV1 10 100

Rat

io o

f Shc

herb

akov

's to

Lis

owsk

i's ra

tios

0.95

1.00

1.05

1.10

239Pu(n,f)/235U(n,f) 238U(n,f)/235U(n,f) 238U(n,f)/235U(n,f)*1.03

Conclusions and Recommendations

The work on the evaluation is progressing. However, there is still much work to be done to fully complete the evaluation. A special side meeting is planned at the ND2004 conference that will help the participants to prepare for the next RCM in October. The immediate focus is on producing the standards for the new ENDF/B-VII library. The objective is to provide an interim library of standard cross sections for that library this year. Detailed uncertainty information can be supplied at a later time. Based on the activities that have been focused on this evaluation, it seems reasonable to expect that there will be no remaining technical problems that can not be solved in a timely manner, though a certain level of compromise may be required.Discrepancies in data on the 235U(n,f), 238U(n,f) and 239Pu(n,f) cross sections and theirratios at energies above about 20 MeV require new measurements. Such work should be done through an international collaboration, such as a WPEC Subgroup.

report of subgroup 7 - nuclear data standards …...report of subgroup 7 nuclear data standards...

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