sensitivity of activation cross sections of tungsten to nuclear reaction mechanisms

EFF-DOC-893, EFF/EAF Monitoring Meeting, NEA-DB, Paris, May 10-12, 2004

1

Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms

V. Avrigeanu1, R. Eichin2, R.A. Forrest3, H. Freiesleben2, M. Herman4, A.J. Koning5, and K. Seidel2

EFF-DOC-893

1EURATOM-MEC Fusion Association, “Horia Hulubei” National Institute for Physics & Nuclear Engineering, P.O Box MG-6, 76900 Bucharest, Romania2EURATOM-FZK/TUD Fusion Association, Technische Universität Dresden, D-01062 Dresden, Germany3EURATOM-UKAEA Fusion Association, Culham Science Center, Abingdon OX143DB, United Kingdom4Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-50005Nuclear Research and Consultancy Group NRG, P.O. Box 25, 1755 ZG Petten, The Netherlands


2

Outline [e.g.1, EFF-DOC-872, Nov. 2003]

• Nuclear cross sections calculations- Search for appropriate optical model potentials: n+182,183,184,186W

- p+ 181Ta- Compilation of the available experimental data (E<20 MeV)- Nuclear model calculations (E<20 MeV)- Comparison with all activation experimental data

• Processing of model calculations results- Cross sections of all individual channels with activation data-

• • [Benchmark experiment analysis updating

– calculated-to-experimental (C/E) activity: reduced deviation from unity ]

1P. Pereslavtsev and U. Fischer, Evaluation of n+184W cross-section data for EFF up to 150 MeV


3

Flowchart of model calculations

• EMPIRE-II v.2.18 [ECIS95/SCAT2, DEGAS, MSD-TUL/MSC-H, HF]

t, R, CC, abs - Tl(E) neutron deformed optical potential - p-, - spherical optical potentials - EMPIRE-specific level density, Nmax< 40

- DEGAS [g=A/13 MeV-1, K=100 MeV3]

• STAPRE-H v.2002 [SCAT2, GDH, HF] - p-, - spherical optical potentials - BSFG, E*<Bn: (a, D0-, Nmax-fit a(E*), E*>Bn: Junghans/Koning/Chadwick I/Ir: 0.5(g.s.)-0.75(Bn)-1(15 MeV) - GDH [ gFGM(), AK(p,h), fK(p,h,E,F1(l,Ei)) ]

• TALYS-0.58 [Koning and Duijvestijn]


4

Optical model potentials

• Neutrons (n+182,183,184,186W): SPRT analysis (SPR added in EMPIRE-II output)

– P.G. Young+ (1990) [as RIPL-2 in EMPIRE-II] (local)

– J.P. Delaroche, as in NEANDC-253”U”, OECD/NEA-DB, 1989 (local)

– P.G. Young, NEANDC-222”U”, OECD/NEA-DB, 1986 (global: II.B)

– P.G. Young+ (1990) - modified (local)

– RIPL-2/P.G. Young+ (1986) - modified (local)

• Protons (p+181Ta)– R.L. Walter and P.P. Guss, Rad. Effects 92, 1079 (1986) (global)

– N. Yamamuro, NDST-1988, Mito, Japan, p.489 (global)

– Walter-Guss (1986) - modified (local)

• Alphas– V. Avrigeanu, P.E. Hodgson, M. Avrigeanu, Phys.Rev.C 49,2137(1994) (global)


5

Optical model parameters used to describe the scattering of neutrons on W isotopes, and the corresponding absorption cross section for the

element W at the incident neutron energy E=14.1 MeV

Optical Potential(MeV)

R(fm)

A(fm)

abs (W)

(b)Modified Young (1986) Potential 2.627a

VR=49.8-0.3E-16b 1.26 0.61WV=-0.70+0.12, E>5.8 MeV 1.26 0.61WD=5.0+0.8E-8eV 12.2-0.1E-8eV

1.26 0.52

VSO=6.2 1.12 0.47Modified RIPL-2 Potential 2.402a

VR=49.23-0.25E-16eV =49.73-0.30E-16, E>10MeV

1.26+0.0033E, E<10 MeV1.359-0.0066E, 10<E<15 MeV1.26, E>15MeV

0.62+0.001E, E<10 MeV0.65-0.002E, 10<E<15MeV0.62, E>15MeV

WV=-1.4+0.2E, E>7 MeV 1.26 0.61WD=6.57+0.4E-8, E<4.5 MeV 8.82-0.1E-8, E>4.5 MeV

1.26 0.45

VSO=6.2 1.12 0.47a For comparison with the sum of

non=2.36±0.05 b at incident energy E=14.1 MeVcorresponding to inelastic scattering from above ~2 MeV of the excitation energy18, and a crosssection of ~0.04 b for statistical inelastic scattering on low-lying levels below ~2 MeV.

b =(N-Z)/A


6

Comparison of experimental and calculated neutron scattering parameters of 182,184,186W

PotentialS0*104

182WS1*104 R’(fm) S0*104

184WS1*104 R’(fm) S0*104

186WS1*104 R’(fm)

Exp.20 2.3(3) 7.3(3) 2.8(4) 0.58(7) 7.3(3) 2.1(4) 0.37(5) 7.3(3)RIPL-24 2.69 0.90 7.13 3.01 0.77 7.31 3.23 0.69 7.82Ref.15 2.55 1.14 7.37 2.75 0.99 7.51 2.80 0.87 7.86Ref.16 2.39 1.17 7.40 2.58 1.02 7.49 2.66 0.91 7.79Ref.16-mod. 2.23 1.07 7.38 2.41 0.94 7.46 2.52 0.85 7.74RIPL2-mod 2.24 1.11 7.46 2.39 0.99 7.52 2.57 0.90 7.74


7

Comparison of calculated and experimental neutron total cross sections for 182,183,184,186W isotopes with emphasis of the lower energy region

0.1 1 10

5

6

7

8

9Whalen+ (1966)Martin+ (1967)Foster+ (1971)Djumin+ (1977)Guenther+ (1982)Knopf+ (1987)Dietrich+ (2003)

RIPL2 (Young+, 1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL2-mod. (a)

n + 182

W

(b)

0.01 0.1 1 10

10

RIPL2 (Young+,1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL2-mod. (b)

n + 183

W Ohkubo+ (1978) #1 Ohkubo+ (1978) #2 Knopf+ (1982)

Abfalterer+ (2001): nat

W

0.1 1 10

5

6

7

8

9Whalen+ (1966)Martin+ (1967)Foster+ (1971)Djumin+ (1977)Guenther+ (1982)Knopf+ (1982) Dietrich+ (2003)

(c)

n + 184

W

RIPL2 (Young+, 1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL2-mod.

(b

)

En (MeV)0.1 1 10

5

6

7

8

9 Whalen+ (1966) Martin+ (1967) Foster+ (1971) Djumin+ (1977) Guenther+ (1982) Knopf+ (1982) Dietrich+ (2003)

(d)

n + 186

W

RIPL2 (Young+, 1990) Vonach-NagelN (1989) Young (1986)/Set II-B RIPL2-mod.

En (MeV)


8

Comparison of calculated and experimental neutron total cross sections for 182,183,184,186W isotopes

5

6

7

Whalen+ (1966) Martin+ (1967) Foster+ (1971) Djumin+ (1977) Guenther+ (1982) Knopf+ (1987) Dietrich+ (2003) RIPL2 (Young, 1990) Vonach-Nagel (1989) Young (1986) RIPL-2 mod.

(a)

n + 182

W

(b

)

5

6

7 Ohkubo+ (1978) #1 Ohkubo+ (1978) #2 Knopf+ (1982)


W RIPL2 (Young, 1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL-2 mod.

(b)

n + 183

W

0 5 10 15 20 25 30

5

6

7

Whalen+ (1966)Martin+ (1967)Foster+ (1971)Djumin+ (1977)Guenther+ (1982)Knopf+ (1982) Dietrich+ (2003) RIPL2 (Young+, 1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL-2 mod.

(c)

n + 184

W

(b

)

En (MeV)0 5 10 15 20 25 30

5

6

7

(d)

n + 186

W Whalen+ (1966) Martin+ (1967) Foster+ (1971) Djumin+ (1977) Guenther+ (1982) Knopf+ (1982) Dietrich+ (2003) RIPL2 (Young, 1990) Vonach-Nagel (1989) Young (1986)/Set II-B RIPL-2 mod.

En (MeV)


9

Comparison of neutron total cross sections for 182,183,184,186W isotopes calculated by using presently modified OMPs

5

6

7

Whalen+ (1966) Martin+ (1967) Foster+ (1971) Djumin+ (1977) Guenther+ (1982) Knopf+ (1987) Dietrich+ (2003) RIPL2 (Young, 1990) - mod. Young (1986)/Set II-B mod.

(a)

n + 182

W

5

6

7 Ohkubo+ (1978) #1 Ohkubo+ (1978) #2 Knopf+ (1982)


W RIPL2 (Young, 1990) -mod. Young (1986)/Set II-B - mod.

(b)

n + 183

W

0 5 10 15 20 25 30

5

6

7

Whalen+ (1966)Martin+ (1967)Foster+ (1971)Djumin+ (1977)Guenther+ (1982)Knopf+ (1982) Dietrich+ (2003) RIPL2 (Young+, 1990) - mod. Young (1986)/Set II-B mod.

(c)

n + 184

W

En (MeV)0 5 10 15 20 25 30

5

6

7

(b

)

(d)

n + 186

W Whalen+ (1966) Martin+ (1967) Foster+ (1971) Djumin+ (1977) Guenther+ (1982) Knopf+ (1982) Dietrich+ (2003) RIPL2 (Young, 1990) - mod. Young (1986)/Set II-B - mod.

En (MeV)


10

Comparison of the calculated and measured proton reaction cross sections and (p,n) reaction cross sections for 181Ta

100

1

2

(a)

p + 181

Ta

Wilkins-Igo (1963) Kirkby+ (1966) Abegg+ (1979) Perey (1963) Menet+ (1971) Koning+ (2002) Walter+ (1985) WG-Yamamuro (1988) Walter+ - mod

R

(b)

En (MeV)4 8 12

1E-5

1E-4

1E-3

0.01

0.1

(b)

181Ta(p,n)

181W

Hansen+ (1962)/T0121 Chodil+ (1967)/C0693 Thomas+ (1967)/C0695 Zhuravlev+ (1984)/A0271 Perey (1963) Menet+ (1971) Koning+ (2002) Walter+ (1985) WG-Yamamuro (1988) WG -mod

(b

)

En (MeV)

Walter-Guss (1986) - modified (local): WD=10.48-0.250E+14.94, E<10 MeV 9.55-0.157E+14.94, E>10 MeV

aD= 0.742-0.0115E, E<20 MeV 0.512, E>20 MeV


11

Nuclear Level Density

0 1 21

10

100

NUDAT (1994) BSFG

Bn=7.627, I

0=7/2

D0=0.0024(3) keV

178Hf

N (

E*)

E* (MeV)0 1 2

NUDAT (1994) BSFG

Bn=6.100, I

0=0

D0=0.057(6) keV

179Hf

Cumulative number of levels against excitation energy for, e.g., 178,179Hf, and corresponding prediction of the BSFG model


12

The -ray strength functions

0180W 182W 183W 184W 186W

RIPL-220 70(15) 62(15) 77(12) 69(17) 61(8)1040/D0 (Ref.30) 7.97(37) 45.6(8) 6.00(36) 5.51(25)0 (from Ref.30 and D0 of Ref.20) 48 55 42 470 for best normalization of fE1(E) 40 47 50 42 35

20A.V. Ignatyuk, at http://161.5.7.5/RIPL-2/resonances/ .28D.G. Gardner and F.S. Dietrich, Report UCRL-82998, LLNL-Livermore, 1979.29M. Avrigeanu, V. Avrigeanu, G. Cata, and M. Ivascu, Rev. Roum. Phys. 32, 837 (1987).30R.L. Macklin, D.M. Drake, and E.D. Arthur, Nucl. Sci. Eng. 89, 98 (1983).

• Modified energy-dependent Breit-Wigner (EDBW) model28,29: fE1(E)

• Comparison of experimental20,30 and the calculated average radiative widths- 0 (meV) used for normalization of fE1(E) capture data description


13

Comparison of calculated and measured neutron capture cross sections of 180,182-184,186W isotopes

0.01 0.1 1

0.1

1

=70+15 meV [RIPL2]

Bokhovko+ (1986)

=70 meV 55 meV 40 meV 40 meV, E

S=0

180W(n,)181

W

(b

)

1E-3 0.01 0.1 1

0.1

1 =62+15 meV [RIPL2]


S=0

Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Grenier+ (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987)

182W(n,)183

W

1E-3 0.01 0.1 10.01

0.1

1

10

=77+12 meV [RIPL2]


S=0

Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Grenier (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987)

183W(n,)184

W

1E-3 0.01 0.1 10.01

0.1

1=69+17 meV [RIPL2]


S=0

Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Joly+ (1981)Beer+ (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987)

184W(n,)185

W

(b

)

En (MeV)1E-3 0.01 0.1 1

0.01

0.1

1

En (MeV)

Bokhovko+ (1986)Knopf+ (1987)Trofimov+ (1987)Zhang+ (2001)


S=0

=61+8 meV [RIPL2]

Kononov+ (1965) Kapchigashev+(1966)Friesenhahn+ (1966)Chaubey+ (1966)Zaikin+ (1968)Diksic+ (1970)Lindner+ (1976)Gleason (1977)Bradley+ (1979)Joly+ (1981)Macklin+ (1983)

186W(n,)187

W

En (MeV)


14

Sample case of isomeric state populated by side- and continuum-decay cascade-feeding

10 12 14 16 18 201E-4

1E-3

0.01

0.1

1

E*=2.425 MeV, 21/2+ [16

th]

Greenwood+ (1987) TALYS_0.49 SH (2001) SH (2002)

94Mo(n,2n)93Mo

Fujino+ (1977) Rao+ (1979) Amemiya+ (1982) Marcinkowski+ (1986) Ikeda+ (1988) Kong+ (1995) Molla+(1997) IRMM (2001)

94Mo(n,2n)93Mom

(

b)

En (MeV)

[http://tandem.nipne.ro/~vavrig/Publications/2003/papmo_1z.ps]


15

Comparison of the measured and calculated reaction cross sections for the target nucleus 180W

Calculated values by means of the computer codes EMPIRE-II and TALYS with default global parameters (except the local OMPs) and STAPRE-H with local parameter set given in this work.

0.01 0.1 1

0.1

1

Bokhovko+ (1986)

CC+GDH+HF EMPIRE-II TALYS-0.58

(a)

180W(n,)181

W

(b)

10 15 200.00

0.01

0.02

CC+GDH+HF TALYS-0.58

[1+ 8.152 h]

Qaim+ (1975)

(b)

180W(n,p)

180mTa

10 15 200

1

2

Qaim+ (1975)


(c)

180W(n,2n)

179g+mW

(b

)

En (MeV)10 15 200.0

0.4

0.8


[1/2- 6.4 min]

Qaim+ (1975)Filatenkov+ (2002)

(d)

180W(n,2n)

179mW

En (MeV)


16


Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+

(1980).

1E-3 0.1

0.1

1

(b

)


Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Grenier+ (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987) (a)

182W(n,)183

W

(b

)

10 15 200

1

2

Druzhinin+ (1966)Dilg+ (1968) Maslov+ (1972)Qaim+ (1975)Frehaut+ (1980)LNZ (1997)


(b)

182W(n,2n)

181W

10 15 200.000

0.005

0.010

0.015

0.020

[3- 114.43 d]

Qaim+ (1975) Grallert+ (1993)LNZ (1997)Filatenkov+ (2002)

CC+GDH+HF EMPIRE-II TALYS-0.58 (c)

182W(n,p)

182Ta

10 15 200.0000

0.0002

0.0004

Qaim+ (1975) Kasugai+ (1992)Filatenkov+ (2002) CC+GDH+HF

[10- 15.84 min]

(d)

182W(n,p)

182m2Ta

10 15 201E-8

1E-6

1E-4

Qaim+ (1975) CC+GDH+HF TALYS-0.58

[25/2- 25.05 d]

182W(n,)

179m2Hf

Filatenkov+ (2002) CC+GDH+HF

[1/2- 18.67 s]

(e)

182W(n,)

179m1Hf

10 15 201E-12

1E-10

1E-8

1E-6

1E-4

[16+ 31 y]

Hanlin+ (1994)Ikeda+ (1996)LNZ (1997)Filatenkov+ (2001) CC+GDH+HF

(f)

182W(n,n')

178m2Hf

En (MeV)


17


Calculated values by means of the computer codes EMPIRE-II and TALYS with default global parameters (except the local OMPs) and STAPRE-H with local parameter set given in this work.

1E-3 0.01 0.1 10.01

0.1

1

10


Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Grenier (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987) (a)

183W(n,)184

W

(b)

10 15 200.00

0.01

0.02

Qaim+ (1975) Grallert+ (1993)Filatenkov+ (2002)


(b)

183W(n,p)

183Ta

10 15 200.0000

0.0002

0.0004

[8- 5.5 h]

Qaim+ (1975)Filatenkov+ (2002) CC+GDH+HF TALYS-0.58

(a)

183W(n,)

180mHf

(b

)

En (MeV)10 15 200

1

2


Frehaut+ (1980)

(d)

183W(n,2n)

182W

En (MeV)


18


Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+ (1980).

1E-3 0.01 0.1 10.01

0.1

1

(b

)


Kononov+ (1965) Kapchigashev+ (1966)Friesenhahn+ (1966)Block+ (1966)Joly+ (1981)Beer+ (1981)Macklin+ (1983)Bokhovko+ (1986) Knopf+ (1987) (a)

184W(n,)185

W

(b

)

10 15 200.000

0.005

0.010

0.015

Qaim+ (1975)Ikeda+ (1988)Kasugai+ (1992)Grallert+ (1993)LNZ (1997)Filatenkov+ (1999)Filatenkov+ (2002)


(b)

184W(n,p)

184Ta

10 15 200.000

0.001

0.002

0.003

(c)


Qaim+ (1975) Kasugai+ (1992) Grallert+ (1993)Filatenkov+ (2002)

184W(n,)

181Hf

En (MeV)

10 15 200

1

2

Frehaut+ (1980)

184W(n,3n)182W


(d)

184W(n,2n)

183W

10 15 200.0

0.5

1.0

En (MeV)

Prasad+ (1966) Anders+ (1982)

[11/2+ 5.2 s]


(e)

184W(n,2n)

183mW

En (MeV)


19


Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set. Normalization factor of 1.078 [Vonach+, 1990] is applied to data of Frehaut+ (1980).

1E-3 0.01 0.1 10.01

0.1

1

(b

)

(a)

Bokhovko+ (1986)Knopf+ (1987)Trofimov+ (1987)Zhang+ (2001)


Kononov+ (1965) Kapchigashev+(1966)Friesenhahn+ (1966)Chaubey+ (1966)Zaikin+ (1968)Diksic+ (1970)Lindner+ (1976)Gleason (1977)Bradley+ (1979)Joly+ (1981)Macklin+ (1983)

186W(n,)187

W

(b

)

10 15 200.000

0.003

0.006

0.009

Coleman+ (1959)Poularikas+ (1960) Mukherjee+ (1963) Qaim+ (1975)Kasugai+ (1992)Sutoh+ (1994)Murahira+ (1995)Filatenkov+ (1999)Filatenkov+ (2002)


(b)

186W(n,p)

186Ta

10 15 200.0000

0.0005

0.0010

0.0015

Qaim+ (1975)Ikeda+ (1988)Kasugai+ (1992)Grallert+ (1993)LNZ (1997)Filatenkov+ (2002)


(c)

186W(n,)

183Hf

En (MeV)

10 15 200

1

2186

W(n,3n)184

W


Druzhinin+ (1966)Frehaut+ (1980) LNZ (1997)Filatenkov+ (2002)

(d)

186W(n,2n)

185W

10 15 200.0

0.5

1.0

1.5

En (MeV)

Rurarz+ (1971) Kao+ (1974)Qaim+ (1975)Filatenkov+ (1999)

[11/2+ 1.67 min]


(e)

186W(n,2n)

185mW

En (MeV)


20

Sensitivity of calculated (n,2n) reaction cross sections vs. reaction mechanisms & model parameters

Calculations with EMPIRE-II and default global parameters excepting local OMPs. A normalization factor of 1.078 (Vonach+, 1990) was applied to data of Frehaut+ (1980).

0

1

2

Druzhinin+ (1966)Dilg+ (1968) Maslov+ (1972)Qaim+ (1975)Frehaut+ (1980)LNZ (1997)

n/RIPL-2 mod., MSD/MSC n/RIPL-2 mod., DEGAS n/RIPL-2, DEGAS (a)

182W(n,2n)

181W

10 15 200

1

2

Frehaut+ (1980)

n/RIPL-2 mod., MSD/MSC n/RIPL-2 mod., DEGAS n/RIPL-2, DEGAS

(b)

183W(n,2n)

182W

0

1

2

Frehaut+ (1980)

184W(n,3n)

182W


(c)

184W(n,2n)

183W

10 15 200

1

2

En (MeV)

(b

)

(b)

186W(n,3n)

184W

n/RIPL-2 mod., MSC/MSD n/RIPL-2 mod., DEGAS n/RIPL-2, DEGAS

Druzhinin+ (1966)Frehaut+ (1980) LNZ (1997)Filatenkov+ (2002)

(d)

186W(n,2n)

185W

En (MeV)


21

Sensitivity of calculated (n,p) reaction cross sections vs. reaction mechanisms & model parameters

Calculations with EMPIRE-II and default global parameters excepting local OMPs.

0.000

0.005

0.010

[3- 114.43 d]


n/RIPL-2 mod., MSD/MSC n/RIPL-2 mod., DEGAS n/RIPL-2, DEGAS (a)

182W(n,p)

182Ta

(b

)

10 15 200.000

0.004

0.008


n/RIPL-2 mod., MSD/MSC n/RIPL-2 mod., DEGAS n/RIPL-2, DEGAS (b)

183W(n,p)

183Ta

(b

)

0.000

0.004

0.008

184W(n,pn)183Ta



(c)

184W(n,p)

184Ta

10 15 200.000

0.002

0.004

En (MeV)

186W(n,pn)

185Ta

Coleman+ (1959)Poularikas+ (1960) Mukherjee+ (1963) Qaim+ (1975)Kasugai+ (1992)Sutoh+ (1994)Murahira+ (1995)Filatenkov+ (1999)Filatenkov+ (2002)


(d)

186W(n,p)186Ta

En (MeV)


22

Sensitivity of calculated (n,p) reaction cross sections vs. reaction mechanism codes

Calculations with EMPIRE-II and TALYS, and default global parameters (except local OMPs), and STAPRE-H with local parameter set.

0.00

0.01

0.02

[3- 114.43 d]



(a)

182W(n,p)

182Ta

(b

)

10 15 200.00

0.01

0.02



(b)

183W(n,p)

183Ta

(b

)

En (MeV)

0.000

0.005

0.010

0.015



(c)

184W(n,p)

184Ta

10 15 200.000

0.005

0.010

Coleman+ (1959)Mukherjee+ (1963) Qaim+ (1975)Kasugai+ (1992)Sutoh+ (1994)Murahira+ (1995)Filatenkov+ (1999)Filatenkov+ (2002)

CC+GDH+HF EMPIRE-II TALYS-0.58(d)

186W(n,p)186Ta

En (MeV)


23

Conclusions• Achievements

- Appropriate optical model potentials: n+182,183,184,186W- Unitary description of all activation experimental data (E<20 MeV) by

using a local parameter set in STAPRE-H code- Good results of blind calculations and global parameters within

EMPIRE-II and TALYS codes- Similar sensitivity of calculations vs. reaction mechanisms & model

parameters

• Problems- Major uncertainty of calculated isomeric cross sections: level schemes

& branching ratios

- (n,p)-, (n,)-reaction excitation functions at En>15 MeV

• Completion - Similar analysis for: n+180,181Ta, n+174,176,177,178,179,180Hf

- Need for (n,p)-, (n,)-reaction data at En>15 MeV (e.g., JRC/IRMM)

sensitivity of activation cross sections of tungsten to nuclear reaction mechanisms

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