THERMAL NEUTRON CROSS SECTIONS AND RESONANCE'.

INTEGRALS FOR THE 1 9 9 4 HANDBOOK OF CHEMISTRY AND PHYSICS

Norman E. Holden High Flux Beam R e a c t o r

B r o o k h a v e n Nat ional L a b o r a t o r y Upton, New York 11973 USA

( 5 1 6 ) 2 8 2 - 5 2 0 4

ABSTRACT t

A re-evaluation of all thermal neutron cross sections and neutron resonance integrals has been performed, utilizing the previous database of the "Barn Book" and all of the more recently published experiments. Only significant changes or previously undetermined values are recorded in this report. The source for each value is also recorded in the accompanying table.

I. INTRODUCTION

It has been more than a decade since the last publication of the "Barn Book", BNL-325 (1).

.Although thermal neutron cross sections were re- evaluated in the Table of the Isotopes (2), no re- evaluation of neutron resonance integrals has been performed since the Barn Book. A reevaluation of both cross sections and resonance integrals have been performed for "Neutron Scattering and Absorption Properties" in the Handbook of Chemistry and Physics (3).

II. DISCUSSION

T h e d neutrons refa to a standard energy of room temperature, 20.43OC, corresponding to 0.0253 ev or 2200 m / s velocity. Resonance integrals refer to an integral of the cross section with a neutron flux density distribution proportional to the reciprocal of the neutron energy, i.e. 6 EE. Resonance integrals c8n be measufed directly or calculated from measured

factor is 0.449. Only previously undetermined values or significant changes to existing data (recommended values outside the range of Barn-Book uncertainties) are recorded in this report. Source changes ares recorded in the table.

In general, the changes recorded in the accompanying , table represent measurements made since the publication of the last barn-books. These new references would correspond to data where none previously existed, in which case only the new reference is given, or the new data required a reevaluation of all of the old data with the new value. In this later case, the notation re-evaluation is also included with the new reference.

A second situation arises when some of the parameters used in the cross section measurements have changed, since the evaluations were done for the barn-book. These changes could refer to a revised cross section standard, which causes a direct correction to the originally measured value, or a ' revised cross section value assumed for a double neutron capture experiment, in which case an inverse correction must be made to the measured value. Other corrections correspond to improved half-life values, improved isotopic abundance values, and improved gamma ray intensity values. In addition, as isotopic cross section values are revised, the isotopically weighted fit to the natural element cross section values may also change. These changes are also recorded in the tables.

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A final category of changes correspond to re-evaluation of existing data. In general, the barn-book assessments treated the experimenter's

resonance parameters. In the absence of resonance parameters, a resonance integral can be determined as a percentage of the cross section. For a cutoff energy of 0.5 ev (the standard in this evaluation), the -

- -_ _ . ~ - - -- _- - -

OFFEClAt

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

DISCLAIMER

Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

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uncertainties as sacrosanct and strictly adhe& to variance weighing to determine what the recommended value should be. Various cross section measurements have been made over the years, which quote uncertainties that both disagree with and exclude many other good measurements from consideration, if one should use variance weighing indiscriminately. Undoubtedly, systematic uncertainties have not been carefully considered in many of these measurements. Much less reliance was placed on Maxwellian averaged capture and fission cross sections compared to 2200 meterlsecond values for the fissile elements in this effort.

For resonance integrals, RI/a is often measured so a cross section change results in a change in resonance integral value.

111. CONCLUSIONS

In addition to the predominantly capture and fission cross section data given in the accompanying table, there have been numerous measurements of the @,a) and the (n,y a) cross sections. These cross sections have not been included in this table because of space considerations.

A cursory look at the table indicates that there continues to be much activity ongoing in the area of thermal neutron cross section and resonance integral measurements.

In the tables given below, the values are implicitly expressed in barns (barn = 10'" m ), or explicitly in millibarns (mb) or microbarns (pb), which correspond to 10" or

f

barns, respectively.

The various references given in the table are standard notation from the cross section bibliography, CINDA (4).

REFERENCES

1. S.F.Mughabghab, M.Divadeenam, N.E.Holden, Neutron Cross Sections - Vol. 1 Neutron Resonance Parameters and Thermal Cross Sections, Part A Z = 1-60. Academk Press Inc., New Yo&, New York

Academic Press Inc., Orlando, Florida (1984). (1981); S.F.Mughabghab, N Part B, 2 = 61-100.

2. N.E.Holden, Table of the Isotopes, Handbook of Chemistry and Physics, 72nd edition, Section 11, pp. 28-132, Chemical Rubber Company Press Inc., Boca Raton, Fl(l991).

3. N.E.Holden, Neutron Scattering & Absorption. Properties, Handbook of Chemistry & Physics, 75th edition, Chemical Rubber Company Press, Inc., Boca Raton, F1 (1994).

4. CINDA 93 - The Index to Librature and Computer Files on Microscopic Neutron Data, International Atomic Energy Agency, Vienna, Austria (1993).

*This work was performed under the auspices of the U.S. Department of Energy (contract DE-AC02-76CH00016)

NUCLIDE REACTION VALUE REFERENCE

%a 'Be 1%

0.05 f 0.01 mb 3.9 f 0.1 x lo' 0.3 f 0.1 7 . f 1. mb 8 . f 2. mb

80. f 1. mb 0.04 f 0.01 mb

2.6 f 0.3 10' 0.13 f 0.03 7 3 f 6 m b 0.16 f 0.02 0.46 f 0.03 0.29 f 0.06 0.20 f 0.03

2.8 t 0.3 x io4

46 f 2. mb c 1.5 mb 0.4 f 0.1 40 f 20 c 10. c 10. 2.7 f 0.5. 13. f 2. 1.2 f 0.2 c 10. 1.2 f 0.2 1.8 f 0.1

= 270. 66. f 8. 3.0 f 0.2

2.3 f 0.1 0.42 f 0.04

4.0 f 0.4

46. f 6. 3.3 f 1.0 x 10' 0.46 f 0.04 M data 0.51 f 0.02

0.06 f 0.01 c 20. 14. f 2. mb 16 f 5 2.5 f 0.03 0.25 f 0.04

4. f 1. 5. f 1. < 20. 0.49 f 0.02

0.30 f 0.03

PRL Q,2721(89) PRjC &917(88) ZP/A =,271(86) NP/A =,189(87) PR/C &1194(87), PRfC &1633(89) INDC(CCP)-318,11(90 NIH mr460(90) Revised a standard; PR/C aI2019(88) PR/C &2019(88) PR/C 41,1272 (90) PR/C pt,2874(91) ADP &630(87) PR/C x118(85) PR/c &l8(85) PR/C 1P126(84) I 91 JUL 583(91) PR/C fl12107(93) NIM/B 12,618 (90) JRC =,131(89) Reevaluation RE =;221(86), N o reactor a use recent maas. JNM w, 1335 (88) JRC fu1131(89) RE s1221(86) JRC m,131(89) Revised isotopic i abundance value ' RE S1217(86) 1 RE =,217,221(86) '

Reevaluation 87 KIEV 2,224(87) ZP/A 129(87), Reevaluation ZP/A =,347(84), 91 JUL 583(91) 78Hayaquez 495(78) NP/A &&209(83) 78Hayaquez 495(78) deleted value 70nayaquez 495(78), Reevaluation Reevaluation RE =,221(86) JRC &131(83) ASP =,71(85) ZPA 326 227(87) 78Mayaquez 495(78), 91 JUL 583(9l) ORNL-3832, 4(65) ORNL-3832, 4(65) RE S1221(86) 78Mayaquez 495(78), 91 JUL 583(91) Rev. double capt. a.

ZP/A X&129(87)1

NUCLIDE REACTION VALUE REFERENCE

78Mayaquez 495 ZP/A =,195(73) SAE =,483(81)

NUCLIDE REACTION VALUE REFERENCE

(m+g) 7.7 f 0.6 (rn+g) 0.7 f 0.4

Rf 20 f 4 ab6 . = 180.

m-state = 12. mb abs . 197. f 4. ml-state 73. f 8 . m2-state 88. f 8. g-state 44. t 2. g-direct 0.40 f 0.07

m-state 0.16 f 0.03

RI 6.7 t 1.2 x 103

= 9. 210. f 50. 1.3 f 0.2 4.2 f 0.1 4 7 f 3 * 0.25 i 0.06 2.4 f 0 .5 370. t 40.

0.20 t.0.07 22. f 7 . = 0.7 3.0 f 0.3 mb 90 f 20 0.25 f 0.01 0.36 f 0.07 1. 5. f 1. 4. f 1. 85. f 30. 0.1 + 1.3. 0.45 f 0.05 0.45 f 0.05 5. f 1: 9.2 f 0.2

4.5 f 0.3 (1013

(n,y) 47. f 6.

RI 210 f 90 (n,y) 1.0 f 0.1 (m+g) m-state

1.8 f 0.2 x 10' 0.8 t 0.1 x 10' = 103 = 150. 1.6 t 0.1 2.8 t 0.2 X 10' 7.2 f 0.5

<100,000 1.1 f 0.2 x 104 3.7 t 0.2 x 10' 1.5 t 0.3 x 103 1600 f 200 16,000 f 2,000

7 . f 2. x le

2. t 1. x lV 60. f 20. 1.5 t 0.7 2.0 i 0.6 x 10' 5 .7 f 1.1 x 10' 8. f 2. x 10' 1.7 t 0.2 x 10' (420 + 100) 9140 f 650 1140 f 90 1.7 t 0.2 x 10'

7 . f 1. x lol 2.0 f 0.6 3.7 f 0.4 x 10' 1.0 f 0.2 x 10' 52. t 10. - 1.3

=,l83(85) I " ' i 78nayaquez 495 ,

SAE =,912(87)

22,183(85) SAE a, 912(87) t

JINR-P3-83-634 (83) Isotopic Sum Isotopic Sum Reevaluation SAE a,395(90) SAE =,395(90) SAE ar395(90) C I P / B &520(84) ' RCA a, 183(83) 1

ORNL-3488 15(63)

SAE a, 851(87)r NST &577(90) 91 JUL 583(91) 78Mayaquez 495 Revised standard o SAE pP,799(91) ; SAE &799(91) NPA =,54(93) 82Smolenice 249(82) 78Mayaquez 49s Revised standard a 78Mayaquez 495(78), 91 JUL 583(91)

71Paris 431(77) 79Knox 907(79) 78Mayaquez 495 3 Reevaluation Reevaluation Reevaluation Reevaluation NSE =,194(87) NSE =,194(87) 78nayaquez 495.

corrected units '

SAE ar851(79)r

87KieY 1,225(87), SAB §&,233(90) TMI a,163(86) Reevaluation JRC =,43(89) Reevaluation Revised standard o NIM I,tt19B(90) Rmevaluat ion JRC =,131(89) SAE 11, 73(92) SAX.& 73(92) Revised to fit new isotopic values Roevaluation Reevaluation Rev double capt a , Reevaluation Revised isotopic sum' Reevaluation

1.2 f 0.1 x 10'

60 f 10

8.3 f 0.7 x io' a20 loo 3.2 t 0.3 1000 f 300 106. t 3.

6.0 f 0.2 x 10'

46. f 5. 30. f 25. 8.2 f 0.6 x lo3 = 4. 10.5 f 0.3 2.0 t 0.2

= 3.3 37. t 2.

74 t 1

2. t 1. x 10' 40. f 20. 9.2 f 0.2 x 10'

1.5 f 0.3 x 10' 8. f 2. 0.6 f 0.1 4.0 f 0.2 26.5 i 1.5 x 103

3.3 f 0.1

= 5. 750 f ao 250 -

47. f 2.

96. f 2. < S I & 586. f 2. 700 f 400

1030 f 100

5.3 f 0.1 x Id

2.7 t 0.2 x 103

< 1. 19. f 2. 1000 f 60

2.3 t 0.3 x lo3

752. f 3. - 4.4 mb < 100. 6.2 t 0.2 x 10' 1.7 f 0.4 x IO' 80. f 6.

74. f 4.mb - 20 .I 80. - 0.1 160 f 40 110 f 90

1.8 f 0.2 x lo'

5.1 f 0.2 x 10'

3.5 f 0.2 x 10'

4.5 0.5 x 103

78May&qUeZ 495(78), 91 JUL 583(91) 78Mayaquez 495(78),

Revised isotopic sum, JRC U,l31(89) 87Kiev 2,209 (87) 87Kiev &204(87) Revised to fit new isotopic values 78Mayaquez 495(78), 91 JUL 583(91) Reevaluation Rov double capt a Reevaluat Lon Reevaluation ZN &&, 909( 87) ZN mr909(87), 83Kiev,215(83) I

83Kiev 1,215(83) ZN mr909(87), 78Mayaquez 495(78)# '

91 JUL 583191)

91 JUL 5a3(9i)

78Mayaquez'495( 78 91 JUL 583(91) Reevaluation Reevaluation ARI &183(82) 78Mayaquez 495(78 NP/A -,240( 87) SNP a, 348 (76) Reevaluation SNP &348(76) Gryntakin thesis Tech.Univ.Munchen Revised isotopic abundance values oRo-3346-41(Rev) Reevaluation

Reevaluation Reevaluation Reevaiuatfon Reevaluation MonP-17816(46) PAC h,r,1505(89) SAE &230(84) SAE Ipr230(84) SAE &Qq,141(86)r 87Kiev ar99(87) Reevaluation Reevaluation 87Kiev 1,76(87)r sAE ar223(90) Reevaluation . Reevaluation PAC &1505(89) W-67219( 601, Reevaluation SAE 4pr373(76) JIN &2427(74) SAE &808(76), Reevaluation NSE =,293(89) Reevaluation SAE a,274(78) JIN a,l865(78t ANL-5980 (59) NSE m,349(91) NSE ipe,349(91)

NSE =,349(91)

._

~eevaluation