Fast neutron induced reactions leading to activation products: selected cases relevant to development of low activation materials, transmutation and hazard assessment of nuclear wastes

Neutron induced cross sections are of interest for practical applications and for testing nuclear models. In this work (n,p), (n,np), (n,α), (n,nα), (n,n’γ), (n,2n) and (n,3n) reactions on vanadium, molybdenum, technetium and lead have been measured in the energy range of 0.5 to 20.6 MeV using the activation technique . The radioactive reaction products with half-lives between 58 seconds and 20300 years have been measured offline via high-resolution γ-ray-spectrometry and Liquid Scintillation Counting, the latter in combination with radiochemical separation. Irradiations with neutron energies in the range of 0.5 to 6 MeV were done using the H(p,n)He reaction with a solid-state Ti/T target while energies between 7.4 and 12.5 MeV were covered with the H(d,n)He reaction utilizing a D2 gas target. Irradiations in the energy range from 13.4 to 20.6 MeV were performed using the H(d,n)He reaction, again with a solid Ti/T target. Most of the reactions were investigated using a light mass setup to minimise scattering effects, but for short half-lives a pneumatic sample transport system was used as well. A special sample holder was developed for the measurement of the Mo(n,x)Nb reaction. All cross sections were measured relative to the Al(n,α)Na standard cross section and all necesarry corrections due to the irradiation process and the measurement of the induced activity have been applied. Nuclear model calculations were performed for all investigated reactions. For reactions on Tc and Pb the original STAPRE code was used, while for reactions on V and Mo a modified version STAPRE-H was employed. As a result of this thesis work an extended database for neutron induced cross sections on four elements was obtained. It was possible to establish first excitation functions for reactions on a radioactive target nucleus, one very long-lived product and one purely β− emitting product. It was found that existing evaluations are not always reliable in the prediction of unknown cross sections. Although the experimental results of this work helped to considerably improve the calculations, some deficiencies still exist in case of complex particle emission (like d,t,α) and second chance emission (n,np) or (n,pn) etc.

[1]  Yujiro Ikeda,et al.  Neutron Activation Cross-Section Measurements from 16 to 20 MeV for Isotopes of F, Na, Mg, Al, Si, P, Cl, Ti, V, Mn, Fe, Nb, Sn, and Ba , 2000 .

[2]  G. Winkler.  Prerequisites for Accurate Activation Cross-Section Measurements , 1992 .

[3]  J. F. Briesmeister.  MCNP-A General Monte Carlo N-Particle Transport Code , 1993 .

[4]  C. Luke,et al.  Determination of Impurities in Germanium and Silicon , 1953 .

[5]  Horst Liskien,et al.  Neutron production cross sections and energies for the reactions T(p,n)3He, D(d,n)3He, and T(d,n)4He , 1973 .

[6]  G. Pető,et al.  Influence of direct inelastic scattering on (n, 2n) cross sections , 1967 .

[7]  Richard B. Firestone,et al.  Table of Isotopes , 1978 .

[8]  R. Haight,et al.  Measurement of the activation cross section for the reaction 93Nb(n,n′)93mNb in the neutron energy range 6–9 MeV , 1993 .

[9]  R. W. Fink,et al.  Neutron activation cross sections at 14.4 MeV For some naturally occurring heavy elements in the region 76 ≦ Z ≦ 82 , 1972 .

[10]  G. Winkler,et al.  The 238 U(n,f) Cross Section and its Ratio to the 27 Al(n,α) 24 Na and 56 Fe(n,p) 56 Mn Cross Section in the 14 MeV Region , 1992 .

[11]  G. Stöcklin,et al.  ACTIVATION CROSS SECTIONS OF FAST NEUTRON INDUCED NUCLEAR REACTIONS: PRECISION MEASUREMENTS AND SYSTEMATICS. , 1971 .

[12]  A. Paulsen,et al.  Neutron production cross sections and energies for the reactions 7Li(p,n)7Be and , 1975 .

[13]  D. Sarkar,et al.  ISOMERIC CROSS SECTION RATIOS FOR (n,2n) REACTIONS AT 14.8 MeV. , 1967 .

[14]  G. Petö,et al.  Measurement of the cross section for the reaction 93Nb(n, n′) 93mNb at 2.8 MeV , 1988 .

[15]  M. M. Bretscher,et al.  Measurement of 14.7 MeV neutron-activation cross sections for fusion , 1987 .

[16]  S. Amemiya,et al.  Neutron Activation Cross Section of Molybdenum Isotopes at 14.8 MeV , 1982 .

[17]  A. Marcinkowski,et al.  Cross sections of fast neutron induced reactions on selenium isotopes , 1986 .

[18]  W. Westmeier,et al.  On the photopeak efficiency of germanium gamma-ray detectors , 1987 .

[19]  Editors , 1986, Brain Research Bulletin.

[20]  H. Klein,et al.  Neutron Production from the Deuteron Breakup Reaction on Deuterium , 1990 .

[21]  S. Qaim,et al.  Measurement of ( n,p ) and ( n,α ) Reaction Cross Sections on Some Isotopes of Nickel in the Energy Region of 5 to 10 MeV Using a Deuterium Gas Target at a Compact Cyclotron , 1984 .

[22]  J. CHADWICK,et al.  Possible Existence of a Neutron , 1932, Nature.

[23]  C. S. Khurana,et al.  Cross-sections for (n, 2n) reactions at 14.8 MeV , 1961 .

[24]  J. Chadwick,et al.  The existence of a neutron , 1932 .

[25]  C. L. Dunford,et al.  NuDat system for access to nuclear data , 1998 .

[26]  D. Gardner,et al.  Cross section of some reactions of 99Tc with 14.1 MeV neutrons , 1965 .

[27]  S. Qaim,et al.  Excitation functions of some neutron threshold reactions on isotopes of molybdenum , 1985 .

[28]  G. Stöcklin,et al.  Fast neutron induced [(n,t) + (n,n′t)] reaction cross-sections in the medium and heavy mass regions , 1974 .

[29]  V. Poznyak,et al.  Cross sections for (n, p) and (n, α) reactions on chromium, iron, copper, and molybdenum nuclei at a neutron energy of 14.8 MeV , 1980 .

[30]  M. Salvatores,et al.  Status of the JEF evaluated data library , 1994 .

[31]  A. G. Malonda,et al.  Evaluation of counting efficiency in liquid scintillation counting of pure β-ray emitters , 1982 .

[32]  S. Qaim,et al.  NUCLEAR DATA MEASUREMENTS FOR FR-WALL AND STRUCTURAL MATERIALS , 1976 .

[33]  S. Cierjacks,et al.  Mesure de quelques sections efficaces (n, α) dans l'intervalle des énergies des neutrons 12 à 19,6 Mev , 1961 .

[34]  Recent developments in ultra low-level γ-ray spectrometry at IRMM , 2000 .

[35]  A. Grallert,et al.  Improved gas-cell D-D neutron sources , 1994 .

[36]  S. Qaim.  Nuclear reaction cross-sections for 14·7 MeV neutrons on 99Tc , 1973 .

[37]  E. Arthur,et al.  GNASH: a preequilibrium, statistical nuclear-model code for calculation of cross sections and emission spectra. [In FORTRAN for CDC 7600] , 1977 .

[38]  W. Grochulski,et al.  Cross sections for the (n, n') and (n, 2n) reactions on 113In and 204Pb , 1973 .

[39]  Carlo Rubbia,et al.  Conceptual design of a fast neutron operated high power energy amplifier , 1995 .

[40]  D. B. Gayther,et al.  The determination of the 93Nb(n,n′) 93mNb cross-section in the neutron energy range 1–6 MeV , 1991 .

[41]  M. Salvatores,et al.  The transmutation of long-lived fission products by neutron irradiation , 1998 .

[42]  I. Kimura,et al.  Calibrated fission and fusion neutron fields at the Kyoto University Reactor , 1990 .

[43]  E. Gadioli,et al.  Pre-Equilibrium Nuclear Reactions , 1992 .

[44]  S. Qaim,et al.  Activation and mass spectrometric study of3He particle emission in the interactions of fast neutrons with medium mass nuclei , 1979 .

[45]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[46]  H. Takano,et al.  Japanese Evaluated Nuclear Data Library Version 3 Revision-3: JENDL-3.3 , 2002 .

[47]  D. Nethaway,et al.  Excitation functions of neutron-induced reactions , 1960 .

[48]  R. Stephenson.  A and V , 1962, The British journal of ophthalmology.

[49]  J. H. Hubbell,et al.  XCOM: Photon Cross Section Database (version 1.2) , 1999 .

[50]  Kevin Barraclough,et al.  I and i , 2001, BMJ : British Medical Journal.

[51]  Yasuyuki Kikuchi.  Japanese Evaluated Nuclear Data Library, Version-3, JENDL-3 , 1992 .

[52]  N. Bohr.  Neutron Capture and Nuclear Constitution , 1936, Nature.

[53]  C. Luke.  Photometric Determination of Antimony and Thallium in Lead , 1959 .

[54]  J. Ziegler,et al.  Hydrogen Stopping Powers and Ranges in All Elements , 1977 .

[55]  K. Debertin,et al.  Gamma- and X-Ray Spectrometry with Semiconductor Detectors , 1988 .

[56]  G. Sibbens,et al.  Self-absorption correction in standardisation of 204Tl. , 2002, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[57]  A. H. Wapstra,et al.  The 1995 update to the atomic mass evaluation , 1995 .

[58]  P. Odern.  RECENT PROGRESS ON 14 MeV NEUTRON ACTIVATION CROSS SECTION MEASUREMENTS , 1992 .

[59]  R. L. Clarke,et al.  CROSS-SECTION MEASUREMENTS OF REACTIONS INDUCED BY NEUTRONS OF 14.5 MEV. ENERGY , 1953 .

[60]  H. Reiss,et al.  Statistical model analysis of cross sections of (n,t) and (n,/sup 3/He) reactions induced by 14. 6 MeV neutrons on target nuclei with A=27 to 59 , 1980 .

[61]  G. Petö,et al.  Isomeric cross-section ratios for (n, 2n) reactions , 1968 .

[62]  S. Qaim,et al.  Excitation Functions of Neutron Threshold Reactions on Some Isotopes of Germanium, Arsenic, and Selenium in the 6.3- to 14.7-MeV Energy Range , 1994 .

[63]  C. M. Bartle,et al.  The production of a 2 10 MeV collimated monoenergetic neutron beam of known flux using the associated particle technique , 1974 .

[64]  Z. Kormány.  A new method and apparatus for measuring the mean energy of cyclotron beams , 1994 .

[65]  B. Minetti,et al.  Isomeric cross-section ratio for (n, 2n) reactions induced by 14.7 MeV neutrons , 1968 .

[66]  D. L. Smith,et al.  A least-squares computational ``tool kit``. Nuclear data and measurements series , 1993 .

[67]  Julius Csikai,et al.  Handbook of Fast Neutron Generators , 2001 .

[68]  Y. Kanda.  The excitation functions and Isomer ratios for neutron-induced reactions on 92Mo and 90Zr , 1972 .

[69]  N. Cindro,et al.  REACTION MECHANISM AND SHELL EFFECTS FROM THE INTERACTION OF 14.6 MeV NEUTRONS WITH NUCLEI , 1962 .

[70]  G. Goldstein.  Activation cross sections for the reactions of 14·8-MeV neutrons with 99Tc☆ , 1966 .

[71]  E. Rutherford,et al.  Collision of α particles with light atoms. IV. An anomalous effect in nitrogen , 1919 .

[72]  B. M. Bahal,et al.  Measurements of 14 mev neutron activation cross sections , 1986 .

[73]  H. Klein,et al.  Energy and angle straggling effects in a D(d, n)3He neutron source using a gas target , 1982 .

[74]  J. Hoste,et al.  The 204Pb (n, p) 204Tl Reactor Cross-Section and the Neutron Activation Analysis of Thallium in Lead , 1965 .

[75]  J. Birks.  Liquid scintillation counting , 1974, Nature.

[76]  R. W. Fink,et al.  Activation Cross Sections for ( n , 2 n ) Reactions at 14.4 MeV in the Region Z = 40 − 60 : Precision Measurements and Systematics , 1970 .

[77]  R. Prasad,et al.  Measured (n, p) reaction cross-sections and their predicted values at 14.8 MeV , 1971 .

[78]  P. K. Kuroda,et al.  14·8 MeV neutron-induced (n, 2n), n, p) and (n, α) cross-sections for some closed shell nuclides , 1975 .

[79]  E. Perillo,et al.  Activation cross sections of Mo isotopes for 14.1 MeV neutrons , 1967 .

[80]  S. Qaim.  A study of (n,nα) reaction cross sections at 14.7 MeV , 1986 .

[81]  R. Aman,et al.  Spectrophotometric Determination of Thallium in Zinc and Cadmium with Rhodamine B , 1961 .

[82]  S. Qaim,et al.  3He particle emission in fast neutron induced reactions , 1983 .

[83]  A. Paulsen,et al.  Determination of 1 MeV neutron fluxes from the T(p,n)3He reaction by the associated particle method , 1969 .

[84]  S. Qaim.  Activation cross sections, isomeric cross-section ratios and systematics of (n, 2n) reactions at 14–15 MeV , 1972 .

[85]  P. D. P. Taylor,et al.  Isotopic compositions of the elements 1997 (Technical Report) , 1998 .

[86]  S. Gujrathi,et al.  Decay of 98Nb and the energy levels of 98Mo , 1966 .