Thermal Neutron Activation Cross Sections Of Some Nuclides Used In Activation Measurements

Author : European Communities
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (111 download)

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Download or read book Neutron Activation Cross Sections for Safety of Nuclear Power Plants written by European Communities and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of new activation cross section measurements are presented for the following neutron-induced reactions: 58Ni(n,p)58m+gCo, 58Ni(n,p)58mCo, 58Ni(n,x)57Co, 58Ni(n,2n)57Ni, 60Ni(n,p )60m+gCo, 60Ni(n,p)60mCo, 61Ni(n,p)61Co, 61Ni(n,x)60mCo, 62Ni(n,x)61Co, 59Co(n,2)58m+gCo, 63Cu(n ,a)60m+gCo, 90Zr(n,a)87mSr, 90Zr(n,p)90mY, 91Zr(n,x)90mY, 91Zr(n,p)91mY, 92Zr(n,x)91mY, 92Zr(n,p)92Y, 204Pb(h,n')204Pb, 204(n,2n)203m1+m2Pb, and 207Pb(n,p)207 TI with emphasis on incident energies between 14 and 20 MeV. ln addition, new results have been obtained for the isomeric cross section ratios of the 58Ni(n,p )58m,gCo, the 60Ni(n ,p )60m,gCo and 59Co(n,2n)58m,gCo reactions. The irradiations were carried out at the 7 MV Van de Graaff accelerator at IRMM, Geel. Quasi mono-energetic neutrons with energies between 13.3 and 20,5 MeV were produced via the 3H(d,n)4He reaction, and for the production of neutrons with energies between 1 and 3.4 MeV the 3H(p,n)3He reaction was used. In some cases isotopically enriched materials were used to enhance the reaction yield or to facilitate correction for interfering reactions leading to the same product. The half lives for the reaction products range from 6.3 s to 5.3 years. A pneumatic sample transport system was used for the measurements of short-lived reaction cross sections. All reaction cross sections measured in the present work are referenced to the 27Al(n,a)24Na standard reaction cross section. The neutron flux spectra were determined using neutron-spectrum information obtained by the time-of-flight method and the spectral index method that involves 115In(n,n')115mIn, 58Ni(n,p)58m+gCo, 27Al(n,p)27Mg, 56Fe(n,p)56Mn, 27Al(n,a)24Na and 93 Nb(n,2n)92mNb monitor reactions with distinct energy thresholds. Standard y-ray spectrometry was employed for the measurement of radioactivity. Three lead-shielded HPGe detectors and one planar HPGe detector with carbon fibre window were used depending on the energy of the measured y-line. Isomeric cross section ratios of the two investigated reactions leading to the production of 58Co were determined by measurement of the complex decay curve of 58gCo. Corrections have been applied for sample irradiation and counting geometry, beam intensity variations during irradiation, background neutrons, neutron absorption and scattering, y-ray absorption and y-ray sum coincidences. The present results are compared with other measurements, and evaluated data. The experimental data are compared with STARPE-H code calculations. In some cases a comparison with TALYS code calculations is included as well.