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Abstract  

The McMaster University Nuclear Reactor (MNR) is a unique Canadian facility in a university environment welcoming researchers from across Canada and abroad. The irradiation and analytical facilities available cover a broad spectrum of nuclear analytical techniques from standard INAA to fully automated counting systems for prompt gamma activation analysis and delayed neutron counting. In addition, neutron beams provide for a wide spectrum of applied and basic nuclear research applications. This paper describes the state-of-the-art facilities available at McMaster.

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Abstract  

Nuclear Analytical Chemistry at Texas A&M University is based in large part on the facilities of the Center for Chemical Characterization and Analysis and the Nuclear Science Center. This paper describes the capabilities of these two centers for instrumental and fast neutron activation analysis, neutron depth profiling, prompt gamma activation analysis, neutron radiography and the unique features of the large volume irradiation cell and reactor pulsing operation.

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Abstract  

Prompt gamma activation analysis (PGAA) is one of the most powerful analytical methods for the determination of boron because of its very large neutron capture cross section. The peak of boron in the PGAA spectra is highly broadened due to the Doppler-effect. An improved method is presented to fit the boron peak, and to resolve interference with the gamma-rays of sodium and other matrix components. The method has been checked on test samples and on geological samples as well.

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Abstract  

Based on recently measured k0-factors and related nuclear data, an evaluation was performed, via the `activation method', of thermal (n,) activation cross sections. It concerns 15 analytically-relevant cases with a short half-life and/or with a complex activation-decay scheme: 20F, 41Ar, 60mCo/60Co, 71Zn, 77mSe, 80mBr/80Br, 104mRh/104Rh, 109mPd/109Pd/109mAg, 110Ag, 122mSb/122Sb, 124m2Sb/ 124m1Sb/124Sb, 134mCs/134Cs, 179mHf, 199mPt/199Pt/199Au and 205Hg.

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Two non-destructive and position sensitive methods were used to analyzea sample coming from the reactor site of Okelobondo near Oklo (Gabon). Atthe European Synchrotron Radiation Facility (ESRF), uranium and lead werevisualized in this piece by element sensitive tomography. The same samplewas then studied with the new prompt gamma activation (PGA) facility at theSwiss spallation neutron source SINQ (PSI Villigen). A neutron focusing capillarylens permits to upgrade PGA to a position sensitive method. In the Oklo samplethe concentration of uranium but also of 7 other elements were spatially analyzed.

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Investigations on isochronal annealing behaviour of /n, / activated56Mn recoils in crystalline potassium and ammonium permanganates have given different results indicating a varying degree of sensitivity of the samples to recoil annealing. The presence of ammonium ion in ammonium permanganate shows the reduction of recoil species during annealing. Vand-Primak model has been utilized to deduce the kinetic behaviour by which the energy of activation is found to be 1.1 and 1.2 eV for KMnO4 and NH4MnO4, respectively. Furthermore, the present work reveals the role of defects in the transient reactions of the lattice stable precursors and hence the mechanism of the recoil reactions.

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Abstract  

127-year108Agm is an (n,) activation product of107Ag and is produced in nuclear power reactors. Due to the wide range of reported values for the o 0 cross section of the107Ag(n,)108Agm reaction new measurements were made—resulting in a o 0 value of 0.477±0.033 barn, and an I value of 0.80±0.15 barn. The environmental importance of the110Agm and108Agm radionuclides is discussed.

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Abstract  

The feasibility of measuring total body carbon (TBC) based on prompt-gamma activation analysis (PGAA) of the human body was examined. Preliminary analyzes for 33 healthy pre-menopausal women indicated a range of TBC values (7.1±4.4 kg) which translated to 17.1±6.5 kg body fat (27.9%±7.9% of body weight). An advantage of the PGAA measurement is that fat mass can be obtained simultaneous with that of total body protein mass, both indices serving as useful body composition markers of the nutritional status.

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Abstract  

The hydrogen concentration for the reference material low-alloy steel was estimated using prompt gamma neutron activation analysis. The hydrogen concentration had a range of 0.91–1.14 mg/kg as measured by the prompt gamma activation method but the reference value was about 1.0 mg/kg as measured by the ICP/AES method. The relative error appeared to be 14% and the differences showed as the background by blank. The standard reference material (NIST SRM) was used for the analytical control.

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Abstract  

Different methodologies of neutron activation analysis (NAA) are now available at the Technological and Nuclear Institute (Sacavém, Portugal), namely Compton suppression, epithermal activation, replicate and cyclic activation, and low energy photon measurement. Prompt gamma activation analysis (PGAA) will be implemented soon. Results by instrumental NAA and PGAA on environmental and nutritional samples are discussed herein, showing that PGAA — carried out at the Institute of Isotope Research (Budapest, Hungary) — brings about an effective input to assessing relevant elements. Sensitivity enhancement in NAA by Compton suppression is also illustrated. Through a judicious combination of methodologies, practically all elements of interest in pollution and nutrition terms can be determined.

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