Nucleonics

Lyon, W. S.; Ricci, E.; Ross, H. H.

doi:10.1021/ac60313a010

Cited by 10 publications

(2 citation statements)

References 34 publications

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“…Currently, screening of suspected paints is oriented to the detection of those containing greater than ~0.5% of lead. The accurate determination of lead at this level is not particularly difficult by a variety of methods, but they usually require time consuming manipulations such as dissolution prior to measurement, although Rasberry (1) has studied portable X-ray fluorescence analyzers developed specifically for use in screening, in situ, wall paint for lead.…”

Section: Resultsmentioning

confidence: 99%

“…If a nuclear reaction is induced in one of the sample elements by this radiation, at each photon energy k the reaction yield is proportional to the cross section a(k), given in cm1 2. The total yield in reactions per second is, then (11, 12), Y(E") = n j" N(En,k)a(k)dk (1) where n is the number of atoms of reacting element per cm2 of sample seen by the bremsstrahlung, and N(E0,k) is the spectrum function-i.e.. the number of photons of energy k, per unit energy k, which enter the sample per second. This function can thus be explicitly written as…”

Section: Bremsstrahlung Photon Energy Distributionmentioning

confidence: 99%

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Sensitivities for photon activation analysis with thick-target, 110-MeV electron bremsstrahlung

Ricci¹

1974

Anal. Chem.

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Recent reviews (1, 2) have described active progress in photon activation analysis (PAA). In particular, during the past few years, several authors have developed useful specific methods and determined elemental sensitivities, for a variety of bremsstrahlung production conditions (3)(4)(5)(6)(7)(8). Yet, most of this work involved the use of relatively thin electron targets (2-6 mm thick) and electron energies below 40 MeV. Only two groups reported photon-activation yield determinations with bremsstrahlung from 70-72 MeV electrons (7, 8). and none beyond this electron energy.The Oak Ridge Electron Linear Accelerator (ORELA) was designed with the main purpose of producing neutrons; these are used to determine cross sections of interest to the Liquid Metal Fast Breeder Reactor and other programs. The ORELA can accelerate electrons up to energies of 150-160 MeV. but normal operation-particularly during our experiments-has been at or near 110 MeV. Because of ORELA's main application, the electrons-whose energy is seldom lowered below 100 MeVare made to impinge on a massive (3.03-cm thick) tantalum target. The beam power can easily be raised to a maximum of 50 kVV-approximately equivalent to a 350 µ current-but a beam of 30 kW or less is frequently used, as was the case in our work. The beam is pulsed, and to reach a 30to 50-kW power at 100-140 MeV, typical conditions are 800 pulses per second of 20-to 50-nsec duration and 10to 15-A peak intensity.These somewhat rigid operation conditions-quite different from those characterizing most PAA experiments to date-govern bombardments at the ORELA. Also, economic efficiency reasons call for simultaneous use of the accelerator for both PAA and neutron physics experiments. Consequently, two important tasks became clear early in our work. First, to design a pneumatic system that would convey the sample-with the accelerator on, and while being used for other experiments-to a position where it could be cooled and bombarded homogeneously with ORELA's bremsstrahlung. Second, to determine experimentally PAA sensitivities and interferences for ORE-LAY conditions, and to put them in perspective with values from other authors (3-8), in light of differences between the bremsstrahlung photon-energy distributions involved. For the first task, we designed an original system (9) . which we describe in detail and assess elsewhere (10). This paper concerns experiments and discussions relative to the second task.

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Section: Resultsmentioning

confidence: 99%

Section: Bremsstrahlung Photon Energy Distributionmentioning

confidence: 99%

Sensitivities for photon activation analysis with thick-target, 110-MeV electron bremsstrahlung

Ricci¹

1974

Anal. Chem.

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Analyse von stabil-isotop markierten Verbindungen

Schmidt

1974

Messung Von Radioaktiven Und Stabilen Isotopen

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Analysis of traces at ORNL's new high-flux neutron activation laboratory

Ricci

Handley

Dyer

1974

J. Radioanal. Chem.

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A new facility for neutron activation analysis (3SAA) with a thermal flux of 5 x 10 cm" sec" has recently been installed at the ORNL High Flux Isotope Reactor. This unusually high flux together with a small computer and necessary software for 7-ray spectrometry with a Ge(Li) detector makes possible shorter irradiation, faster data analysis, and more economical analysis than is possible using more conventional facilities. We discuss features and tests of the new High-Flux NAA Laboratory, as well as results of comparator and absolute HAA of several types of environmental matrices for mercury, cadmium, bromine, arsenic, chlorine and sodium. WEW ANALYTICAL TRENDS AMD THE HEW LABORATORYThe present need in biomedical and environmental sciences is for determination of many trace elements in a variety of samples. Thus, one approach is to develop methods for multielement analysis at reasonable cost.** In such determinations, however, quality cannot be sacrificed for speed. Our aim is to develop techniques (preferably instrumental) for simultaneous analysis of numerous trace elements while concurrently reducing the price of quality serial analyses for specific elements by non-destructive methods.The new High-Flux BAA Laboratory can meet these demands. The very high thermal neutron flux permits determination of elements with extreme sensitivity, while also requiring shorter irradiations. Thus, a larger number of samples ca*i us irradiated than would be possible at a lower flux. Figure 1 shows the new facility in detail; particularly, the pneumatic transfer system. Hot-sample handling cell and counting room are provided along

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Nucleonics

Cited by 10 publications

References 34 publications

Sensitivities for photon activation analysis with thick-target, 110-MeV electron bremsstrahlung

Sensitivities for photon activation analysis with thick-target, 110-MeV electron bremsstrahlung

Analyse von stabil-isotop markierten Verbindungen

Analysis of traces at ORNL's new high-flux neutron activation laboratory

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