Photon-activation analysis of standard rocks using an automatic .GAMMA.-ray counting system with a micro-robot.

Yoshida, Takeyoshi; Masumoto, K.; Aoki, Kenichiro

doi:10.2465/ganko1941.81.406

Cited by 14 publications

(2 citation statements)

References 25 publications

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“…Therefore, photon activation data of Hasenaka et al (1993) determined at Tohoku University were used for all such samples. The analytical procedures and uncertainties were shown in Yoshida et al (1986). The analytical uncertain-ties for isotopes are directly quoted for each sample.…”

Section: Brief Sample Description and Analytical Methodsmentioning

confidence: 99%

Sr, Nd, and Pb isotopic and trace element geochemical constraints for a veined-mantle source of magmas in the Michoacan-Guanajuato Volcanic Field, west-central Mexican Volcanic Belt

Verma¹,

Hasenaka²

2004

Geochem. J.

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This study reports new geochemical and radiogenic isotope data for Pliocene to Holocene (<2.8 Ma) alkaline (trachybasalt, basaltic trachyandesite, and trachyandesite) as well as subalkaline (basalt to dacite) volcanic rocks from the Michoacán-Guanajuato volcanic field (MGVF), located in the west-central part of the Mexican Volcanic Belt (MVB). There is no clear correlation of most geochemical parameters with differentiation indicators such as SiO 2. The rare-earth elements show light-REE enrichment, flat heavy-REE pattern, and absence of Eu anomaly. Depletion of Nb as compared to large ion lithophile elements such as Ba is observed for most rocks, probably suggesting involvement of subducted Cocos or Rivera plate. However, other HFSE such as Zr and Ti and key trace elements such as B and Be, and isotopic data do not support this conclusion. In most binary plots, the MGVF data lie at mantle compositions toward the lower end of subduction-input parameters, as is the case of magmas from well-known rifts; this contrasts with the data for subductionrelated Central American Volcanic Arc (CAVA) rocks that clearly show high values of subduction input. The average isotopic ratios of the MGVF rocks show the following ranges:

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Section: Brief Sample Description and Analytical Methodsmentioning

confidence: 99%

Sr, Nd, and Pb isotopic and trace element geochemical constraints for a veined-mantle source of magmas in the Michoacan-Guanajuato Volcanic Field, west-central Mexican Volcanic Belt

Verma¹,

Hasenaka²

2004

Geochem. J.

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“…As pelitic migmatites are fine grained heterogeneous rocks, different facies of pelitic migmatites including leucosome and melanosome were analyzed. The compositions of bulk rocks for major, trace and rare earth elements (REE) were determined by means of X ray fluorescence analysis, photon-activation analysis (Yoshida et al, 1986), and inductively coupled argon plasma emission spec trophotometry (Tagiri, et al, 1989), respec tively. Analyzed rocks were put into three metamorphic groups according to the metamor phic zones A + B + C, D and E, three granitoid groups of zone D migmatites, cordierite tonalites and biotite tonalites.…”

Section: Bulk Rock Chemistry Of Pelitic Metamorphic Rocks and Granitoidsmentioning

confidence: 99%

Anatexis and chemical evolution of pelitic rocks during metamorphism and migmatization in the Hidaka metamorphic belt, Hokkaido.

1989

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The southernmost Hidaka metamorphic belt consists mainly of cordierite tonalite intrusions and pelitic metamorphic rocks ranging from the greenschist to the granulite facies. Anatectic migmatites are common in the higher amphibolite and granulite facies zones. Compositional changes in major, rare earth elements and some other trace metals are so small that they are undetectable among the pelitic metamorphic rocks of zones A + B + C and D, but they are large enough to be detected in the higher am phibolite (zone D) to the granulite facies rocks (zone E). The enrichment of Fe, Mg, Na, Eu, and Sc, and the depletion of K, P, La, Ce, Nd, Cs and Rb are statistically significant in pelitic granulites, while heavy REEs are very variable. The chemical variation of pelitic granulite was derived from the accumulation of plagioclase +garnet. This suggests that more than 50-60% of the total volume of pelitic granulite was melted to produce a large amount of tonalitic magma, leaving pelitic granulite as a restite.Migmatites of the higher amphibolite facies are anatexites, and their K, P, Cs, Rb and light REE content is the same as that of lower grade metamorphic rocks. Migmatites of the higher amphibolite facies melted incipiently to segregate only a small amount of melt, and could not produce a large magmatic mass such as the cordierite tonalites.Cordierite tonalites are S-type granites, and their major elements, Cs, Rb and light REE concentra tions are similar to those of lower grade metamorphic rocks. The chemical variation of cordierite tonalites is explained by the extraction of plagioclase +garnet from a tonalitic magma and the variation of original sedimentary rocks. The small chemical difference between the cordierite tonalites and the lower grade metamorphic rocks suggests that the former was derived from a massive melting of meta pelites or that much of the restite is retained. The material migration among higher amphibolite facies rocks, pelitic granulites, migmatites and cordierite tonalites took place through mineral /melt interac tion in the lower crust.

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Photon Activation Analysis

Segebade

Weise

Lutz³

2000

Encyclopedia of Analytical Chemistry

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From the large number of analytical methods, activation analysis techniques are the only ones which are based upon nuclear reaction. The material sample studied is exposed to high‐energy radiation which can be partly absorbed by a nucleus in the sample. Thus the nucleus is excited to a high energy level which can decay through quasi‐prompt emission of a nuclear particle or photon. The product nuclide produced is mostly radioactive, and so emits delayed radiation. Both this and the aforementioned prompt radiation can be measured using appropriate radiation detectors. By evaluating the energy and the count rate of the particles detected, qualitative and quantitative analyses of the target material under study can be performed. Thus it is clear that elements only, not chemical species, can be determined directly. A large variety of particles can be used for activation, namely uncharged ones (neutrons, photons) or charged particles like protons, deuterons, tritons and even heavier ones. Mostly thermal neutrons from nuclear research reactors are used since this technique offers the highest average analytical sensitivity. During photon activation, the target nucleus is activated by photonuclear reaction. This is induced to “normal” material at high energies, usually not below about 10 MeV. The photonuclear reaction data of the elements suggest an activation energy around 30 MeV with respect to analytical sensitivity and interfering reactions, respectively. This energy is best achievable with bremsstrahlung sources like high‐power linear accelerators or microtrons. Favorable irradiation parameters are: 30 MeV electron energy at 100–150 µA mean electron beam current. With the help of suitable radiation spectrometers, e.g. high‐resolution germanium detectors connected to appropriate pulse processing electronics, photon (γ or characteristic X‐ray) spectra can be taken by which simultaneous multicomponent analyses can be carried out without chemical separations, sometimes even nondestructively. Moreover, partly extreme sensitivities can be achieved, and some elements can be analyzed whose determinations are difficult or impossible using other techniques, e.g. light elements like carbon, nitrogen, oxygen and fluorine. A further advantage is the relative freedom from blanks in many cases; after bremsstrahlung exposure, undesirable surface contaminants can be removed from the sample, and the recontamination that eventually occurs is inactive, and thus can be disregarded. Since the activation and measuring process is independent of the chemical status of the component studied, a large variety of matrices can be analysed. Photon activation has been applied in several areas including: geo‐ and cosmochemistry; environmental, biological and medical science; industrial product and high‐purity material analysis; archaeological and forensic science; certification of reference materials. The disadvantages of the method are common to all activation analysis techniques, e.g. the instrumental equipment costs. The cost of a high‐performance germanium spectrometer is about US $30 000, and this does not include the permanent costs of maintenance and liquid nitrogen supply. Also, additional personnel qualifications are required for radioactive laboratory work. Finally, the handling of radioactive waste unavoidably produced during activation analysis might be problematic in some cases.

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Photon-activation analysis of standard rocks using an automatic .GAMMA.-ray counting system with a micro-robot.

Cited by 14 publications

References 25 publications

Sr, Nd, and Pb isotopic and trace element geochemical constraints for a veined-mantle source of magmas in the Michoacan-Guanajuato Volcanic Field, west-central Mexican Volcanic Belt

Sr, Nd, and Pb isotopic and trace element geochemical constraints for a veined-mantle source of magmas in the Michoacan-Guanajuato Volcanic Field, west-central Mexican Volcanic Belt

Anatexis and chemical evolution of pelitic rocks during metamorphism and migmatization in the Hidaka metamorphic belt, Hokkaido.

Photon Activation Analysis

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