Análise por activação com neutrões no RPI (II)

1. Na sequência do post anterior sobre análise por activação com neutrões, importa referir que, na determinação de certos elementos químicos – em especial os chamados metais de terras raras (cério, neodímio, lantânio...) e outros (zircónio, ruténio, molibdénio…) – é necessário corrigir os resultados do fenómeno dito de interferência de cisão nuclear, isto se a amostra contiver também urânio. A interferência decorre do seguinte: da cisão de átomos do urânio-235 presentes na amostra resulta a formação de nuclidos radioactivos que são idênticos aos que servem de base à determinação dos citados elementos químicos. A correcção da interferência consiste em subtrair aos valores “brutos” das concentrações a parte correspondente à cisão nuclear do urânio-235.

Esquema ilustrativo do fenómeno de interferência nuclear de cisão

no caso da análise do molibdénio numa amostra contendo urânio.

2. De entre os trabalhos produzidos nesta área, são de reter os seguintes:

[1] M.A. Gouveia, M.I. Prudêncio, M.C. Freitas, E. Martinho, J.M.P. Cabral: Interference from uranium fission products in the determination of rare earths, zirconium and ruthe­nium by instrumental neutron activation analysis in rocks and minerals. Journal of Radioanalytical and Nuclear Chemistry 114 (1987) 309

[2] E. Martinho, M.A. Gouveia, M.I. Prudêncio, M.F. Reis, J.M.P. Cabral: Factor for correcting the ruthenium interference in instrumental neutron activation analysis of barium in uraniferous samples. Applied Radiation and Isotopes 42 (1991) 1067

[3] E. Martinho, M.C. Freitas: On the fission interference correction and its dependence on the epithermal to thermal neutron flux ratio in thermal NAA of molybdenum. Biological Trace Element Research 71-72 (1999) 471

3. Segundo o Science Citation Index (Web of Knowledge), [1] foi o artigo mais citado:

Title: Rare earth and other trace and major elemental distribution in a pedogenic calcrete profile (Slimene, NE Tunisia)
Author(s): M.I. Prudêncio, M.I. Dias, J.C. Waerenborgh, F. Ruiz, M.J. Trindade, M. Abad, R. Marques, M.A. Gouveia
Source: CATENA  Volume: 87   Issue: 1   Pages: 147-156    Published: 2011

Title: UPPER CRETACEOUS CLAYEY LEVELS FROM WESTERN PORTUGAL (AVEIRO AND TAVEIRO REGIONS): CLAY MINERAL AND TRACE-ELEMENT DISTRIBUTION
Author(s): Marques Rosa; Isabel Dias M.; Isabel Prudêncio M.; Rocha F.
Source: CLAYS AND CLAY MINERALS  Volume: 59   Issue: 3   Pages: 315-327    Published: 2011

Title: Patterns of rare earth and other trace elements in different size fractions of clays of Campanian-Maastrichtian deposits from the Portuguese western margin (Aveiro and Taveiro Formations)
Author(s): Marques Rosa; Isabel Prudêncio M.; Isabel Dias M.; Roca F.
Source: CHEMIE DER ERDE-GEOCHEMISTRY  Volume: 71   Issue: 4   Pages: 337-347  Published: 2011

Title: Clay resources in the Nelas region (Beira Alta), Portugal. A contribution to the characterization of potential raw materials for prehistoric ceramic production
Author(s): Marques, R.; Jorge, A.; Franco, D.; Dias, M.I.; Prudêncio, M.I.

Source: CLAY MINERALS  Volume: 45   Issue: 3   Pages: 353-370   Published: 2010

Title: Chemical tracers of Lusitanian amphorae kilns from the Tagus estuary (Portugal)
Author(s): M.I. Dias a, M.I. Prudêncio, M.A. Gouveia, M.J. Trindade, R. Marques, D. Franco, J. Raposo, C.S. Fabião, A. Guerra
Source: JOURNAL OF ARCHAEOLOGICAL SCIENCE  Volume: 37   Issue: 4   Pages: 784-798    Published: 2010

Title: Soils in the semi-arid area of the El Melah Lagoon (NE Tunisia) - Variability associated with a closing evolution
Author(s): M.I. Prudêncio, M.I. Dias, F. Ruiz, J.C. Waerenborgh, J. Duplay, R. Marques, D. Franco, R. Ben Ahmed, M.A. Gouveia, M. Abad
Source: CATENA  Volume: 80   Issue: 1   Pages: 9-22   Published: 2010

Title: Geochemical signatures of Roman amphorae produced in the Sado River estuary, Lusitania (Western Portugal)
Author(s): M.I. Prudêncio, M.I. Dias, M.A. Gouveia, R. Marques, D. Franco, M.J. Trindade
Source: JOURNAL OF ARCHAEOLOGICAL SCIENCE  Volume: 36   Issue: 3   Pages: 873-883    Published: 2009

Title: Neutron activation analysis of archaeological materials: An overview of the ITN NAA laboratory, Portugal
Author(s): Dias M. I.; Prudêncio M. I.
Source: ARCHAEOMETRY  Volume: 49   Pages: 383-393    Part: Part 2   Published: 2007

Title: Biogeochemistry of trace and major elements in a surface environment (volcanic rock, soil, mosses, lichens) in the S. Miguel Island, Azores, Portugal
Author(s): Prudêncio M. I.
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY  Volume: 271   Issue: 2   Pages: 431-437    Published: 2007

Title: Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)
Author(s): M I Prudêncio, R Marques, L Rebelo, G T Cook, G O Cardoso, P Naysmith, S T Freeman, D Franco, P Brito, M I Dias
Source: RADIOCARBON  Volume: 49   Issue: 2   Pages: 1145-1151   Published: 2007

Title: Raw material sources for the Roman Bracarense ceramics (NW Iberian Peninsula)
Author(s): M. Isabel Prudêncio, M. Amália Sequeira Braga, Felisbela Oliveira, M. Isabel Dias, Manuela Delgado and Manuela Martins
Source: CLAYS AND CLAY MINERALS  Volume: 54   Issue: 5   Pages: 638-649   Published: 2006

Title: Instrumental neutron activation analysis in geochemistry: Emphasis on spectral and uranium fission product interferences
Author(s): Tshiashala MDA
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY  Volume: 265   Issue: 3   Pages: 511-514    Published: 2005

Title: Potential of radiochemical neutron activation analysis as a primary ratio method
Author(s): Polkowska-Motrenko H; Danko B; Dybczynski R
Source: CHEMIA ANALITYCZNA  Volume: 50   Issue: 1   Pages: 155-167   Published: 2005

Title: Analytical methods for the determination of ruthenium: The state of the art
Author(s): Balcerzak M
Source: CRITICAL REVIEWS IN ANALYTICAL CHEMISTRY  Volume: 32   Issue: 3   Pages: 181-226    Published: 2002

Title: Trace determination of lanthanides in metallurgical, environmental, and geological samples
Author(s): Rao TP; Biju VM
Source: CRITICAL REVIEWS IN ANALYTICAL CHEMISTRY  Volume: 30   Issue: 2-3   Pages: 179-220  Published: 2000

Title: New data on sixteen reference materials obtained by INAA
Author(s): Gouveia MA; Prudêncio MI
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY  Volume: 245   Issue: 1   Pages: 105-108    Published: 2000  

Title: Environmental control in the uranium mine Lagoa Real, Brazil
Author(s): Tagliaferro FS; Fernandes EAD; Sarries GA
Source: BIOLOGICAL TRACE ELEMENT RESEARCH  Volume: 71-2   Pages: 299-308    Published: 1999

Title: Determination of hafnium and zirconium in geological materials by neutron activation analysis
Author(s): Lins JP; Saiki M
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY  Volume: 216   Issue: 2   Pages: 199-201    Published: 1997

Title: ELEMENTAL CONCENTRATION DATA FOR USGS GEOCHEMICAL-EXPLORATION REFERENCE MATERIALS GXR-1 TO GXR-4 AND GXR-6
Author(s): M. A. Gouveia, M. I. Prudêncio, J. S. Barros, L. Morgado, J. M. P. Cabral
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES  Volume: 179   Issue: 1   Pages: 165-172    Published: 1994

Title: INTERFERENCE IN NEUTRON-ACTIVATION ANALYSIS OF ROCKS BY URANIUM FISSION
Author(s): K. S. Park, N. B. Kim, H. J. Woo, K. Y. Lee, Y. Y. Yoon, J. H. Lee

Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES  Volume: 168   Issue: 1   Pages: 153-161    Published: 1993

Title: INAA OF ZR, LA, CE AND ND IN GEOLOGICAL SAMPLES IN THE PRESENCE OF DIFFERENT URANIUM CONCENTRATIONS
Author(s): S. M. Al-Jobori, M. J. Al-Atia, M. Jalil, A. K. Hussien
Source: JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES  Volume: 139   Issue: 1   Pages: 31-36    Published: 1990

Nota: Registo para memória futura dos meus tetranetos.