Biomedical subjects

M P Rubio Montero

Publications and source records attributed to M P Rubio Montero.

6 recordsLinked to original sources

PubMed2006

Multi-technique characterization of a nuclear bomb particle from the Palomares accident.

A January 1966 accident dispersed Pu and other nuclear bomb materials in the vicinity of Palomares, a village in southeastern Spain. Radioactive particles were identified in a soil sample collected in 1998 and analytical results obtained from one of the isolated particles are presented here. Isolation of the particle was performed using gamma-ray spectrometry and imaging plates. Scanning electron microscopy with X-ray microanalysis revealed the presence of U and Pu as well as Pb and Fe in the particle of approximately 10microm diameter. Radioisotopes of U, Pu, and Am were quantified using radiometric methods, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry. The elevated (235)U/(238)U atom ratio indicates enriched U, and the Pu atom ratios are consistent with weapons-grade material. This work demonstrates that the analysis of individual particles provides information not available through bulk sample analysis.

Mass Spectrometry↗

PubMed2001

Activity of (239 + 240)Pu and 238Pu in atmospheric deposits.

Radioactive concentrations of (239 + 240)Pu and 238Pu were determined in rainwater samples collected at Badajoz (in a semi-arid zone in the south-west of Spain) from 1992 to 1996. Total plutonium deposition (including dry and wet deposition) was investigated during dry and wet periods. Anomalously high depositions of (239 + 240)Pu ((6.8 +/- 0.4) mBq/m2) and 238Pu ((2.2 +/- 0.2)mBq/m2) were found in the second-half of 1995. The 238Pu/(239 + 240)Pu activity ratio (0.32 +/- 0.04) obtained for that sample was higher than in global fallout.

Dose-Response Relationship, Radiation↗

PubMed1999

Radioactivity in bottled mineral waters.

Consumption of bottled mineral water is a growing practice and is sometimes a necessity rather than a choice. In this work, a study of the radioactive content of a wide selection of commercial bottled mineral waters for human intake was carried out. The origins of the analyzed waters were very different, coming from various locations in France, Portugal and Spain. Their total alpha and beta activity concentrations were determined and also gamma spectrometry was used to detect some radionuclides. In some cases, the waters presented high values of the total alpha and beta activity concentrations surpassing the reference levels established by the CSN, the Spanish. Regulatory Organization. In these cases, a determination of uranium and 226Ra was also performed by using low-level liquid scintillation counting. The results revealed a strong correlation between radioactive content and dry residue, and lead one to conclude that high radioactive content is mainly related to the mineralization in waters of underground origin.

Alpha Particles↗

PubMedDate not supplied

Fast adaptive alpha-particle spectrum fitting algorithm based on genetically estimated initial parameters.

This work presents a high performance procedure for the unfolding of alpha particle spectra based on genetically estimated initial parameters. The process starts with the search for a globally optimized set of fitting parameters from a population of randomly generated solutions. The solution found with the genetic algorithm is then transferred to a Levenberg-Marquardt procedure in order to calculate the covariance matrix for the fit. The proposed method provides the set of final parameters and their associated standard deviation. Several fitted spectra demonstrate the effectiveness of the proposed method in searching for and finding initial conditions in a fast and automated process.

Algorithms↗

PubMedDate not supplied

Study of inhomogeneities in sources prepared for alpha-particle spectrometry using scanning probe microscopy.

For high-resolution alpha-particle spectrometry, sources of high quality must be prepared by methods giving the thinnest and most homogeneous deposit possible on a suitable support. Surface characteristics of several types of alpha-particle sources were studied using a scanning probe microscope. Major inhomogeneities were observed, which means that the materials and techniques used for thc preparation of sources must be improved.

Journal Article↗

PubMedDate not supplied

The effect of energy losses in alpha-particle sources on the shape of peaks in spectra obtained with wide-angle geometry.

It has been shown that two main effects contribute to the tailing in the shapes of alpha-peaks measured with silicon detectors: the ionization loss in the source and the response of the detector. We studied the relative influence of both factors in measurements with small source-to-detector distances. The computer simulation code 'the stopping and range of ions in matter' has been used to obtain the energy spectra of a 226Ra source as a function of the source thickness. Results of the simulation are compared with experimental measurements.

Journal Article↗