Massimiliano Clemenza

Measurement of airborne 131I, 134Cs and 137Cs due to the Fukushima reactor incident in Milan (Italy)

After the earthquake and the tsunami occurred in Japan on March 2011, four of the Fukushima reactors had released in air a large amount of radioactive isotopes that diffused all over the world. The presence of airborne (131)I, (134)Cs, and (137)Cs in air particulate due to this accident were detected and measured in the Low Radioactivity Laboratory operating in the Department of Environmental Sciences of the University of Milano-Bicocca. The sensitivity of the detecting apparatus is of 0.2xa0uBq/m(3) of air. Concentration and time distribution of these radiocontaminations ranging from a few to 400xa0uBq/m(3) for the (131)I and of a few tens of uBq/m(3) for the (137)Cs and (134)Cs.

A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores.

Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10(-13)-10(-6)xa0g, improving previous results of 1-3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%.

Assessing the geochemical fingerprint of the 2010 Eyjafjallajökull tephra through instrumental neutron activation analysis: a trace element approach

The first characterization by INAA of the tephra erupted during the most explosive phase of the 2010 Eyjafjallajökull (Iceland) eruption is here presented. To evaluate the homogeneity of the tephra and fragmentation processes not only bulk samples were considered, but also other grain size fractions and previously published data. Concentrations of 42 elements were determined. Specific attention was given to incompatible elements, which appeared to be the most significative in order to define a geochemical fingerprint of the event.

The Medical Mystery of Napoleon Bonaparte An Interdisciplinary Expose

Napoleon Bonaparte (1769 to 1821) is one of the most studied historical figures in European history. Not surprisingly, amongst the many mysteries still surrounding his person is the cause of his death, and particularly the suspicion that he was poisoned, continue to intrigue medical historians. After the defeat of the Napoleonic Army at the battle of Waterloo in 1815, Napoleon was exiled to the small island of Saint Helena in the South Atlantic, where he died 6 years later. Although his personal physician, Dr François Carlo Antommarchi, stated in his autopsy report that stomach cancer was the cause of death, this diagnosis was challenged in 1961 by the finding of an elevated arsenic concentration in one of Napoleons hair samples. At that time it was suggested that Napoleon had been poisoned by one of his companions in exile who was allegedly supported by the British Government. Since then Napoleons cause of death continues to be a topic of debate. The aim of this review is to use a multidisciplinary approach to provide a systematic and critical assessment of Napoleons cause of death.

Cryoconite as a temporary sink for anthropogenic species stored in glaciers

Cryoconite, the typical sediment found on the surface of glaciers, is mainly known in relation to its role in glacial microbiology and in altering the glacier albedo. But if these aspects are relatively well addressed, the same cannot be said about the geochemical properties of cryoconite and the possible interactions with glacial and peri-glacial environment. Current glacier retreat is responsible for the secondary emission of species deposited in high-altitude regions in the last decades. The role played by cryoconite in relation to such novel geochemical fluxes is largely unknown. Few and scarce observations suggest that it could interact with these processes, accumulating specific substances, but why, how and to what extent remain open questions. Through a multi-disciplinary approach we tried to shed lights. Results reveal that the peculiar composition of cryoconite is responsible for an extreme accumulation capability of this sediment, in particular for some, specific, anthropogenic substances.

Determination of Th, U and K contamination in materials used in a low background detector by nuclear measures

In a low background detector high contamination of U, Th and K in the materials used couldnt be accepted. All materials furnished should be tested and measures optioned have a sensibility of 10−11−10−12g/g. Such measures need an adequate irradiation time and flux. An optimum cooling time and other parameters should be optimised in order to reach the goal. Analysis are made by Neutron Activation Analysis (NAA) while analysis of the natural gamma activity are made by long time measures in a low background detector.

Neutron activation analysis on sediments from Victoria Land, Antarctica: multi-elemental characterization of potential atmospheric dust sources

The elemental composition of 40 samples of mineral sediments collected in Victoria Land, Antarctica, in correspondence of ice-free sites, is presented. Concentration of 36 elements was determined by instrumental neutron activation analysis, INAA. The selection of 6 standard reference materials and the development of a specific analytical procedure allowed to reduce measurements uncertainties and to verify the reproducibility of the results. The decision to analyze sediment samples from Victoria Land ice-free areas is related to recent investigations regarding mineral dust content in the TALos Dome ICE core (159°11′E; 72°49′S, East Antarctica, Victoria Land), in which a coarse local fraction of dust was recognized. The characterization of Antarctic potential source areas of atmospheric mineral dust is the first step to identify the active sources of dust for the Talos Dome area and to reconstruct the atmospheric pathways followed by air masses in this region during different climatic periods. Principal components analysis was used to identify elements and samples correlations; attention was paid specially to rare earth elements (REE) and incompatible/compatible elements (ICE) in respect to iron, which proved to be the most discriminating elemental groups. The analysis of REE and ICE concentration profiles supported evidences of chemical weathering in ice-free areas of Victoria Land, whereas cold and dry climate conditions of the Talos Dome area and in general of East Antarctica.

Ultra Sensitive Neutron Activation Measurements of {sup 232}Th in Copper

Copper, thanks to its low content in radioactive contaminations, is a material widely used for shielding, holders and other objects close to the sensitive parts of the detectors in many experiments in rare event physics. This implies that tools able to reach sensitivity of the order of <10−12 gram of contaminants per gram of copper are of crucial importance. A methodology based in Neutron Activation Analysis (NAA) has been developed to obtain an extremely high sensitivity in the analysis of 232Th in copper samples. A detection limit of 5×10−13u2009g 232Th/g Cu has been achieved through the irradiation of 200 g of copper sample which subsequently was radio‐chemically concentrated using nitric acid and then actinide resin from Eichrom Inc. Several elutions were performed with various inorganic acids to concentrate the 232Th activation product (233Pa) from the copper matrix and to also eliminate the radioactive background induced by the neutron bombardment to reach higher sensitivity.

Fuel burnup analysis of the TRIGA Mark II reactor at the University of Pavia

Abstract A time evolution model was developed to study fuel burnup for the TRIGA Mark II reactor at the University of Pavia. The results were used to predict the effects of a complete core reconfiguration and the accuracy of this prediction was tested experimentally. We used the Monte Carlo code MCNP5 to reproduce system neutronics in different operating conditions and to analyze neutron fluxes in the reactor core. The software that took care of time evolution, completely designed in-house, used the neutron fluxes obtained by MCNP5 to evaluate fuel consumption. This software was developed specifically to keep into account some features that differentiate low power experimental reactors from those used for power production, such as the daily ON/OFF cycle and the long fuel lifetime. These effects can not be neglected to properly account for neutron poison accumulation. We evaluated the effect of 48xa0years of reactor operation and predicted a possible new configuration for the reactor core: the objective was to remove some of the fuel elements from the core and to obtain a substantial increase in the Core Excess reactivity value. The evaluation of fuel burnup and the reconfiguration results are presented in this paper.

Low-background neutron activation analysis: a powerful tool for atmospheric mineral dust analysis in ice cores

AbstractnThe application of instrumental neutron activation analysis (INAA) for multi-elemental analysis of samples of extremely reduced mass such as dust samples extracted from ice cores requires specific efforts towards the development of a “low level counting” analytical technique. An analytical protocol specifically designed for this kind of samples, based on low-background INAA (LBNAA) is here presented. A first application of the method was successfully performed on samples from the new alpine firn core NextData-LYS12. Sub-ng detection limits were reached for many elements. According to this point the technique is also potentially suitable to be applied to polar ice core samples.