Biomedical subjects

L Garlati

Publications and source records attributed to L Garlati.

5 recordsLinked to original sources

PubMed2005

Secondary photon fields produced in accelerator-based sources for neutron generation.

Neutrons can be produced with low-energy ion accelerators for many applications, such as the characterisation of neutron detectors, the irradiation of biological samples and the study of the radiation damage in electronic devices. Moreover, accelerator-based neutron sources are under development for boron neutron capture therapy (BNCT). Thin targets are used for generating monoenergetic neutrons, while thick targets are usually employed for producing more intense neutron fields. The associated photon field produced by the target nuclei may have a strong influence on the application under study. For instance, these photons can play a fundamental role in the design of an accelerator-based neutron source for BNCT. This work focuses on the measurement of the photon field associated with neutrons that are produced by 4.0-6.8 MeV protons striking both a thin 7LiF target (for generating monoenergetic neutrons) and a thick beryllium target. In both cases, very intense photon fields are generated with energy distribution extending up to several MeV.

Beryllium↗

PubMed2005

A very low-background gamma-ray counting facility in the Baradello underground laboratory.

An underground station for the measurement of low-level radioactivity is in operation in Northern Italy in the town of Como under the Baradello hill. The rock cover is -300 m water equivalent. This paper reports about the preliminary measurements carried out to characterise the site of the Baradello hill and the installation of a high-purity Ge detector with a radio-pure copper shielding. Features and levels of the achieved background are reported and discussed, in comparison with other above ground and underground low-radioactivity stations. Sensitivities to radioactivity in typical environmental matrices are evaluated, confirming the very low-gamma background attained in the laboratory.

Air Pollutants, Radioactive↗

PubMed2004

Uncertainties evaluation for electrets based devices used in radon detection.

In recent years uncertainty evaluation in measurements has achieved great importance. National and international standards offer guidelines to evaluate uncertainties, but these procedures are, until now, not well understood by the operators. This is because of the fact that a detailed uncertainty evaluation is not an easy operation and a standard rule to apply in all cases is not available. Every measurement procedure has its own uncertainty evaluation. In this work, attention is focused upon the electret ion chambers (EIC), widely used in radon concentration measurements. Measurements of gamma radiation sensitivity are performed in a secondary standard calibration laboratory and measurement of radon concentration sensitivity is performed in a radon chamber 0.8 m3 in volume. Raw data are analysed to evaluate the calibration factors and the combined uncertainties are determined. The aim of the work is to give a practical method to assess the uncertainty of a radon measurement.

Calibration↗

PubMed2004

Characterization of an underground site in Northern Italy in view of low radioactivity measurements.

A low background station for the measurement of low level radioactivity is under development in Northern Italy. The rock cover is about 300 m water equivalent. We report and discuss measurements of radon concentration in air and of gamma, muon and neutron fluxes performed in the neighborhood of the station site. We present and apply a simple analytical model capable to disentangle the contribution to the measured gamma activities due to 222Rn in air from the one due to 238U and its daughters in the rocks.

Environmental Monitoring↗

PubMed2004

Uncertainty evaluation of radon measurements with LR115 detector and spark counter.

To evaluate the uncertainties for nuclear track detectors used in radon measurements, a full understanding is required of the physical phenomena involved and the behaviour of the instruments utilised in the measuring process. As it concerns the LR115 nuclear track detector, an overall evaluation of uncertainty was given. It was assessed taking into account different contributions and determining their relative weights. Since such detectors are often read by a spark counter device, a model to describe its behaviour was developed and a saturation factor was estimated. Its expression and its associated uncertainty are given. Hence, it has been possible to draw a calibration curve, in which all the uncertainty sources have been considered.

Air Pollutants, Radioactive↗