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Alongside with the development of Neutron Capture Therapy (NCT) and the use of thermal neutrons for radiotherapeutic purposes, many efforts have been devoted to the characterization of the beam in order to optimize therapy procedures. Reliable dose measurements should be able to determine the various (neutrons and photonic) components of the mixed beam usually employed for therapy. This paper studies the effect of additives such as Boric and Gadolinium nuclei on the sensitivity of neutron organic (alanine and ammonium tartrate) dosimeters analyzed through Electron Spin Resonance (ESR) technique. These dosimeters were exposed to a mixed (neutron-gamma) field mainly composed of thermal neutrons. The choice of 10B and 64Gd as nuclei additives is due to their very high capture cross section for thermal neutrons. Also, after the nuclear reaction with thermal neutrons are emitted particles, which in turn release their energy in the vicinity of the reaction site. The irradiation with mixed (neutron-gamma) field were performed within the thermal column of the TRIGA reactor, University of Pavia. Dosimeters readout was performed through the Electron Spin Resonance (ESR) spectrometer Bruker ECS106 located at the Laboratory of Dosimetry ESR / TL of the Department of Physics and Chemistry - University of Palermo. We found that the addition of Gadolinium allows to largely increase the sensitivity of the dosimeters for thermal neutrons. In particular, a low concentration (5% by weight) of gadolinium oxide leads to an improvement of the sensitivity of neutrons more than 10 times. In addition, for this low content of gadolinium the photon tissue equivalence is not heavily reduced. This experimental analyses are compared with computational analyses carried out by means of Monte Carlo simulations performed with the MCNP (Monte Carlo N-Particle) transport code. A good agreement was observed for alanine dosimeters.

Gel dosimeters for three-dimensional mapping of radiotherapy doses were introduced at Yale University in the mid-1980’s. Soon after, R&D in this field also started in Italy. Early work was done at the Istituto Superiore di Sanità, and at the Universities of Pisa and Milan. Several institutes now collaborate on this topic with support from the Italian Ministry for University and Research (MIUR) through Grant PRIN SNALEM2010 “Development and application of new materials for ionizing radiation dosimetry”. This presentation describes this research, which aims at developing new formulations of hydrogel matrices with improved characteristics of stability, sensitivity and spatial resolution compared to those of earlier Fricke-gel and polymer-gel systems. An additional goal of our research is the simplification of the manufacturing processes in order to facilitate the diffusion of this technology and its transition from the bench to the bedside.

The use of neutrons for cancer treatments has stimulated the research for beam characterization in order to optimize the therapy procedures in Neutron Capture Therapy (Altieri, 2008). Several research laboratories have shown an increasing interest aimed at extending the applicability of Electron Spin Resonance (ESR) dosimetry to radiotherapy with different types of radiation beams. In particular, ESR spectrometry provides absorbed dose measurements through the detection of the stable free radicals produced by ionizing radiations. The ESR dosimetric method has many advantages such as simple and rapid dose evaluation, the readout procedure is non-destructive, linear response of many organic and inorganic compounds (Baffa,2014). In this work we study the response of phenolic compounds with and without gadolinium addition for electron spin resonance (ESR) dosimetry exposed to a gamma and mixed (n, gamma) field mainly composed of thermal neutrons. The compound IRGANOX 1076 phenol gives a phenoxy radical stabilized by the presence of two bulky groups [3]. Moreover, its high molecular weight, the low volatility and the compatibility with the dosimeter binding material (paraffin) are advantages with respect to lower molecular weight phenols. In this work we report the ESR investigation of phenols pellets and thin films with and without Gd2O3 (5% by weight) exposed in the thermal column of the Triga Mark II reactor of LENA of Pavia. Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The choice of Gd as the additive nucleus has been made because we are interested in applications for mixed field (neutrons/photons) Gd-ESR dosimetry has an high neutron capture cross section and, furthermore, the high LET secondary particles release their energy entirely in the dosimeter. The low content of gadolinium guarantees a good tradeoff between the sensitivity to thermal neutrons. However, the use of gadolinium reduces or abolishes tissue equivalence because of its high atomic number (Marrale, 2015). The dosimetric features of these ESR dosimeters have been investigated. In particular, we analyzed the ESR spectra of these compounds and their dependence on microwave power and modulation amplitude, their response after gamma and neutron irradiations, the detection limits for both beam typologies, signal stability after irradiation. The results of ESR experiments are compared with Monte Carlo simulations aimed at obtaining information about the total dose measured by means of ESR dosimeters.

Sewage sludge, a residual product of wastewater treatment, still contains a substantial amount of energy, and its disposal is one of the most important cost factors (up to 30-50% of the total operational cost) in the balance sheets of wastewater treatment facilities. In this study, microwave-controlled pyrolysis of digested urban waste sludge was applied for the production of oil and (Syn)gas, that were afterwards characterized and compared to mainstream alternative fuels (biodiesels). An energetic balance of the process is performed and described. A key factor in deciding the positivity of the energetic balance (and therefore the economic validity of the process) is the correct "tuning" of the microwave source device: based on the experiments illustrated, an energy-positive recovery of resources on one side, and considerable reduction of sludge volumes (affecting ultimate sludge disposal costs) may be achieved with the proposed technology., Proceedings of the 24th European Biomass Conference and Exhibition, 6-9 June 2016, Amsterdam, The Netherlands, pp. 1270-1274

In the last decades several research laboratories have shown an increasing interest aimed at extending the applicability of Electron Paramagnetic Resonance (EPR) dosimetry to radiotherapy with different types of radiation beams. EPR is a spectroscopic method for investigating the structure and dynamics of such paramagnetic species. Free radicals are known to be produced when a compound is irradiated with ionizing radiations. The concentration of radiation-induced free radicals is proportional to the energy released inside in the medium and this allows for dosimetric measurements through EPR technique. The use of alanine as a dosimetric material gave the possibility to apply EPR spectroscopy for high-dose standardization and dose control in radiation processing (Marrale 2016). The EPR dosimetric method has many advantages such as simple and rapid dose evaluation, the readout procedure is non-destructive, linear response of many organic and inorganic compounds. EPR detectors show a behavior that suggest possible applications for various kinds of beams used for radiation therapy. Nowadays, the most widely used organic compound as a dosimeter is the alanine. However, many researches are in progress with the aim at improving sensitivity of EPR dosimetry for doses much smaller than 1 Gy. More sensitive materials than alanine are needed to make the EPR dosimeter competitive with other dosimetry systems. Our research group has started an investigation of the EPR response of some phenols compounds for possible EPR dosimetric applications suitable features, such as high efficiency of radiation-matter energy transfer and radical stability at room temperature. Phenols are compounds possessing a benzene ring attached to a OH group. After irradiation the final product is a stable phenoxy radical. The stability of such radical can be improved by adding other alkyl chains which can be attached to the benzene ring. The phenol octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate gave interesting results. Moreover, its high molecular weight, the low volatility and the compatibility with the dosimeter binding material (wax) are advantages with respect to lower molecular weight phenols. In this work we report the EPR investigation of phenols exposed to clinical photon and electron beams (Gallo, 2016). The dosimetric features of these EPR dosimeters (dependence on microwave power and modulation amplitude, their response after gamma and electron irradiations, dependence on beam type and energy, the detection limits for both beam typologies, signal stability after irradiation) were investigated and the results are reported.

Along with the Neutron Capture Therapy (NCT) development and with the use of thermal neutrons for radiotherapeutic purposes, many efforts have been devoted to the beam characterization in order to optimize the therapy procedures. Reliable dosimetric measurements should be able to determine the various components (neutronic and photonic) of the mixed beam usually employed for therapy [1]. We have studied the effect of the additive such as gadolinium and 10B-boric acid on the neutron sensitivity of alanine ESR dosimeters exposed to a gamma and mixed (n, gamma) field mainly composed by thermal neutrons. We have chosen both this additive nuclei because of their very high capture cross section to thermal neutrons. Furthermore, in the nuclear reaction with thermal neutrons particles, which in turn release their energy in the neighbourhood of the reaction site, are ejected [2]. We completed our study through a Monte Carlo simulation aimed at obtaining information about the reliability of this powerful tool in predicting the response enhancement achievable with the addition of gadolinium and 10B-boric acid in alanine dosimeters. These computational values obtained through simulation are compared with the experimental results.

""Long-term biological effects of low-dose radiation are little known nowadays and its carcinogenic risk is estimated on the assumption that the risk remains linearly proportional to the radiation dose down to low-dose levels. However in the last 20 years this hypothesis has gradually begun to seem in contrast with a huge collection of experimental evidences, which has shown the presence of a plethora of non-linear phenomena (including hypersensitivity and induced radioresistance, adaptive response, and non-targeted phenomena like bystander effect and genomic instability) occurring after low-dose irradiation. These phenomena might imply a non-linear behaviour of cancer risk curves in the low-dose region and question the validity of the Linear No-Threshold (LNT) model currently used for cancer risk assessment through extrapolation from existing high-dose data. Moreover only few information is available regarding the effects induced on cryopreserved cells by multi-year background radiation exposure, which might induce a radiation-damage accumulation, due to the inhibition of cellular repair mechanisms. In this framework, the multi-year EXCALIBUR (EXposure effeCts At Low doses of Ionizing radiation in Biological CultURes) experiment, funded by INFN-CNS5, has undertaken a multiscale approach investigation on the biological effects induced in in vitro and in vivo biological systems, in culture and cryopreserved conditions, as a function of radiation quality (X\\\/γ-rays, protons, He-4 ions of various energies) and dose, with particular emphasis on the low-dose region and non-linear phenomena, in terms of different biological endpoints. PACS 87.53.-j-Effects of ionizing radiation on biological systems. PACS 87.53.Ay-Biophysical mechanisms of interaction. PACS 87.53.Bn-Dosimetry\\\/exposure assessment. PACS 87.18.Gh-Cell-cell communication; collective behavior of motile cells""

This work investigated rubber-clay nanocomposites, in particular: filler-elastomer interface, multiscale clay organization in the rubber matrix, both in the absence and in the presence of carbon black, hybrid clay/carbon black filler network, dynamic-mechanical properties of raw and sulphur cured compounds. Studies performed with various techniques such as Electron Paramagnetic Resonance spin labelling, Solid State Nuclear Magnetic Resonance, Transmission Electron Microscopy and X-ray diffraction pattern allowed to observe a nice distribution and dispersion of the layered clay, with the development of filler-matrix interface. Composites were prepared with either intercalated or exfoliated organoclays, both in the absence and in the presence of carbon black, observing in the latter case the formation of a hybrid filler network formed by layered and spherical particles. Dynamic-mechanical investigations revealed that the replacement of a part of carbon black with an organoclay promotes a stronger filler-rubber interaction. The exfoliated organoclay is demonstrated as the ideal filler for compounds that have to explore a wide range of temperatures, as it gives rise to a better stability of properties.