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The production of medical radionuclides is one of the research activities carried out in the framework of the SPES (Selective Production of Exotic Species) project under the completion stage at the Legnaro National Laboratories of the National Institute for Nuclear Physics (INFN-LNL). The heart of SPES is the 70-MeV proton cyclotron having a dual-beam extraction, installed and commissioned in a new building equipped with ancillary laboratories currently under construction. The SPES main goal is the realization of an advanced ISOL (Isotope Separation On-Line) facility to produce re-accelerated exotic ion beams for fundamental nuclear physics studies. The cyclotron double-beam extraction system allows to simultaneously carry out applied research, such as radionuclides production for medicine (SPES- γ ). This paper summarizes the results obtained with the interdisciplinary projects LARAMED (LAboratory of RAdionuclides for MEDicine) and ISOLPHARM (ISOL technique for radioPHARMaceuticals). The first one, based upon the direct activation method, is focused on the production of the radionuclides under the spotlight of the international community (e.g., 99 m Tc, 67 Cu, 52 / 51 Mn, 47 Sc and Tb isotopes), from the nuclear cross-section measurements up to the preclinical studies. The other one exploits the ISOL technique for the development and production of radioisotopes with high-specific activity, such as 111 Ag, going beyond the state of the art in the field. The most recent SPES- γ research activities and future perspective are here described, characterized by a consolidated network of collaborations with national and international institutions. [ABSTRACT FROM AUTHOR]

Graphite is often employed for several high temperature research and industrial applications, thanks to its refractoriness and its physical properties such as high thermal conductivity, low thermal expansion and excellent thermal shock resistance. However, its mechanical properties at high temperatures are often unknown and are strongly influenced by its microstructure and composition. This work is focused on a comparative analysis of the compressive strength up to 2000°C of three different commercial graphite grades provided by TOYO TANSO. Two grades of the same kind but different density, IG-43 and IG-45, and a grade with finer grains, TTK-4, were considered. Such materials were selected as their nominal physical and chemical properties are suitable for withstanding the extreme working conditions typical of nuclear applications characterized by high temperature, high vacuum and radiation damage. For the performance of the compressive tests, a custom-built vacuum experimental equipment was used, capable of resistively heating conductive samples at a temperature level up to 2000°C. Specimens with an hourglass shape were manufactured and tested in triplicate at room-temperature, 1000°C and 2000°C for each type of graphite. The dependence of the compressive strength on the graphite grade density and microstructure was highlighted, resulting in higher resistance for denser grades, in accordance with data reported by the supplier. Results collected for the room-temperature tests were consistent with the material datasheets, whereas at 2000°C, an increase of approximately 30%-40% of the compressive strength was displayed compared to its room-temperature value. [ABSTRACT FROM AUTHOR]

In the framework of ISOL (isotope separation on-line) facilities, porous carbides are among the most employed target materials for the production of radioactive ion beams for research. As foreseen by the ISOL technique, a production target is impinged by an energetic particle beam, inducing nuclear reactions from such an interaction. The resulting radionuclides are subsequently released, thanks to the high target working temperature (1600–2000 °C); ionized; and extracted into a beam. Since the target microstructure and porosity play a fundamental role in the radionuclide release efficiency, custom-made target materials are often specifically produced, resulting in unknown thermal and structural properties. Considering that such targets might undergo intense thermal stresses during operation, a thermal and structural characterization is necessary to avoid target failure under irradiation. In the presented work, a custom-made porous titanium carbide that was specifically designed for application as an ISOL target was produced and characterized. The thermal characterization was focused on the evaluation of the material emissivity and thermal conductivity in the 600–1400 °C temperature range. For the estimation of a reference material tensile stress limit, the virtual thermoelastic parameter approach was adopted. In particular, for the aforementioned temperature range, an emissivity between 0.7 and 0.8 was measured, whereas a thermal conductivity between 8 and 10 W/mK was estimated. [ABSTRACT FROM AUTHOR]

A study of the residual activation of the Front-End system structure of the SPES (Selective Production of Exotic Species) facility, currently under construction at the Legnaro National Laboratories of INFN, Italy, is performed. The study provides useful information for the planning of inspections, maintenance operations and decommissioning of the facility as well as for the assessment of radiological conditions and safety requirements in the design and operation of any accelerator-driven radioactive ion beam facility. To better assess the obtained results, two Monte Carlo codes were independently used: MCNPX combined with CINDER'90 and FLUKA. The results of the two calculation procedures are compared at each step: fissions, fluxes, activation, dose rate. Since the energy range considered does not represent a typical application for any of the two codes, the comparison of the collected results can provide useful inputs for the developers. In particular, the agreement of the two codes on the global quantities is good, being of the order of 20–40% on average, and never larger than a factor 2. Nevertheless, the comparative study shows that, in this energy range, FLUKA seems to underestimate the angular straggling of protons and to overestimate the proton interaction cross-sections, with respect to MCNPX. [ABSTRACT FROM AUTHOR]

In the facilities for the production of Radioactive Ion Beams (RIBs) according to the Isotope Separation On-Line (ISOL) technique, a production target is typically impinged by a high-power primary beam, generating radioactive isotopes for basic research and technological applications. With the aim to guarantee an efficient extraction of the aforementioned isotopes, the production target must work in a high vacuum environment, at temperatures that are usually between 1600 °C and 2200 °C. Its main components are often characterized by intense temperature gradients and consequently by severe thermal stresses. Carbides are widely used for target manufacturing, and in this work a specific method for their thermal and mechanical characterization is presented and discussed. It is based on the comparison between experimental measurements and numerical simulations, with the introduction of the novel Virtual Thermoelastic Parameters approach for the structural verification procedure. High-performance silicon carbides (SiC) are taken as a reference to describe the method. Measured emissivity and thermal conductivity data are presented and discussed, together with the experimental estimation of material limitations for both temperature and stress fields. The aforementioned results can be promptly used for the design process of high-power ISOL targets. [ABSTRACT FROM AUTHOR]

The ISOLPHARM (ISOL technique for radioPHARMaceuticals) project is dedicated to the development of high purity radiopharmaceuticals exploiting the radionuclides producible with the future Selective Production of Exotic Species (SPES) Isotope Separation On-Line (ISOL) facility at the Legnaro National Laboratories of the Italian National Institute for Nuclear Physics (INFN-LNL). At SPES, a proton beam (up to 70 MeV) extracted from a cyclotron will directly impinge a primary target, where the produced isotopes are released thanks to the high working temperatures (2000 °C), ionized, extracted and accelerated, and finally, after mass separation, only the desired nuclei are collected on a secondary target, free from isotopic contaminants that decrease their specific activity. A case study for such project is the evaluation of the feasibility of the ISOL production of 64Cu and 67Cu using a zirconium germanide target, currently under development. The producible activities of 64Cu and 67Cu were calculated by means of the Monte Carlo code FLUKA, whereas dedicated off-line tests with stable beams were performed at LNL to evaluate the capability to ionize and recover isotopically pure copper. [ABSTRACT FROM AUTHOR]