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In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low- and intermediate-level radioactive waste management, a set of 32 solid state thermal neutron detectors named SiLiF has been built and characterized. MICADO encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The SiLiF detectors are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. These detectors were extensively tested with an AmBe neutron source, and the results show a quite uniform and reproducible behavior.

The worldwide need to replace 3He for the neutron detection has triggered R&D on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to the one of 3He tubes., Submitted to Nuclear Instruments and Methods in Physics Research, section A

We show the results of some test beams performed on a new monolithic strip silicon detector telescope developed in collaboration with the INFN and ST-microelectronics. Using an appropriate design, the induction on the ΔE stages, generated by the charge released in the E stage, was used to obtain the position of the detected particle. The position measurement, together with the low threshold for particle charge identification, allows the new detector to be used for a large variety of applications due to its sensitivity of only a few microns measured in both directions.

Fusion barrier distributions for the 20 Ne + 112,116,118 Sn systems have been extracted from quasi-elastic scattering cross sections measured at the Warsaw HIL Cyclotron. Results are compared to coupled-channels calculations performed with the CCFULL code. The overall widths of the distributions are reproduced on taking account of the low-lying collective states of the target and projectile but some puzzling discrepancies in their shapes remain to be explained.

The possibilities presented by the improved portable PIXE system are discussed. Examples are given of applications in the cultural heritage field, and in particular in the characterization of pigments and silver patina on ancient Roman coins. The limitations of the system are also discussed.

At the Istituto Nazionale di Fisica Nucleare Laboratorio Nazionale del Sud of Catania, a K=800 superconducting cyclotron is in operation since 1994. The accelerator beam extraction is accomplished using electrostatic deflectors constituted by HV electrodes generating electric fields to 140 kV/cm in 6 to 8 mm gaps. The electrostatic performance is strongly dependent on the presence of high magnetic fields (up to 5 T) and of high ion energy and intensity of heavy ion beams. The behavior of these systems is mainly determined by the field electron emission effects on the cathode surface, by electron focalization processes due to the magnetic field and by heating effects due to the ion beams. A detailed study of these effects is under development starting with point, the characterization of the electrode surface vs. the material used (Ti, Cu, stainless steel, etc.) and of the best mechanical and chemical treatment available, Moreover, we are studying the electrostatic performance by using titanium surfaces and nitriding over a wide temperature range (300 to 800/spl deg/C). Preliminary results concerning the use of thermal processed polished surfaces are presented and discussed.

An oven for the feed of vapors from solid materials in the Superconducting Electron cyclotron Resonance ion SourcE (SERSE) has been designed, built and tested at the Laboratorio Nazionale del Sud. It is based on an electrically heated tungsten filament. In order to have a correct temperature distribution in the whole system and to lower the heating power, a finite elements code has been used for the design of busses and thermal shielding. A crucible temperature of 2000 °C has been measured by a pyrometer and a W/Re thermocouple. The tungsten filament as well as the other components have shown no significant damage, confirming the robustness and reliability of the system. Satisfactory Ni evaporation rates have been measured.

A new portable XRF spectrometer which allows control of the energy and the intensity stability of the emitted x-ray beam has been designed and built. The control is obtained by measuring the x-ray fluorescence generated by a double Ag/Ba thin target when crossed by the x-ray beam during a measurement. The silver and barium fluorescence K lines are detected by an ancillary Si-PIN detector and analysed by software developed at the LNS/INFN laboratories. The new portable spectrometer, the beam stability control method, the evaluation of the system and some quantitative applications of interest in the cultural heritage field are presented and discussed. Copyright © 2004 John Wiley & Sons, Ltd.

A semiconductor detector coupled with a neutron converter is a good candidate for neutron detection, especially for its compactness and reliability if compared with other devices, such as 3He tubes, even though its intrinsic efficiency is rather lower. In this paper we show a neutron detector design consisting of a 3 cm × 3 cm silicon pad detector coupled with one or two external 6LiF layers, enriched in 6Li at 95%, placed in contact with the Si active surfaces. This prototype, first characterized and tested at INFN Laboratori Nazionali del Sud and then at JRC Ispra, was successfully shown to detect thermal neutrons with the expected efficiency and an outstanding gamma rejection capability.