Alfonso Santagata

Experimental Results of an Accelerator-Driven Neutron Activator for Medical Radioisotope Production

In the framework of the EC funded INBARCA project (Innovative Nanosphere Brachytherapy with Adiabatic Resonance Crossing using Accelerators) a compact, accelerator driven neutron activator has been designed and constructed, with the aim of efficiently utilising ion-beam generated neutrons for the production of radioactive nanoparticles for brachytherapy. The design is based on a modified version of the Adiabatic Resonance Crossing concept, first proposed by C. Rubbia of CERN. The neutron activator has been tested in two experimental configurations, with and without a central lead block. The activation performance on different materials was quantified by γ-spectrometry. Monte Carlo simulations accompanied all experimental runs, and neutron unfolding techniques were used to derive the experimental neutron spectrum. This paper compares the simulated and the unfolded neutron spectra thus obtained, as well as the experimental and simulated activation results for pure Au, Ag, Mo, Ni, Ho and Re foils as well as for Re and Ho nanoparticles.

DISIS - a computer simulation code for discrete scintillation imagers

A computer simulation code has been developed in order to foresee the response of discrete scintillation imaging devices. Discrete Scintillation Imager Simulator (DISIS) has been designed for imagers based on a scintillation array coupled to a position sensitive light sensor (like position sensitive photomultiplier tube or avalanche photodiode array) by a planar light guide. The simulator is a deterministic code that uses: (i) a model describing the single photon light distribution emerging from a crystal pixel for charge integrals evaluation; (ii) the assigned algorithm for centroid calculation; and (iii) the Gaussian spread for localizing, crystal by crystal, the events on the image. In particular DISIS allows us to study the spatial response over the imager field of view changing parameters individually. The imager optimization can be obtained searching an acceptable pixel identification. To this aim a good trade-off between the spread of light distribution, the light sampling capability over the light-sensor area and the centroiding algorithm has to be found.