Laboratorio di Tecniche Nucleari per i Beni Culturali - Firenze


Labec overview and history


(Click on photos to enlarge)



LABEC is a laboratory in the Sezione di Firenze of INFN, established with the main purpose of performing applications of nuclear techniques in the field of problems related to the Cultural Heritage. Its acronym, indeed (LAboratorio BEni Culturali), recalls just this "mission". However, applications of nuclear techniques also to other fields are currently being performed: studies on environmental problems (mainly, but not only, air quality monitoring), applications to geological studies such as chronological reconstruction of past volcanic eruptions or geochemical modelling of magma evolution, applications to material science in general, and others.

The main equipment of LABEC is a Tandem accelerator, 3 MV terminal voltage, which has been constructed by High Voltage Engineering Europe. The accelerator is equipped with three independent ion sources, one of which (a multiple-sample Cs-sputter source) is dedicated to measurements of Accelerator Mass Spectrometry (AMS); the other two sources (a single-sample Cs-sputtering and a Duoplasmatron) are instead used to produce all kinds of beams (from protons to heavy ions) mainly for applications of Ion Beam Analysis (IBA), but also for other purposes such as studies of radiation damage to materials exposed to accurately controlled doses (even very weak), tests of radiation detectors responses, etc. 

The high energy side of the accelerator is equipped with a multi-element detection line for AMS, designed to perform the detection of the rare isotopes 14C, 10Be, 26Al and 129I (for these measurements, the multi-sample Cs sputter source is correspondingly used on the low energy side of the accelerator). As far as AMS is concerned, we are presently active with just 14C measurements, basically in connection with problems of dating of archaeological finds; in the future, the possibility of measuring 129I for environmental monitoring and 10Be for geological dating will be the next steps in the development of the AMS potentials of LABEC.
In alternative to AMS, we can operate the accelerator (using one of the other two ion sources mentioned above) to produce beams of protons, alpha particles, or any other kind of ions, and perform Ion Beam Analysis, i.e. determine the composition of a material - used as a target - exploiting the interaction products of the beam with the atoms or nuclei of the material itself. We can perform all IBA techniques, i.e. PIXE (Particle-Induced X ray Emission), PIGE (Particle-Induced Gamma ray Emission), PESA (Particle Elastic Scattering Analysis, in particular  Rutherford Backscattering Spectrometry, RBS), NRA (Nuclear Reaction Analysis). Four independent beamlines are already active (as to May 2008) for these measurements, one more will be completed in the future. The peculiarity of most IBA set-ups installed at LABEC is that we use an external beam, which is a great advantage especially in the field of applications to the Cultural Heritage: the precious works can be analysed in their "natural" environment, i.e. they have not to undergo the stress of being placed in vacuum (which might produce serious damage) and the ease of operation during the measurement is much improved. One of the external beam setups is in addition a microbeam, down to 10 um size, with possibility to perform beam scanning on the analysed sample in order to reconstruct maps of elemental distribution over the scanned area through IBA. In particular, micro-PIXE maps can provide elemental distributions of even trace elements in the sample.

Besides the accelerator, LABEC hosts dedicated laboratories for: sample preparation for AMS; R&D of electronics; ultra-high vacuum tests; detector repair and development. LABEC is hosted in a building expressly constructed by the University of Florence and served by all necessary equipments (including coolant liquids systems, gas handling, compressed air). The overall area of LABEC specific laboratories is of about 1200 m2, plus a number of facilities (50 seats seminar room, two large meeting rooms equipped with teleconference service, storage rooms) shared with other experimental activities of INFN hosted within the same building. Also shared with the other groups of INFN (and in general of those working within the Department of Physics of the University) are the services of a large, well equipped mechanical workshop.

Before LABEC, a well established activity of the group in the field of applied nuclear physics was anyway present in Florence already since the Eighties. This activity was carried out at an accelerator laboratory based on a single-ended 3 MV Van de Graaff, which had been taken to Florence at the beginning of the Seventies after serving for many years as the injector of the electrosynchrotron in the INFN National Laboratories in Frascati. In Florence, this Van de Graaff was fully refurbished and transformed into a positive ion accelerator, to perform first basic nuclear physics experiments, and later, as mentioned, applied nuclear physics.