Research activities

MAIN RESEARCH ACTIVITIES

FUNDAMENTAL PHYSICS
THE PVLAS EXPERIMENT (Trieste 1993 - 1994; Ferrara 1994 - present)
Since 2008 I am the spokesman of the PVLAS experiment.
The PVLAS experiment, financed by INFN, aims at the first measurement of the magnetic birefringence of vacuum induced by an intense magnetic field. This effect, predicted by QED, is connected to photon-photon scattering by means of the "vacuum polarization". Furthermore the PVLAS experiment will put new laboratory limits on the mass and coupling constants of hypothetical neutral particles which couple to two photons. These hypothetical particles could contribute to dark matter. The experiment is in a phase of being upgraded in sensitivity after a long period of data taking and analysis. The best limits on the vacuum magnetic birefringence and consequently on the low energy photon-photon cross sections have been set by this experiment. Furthermore the experiment has produced new precise measurements of the Cotton-Mouton constant for various gases.
Experience:
- Design, realization and optimization of the phase locking electronics system for a Nd:YAG laser to a very high finesse cavity
- Modification of the Pound-Drever-Hall phase locking scheme to a cavity.
- Optimization of a very sensitive ellipsometer based on a Fabry-Perot cavity.
- Design and implementation of an ellipsometer with a 3.3 m long cavity with finesse F = 7e5.
- Measurement of the intrinsic birefringence of interferential mirrors.
- Sensitivity measurements with the ellipsometer.
- Use of superconducting magnet.
- Data analysis.
- Study of the consequences of the intrinsic birefringence of cavity mirrors within a sensitive ellipsometer.
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MEDICAL PHYSICS (Ferrara, 1994 - present)
- PET/SPECT/CT (Positron emission tomography, Single Photon Emission Tomography, Computerised Tomography) allow ‘in vivo’ functional imaging of organs. Both allow the detection, for example, of dead cariac tissue following a heart attack, malfunctioning of cerebral activity and tumors. These pathologies are not ususally detectable using morphological diagnostics such as x-rays and magnetic resonance. Furthermore gene expression studies (molecular imaging) may be performed with these techniques. The spatial resolution and sensitivity of these systems have evolved so as to be able to image small animals, thus opening a new line in experimentation of new drugs. At the Department of Physics of the University of Ferrara an integrated high resolution PET SPECT small animal tomograph has been developed dedicated to small animal imaging. The system is based on YAP:Ce (Ytirum Aluminum Perovskite doped with Cerium) scintillator matrices coupled to position sensitive photomultiplier tubes. The capability of imaging both in PET and SPECT remains unique.
A CT scanner on the same gantry, so as to provide both functinal and morphological images simultaneously, has also been successfully integrated. The prototype has already been tested on a benchtop system with promising results. We are also in the process of designing a new PET scanner for small animals based on multilayers of silicon double sided detectors. Simulations and proof of principle measurements have shown the enormous capabilities of such a scanner both in spatial resolution as in sensitivity. Such a scanner would be limited only by the positron range of the radionuclides eliminating all other sources of error.

Experience in PET (Positron Emission Tomography)
- Use of a matrix of new scintillator (YAP:Ce) coupled to a position sensitive photomultiplier.
- Measurement of the scintillation characteristics of the YAP:Ce scintillator.
- Development of position sensitive detectors for PET.
- Design and realization of a small animal PET scanner.
- Validation and characterization ot the tomograph at the San Raffaele Hospital in Milan.
- Study of the possibile use of multilayer silicon double sided detectors for ultra high resolution PET and high sensitivity (> 5%).

Experience in SPECT (Single photon emission comupterized tomography)
- Modification of the Ferrara PET small animal scanner for SPECT applications.
- SPECT measurements with phantoms for characterization.
- Validation and experimentation with radiopharmaceuticals of the tomograph in SPECT mode.
- Quantitative activity measurements with rats in SPECT mode.
- Spatial resolution improvement in SPECT mode using oversampling during data acquisition.

Integrated PET-SPECT scanner
- Simultaneous data acquisition in both PET and SPECT mode with the Ferrara YAP-(S)PET.

- OPTICAL FLUORESCENCE TOMOGRAPHY
At the University of California at Davis, we began a new in-vivo imaging technique for small animals based on the fluorescent light emitted by fluorophores which can be bound to biological molecules.
In fact light with wavelength longer than 600 nm is principally diffused by biological tissues and not absorbed. This technique has the advantage of using fluorophores which do not decay in time, as do radionuclides used in PET and SPECT. Processes can therefore be monitored for longer periods of time.
Experience
- Study of the actual possibility of the technique.
- Design and realization of the apparatus
- Hyperspectral measurements and spectral deconvolution to obtain multi-fluorophore images.



===============================================================Previous research activity
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GAL Experiment (Pisa 1988-1989, Thesis work)
Experiment on the equivalence between gravitational and inertial mass.
The aim of the experiment was to measure the relative difference in free-fall gravity for different materials to a level of ∆g/g - Development at Pisa of a collimator capable of measuring parallelism between beams to a level 1e-6 rad.
- Development at CERN of an interferometer with parallel, vertical arms, each 7 m long.
- Precesion optics and mechanics.
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INTERMEDIATE ENERGIES (Bologna 1990 - 1993, PhD program)
Cold Fusion (1990 - 1993)
The aim of the measurements undertaken at the Gran Sasso National Laboratories were to detect fast neutrons (2.5 MeV) emitted by metal composite metal samples loaded with deuterium both via electrolysis and pressure.
Experience:
- Development of fast neutron spectrometer based on liquid scintillator and Li6 doped glass with a double pulse shape discrimination.
- Calibration of the spectrometer by means of the time of flight technique.
- Monte Carlo simulation of the detector.
- Optimization of a neutron detection system for detecting burst and continuous emission of fast neutrons.
- Measurement of the fast neutron flux of Hall C at the Gran Sasso National Laboratories of INFN.
- Search for emission of neutron following the adsorption of deuterium in metal samples at the Gran Sasso National Labs of INFN.

Obelix (1990 - 1993)
The program of the Obelix experiment, at CERN, was the study of the annichilation mecchanism of antiprotons and antineutrons on nuclei, spectroscopy of 'ordinary' and 'exotic' meson emitted during annichilation, and the verification of fundamental simmetries.
- Design and construction of the electromagnetic calorimeter for the Obelix experiment.
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X-RAY ASTRONOMY
BeppoSAX (Ferrara 1990 - 1999)
The BeppoSAX satellite, launched on April 1996, was a satellite dedicated to X-ray astronomy, in the energy band 0.1 - 300 keV, capable of producing both images and energy spectra.
Furthermore it was implemented with a gamma ray burst monitor (20 - 600 keV) which opened the way to the dicovery of the gamma ray burst X-ray counterpart.

PDS (1990 - 1999)
The PDS (Phoswich Detector System) detector on board BeppoSAX is the narrow field high energy detector (15 - 300 keV). The active shielding surrounding the PDS detector constitutes the gamma ray burst monitor (20 - 600 keV).
Experience:
- Energy calibration of the detector at LABEN.
- Monte Carlo calculation of the response matrix for the PDS detector.
- Energy and angular calibration of the gamma ray burst monitor at ESTEC, The Netherlands.

Gamma ray bursts (1996 - 1999)
- Participation to the measurements, analysis and discovery of the X-ray counterpart of the gamma ray bursts.