Riccardo Ciolini

Evaluation of air photoactivation at linear accelerators for radiotherapy

High-energy x-rays produced by radiotherapy accelerators operating at potentials above 10 MV may activate the air via (γ, n) reactions with both oxygen and nitrogen. While the activation products are relatively short-lived, personnel entering the accelerator room may inhale some radioactive air, which warrants internal dosimetry assessments. This work illustrates a method based on the use of ammonium nitrate solutions for the evaluation of photon-induced air activation and for the estimate of internal doses to radiotherapy personnel. Air activation and internal dosimetry assessments based on our method are presented for some widespread radiotherapy linear accelerator models. Our results indicate that the equivalent dose to the lungs of radiotherapy personnel is negligible for beam energies below 18 MeV.

Development of anthropomorphic hand phantoms for personal dosimetry in 90Y-Zevalin preparation and patient delivering

Anthropomorphic tissue-equivalent hand phantoms were achieved to measure the extremity dose involved in Zevalin (90)Y-labelling and patient delivering procedure for radioimmunotherapy treatment of non-Hodgkin lymphoma. The extremity doses to hands and wrists of operators were measured by using thermoluminescent detectors mounted on the developed phantoms. Measurements of chest- and lens-equivalent doses performed on a Rando phantom are also reported.

Application of a Bonner sphere spectrometer for the determination of the angular neutron energy spectrum of an accelerator-based BNCT facility

Experimental activities are underway at INFN Legnaro National Laboratories (LNL) (Padua, Italy) and Pisa University aimed at angular-dependent neutron energy spectra measurements produced by the (9)Be(p,xn) reaction, under a 5MeV proton beam. This work has been performed in the framework of INFN TRASCO-BNCT project. Bonner Sphere Spectrometer (BSS), based on (6)LiI (Eu) scintillator, was used with the shadow-cone technique. Proper unfolding codes, coupled to BSS response function calculated by Monte Carlo code, were finally used. The main results are reported here.

Measurements of EM Emission in Rail Launcher Operation

This paper focuses on the measurement of electromagnetic interference (EMI) from high-power systems characterized by fast and intense electromagnetic transients, such those encountered in the operation of rail electromagnetic launchers. In order to develop a preliminary measurement analysis, an experimental setup was assembled consisting in a single capacitor module, a controlled switch and two Cu-Cr rails. We provide a phenomenological discussion and present the results of a series of static experiments.

Application of the BINS superheated drop detector spectrometer to the 9Be(p,xn) neutron energy spectrum determination

In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the 9Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

Silicon Carbide Schottky Diodes for Alpha Particle Detection

The fabrication and characterization of SiC Schottky diodes for the detection of alpha particles at room temperature are described. A 5 × 5 matrix of diodes has been fabricated in order to verify the dependence of the device response on randomly distributed wafer defects. A dedicated exposure apparatus has been fabricated to test the detectors. Some preliminary alpha energy spectra obtained with the lowest reverse current diodes are shown.

Handling and Conditioning Techniques of Activated Swarfs for the Decommissioning of the E. Fermi Nuclear Power Plant

In this paper a new technique to handle solid radioactive materials inside a liquid matrix is presented. The conceptual design of the device profits of the experience and know-how gained in decontamination procedures. The proposed system makes use of an ejector for the suction of a water-highly radioactive swarf mixture from the purifiers pool of the Italian E. Fermi nuclear power plant and moving it in a suitable container for the subsequent conditioning. A dedicated circuit with an ejector to demonstrate the feasibility of the method was realized. A minimum inlet flow rate was found to have swarf suction. The feasibility of the method was demonstrated, even if it is required to homogenize the inlet mixture to avoid swarf packing conditions inside the ejector.

Analysis of the response of innovative neutron detectors with monoenergetic neutron beams

Various neutron detectors are currently under development at the University of Pisa. The response of these devices is investigated using monoenergetic neutron beams produced at the CN accelerator of INFN Legnaro National Laboratories with thin lithium target bombarded by protons at different energies, exploiting the 7Li(p,n)7Be reaction.