Biomedical subjects

R Bedogni

Publications and source records attributed to R Bedogni.

6 recordsLinked to original sources

PubMed2006

Inter-comparison among different TLD-based techniques in a standard multisphere assembly for the characterisation of neutron fields.

In the framework of collaboration among the ENEA Radiation Protection Institute (Bologna), the ENEA Fusion Department (Frascati) and the INFN-LNF-Radiation Protection Group (Frascati), an experimental campaign was organised on the usage of thermoluminescence dosemeters (TLDs) for the dosimetric and spectrometric characterisation of neutron fields. Commercially available TLDs of different material and different sensitivity to photons and thermal neutrons were selected, namely TLD600H and TLD700H from Harshaw, GR206 and GR207 from SSDML (China), MCP-6s from TLD Poland. The detectors were first calibrated in standard fields of photons ((60)Co) and thermal neutrons at the ENEA-IRP Secondary Standard Calibration Laboratory of Bologna, then exposed in fast neutron standard fields of different energy, using a standard multisphere moderating assembly. The paper compares the dosimetric characteristics of the studied TL detectors, underlining the (n-gamma) discrimination capability, and discusses their spectrometric performances addressed to radiation protection applications.

Calibration↗

PubMed2005

Development of automatic systems for the ionising radiation metrology at the ENEA-IRP secondary standard laboratory.

The ENEA IRP Secondary Standard Dosimetry Laboratory of Bologna (Italy) has been operated for more than 30 y as a secondary standard laboratory for X rays, gamma, beta and neutron radiation metrology. For photon radiation, the instruments for radiation protection and clinical dosimetry are calibrated in agreement with the ISO standards, using remotely controlled irradiation units: two 60Co, one 137Cs and three X-ray units (160, 320 and 420 kV, respectively). The calibration procedures, approved by the National Primary Laboratory, have been recently implemented in a software package, which controls the irradiation units and acquires the reference measurements. The system, developed at the laboratory under the LabVIEW programming language, guarantees a constant surveillance of all devices and operations, avoids procedural mistakes and automates the record-keeping and reporting activities. This results in an increase in the reliability of the calibration service.

Guidelines as Topic↗

PubMed2004

Developing a thermal neutron irradiation system for the calibration of personal dosemeters in terms of Hp(10).

At the ENEA Radiation Protection Institute in Bologna a thermal neutron irradiation facility is available for the calibration of neutron dosemeters. It consists of a 1 m x 1 m x 1 m polyethylene cube containing three 241Am-Be sources of about 185 GBq. The cube contains three co-axial cylindrical calibration cavities of different dimension. Due to their limited dimensions, the cavities do not allow the calibration of thermal neutron personal dosemeters in terms of Personal Dose Equivalent Hp(d), that should be carried out on the 30 cm x 30 cm x 15 cm ISO phantom. The study herewith presented was addressed at adapting the facility for external irradiation of personal dosemeters on the ISO phantom. Extensive Monte Carlo studies were carried out to characterise the neutron fluence spatial distribution along the front face of the phantom. A satisfying neutron field homogeneity within the measurement area has been obtained by means of a pyramidal polyethylene fluence flattening filter and the selection of the proper cube to phantom distance. This new irradiation set-up was experimentally tested through measurements with activation foils, according to the spatial mapping array taken from the calculations.

Body Burden↗

PubMed2004

The ENEA criticality accident dosimetry system: a contribution to the 2002 international intercomparison at the SILENE reactor.

The present paper summarises the activity carried out at the ENEA Radiation Protection Institute for updating the methodologies employed for the evaluation of the neutron and photon dose to the exposed workers in case of a criticality accident, in the framework of the 'International Intercomparison of Criticality Accident Dosimetry Systems' (Silène reactor, IRSN-CEA-Valduc June 2002). The evaluation of the neutron spectra and the neutron dosimetric quantities relies on activation detectors and on unfolding algorithms. Thermoluminescent detectors are employed for the gamma dose measurement. The work is aimed at accurately characterising the measurement system and, at the same time, testing the algorithms. Useful spectral information were included, based on Monte Carlo simulations, to take into account the potential accident scenarios of practical interest. All along this exercise intercomparison a particular attention was devoted to the 'traceability' of all the experimental and computational parameters and therefore, aimed at an easy treatment by the user.

Algorithms↗

PubMed2002

A personal neutron monitoring system based on CR-39 recoil proton track detectors: assessment of Hp(10) using image process algorithms.

At the Individual Monitoring Service (IMS) of the ENEA Institute for Radiation Protection (IRP), the Hp(10) fast neutron dosemeter consists of a CR-39 (PADC, poly allyl diglycol carbonate) recoil protons track detector. The tracks across the detector surface are magnified through a chemical etching procedure and counted by a semi-automated system which consists of a microscope, a camera and a PC. A new analysis system, based on the National Instruments vision tools, was developed. The track area distribution for each reading field is recorded and numerical algorithms were developed in order to correct the energy dependence of the response and to recognise the tracks due to the background. This improves the dose evaluation system in terms of accuracy and discrimination or the background.

Fast Neutrons↗

PubMed2001

ENEA personal dosemeters for assessing Hp(10) and Hp(0.07).

Although, at present, neither Italian legislation nor technical protocols require that personal dosimetry is performed to assess Hp(d), the ENEA Individual Monitoring Service (IMS) is able to supply thermoluminescence (TL) whole-body and extremity dosemeters for photon and beta fields, based on LiF(Mg,Cu,P) detectors and these have been fully developed at the ENEA Institute for Radiation Protection (IRP). All irradiation tests have been performed with ISO phantoms and ISO recommended reference radiations at the ENEA-IRP Secondary Standard Dosimetry Laboratory. The whole-body dosemeter contains two LiF(Mg,Cu,P) (GR200) detectors that are filtered differently. One is filtered on both sides by 290 mg.cm-2 mass per area (270 mg.cm-2 Al + 20 mg.cm-2 plastic protective layer); the other is filtered on both sides by a plastic layer of 20 mg.cm-2 mass per area. In photon radiation fields, the maximum uncertainty due to the energy dependence of the response, is +/- 4% for Hp(0.07) in the energy range 13 keV to 202 keV, and +/- 15% for Hp(10) in the range 13 keV to 1.25 MeV. The dosemeter response in terms of Hp(d,alpha) in beta fields has been investigated recently. The results of a EURADOS trial performance test for photon and beta fields are reported and discussed in this paper. The extremity dosemeter currently used at ENEA IMS consists of a GR200 detector glued on a kapton strip identified by a bar code. Its response in terms of Hp(0.07,alpha) has been measured recently and the results are given. Moreover, different dosemeter assemblies have been tested to compare the performances in photon and beta fields. Therefore, the following three constructions have been prepared: (1) an MCP-Ns (8.5 mg.cm-2 mass per area) detector with a Mylar filter of 0.5 mg.cm-2 mass per area; (2) a polyethylene filter of 12 mg.cm-2 mass per area; and (3) a GR200 (210 mg.cm-2 mass per area) detector with a Mylar filter of 0.5 mg.cm-2. Finally, a brief discussion on international and Italian requirements for personal monitoring is given.

European Union↗