Objective Research has been undertaken to develop a pocket sized personal dosimeter using semiconductor materials. This dosimeter was intended to give a reading as close as possible to the dose equivalence existing around reactors, accelerators, X-ray sources, etc. Furthermore, the pocket dosimeter should have a flat energy response in accordance with the most recent International Commission on Radiological Protection (ICRP) recommendations.The response of a number of silicon detectors has been measured. They were exposed to different types of photons from radioactive sources such as americium-241, caesium-137 and cobalt-60, as well as from heavily filtered X-rays.A silicon detectors with a large sensitive layer (900 um) was exposed to californium and plutonium beryllium neutronsources and the neutron spectra were obtained at a fixed distance using different thicknesses of polythene radiator discs mounted in front of the detector window. The measurements show that the sensitivity varies strongly with radiator thickness. The maximum neutron response for californium neutrons occurs with about 1 mm polythene while for plutonium beryllium it is 2 mm. The influence of the bias voltage on neutron response was also investigated using silicon detectors placed at a distance of 5 cm from the axis of a plutonium beryllium source and some spectra were obtained between 0 V and 250 V. The detectors were exposed with a polythene radiator of 2 mm thickness.In conclusion the detection of fast neutrons by proton recoil is a useful application of silicon detectors. The main problem arises in the discrimination against gamma radiation and obtaining a resonable energy response and sensitivity. Using californium (2.3 meV) and plutonium beryllium (4.3 meV) a factor of 2.5 in efficiency can be observed. The detectors can be used for neutron flux measurements as well as a simple spectrometer. The response of the silicon detectors is comparable to both neutron film and large proton recoil counters.THE PROJECT PROVIDES FOR THE DESIGN, CONSTRUCTION AND DEVELOPMENT OF A POCKET-TYPE PERSONAL DOSIMETER THAT USES A SEMICONDUCTOR MATERIAL, SUCH AS SI OR CDTE IN PARTICULAR, FOR THE DETECTOR UNIT. IT WILL BE CARRIED OUT IN COOPERATION WITH OTHER RESEARCH BODIES SUCH AS THE AARHUS UNIVERSITY PHYSICS INSTITUTE, THE STRASBOURG CENTRE FOR NUCLEAR RESEARCH, THE PHYSIKALISCHE TECHNISCHE BUNDESANTALT, BRAUNSCHWEIG AND THE CERN, GENEVA. THE PHYSICS DEPARTMENT OF THE LA SAPIENZA UNIVERSITY, ROME, WILL WORK ON THE FOLLOWING ASPECTS OF THE PROJECT IN PARTICULAR: - DESIGN AND CONSTRUCTION, IN COOPERATION WITH THE STRASBOURG TEAM, OF THE AMPLIFICATION SYSTEM TO BE USED IN CONJUNCTION WITH THE DETECTOR UNIT. THE ASSOCIATED ELECTRONICS SHOULD BE AS COMPACT AS POSSIBLE AND HIGHLY SENSITIVE; - STUDY OF THE DOSIMETER RESPONSE TO VARIOUS TYPES OF IONIZING RADIATION, SUCH AS GAMMA AND X-RAYS, THERMAL AND FAST NEUTRONS AND MIXED FIELDS OF THE SAME TYPES OF RADIATION. SPECIAL ATTENTION WILL BE DEVOTED TO ENERGY DEPENDENCE AND THE POSSIBLITY OF OBTAINING A FLAT RESPONSE TO ALL THE ENERGIES POSSIBLY INVOLVED. ANOTHER PARAMETER THAT WILL BE TESTED IS THE LINEARITY OF THE RESPONSE AS A FUNCTION OF DOSE AND THE MINIMUM DETECTABLE DOSE. A SPECIAL STUDY WILL BE CARRIED OUT TO DETERMINE THE BEHAVIOUR OF THE DOSIMETER IN THE EVENT OF HIGH DOSE LEVEL ACCIDENTAL IRRADIATION; - THE DETECTOR WILL SUBSEQUENTLY BE SUBJECTED TO VARIOUS ENVIRONMENTAL TESTS IN ORDER TO STUDY ITS BEHAVIOUR IN LIMITING CONDITIONS OF MOISTURE AND TEMPERATURE; - WITH REGARD TO ITS SUITABILITY FOR USE IN ACCIDENT DOSIMETRY, THE TEAM WILL EXAMINE THE TYPE OF RADIATION DAMAGE CAUSED AND WHETHER IT IS PERMANENT OR NON-PERMANENT AND, IN THE CASE OF THE LATTER, THE PROCEDURES FOR RESTORING THE INITIAL CHARACTERISTICS; - LASTLY, THE DETECTOR'S SUITABILITY FOR USE IN CLINICAL DOSIMETRY (BOTH DIAGNOSIS AND TREATMENT) WILL BE STUDIED. Fields of science natural scienceschemical sciencesinorganic chemistryalkaline earth metalsnatural sciencesphysical sciencesnuclear physicsnatural sciencesphysical scienceselectromagnetism and electronicssemiconductivitynatural scienceschemical sciencesinorganic chemistrymetalloidsnatural sciencesphysical sciencestheoretical physicsparticle physicsphotons Programme(s) FP1-RADPROT 6C - Multiannual research and training programme (Euratom) in the field of radiation protection, 1985-1989 Topic(s) Data not available Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator UNIVERSITA DEGLI STUDI DI ROMA LA SAPIENZA EU contribution No data Address Piazzale Aldo Moro 5 ROMA Italy See on map Links Website Opens in new window Total cost No data
