With the Health Physics Laboratory we want that the students have: 1. a deepen knowledge of the interaction of radiation with matter; 2. become autonomous in the use of instrumentation and detection techniques and their use for dosimetric and radiation protection purposes, using tools and methodologies, which allow them to master some techniques normally employed in the field of Health Physics: high-resolution gamma, X and alpha spectrometry, liquid scintillation, other radiometric instrumentation (ionization chambers, neutron monitors, Geiger); instrumentation for determining the radon-222 indoor concentration.
Expected learning outcomes
The student at the end of the Laboratory will have acquired the following skills in measurements and evaluations: a. as regards gamma spectrometry with the characterization of instrumentation for HPGe detectors by: · linearity and stability analysis of each component of the electronic chain (preamplifier, amplifier, analog-digital converter); · calibration in energy and efficiency of the detector; · analysis of the dead time of the chain; · measurements on samples of interest of the students. b. for the determination of environmental radioactivity and in particular the concentration of radon-222 radioactive gas: · characterization of different measuring instruments both active (semiconductors and Luca's cells) and passive (active carbon charcoal, CR39); · calibration of the instrumentation; · measures in specific environments chosen by the students.
The course aims to apply, through laboratory experiments, what is illustrated and learned during the Health Physics Course. The themes that are proposed, among which the students, who divide themselves into groups, can choose, are: 1. Characterization of instrumentation for gamma and/or beta and/or alpha spectrometry; 2. Characterization of instrumentation for the measurement of the indoor concentration of radon-222. The program includes a common part which concerns: - Introduction to the course - Regulations: risk information training in laboratory activities: Law 81 and 230. - Alpha, beta, gamma spectrometry. HPGe detectors and scintillators. - Electronic chain for the detection of gamma radiation. - Radioactive sources, methods of use. Elements of error theory. The programs are subsequently differentiated and are specific to each of the topics covered. In particular for point 1. relating to especially gamma spectrometry: - presentation of the detection system used and the electronic chain, the data acquisition and analysis s/w. - study and verification of the linearity and stability of each component of the acquisition chain for spectrometry (MCB, Amplifier, Preamplifier, Detector) - Measures for the evaluation of the electronic chain dead time with evaluation of the capacity of the detection system used for a correct correction. - Energy and efficiency calibration of the chain for gamma spectrometry - point sources. - Determination of the activity of unknown sources in point geometry. - Energy and efficiency calibration of the chain for gamma spectrometry - sources in Marinelli geometry - Measurements of unknown samples. - Measurement campaign with analysis of samples of interest of the single group. For point 2. relating to the measurement of the concentration of radon-222: - presentation of the experimental apparatuses relating to the different active and passive sampling modes of the radon gas, description of the s / w for equipments use, data acquisition and analysis. - Continuous active sampling with semiconductor and Lucas cell detectors. - Active sampling in grab-sampling by means of semiconductor detectors and Lucas cell. - Sampling with passive activated carbon dosimeters. - Sampling with passive dosimeters at CR39. - Procedure for the development of passive dosimeters CR39. - Reading and analysis using optical microscope of traces collected from passive dosimeters at CR39. - Analysis by gamma spectrometry of activated carbon dosimeters. - Campaign of measures in closed places of interest of the group involved with all available techniques. - Data analysis with comparison of the results obtained with all the measurement techniques used.
Prerequisites for admission
1. Health Physics Course; 2. Chemistry Course; 3. Course of Interaction and Detection of Nuclear Radiation. In particular, students must have assimilated the discipline concerning: a. interaction of radiation with matter; b. basic concepts on natural sources of radiations; c. basic concepts on artificial radiation sources; d. know the main types of detectors for ionizing radiations.
The didactic method adopted provides a general introductory frontal explanation on the topics of the Laboratory, addressed to all students. Subsequently each meeting is preceded by the teaching presentation of the objectives of the corresponding and specific experimental part for each group (which carries out different themes) followed by the development of the experiment which allows the verification on the field of what is illustrated and the realization of the experiment itself. At the beginning of each meeting, a critical discussion is also carried out regarding the previous meeting/meetings of any results obtained, of the problems encountered, the possible solutions or the solutions that the students think they propose to overcome them.
1. K. Debertin, R.G. Helmer, "Gamma and X-ray spectrometry with semicunductor detectors", Elsevier Science B. V., 1988, ISBN 0 444 871071; 2. G.R. Gilmore, "Pratical Gamma-ray Spectrometry", New York, John Wiley & Sons, Ltd; 3. G.F. Knoll, "Radiation Detection and Measurement", 3rd Ed., New York, John Wiley & Sons, Ltd; 4. J.R. Taylor, "An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements", University Science Book, ISBN: 0-935702-75-X.; 5. Manuals and specific documentation relating to the instrumentation and s / w programs used; 6. F. Groppi "lecture notes on the Health Physics Laboratory".
Assessment methods and Criteria
For each group, the exam consists of: - in the preparation of a laboratory report on the specific topic treated by the group itself during the laboratory; - a presentation with slides on the specific activity conducted during the laboratory and an interview. The interview focuses partly on the points discussed in the report and partly on the program. The examination takes place for all the groups in the same session so that through the presentation each group presents to the colleagues the methods of performance, the equipment used and the results obtained. The oral discussion will evaluate both the skills acquired through the verification of the understanding of the basic physical phenomena aimed at ascertaining the level of understanding reached in relation to the subject matter and the critical skills in the discussion of the problems encountered during the course and in the ability to solve them . Although the examination is carried out as a group, the mark is individual and also takes into account the peculiarities of the individual students that have emerged during the different experimental phases and throughout the workshop path, both as technical skills and ability to work in a group , and to critically resolve any problems encountered.