Contributi scientifici in memoria di Antonio Fusco.

Come si leggerà nell'Introduzione della sezione propriamente scientifica del Volume, il presente testo nasce dalla volontà e, soprattutto, dall'esigenza culturale di omaggiare il fu Prof. Antonio Fusco. Un debito scientifico ed umano che trova il suo locus naturale in questa prima parte del testo stesso, cui farà poi seguito la parte propriamente scientifica. In siffatta parentesi dovuta per le ragioni appena menzionate, il lettore, l'amico o l'allievo dell'opera del Prof. Fusco potranno trovare un suo sintetico Curriculum Vitae, correlato da una specifica ed accurata prosa, svolta dal già Magnifico Rettore Carlo Cipolli; il quale, oltre che evidenziare, ricordando, i meriti del collega oramai scomparso, aggiunge alsuo scritto un elemento che sarebbe imprescindibile a non trasformare lo stesso in una mera sequenza di parole: l'amicizia e l'affetto per un amico che, oramai, non c'è più. A fine lettura, evidente risuonerà il fatto che la vita di ognuno, se mossa dalla passione per ciò per cui si è predisposti cognitivamente e psicologicamente, può essere ricca di riconoscimenti, riconoscenze e soddisfazioni che, lungi dal divenire un cuscino di allori su cui adagiarsi, per una mente creativa come quella del Prof. Fusco hanno funto solo da motivazioni ad agire instancabilmente guardando sempre al futuro. Il lavoro di una vita che, materialmente, è sancito da un supporto poco più di cm 25x15: una targa. Una materialità evidente che, con grande commozione e riconoscenza, è stata affissa il 25 ottobre 2019 sull'aula fronte l'Aula Magna del Campus "La Folcara", a testimonianza che quello spirito creativo in continua evoluzione non si ferma; non si arresta neppure con la fine biologica di chi lo ha "posseduto". Rimangono le opere ed il pensiero del Prof. Fusco e restano gli affetti. A tal proposito, il lettore troverà una breve e sentita sezione su Testimonianze; coloro i quali hanno avuto modo, nell'arco della vita accademica ed umana, personale, di Fusco di conoscerlo. Ecco, allora, che i ricordi saranno i veri protagonisti di questa parentesi. Dopo di ciò, prima dei contributi prettamente scientifici dei lavori, tenutisi in occasione del Convegno Internazionale Psicologia, Arte, Letteratura. Antiche e Nuove Tendenze, seguiranno i saluti delle autorità che in quei due giorni si sono succedute a rappresentare non solo l'istituzione affiliata, ma anche la relazione di stima e di affetto che le legava al compianto Professore. Si passerà, infine, al volume tradizionalmente inteso.

The radiological environment at the Mayak PA site and radiation doses to individuals involved in emergency and remediation operations after the 'Kyshtym Accident' in 1957.

This article assesses the radiological environment at the nuclear site of the Mayak PA, Russian Federation, during and after the accident in 1957, the so-called 'Kyshtym Accident', and the radiation doses to those who participated in the eradication of its consequences. Based on numerous archival documents, this paper presents the radiation data for 1957-1960, including individual dosimetry monitoring data and estimated doses to the Mayak workers, as well as the to personnel in supporting organisations and the military involved in the remediation operations. From 1957-1959 some 38 500 individuals took part in the clean-up actions and remediation of contaminated areas of the Mayak PA industrial site after the accident, including individuals exposed at the time of the accident: Mayak PA employees, militarypersonnel, and civil construction workers. External equivalent doses to 10 500 individuals were estimated in the range of 220 to 265 mSv, while there were cases of doses up to 950 mSv and higher. The collective dose received during the accident and its aftermath was in the region of 7300 person-Sv. By October-December 1957, the collective dose was about 4500 person-Sv. Collective doses recorded in 1958 and 1959 amounted to 2250 person-Sv and 480 person-Sv, respectively.

Kinetics and mechanism of the reaction of fluorine atoms with pentafluoropropionic acid.

The kinetics of the reaction between fluorine atoms and pentafluoropropionic acid has been studied experimentally at T = 262-343 K. The overall reaction rate constant decreases with temperature: k1(T) = 6.1 × 10(-13) exp(+1166 K)/T) cm(3) molecule(-1) s(-1). The potential energy surface of the reaction has been studied using quantum chemistry. The results were used in transition state theory calculations of the temperature dependences of the rate constants of the two channels of the reaction. The abstraction channel ultimately producing HF, C2F5, and CO2 is dominant at the experimental temperatures; the addition-elimination channel producing C2F5 and CF(O)OH becomes important above 1000 K.

Mayak film dosimeter response studies, part I: measurements.

The Mayak Worker Dosimetry study is a joint Russian/U.S. project to evaluate doses received by workers at the Mayak Production Association facilities from 1948-1972. A key investigation in this project is the characterization of responses of the three types of film dosimeters used to monitor workers during this time period. Experimental irradiations of the dosimeters were performed in the radiation calibration laboratories at the National Research Center for Environment and Health (GSF) in Munich, Germany. The irradiations used photon sources from x-ray beams with ten different energy distributions and with Co and Cs isotopic gamma sources. Irradiations were performed with the dosimeters on phantoms and free-in-air. The dosimeters and phantoms were also positioned at varying angles to the radiation beam. The result of the experiments was a thorough characterization of the dosimeter response as a function of photon energy and as a function of angle for energy and angular ranges that cover the conditions encountered in the Mayak workplaces. The characterization data were then available for use in developing correction factors, which could be applied to worker dosimeter readings to provide a more accurate assessment of worker dose and estimates of doses to organs.

Mayak film dosimeter response studies, part II: response models.

A study was performed of energy and angular responses of the film dosimeters that were used for worker monitoring at the Mayak Production Association (Mayak PA) in 1948-1992. The study used experimental data from tests with three types of individual film dosimeters, and the data were used to determine the dosimeters' energy and angular response characteristics in the range from 9 keV to Co energies, with the dosimeters exposed both free-in-air and on-phantom at horizontal and vertical rotation. Mathematical models of the dosimeters were developed to calculate the response characteristics of the dosimeters. The models of the film dosimeters were validated by comparing calculations to measurements. The models were then used as the basis for individual dose reconstruction in realistic photon spectra and worker exposure geometries at the Mayak PA workplaces. Reconstructed individual doses have been included in the Mayak worker database "Doses-2005" that is used for epidemiological studies of the Mayak workers' radiation exposures and subsequent health effects.

Comparison of EPR occupational lifetime external dose assessments for Mayak nuclear workers and film badge dose data.

The Mayak worker cohort is one of the major sources of information on health risks due to protracted exposures to plutonium and external ionizing radiation. Electron paramagnetic resonance (EPR) measurements in tooth enamel in combination with personal dose monitoring can help to improve external dose assessment for this cohort. Here, the occupational lifetime external exposure was evaluated individually for 44 nuclear workers of three plants of the Mayak Production Association by EPR measurements of absorbed doses in collected tooth enamel samples. Analysis included consideration of individual background doses in enamel and dose conversion coefficients specific for photon spectra at selected work areas. As a control, background doses were assessed for various age groups by EPR measurements on teeth from non-occupationally exposed Ozyorsk residents. Differences in occupational lifetime doses estimated from the film badges and from enamel for the Mayak workers were found to depend on the type of film badge and the selected plant. For those who worked at the radiochemical processing plant and who were monitored with IFK film badges, the dose was on average 570 mGy larger than estimated from the EPR measurements. However, the average difference was found to be only -4 and 6 mGy for those who were monitored with IFKU film badges and worked at the reactor and the isotope production plant respectively. The discrepancies observed in the dose estimates are attributed to a bias in film badge evaluation.