G. Campos Venuti

THE (e,e'p) REACTION IN CALCIUM INDUCED BY 580-750 Mev ELECTRONS

Abstract The spectrum of electron-proton coincidences in calcium as a function of the incoming electron energy is presented and the results are briefly discussed.

Proton angular distribution in the high energy 12C(e, e′p) 11B reaction☆

Abstract The angular distributions of protons extracted by 600 MeV electrons from the 1s and 1p shells of 12 C were measured and the results analyzed in terms of two simple nuclear potential wells.

INDOOR MEASUREMENTS OF 220Rn AND 222Rn AND THEIR DECAY PRODUCTS IN A MEDITERRANEAN CLIMATE AREA

A research program on characteristics of radon exposure in dwellings in Rome was executed. The results of measurements of 220Rn gas concentration, besides 222Rn and their decay product concentrations, are reported. These measurements were carried out in the sitting-room of six dwellings, for 2-d periods in spring 1995, under normal living conditions. The 220Rn concentration was measured at about 1 cm from the wall, using the method of delayed coincidences between 220Rn and 216Po decays. The average value in the dwellings ranged from 5 Bq/m3 to about 1100 Bq/m3. The average 222Rn and 220Rn equivalent equilibrium concentrations, measured in the middle of the room, were within 8–43 Bq/m3 and 0.5–9.5 Bq/m3, respectively. The average potential alpha energy concentration ratio between 220Rn and 222Rn was within 0.9-4.6. The average equilibrium factor of 222Rn ranged from 0.42 to 0.55. The estimate of effective doses is also discussed. These results confirm the significant presence of 220Rn (thoron) and its decay products and the role of certain natural building materials used in some Italian Regions, not only as gamma and 222Rn sources, but also as 220Rn sources.

The absorption of negative pions by complex nuclei (copper, tin and lead)

SummaryAn experiment performed at the electron synchrotron in Frascati is described for measuring the energy spectrum of neutrons emitted in the energy range from about 1 to 50 MeV in the capture of negative pions at rest in complex nuclei. The experimental data obtained using targets of Cu, Sn and Pb are presented and discussed. Each of the energy spectra of neutrons emitted is characterized by a low-energy evaporation part with a maximum at about (2÷3) MeV. Comparison of data obtained in π− absorption in the almost double magic nucleus of Pb, with results of other experiments using the same excitation energies, shows shell-model effects on evaporation processes.RiassuntoViene discussa un’esperienza effettuata presso l’elettrosinorotrone di Frascati per misurare lo spettro di neutroni emessi fra 1 e 50 MeV nella cattura in quiete di mesoni π− in nuclei complessi. Vengono riportati e discussi i risultati sperimentali ottenuti usando come bersaglio Cu, Sn e Pb. Gli spettri energetici dei neutroni emessi inostrano a bassa energia un andamento di tipo evaporativo con un massimo fra 2 e 3 MeV. II confronto dei dati ottenuti nell’assorbimento di π− nel nucleo quasi doppiamente magico del Pb, con i risultati di altre esperienze alle medesime energie di eccitazione, pone in luce un effetto della struttura a shell del nucleo sul processo evaporativo.

Feasibility study of radiation protection guidelines in the use of building materials in the Italian dwellings

The Italian situation concerning the indoor radiation exposure is examined. A tentative comparison of the risk connected with radon and radon daughter indoor exposures and other every day life risks is made. The social economic impact of imposing possible constraints on home building industry is also discussed.

Radioactivity connected with coal burning

The enhanced environmental radioactivity resulting from the operation of a 72 MWe brown coal-fired power plant in central Italy is considered. A source-related control procedure is suggested. The calculated values for the atmospheric dispersion of radioactive effluents and the results of some measurements on brown coals, ash, environmental samples and gamma-exposure levels performed at representative points are reported.

Radon and radon daughter evaluation in a natural radioactivity survey indoors

An indoor survey in order to estimate the population exposure in five towns of an Italian Region is presented. A particular methodology for the campaign was planned and is being applied. Gamma spectrometry of building materials, exposure rate measurements indoors and outdoors and radon concentration measurements indoors were taken with different techniques. A correlation was found between mean gamma exposure rate and mean radon concentration in the houses investigated. An evaluation of mean effective dose equivalents for the inhabitants of the five towns is reported.

Neutron spectra from π- capture in Cu, Sn and Pb

The energy spectra of neutrons emitted per pion capture in Cu, Sn, and Pb were investigated for an incident momentum of 150 Mev/c. Information about both the evaporation process at high excitation energy and the prompt emission of nucleons was obtained. (C.E.S.)

Use of an interactive image analysis system (IBAS) to analyze α-particle track energies in cellulose nitrate nuclear track detectors

Abstract An Interactive Automatic Image Analyzer (IBAS) was used to measure α-particle track areas and elliptical factors on LR115 cellulose nitrate detectors. The experiment was conducted with a mixed Pu-239, Am-241 and Cm-244 α-source attenuated in air at different distances and several incidence angles. Energy resolution was estimated for detectors etched in 2.5N NaOH solution at 60 °C and for different times. Track diameter energy dependence results and IBAS image acquisition limits indicate that an α-spectrometer based on this technique may only be constructed under particular conditions.

An automatic device for counting a large number of tracks in CR39

Abstract In order to perform an indoor survey of internal exposure to radon and its short life daughters using track etching passive detectors, it is necessary to analyze a large amount of information without spending a lot of time and manual work. For this purpose, the possibility of utilizing PEPR (Precision Encoding and Pattern Recognition) normally used in the digitization of low energy particle tracks recorded on Bubble Chamber film has been studied. A special subroutine has been set up for a PDP 11/45 Computer to guide PEPR in studying the tracks of α-particles in CR39.