[Fractal behavior of indoor radon variations]. / Comportamento frattale delle variazioni di radon negli interni.

Recently, a new mathematical theory has been developed which describes the non-linear dynamic and complex systems which are widely diffused in nature. In spite of great variability in the phenomenon appearances, so great as to seem chaotic, the phenomena are described by algorithms which are, at times, very simple; they are characterized by a parameter, the so-called fractal dimension, which is a fractional number. We employed this new theory to verify the fractal behavior of temporal variations of radon 222 concentration, as measured in a house at Angera (Italy), 1986-1987. With significant correlation, the experimental data show the statistics of the system not to be casual and Gaussian, but chaotic and persistent, with Hurst exponent approximately 0.77 and fractal dimension 1.23. If the fractality of radon phenomena is verified also in other systems, the implications will be consistent. Particularly, punctual time predictability of radon concentration would no longer be possible, but a new prevision strategy would be necessary, considering the chaotic behavior of the phenomenon. This would imply, e.g., a new scientific approach both in planning surveys on the doses absorbed by people exposed to radon and in predicting seismic and volcanic phenomena, where radon is known to be a primary precursors of these catastrophic events.

[EPR and TL measurements of BeO "Termalox 995" irradiated with photons]. / Misure EPR e TL di BeO "Termalox 995" irraggiato con fotoni.

Beryllium oxide dosimeters (Termalox 995) have been irradiated (at 60-Co facility) with graduated doses from 3 X 10(-1) to 1 X 10(2) Gy (30 to 10.000 rad). EPR measurements show a very good linear correlation between the amplitude of signal and the absorbed dose. This method has the advantage that the stored information into dosimeter doesn't regress "after reading procedure".

[Accelerators in radiotherapy; analysis of the features of betatrons (author's transl)]. / Gli acceleratori in radioterapia. Analisi delle caratteristiche delle apparecchiature: betatroni

The physical, mechanical and dosimetric features of betatrons are described and discussed. Reference is also made to difficulties that may arise and the limitations associated with their employment as electron accelerators in radiotherapy.