R. Mazzei

Submicroscopic kinetics of track formation in SSNTD

Abstract A theoretical description for submicroscopic kinetics of track formation in SSNTD is proposed. Kinetics of chemical attack in the primary damage region of the track is included. A good correlation between theory and experimental data obtained with Mazzeis replica method is achieved.

Induction time in Makrofol E

Abstract Induction time in Makrofol E is evaluated applying the nuclear track replica method and electron microscopy with 10 A resolution. The induction time is observed in foils with and without pre-etching. The track diameter vs etching time curves do not follow a linear relation for small track diameters.

The submicroscopic track kinetic theory and the variational principle

Abstract The variational principle was used to obtain the general equations for chemical etching track profiles inside and outside the physical damage region produced by energetic ions in Makrofol E. The track profiles developed at very short etching times were used to obtain the velocity profiles in order to perform computer determinations of track profiles for longer etching times. Track profiles obtained by means of the variational principle and the submicroscopic track kinetic theory are in good agreement, and compare favorably with experimental results.

Submicroscopic nuclear track kinetic theory applied to initial chemical etching of makrofol E

Abstract Chemical etching track profiles in the bulk region, as well as in the physical damage region, were described in a track kinetic theory by Mazzei et al. applying submicroscopic evaluations. In the present work this theory proves useful also to analyze the profiles of “new born” tracks. The equation describing height variations along each track profile is similar to that describing track velocity variation along the axis perpendicular to the ion incidence direction. The theory proves that for “new born” tracks, the chemical etching wave fronts generated in any point of the track are not exceeded by that wave front generated along the heavy ion incidence axis.

Applications of the submicroscopic nuclear track kinetic theory

Abstract The submicroscopic track kinetic theory (STKT) is able to deal with a broad range of cases. We derive here its behaviour for very short etching times (new born tracks) and also for long etching times, where the classical track kinetic theory is a particular case of the STKT. Experimental data obtained previously by Bean et al. using the electroconductivity method are then analyzed by the STKT method. We show that good agreement is obtained between Bean and STKT theoretical results for the track diameter evolution.

Compound nucleus cross section in Makrofol E irradiated with 55 MeV alpha particles

Abstract A 55 MeV alpha particle beam is used to generate nuclear tracks in Makrofol E detectors. These tracks were produced by reaction products generated by compound nucleus reactions, as was demonstrated by compound nucleus cross section formation and elastic scattering analysis. The number of tracks versus collected charge and versus removal surface thickness were experimentally evaluated in good agreement with the theoretical predictions. So, an accurate beam dosimetry was performed by track counting method which proved particularly useful for low LET light ions evaluation.

Solvent effect in nuclear track development

Abstract The analysis of the effect of soaking in alcohol and/or water in track development was evaluated in Makrofol E using electron microscopy. Alcohol seems to be the main cause of track development when no other chemical reagent is used. No track development is achieved when water is used as an etching agent.

Replica method for evaluation of submicroscopic nuclear tracks in solid state track detectors

Abstract The examination and evaluation of very small-size etched tracks (⋍ 200 A) generated in Makrofol E detectors after irradiation with alpha-particles have been performed with an improved method using Pt and C replicas analyzed by electron microscopy. Careful handling of the replica allowed to visualize directly ‘finger like’ structures protruding from the replica that correspond to the internal configuration of the tracks.

Alpha and deuteron dosimetry using makrofol E detectors

Abstract Makrofol E foils (300 μm thick) were used for simultaneous dosimetry of α and d ion beams during ‘in vivo’ irradiation. The interaction of the ions with C and O atoms in Makrofol E was used for nuclear track production. Good accuracy in dose evaluations was achieved by means of measurements of optical density differences induced in Makrofol by various doses.

A simple method for the evaluation of induction time in SSNTD

Abstract The classic method for the evaluation of the induction time in SSNTD with electron and light microscopy is based on the analysis of the evolution of track diameters as a function of etching time and the extrapolation to zero diameter. The present study outlines a simple method to evaluate the induction time, which is based on the evaluation of changes in light transmission in the irradiated area of the foil. This change is the result of the collective effect of tracks (diameters of less than 500 A) in saturated foils which can be visualized as individual tracks only by electron microscopy.