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Gas desorption in vacuum from electron irradiated ultra high molecular weight polyethylene (PE) is measured with a high sensible mass quadrupole spectrometer. Measurements are performed in thick PE irradiated with 5 MeV electron beams at doses of the order of tens of kGy. The irradiation modifies the PE molecules producing dehydrogenation, emission of different Cx-Hy groups, C-enrichment and carbon cross-linking processes. Results indicate that the radiation damage depends on the dose and that a significant change of chemical and physical polymer properties is reached for a critical dose of 18 kGy. [ABSTRACT FROM AUTHOR]

The diffusion coefficient of light gas species in polyethylene is measured through a special apparatus which uses a vacuum chamber and a mass quadrupole spectrometer in order to detect the diffused species. Measurements are performed in thin polyethylene films with different molecular weight, which have been irradiated in air with 5 MeV electron beams. The irradiation modifies the poly-ethylene-inducing cross-linking processes, which reduce the diffusion coefficient. Measurements of the diffusion coefficient as a function of the gas specie and of the absorbed dose are reported. The results indicate that the radiation damage depends on the dose, on the dose rate and on the electronic stopping power. A cross-section of the damage process can be deduced. The polymer diffusion is evaluated as a function of the electron irradiation dose. Special attention is given to black polyethylene, rich in additive carbon for industrial applications which can be improved by treatment with electron beams. [ABSTRACT FROM AUTHOR]

A new self-shielded system for surface radiation treatments has been developed, based on a 300 keV electron gun, able to irradiate a 100 mm×10 mm area. The compact and durable system described in this paper provides the required dose of treatment for several industrial or scientific research applications, with a good reproducibility of the parameters. [ABSTRACT FROM AUTHOR]

Effects of radiation damage in ultra high molecular weight polyethylene are investigated by using energetic electron beams. Special attention is devoted to the mechanical characterization of the polymer, before and after the modification induced by 5 MeV electrons, as a function of the absorbed dose. Elastic modules, ultimate tensile and compressive strengths and roughness and hardness, have been measured in pristine and electron irradiated polymers. Infrared spectroscopy, scanning electron microscopy and differential scanning calorimetry are employed in order to investigate the microscopic modifications induced by the electron energy release to the polymeric chains. Results indicate that the polymer loses hydrogen and becomes rich in carbon content. Cross-linking effects are responsible for the higher mechanical resistance, fragility and hardness of the polymer submitted to a high absorbed dose. [ABSTRACT FROM AUTHOR]

Ultra-high-molecular-weight-polyethylene (UHMWPE) is irradiated with 5 MeV electrons in vacuum at different doses. The radiation effects induced by the electron irradiation are investigated by using different physical analyses such as mechanical tensile stress measurement, hardness measurements, specific heat measurements, infrared molecular absorption, surface wetting, polymer darkness and morphological scanning electron microscopy. The results indicate that the effects induced by high electron dose absorption consist mainly of a dehydrogenation of the polymer with an increase of the C-C cross-linking bonds, of an increase of the macroscopic mechanical resistance of the polymer, and of a darkness increase of the polymer color. Obtained results are compared with those produced by ion irradiation of the polymer by using ion implants at different stopping powers. Some applications of electron-irradiated UHMWPE are presented and discussed. [ABSTRACT FROM AUTHOR]

The differential cross-section of the excitation of the first 3 level ofS at E =5.01 MeV in theAl+S collision at E =100 MeV was measured down to σ⋍10mb/sr. Backward oscillations are interpreted as interference with five-nucleon transfer. The analysis of the data is performed in the frame of EFR-DWBA. The deduced B(E3) ↑ value is in good agreement with that measured by other authors in the inverse transition. By phase analysis of the oscillations, the transfer seems to take place in more-than-one-step mechanism. [ABSTRACT FROM AUTHOR]

Copyright of Il Nuovo Cimento: A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Il Nuovo Cimento: A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Il Nuovo Cimento: A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

124Sn+64Ni and 112Sn+58Ni reactions at 35 A MeV incident energy were studied by using the 688 Si–CsI telescopes of the forward part (1°≤θlab≤30°) of CHIMERA multi-detector. The most central part, 1% of the total measured cross section was selected by means of a multidimensional analysis of the experimental observables. The detected isotopes of light fragments (3≤Z≤8) provided information on breakup temperatures of the emitting sources. The space–time structure of these sources was deduced from fragment correlations. An odd–even effect in the fragment production, enhanced by the isospin of the entrance channel, was observed. Freeze-out unbound neutron-to-proton relative densities for both studied reactions have been deduced, indicating for a possible isospin distillation mechanism related to a phenomenon of the liquid–gas phase transition in asymmetric systems. [Copyright &y& Elsevier]

Mass and charge identification of charged products detected with Silicon–CsI(Tl) telescopes of the Chimera apparatus are presented. An identification function, based on the Bethe–Bloch formula, is used to fit empirical correlations between ΔE and E ADC readings, in order to determine, event by event, the atomic and mass numbers of the detected charged reaction products prior to energy calibration. [Copyright &y& Elsevier]