The etching and structural studies of gamma irradiated induced effects in CR-39 plastic track recorder
Abstract In the application of some polymers as track detectors, the attention should be paid to the fact that the track recording properties of these polymers are changed under the influence of certain parameters, such as the electromagnetic radiations and environmental conditions. In this work the etching effects of 60Co gamma irradiated CR-39 polycarbonate have been studied. For deeper study of the structural changes in CR-39, the FTIR and UV–visible spectra have been analyzed. The FTIR spectra shows considerable changes due to the gamma exposure. The contribution of degradation mechanism is discussed.
Abstract Many human operations have created a large population of small orbital debris in near Earth environment. The threat they represent for satellites is a major factor for the preparation of future space missions. Several experiments devoted to the study of this environment, as well as various materials exposed to space, have been retrieved in the past few years. The analysis of the results shows some differences with previous modeling. Comparison with data from LDEF and from EURECA give some insight in the long term evolution of particle size distribution. Chemical identification of particle remnants inside craters is difficult but provides valuable information on the origin of the impactors. Permanent monitoring of environment is obviously needed, especially for the type of orbits where data are presently scarce ie. heliosynchronous and geostationary orbits.