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ISO 15856-2010 pdf free download

ISO 15856-2010 pdf free download.Space systems Space environment Simulation guidelines for radiation exposure of non-metallic materials
Systémes spatlaux — Environnement spatial — Lignes dire ctrices de simulation pour I’exposit ion aux radiations des matériaux non metalliques.
an example of such verification, see Annex C. Sealed radio-isotope sources may be used to validate the reciprocity at low dose rates. The range of operating temperatures on a surface of a space vehicle is generally assumed to vary from -150 C to +150 °C. The actual or predicted operating temperatures of the material should be considered when selecting test temperature requirements It is necessary to conduct accelerated radiation tests in vacuo with a recommended residual pressure no higher than 10-2 Pa to 10’ Pa depending on dose rate and specific property. However, for certain properties and tests it may be possible to conduct tests in an atmosphere of inert gas. The value of maximum dose rate (or an energy flux on a material surface) is determined both by the allowable temperature increase of a sample and the admissible acceleration factor, Take into account that the mean free path of the residual atmosphere may have an effect on desorption of gases from the material. Water desorption is an important concern for composite materials. Dissolved oxygen can react with materials to produce chemical changes that are different from the material experiences in space when irradiated. Radiolysis products (broken chemical bonds and free radicals) may react with the oxygen. IEC 60544-2 discusses this subject.
In connection with the aforesaid, the accelerated radiation tests are only possible when preceded by a conditioning of the material samples in a vacuum in order to remove dissolved oxygen. Heating of a material in vacuum (vacuum bakeout) will Increase the outgassing rate thereby reducing the conditioning time. However, the material should not be heated to a temperature where thermal damage occurs. The dose rate effect on radiation-induced outgassing is most significant. To take it into account in accelerated tests, it is advisable to increase the value of the absorbed dose. A recommendation of the factor of an adsorbed dose reserve is given in Annex C based on a accelerated tests. It is permissible to conduct accelerated tests for the effects of VUV exposure of non-metallic materials at acceleration factors up to 103 (see Reference [21]). NUV exposure acceleration factors of up to 7 have been used. Acceleration factors should be carefully considered and verified for acceptable simulation of space radiation effects in the particular material being tested. Additional information is given in Annex C. Electron irradiation can result in a negative charge build-up in dielectric materials. At accelerated dose rates, this charge build-up will result in effects that are different from those when the materials are exposed in space.
An increase of a negative charge on the surface of the material will repel incident low-energy electrons, thereby reducing the net irradiance of the material. This effect can be reduced by neutralizing the charge with proton irradiation or earthing of the material at on-ground testing.
High-energy electrons depositing within a dielectric material may build up a high bulk voltage charge that can discharge within the material or to the surface and damage the material. This effect limits the maximum dose rates at on-ground tests.ISO 15856-2010 pdf free download.

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