Epitaxially grown polycrystalline silicon (epi-poly) has shown great promise as a MEMS material, offering isotropic material properties with minimal residual stress and stress gradients. While epi-poly has been used previously for MEMS inertial systems or sensors, its use in high precision resonator applications has been restricted to an encapsulation layer for resonators fabricated in single crystal silicon. In this work, encapsulated resonators fabricated with epi-poly as the functional layer were tested alongside single crystal silicon devices with regard to resonant frequency, quality factor, temperature dependence, and stability. Test results indicate that epi-poly resonators have very similar mechanical properties and stability to single crystal silicon resonators when operated in a clean package.
Sonderdruck aus Radiochimica Acta 6, 9-15 (1966) Summary A method was developed by which it is possible to measure the ranges of fission products in aluminium in a "thick target -thick catcher" arrangement. The target consists of a very dilute alloy of 239PU in alumi· nium; the catcher of pure aluminium. Therefore a correction for the different scattering of fission products in target and catcher can be neglected. By means of this method the fragment ranges op39Ba and 1390S as weIl as the cumulative ranges of 139Ba, 1390S and 139Xe were determined. According to our results the fragment ranges B f within an isobaric chain are different. Their relative values normalized to the isobaric range Bis are linearly dependent upon the difference Z-Zp: Hf/Bis = 1.0-0.037 (Z-Zp). Using this equation and assuming a constant range dispersion for an members of an isobaric chain, it follows that the dispersion in the kinetic energy of primary fission fragments is about a factor of 0.5 smalleI' than previous values.
ResumeUne methode a ete developpee qui permet de determiner les parcours des produits de fission dans l'alu·
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