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Title: Thin Si sub 3 N sub 4 windows for MeV ions

Technical Report ·
OSTI ID:7247880
;  [1];  [2]
  1. Oregon Univ., Eugene, OR (USA). Dept. of Physics
  2. Lawrence Livermore National Lab., CA (USA)

We report here the results of studies on (nominal) Si{sub 3}N{sub 4} ultra-thin windows for bringing MeV protons out of vacuum into ambient air with small scattering. The windows were made by anisotropic etching of Si to expose about a square millimeter of silicon nitride film integrally attached to a silicon frame. Three sets of windows of different thicknesses were tested. A number from each set were broken out of the wafers and attached over one mm holes in Aluminum plates with epoxy cement. The windows were successively placed under roughing vacuum using a lubricated O'' ring for a vacuum seal. Breaking pressure was recorded for windows that did not survive. Radius of curvature of films that did survive was obtained by measuring the optical focal length in reflection. Stress and strain were deduced and the results are tabulated. Young's modulus obtained from the data assuming Poisson's ratio to be 0.3 is 346 GPa. That value is compared with values from the literature. 4 refs., 6 figs., 6 tabs.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
DOE/DP
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
7247880
Report Number(s):
UCID-21935; ON: DE90008092
Country of Publication:
United States
Language:
English