  The monocrystalline silicon neutron beam window is one of the key components
of neutron spectrometers and thin circular plate.Monocrystalline silicon is a
brittle material and its strength is not constant but is consistent with the
Weibull distribution. The window is designed not simply through the average
strength, but according to the survival rate. Bending deformation is the main
form of the window, so dangerous parts of the neutron beam window is
stress-linearized to the combination of membrane stress and bending stress.
According to the Weibull distribution of bending strength of monocrystalline
silicon based on a large number of experimental data, finally the optimized
neutron beam window is 1.5mm thick. Its survival rate is 0.9994 and its
transmittance is 0.98447; it meets both physical requirements and the
mechanical strength.
