Mechanical Research and Development of monocrystalline silicon neutron beam window for CSNS

TL;DR

This paper presents the design and development of a monocrystalline silicon neutron beam window for CSNS, optimizing its thickness and stress distribution to ensure high survival rate and transmittance based on Weibull distribution analysis.

Contribution

It introduces a Weibull distribution-based design method for silicon neutron beam windows, optimizing thickness and stress analysis for improved reliability.

Findings

Optimized window thickness is 1.5mm.

Survival rate of the window is 0.9994.

Transmittance of the window is 0.98447.

Abstract

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.