Non-destructively measurement of residual stress accumulated in a material.

Uses X-rays to non-destructively measures the residual stress accumulated in a material during the manufacturing process. Different frame sizes accommodate small, medium and large samples. The position-sensitive proportional counter (PSPC) permits high-speed measurement. Compared with the conventional method, the measurement time can be reduced drastically, 10 to 100 times faster depending upon the kind of measurement. This is a field-oriented X-ray stress analyzer that enables the operator to immediately get the ultimate data on the stress value from a simple operation.

Measurement principle

Incident X-rays are diffracted from specific lattice planes of the crystal grains. The diffracted X-rays enter the PSPC (with length L) and collide with the detector gas, ionizing the molecules. A high voltage is applied across the cathode and anode so that the induced electric charges are collected on the cathode at a position χ.

The corresponding pulses appear at both ends of a delay line after a lapse of time proportional to the incidence position χ. When the delay time per unit length is denoted by D and the time required to produce the output at Preamp A and Preamp B by TA and TB respectively, then the following equations hold:

Therefore the difference of output time between the two amplifiers (TB-TA) is proportional to the position χ. Since the delay time is less than 1.3 μsec, measurement can be carried out virtually simultaneously over the effective length L.