Influence of Collimator Misalignment to the Ħ Assembly X-Ray Stress Measurement Using Position Sensitive Proportional Counter as a Detector
Toru Goto and Yu Gong
Abstract:Recently, the position sensitive proportional counter (PSPC) has been becoming popular as a detector for the X-ray stress measurement. However, Little information is available in the literature regarding the effects of the systematic errors on the stress measurement using PSPC. In this paper, the collimator misalignment is discussed using a model and a simulation method of the W assembly X-ray stress measurement. As one of the results, it was found that the translation and/or the rotation of collimator from the normal position yield error in stress measurement depending on the misalignment conditions. The error in stress measurement due to the collimator misalignment is expressed as a linear relation of the ratio t /R0 or k /R0 (t: translation, k : rotation, R0: goniometer radius) for the translation or the rotation, respectively. If the collimator is misaligned under the combination of translation and rotation, the error can be expressed as the sum of the error caused individually by ranslation and rotation. If the stress is measured under the combination of specimen mis-setting and collimator misalignment, it was found that the error is the sum of the error caused individually by specimen mis-setting and collimator misalignment. Key Words:X-ray stress measurement, PSPC, Error in stress measurement, Collimator misalignment, Specimen mis-setting