The in-situ long trace profiler window glass thermal deformation effect of measurement analysis

摘要

Long trace profiler (LTP) is used to measure the large radius mirror surface profile. The in-situLTP can be used to measure the X-ray mirror of an adaptive mirror bending system inside thevacuum chamber. In this study, the in-situ LTP measure head is outside of vacuum chamber.Therefore, the vacuum chamber and window glass thermal effect can introduce errors into themeasurement results.This study calculated temperature distribution and deformation using the finite element method(FEM) software and calculate incident ray through the window glass. The incident ray throughwindow glass with thermal gradient could increase optical path difference (OPD). The calculationresulted in an evaluation of in-situ LTP measurement error by thermal deformation.