NSLS-II Seminar

A brief development description of the LTP is presented. In past 20 years the significant progresses of the LTP had satisfied synchrotron radiation beam line requirements. A number of LTPs and metrology methods have been developed, which include the first LTP, commercial LTP II, penta-prism LTP, in-situ LTP, portable LTP, vertical scan LTP, multiple functions LTP, in-situ heat load distortion test and in-situ angle monitoring of grating monochromator. The LTP accuracy had improved by one order of the magnitude (from 5 to 0.5 rad). However, the newest state-of-the-art synchrotron radiation light sources (NSLS II and TPS) require focusing SR beam to 1 nm spatial resolution spot to study nanostructures. The great challenge to the optics and in particular to its metrology is: nanometer and nanoradian accuracy including in larger angle test range. A new generation LTP is all-important. The design of nanometer and nanoradian surface profiler (NSP) for NSLS II is presented. In order to reach nanoradian accuracy it is necessary to remove error sources as much as possible or to reduce errors produced by them to the nanoradian level. The following solutions will improve the NSP accuracy by one order of magnitude than recent LTP: optimized optical system design, scan mode selection, non-tilted reference method, quality controlling of optical components, scan air-bearing improvement and temperature control. Nanoradian calibration is the insurance of the nanometer and nanoradian accuracy, so a precise calibration device is absolutely necessary.