Nanometer accuracy with continuous scans at the ALBA-NOM

Josep Nicolas; Pablo Pedreira; Igors Šics; Claudio Ramírez; Juan Campos

doi:10.1117/12.2238128

8 September 2016 Nanometer accuracy with continuous scans at the ALBA-NOM

Josep Nicolas, Pablo Pedreira, Igors Šics, Claudio Ramírez, Juan Campos

Author Affiliations +

Proceedings Volume 9962, Advances in Metrology for X-Ray and EUV Optics VI; 996203 (2016) https://doi.org/10.1117/12.2238128
Event: SPIE Optical Engineering + Applications, 2016, San Diego, California, United States

Abstract

We present the continuous scan operation of the ALBA-NOM as a working mode that allows obtaining low noise in short time, as well as high accuracy measurements. In the traditional step-scan operation, the position of the probe beam is kept fixed while many data points of autocollimator are averaged for noise reduction. This operation mode is very safe, as one has a perfect correspondence between mirror position and measured angle, but it is time inefficient, as it disregards all the data values acquired during motion, and basically averages data values taken under identical conditions. On the other hand, continuous scan is less safe in terms of correspondence between mirror position and slope, especially for NOM systems for which the autocollimator does not accept an electronic trigger. Nevertheless, it is possible to perform independent acquisitions of the autocollimator and of the linear stage data during a scan, and synchronize signals a posteriori. This solves the main problem of continuous scan with a NOM. Continuous scan operation for performing measurements is very efficient for noise reduction per unit time, as it allows integrating every single data value taken by the autocollimator. In addition, it opens the possibility of introducing pitch variations of the mirror between scans. This allows obtaining many independent datasets that can be combined using error suppression techniques to reduce not just noise but systematic errors too. In this paper we report the methods and the main results.

Conference Presentation

Citation Download Citation

Josep Nicolas, Pablo Pedreira, Igors Šics, Claudio Ramírez, and Juan Campos "Nanometer accuracy with continuous scans at the ALBA-NOM", Proc. SPIE 9962, Advances in Metrology for X-Ray and EUV Optics VI, 996203 (8 September 2016); https://doi.org/10.1117/12.2238128

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

;

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE