Abstract
Validation of GISAXS through comparisons with more widely used techniques such as TEM is important for many reasons. First and foremost, it serves as a test of the model and the assumptions which underpin it. Another aspect is that it helps build the profile of the technique within the wider fusion-materials community, by providing a clear demonstration of what it can do, and how it compares to already established techniques. In this section, a study is described where both GISAXS and TEM were performed on the same sample to measure He-induced nano-bubble diameter distributions in W, demonstrating close agreement between the two techniques. For TEM, nano-bubbles must be counted manually,1 so the number used to calculate the distribution is limited by instrument availability and the man-hours one is willing to commit to the task. The process of creating the samples, and the statistical analysis used for the TEM aspect of the study are described, followed by the GISAXS measurement conditions and some of the specific details of the model which was fitted for this sample. For comparison, a number of different nano-bubble size distribution models were tested.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsNotes
- 1.
Automated image recognition has come a long way in recent years, and could be a viable alternative to manual measurement of features imaged via TEM for some applications.
- 2.
In principle, it should be possible to subtract the background by taking a reference pattern and subtracting it from the pattern of interest. Indeed, this was the approach taken in [4]. In practice, the background is approximately constant over most of the pattern, and the fitted background value tended to converge on similar values for all fits with similar measurement optics. This was useful as an added sanity check on the outcome of the fit—a background that deviated significantly from what was expected was a sure indication that the fitting process failed.
- 3.
It is important to emphasise that computers are dumb, mindless machines and should never be trusted to do anything by themselves. One should always be careful to verify that the fits are reasonable, and that the fitting process is working as intended.
References
E. Bernard, R. Sakamoto, N. Yoshida, H. Yamada, Temperature impact on W surface exposed to He plasma in LHD and its consequences for the material properties. J. Nucl. Mater. 463, 316–319 (2015). https://doi.org/10.1016/j.jnucmat.2014.11.041
D. Babonneau, S. Peripolli, M.-F. Beaufort, J.-F. Barbot, J.-P. Simon, GISAXS study of cavities and 113 defects induced by neon and helium implantation in silicon. J. Appl. Crystallogr. 40, s350–s354 (2007). https://doi.org/10.1107/S0021889806043755
B. Efron, C. Stein, The jackknife estimate of variance, 586–596 (1981). https://doi.org/10.1214/aos/1176345462
M. Thompson, P. Kluth, R.P.P. Doerner, N. Kirby, C. Corr, Probing helium nano-bubble formation in tungsten with grazing incidence small angle x-ray scattering. Nucl. Fusion 55, 42001 (2015). https://doi.org/10.1088/0029-5515/55/4/042001
B.E. Dowd, W.H. Greene, E.C. Norton, Computation of standard errors. Health Serv. Res. 49, 731–750 (2014). https://doi.org/10.1111/1475-6773.12122
J. Ma, H. Zhao, P. Schuck, A histogram approach to the quality of fit in sedimentation velocity analyses. Anal. Biochem. 483, 1–3 (2015). https://doi.org/10.1016/j.ab.2015.04.029
M. Thompson, R. Sakamoto, E. Bernard, N. Kirby, P. Kluth, D. Riley, C. Corr, GISAXS modelling of helium-induced nano-bubble formation in tungsten and comparison with TEM. J. Nucl. Mater. 473, 6–12 (2016). https://doi.org/10.1016/j.jnucmat.2016.01.038
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer International Publishing AG, part of Springer Nature
About this chapter
Cite this chapter
Thompson, M. (2018). Validation of GISAXS Model with TEM Data. In: Helium Nano-bubble Formation in Tungsten. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-96011-1_3
Download citation
DOI: https://doi.org/10.1007/978-3-319-96011-1_3
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-96010-4
Online ISBN: 978-3-319-96011-1
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)