The internal shape and alignment of accelerator discs is crucial for efficient collider operation at the future compact linear collider (CLIC). We applied a calibrated custom-made Fourier-domain short coherence interferometer to measure the height of 40 and 60 μm ultraprecisely turned steps (surface roughness Ra≤25 nm, flatness ≤2 μm) on an oxygen-free electronic copper disc. The step heights were quantified to be (39.6±2.6) μm and (59.0±2.3) μm. The uncertainties are quoted at 95% confidence level and include contributions from calibration, refractive index of air, cosine error, surface roughness, and thermal expansion in comparison to standard temperature of 20°C. The results were verified by measuring the same steps using a commercial white light interferometer Veeco—NT3300. Our instrument can ensure that the accelerator discs of the CLIC are aligned within the tolerance required for efficient collider operation.
The internal shape and alignment of accelerator discs is crucial for efficient collider operation in the possible future compact linear collider. We applied a custom made and calibrated Fourier domain short coherence interferometer to measure the height of 40 and 60 μm machined steps on a copper disc in our laboratory. The step heights were determined to be: (43.0 ± 3.1) μm and (46.5 ± 3.2) μm for the 40 μm nominal step, and (46.6 ± 3.6) μm for the 60 μm nominal step. The errors represent 95% confidence level uncertainties and include uncertainty contributions from the calibration, refractive index of air, cosine error, and surface roughness. The step heights were validated by a calibrated contact stylus profilometer which resulted into (44.5 ± 0.8) μm and (45.9 ± 1.0) μm for the 40 μm nominal step, and (45.5 ± 1.7) μm for the 60 μm nominal step at 95% confidence level. The results show feasibility for noncontacting absolute shape and step height characterization with micrometer-level accuracy. This instrument is a first step towards a quality assurance tester for the accelerating structures of the compact linear collider.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
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.