Dr. Clifford T. Tanaka Profile

Dr. Clifford T. Tanaka

Senior Staff Scientist at Trex Advanced Materials

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 22 August 2009 Paper

Recent achievements using chemical vapor composite silicon carbide (CVC SiC)

William Goodman, Clifford Tanaka

Proceedings Volume 7425, 74250B (2009) https://doi.org/10.1117/12.824202

KEYWORDS: Silicon carbide, Polishing, X-rays, Wavefronts, Surface finishing, Metrology, Fringe analysis, Chemical vapor deposition, Composites, Mirrors

Read Abstract +

This annual review documents our progress towards inexpensive mass production of silicon carbide mirrors and optical structures. Results are provided for a NASA Small Business Technology Transfer (STTR) X-Ray Mirror project. Trex partnered with the University of Alabama-Huntsville Center for Advanced Optics (UAH-CAO) to develop fabrication methods for polished cylindrical and conical chemical vapor composite (CVC^TM) SiC mandrels. These mandrels are envisioned as pre-forms for the replication of fused silica x-ray optics to be eventually used in the International X-Ray Observatory (IXO). CVC SiC^TM offers superior high temperature stability, thermal and mechanical performance and polishability required for this precision replication process. In this program, Trex fabricated prototype mandrels with design diameters of 10.5cm, 20cm and 45cm. UAH-CAO was Trex's university partner in this effort and worked on polishing and metrology of the unusual x-ray mandrel geometries. UAH-CAO successfully developed an innovative interferometric method for measuring the CVC SiC^TM x-ray mandrels based on a precision cylindrical lens system. UAH-CAO also developed finishing and polishing methods for CVC SiC^TM that utilized a Zeeko IRP200 computer controlled polishing tool. The three technologies key technologies demonstrated in this program (near net shape forming of CVC SiC^TM mandrels, the x-ray mandrel metrology and free-form polishing capability on CVC SiC^TM) could enable cost-effective manufacture of the x-ray mandrels required for the International X-Ray Observatory (IXO).

Proceedings Article | 14 June 2006 Paper

Chemical vapor composite silicon carbide for space telescopes

C. Tanaka, K. Webb

Proceedings Volume 6265, 62652Q (2006) https://doi.org/10.1117/12.672172

KEYWORDS: Silicon carbide, Mirrors, Space telescopes, Chemical vapor deposition, Natural surfaces, Composites, Photovoltaics, Plano, Telescopes, James Webb Space Telescope

Read Abstract +

Components for space telescopes using high quality silicon carbide (SiC) produced via the chemical vapor composite (CVC) process are currently under development. This CVC process is a modification of chemical vapor deposition (CVD) and results in a dramatic reduction in residual stress of the SiC deposit. The resultant CVC SiC material has high modulus, high thermal conductivity and can be polished to better than 1nm RMS surface roughness, making it ideal for space telescopes requiring lightweight, stiff and thermally stable components. Moreover, due to its lower intrinsic stress, CVC SiC is much more readily scaled to large sizes and manufactured into the complex geometries needed for the telescope assemblies. Results are presented on the optical figure for a lightweight 15cm CVC SiC mirror demonstrating low wavefront error (<30nm peak-to-valley and <5.1nm rms). Theoretical and experimental modal analysis measured the first four resonant modes of the mirror and found a first modal frequency in the vicinity of 2100 Hz, representing a highly stiff mirror.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

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.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

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

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years