Mr. Earle Welsh Profile

Earle Welsh

at Lockheed Martin Missiles and Fire Control

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 | 2 May 2007 Paper

Erosion studies of infrared dome materials

Roger Sullivan, Andrew Phelps, James Kirsch, Earle Welsh, Daniel Harris

Proceedings Volume 6545, 65450G (2007) https://doi.org/10.1117/12.719966

KEYWORDS: Spinel, Magnesium fluoride, Coating, Particles, Mid-IR, Absorption, Resistance, Infrared radiation, Photomicroscopy, Zinc

Read Abstract +

The testing reported in this paper operationalized the material requirement: An infrared transparent dome material must be at least as good as magnesium fluoride in rain tests and substantially better than magnesium fluoride in sand tests. Sand erosion test conclusions, based on changes in midwave infrared transmission, are that Cleartran^TM with the protective coating system tested is not substantially more resistant to large grain sand erosion damage than magnesium fluoride. ALON^TM and spinel are substantially more resistant to large grain sand erosion damage than magnesium fluoride. There is no significant transmission difference due to small grain sand erosion observed between any of the tested coupons. Qualitative analysis of coupon damage after exposure to an artificial rain field on a whirling arm showed that ALON^TM and spinel are at least as rain erosion resistant as magnesium fluoride, but the coated Cleartran^TM coupons delaminated rapidly under the same rain test conditions. Testing coupons exposed sequentially to the milder sand condition followed by the whirling arm rain erosion test demonstrated that magnesium fluoride rain resistance is diminished in the combined test, but that ALON^TM and spinel retain their robust resistance. Coated Cleartran^TM delaminated under the combined conditions as well. It is noteworthy that the results reported for the midwave infrared range also apply to the near infrared region above 1 micron.

Proceedings Article | 18 May 2005 Paper

Tri-mode seeker dome considerations

James Kirsch, William Lindberg, Daniel Harris, Michael Adcock, Tom Li, Earle Welsh, Rick Akins

Proceedings Volume 5786, (2005) https://doi.org/10.1117/12.606158

KEYWORDS: Spinel, Dielectrics, Domes, Zinc, Sensors, Missiles, Infrared radiation, Extremely high frequency, Surface finishing, Manufacturing

Read Abstract +

The dome or window on a sensor suite seems, at first glance, to be a relatively low tech item. In reality, it can be one of the most costly items in the system. The choice of materials is highly dependent on the sensor, the anticipated operating conditions, and other requirements such as electromagnetic interference or radar cross section issues. The situation is further complicated when multiple sensor bands are used. Some dome materials are suitable for visible or near infrared applications, some for midwave infrared applications, and others for long wave infrared applications. Materials are also available which can be used for dual band sensors such as visible and midwave sensors. The Army is currently developing a tri-mode seeker containing semi-active laser, midwave infrared, and millimeter sensors all using a common aperture. This added complexity is nowhere more apparent than in the missile dome. Optically transparent infrared optical materials tend to have relatively high dielectric constants. Millimeter wave radomes typically have low dielectric constants. Electromagnetic shielding for an optical seeker frequently consists of some type of grid that serves as a wideband filter. Electromagnetic shielding for millimeter wave missiles may use complicated frequency selective surfaces that block all but the frequency of interest. Unfortunately, those frequency selective surfaces tend to be predominantly metal and are opaque in the optical regime. This paper will discuss the unique requirements that are placed on a tri-mode seeker as well as efforts to meet those requirements.

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