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Proceedings Paper

Mid-IR interferometric nulling for TPF
Author(s): James Kent Wallace; Vivek Babtiwale; Randy Bartos; Ken Brown; Robert Gappinger; Frank Loya; Dan MacDonald; Stefan Martin; John Negron; Tuan Truong; Gautam Vasisht
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Paper Abstract

By the middle of 2006, the Interferometry Technology development program for NASA's Terrestrial Planet Finder (TPF) Mission has the goal of demonstrating deep and stable interferometric nulling of broadband Mid-IR thermal radiation under conditions that are traceable to the expected on-orbit conditions. Specifically, the task is to demonstrate null levels of 10-6, with a 50% bandwidth centered at 10 μm, with null stabilities of 10-7 all at cryogenic temperatures for observational periods of a couple of hours. The Achromatic Nulling activity at JPL addresses this concern in two testbeds: the warm nulling testbed and the cryonulling testbed. The warm nulling testbed will demonstrate the physics of nulling broadband thermal sources in an environment that is conducive to efficient research. We'll explore nulling techniques, optical-mechanical alignment methods, motion control, and path-length metrology for a single beam interferometer, as well as preliminary planet detection techniques. Ultimate nulling capabilities under conditions that are more flight-like will be demonstrated in the cryogenic nulling testbed. Knowledge gained from operation at room temperature will be applied to the cryogenic experiment where we face the additional challenges of extreme temperatures, cryogenic actuators, component survivability and fluxes that are within an order of magnitude of expected flux levels on orbit. Concurrently, we will develop a low flux mid-IR camera that will allow us to measure the nulls at these faint photon fluxes. This talk will review this development activity and will include recent nulling experimental results and plans for future work.

Paper Details

Date Published: 20 October 2004
PDF: 12 pages
Proc. SPIE 5491, New Frontiers in Stellar Interferometry, (20 October 2004); doi: 10.1117/12.551558
Show Author Affiliations
James Kent Wallace, Jet Propulsion Lab. (United States)
Vivek Babtiwale, Jet Propulsion Lab. (United States)
Randy Bartos, Jet Propulsion Lab. (United States)
Ken Brown, Jet Propulsion Lab. (United States)
Robert Gappinger, Jet Propulsion Lab. (United States)
Frank Loya, Jet Propulsion Lab. (United States)
Dan MacDonald, Jet Propulsion Lab. (United States)
Stefan Martin, Jet Propulsion Lab. (United States)
John Negron, Jet Propulsion Lab. (United States)
Tuan Truong, Jet Propulsion Lab. (United States)
Gautam Vasisht, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 5491:
New Frontiers in Stellar Interferometry
Wesley A. Traub, Editor(s)

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