Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 1: Precision Measurements and Metrology I (with Q)
A 1.3: Vortrag
Montag, 29. Februar 2016, 11:30–11:45, a310
Dilatometer Setup to Characterize Dimensionally Stable Materials by the Coefficient of Thermal Expansion at a Temperature Range from 100 K to 325 K — •Ines Hamann1, Ruven Spannagel1, Thilo Schuldt1, Jose Sanjuan1, Martin Gohlke1, Ulrich Johann2, Dennis Weise2, and Claus Braxmaier1,3 — 1DLR German Aerospace Center, Institute of Space Systems, 28359 Bremen, Germany — 2Airbus Defence & Space, 88039 Friedrichshafen, Germany — 3University of Bremen, ZARM Center of Applied Space Technology and Microgravity, 28359 Bremen, Germany
Space missions with the aim of high precision optical measurements are often limited by the dimensional stability of the instrument which can be exposed to high temperature fluctuations, due to the environment of the space probe. To minimize the change of the geometric dimension due to temperature changes, highly dimensionally stable materials are needed at the specific environmental temperatures. Materials like glass ceramics offer a minimal coefficient of thermal expansion (CTE) but they are also very heavy. Composite materials like CFRP or SiC offer also a very low CTE but with a lower weight and are more and more used for such applications. To characterize such low expansion materials we use a laser dilatometer with a heterodyne interferometer to measure length variations of the sample caused by an applied temperature variation. Using a cryocooler in combination with a heating system, we are able to determine CTEs at the 10 ppb/K level within a temperature range from 100 K to 325 K. In this talk, we present improvements of our setup and recent sample measurements.