Paper
11 November 1996 Thermal analysis on hex-placement patterns of the Gemini primary mirrors
Myung K. Cho, William R. Powell
Author Affiliations +
Abstract
The photoacoustic tow-beam phase lag method was described for studying the thermal diffusivity of metal and superconductor materials in this paper. A beam of laser modulated from an argon ion laser is divided into the two beams, which illuminate respectively front and rear surface of the sample. The phase photoacoustic signal difference (phase lag) can be measured by lock-in amplifier. The phase lag is related to thermal diffusivity of sample. We measured the metal samples such as lead, copper, aluminium and stainless-steel in room temperature, and the results are very agreeable with the other method. We also have studied the temperature dependence of the thermal diffusivity of the high-temperature superconductor Bi1.5Pb0.5Sr2Ca2Cu3O. The experimental results are presented.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Myung K. Cho and William R. Powell "Thermal analysis on hex-placement patterns of the Gemini primary mirrors", Proc. SPIE 2857, Advanced Materials for Optical and Precision Structures, (11 November 1996); https://doi.org/10.1117/12.258296
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KEYWORDS
Mirrors

Active optics

Distortion

Optical calibration

Thermography

Gemini Observatory

Thermal analysis

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