August 1, 2014.
NASA’s Cold Atom Lab (CAL) is a multi-user facility designed to study ultra-cold quantum gases in the microgravity environment of the International Space Station (ISS). One of the main goals of CAL is to explore the unknown territory of extremely low temperatures—possibly as low as the picokelvin range!—where new and fascinating quantum phenomena can be observed. At such temperatures matter stops behaving as particles and instead becomes macroscopic matter waves. CAL will be remotely controlled to perform a multitude of experiments and is scheduled to launch in 2016. In order to anticipate problems that might occur during and post-launch, including high temperatures and increased vibration, environmental testing of lasers was performed. A Tenney environmental test chamber was used to thermally test engineering-model (EM) potassium (767 nm) and rubidium (780 nm) lasers. Cavity temperature and power output were tracked as temperature was increased from 24 to 42°C in 2- to 3-degree increments. A gradual decrease in laser power was observed until just above 35°C, when laser frequencies jumped several GHz and laser power suddenly increased, indicating mode hops. Two thermal tests of a commercial tapered amplifier (TA) were also performed over a temperature range of 20 to 40°C in 2-degree increments. Though the TA’s input power remained well within the normal range of around 13mW, its output power was observed to be less than half its normal value, indicating malfunctioning. In development are a vibrational test plan and measurement techniques for diagnosis during vibrational testing.
Atomic, Molecular and Optical Physics | Condensed Matter Physics | Cosmology, Relativity, and Gravity | Engineering Physics | Instrumentation | Physical Processes | Quantum Physics
James M. Kohel
NASA Jet Propulsion Laboratory (JPL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).
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