An Introduction to Space Instrumentation,
Edited by K. Oyama and C. Z. Cheng, pp. 139-153.
© TERRAPUB, 2013.
H. K. Fang1,2 and C. Z Cheng2,3
1Department of Physics, National Cheng Kung University, No. 1 Ta-Hsueh Rd., Tainan 70101, Taiwan
2Plasma and Space Science Center, National Cheng Kung University, No. 1 Ta-Hsueh Rd., Tainan 70101, Taiwan
3Institute of Space and Plasma Sciences, National Cheng Kung University, No. 1 Ta-Hsueh Rd., Tainan 70101, Taiwan
Problems associated with Retarding Potential Analyzer (RPA), which can be used to measure ion temperature/and density in the lower E region where ion temperature is 200-300 K, are discussed. Two major factors which need to be taken care of to get accurate ion temperature of extremely low values are the effect of mesh size of the grids to be used and the effect of electrode contamination. An electrode baking and vacuum sealing mechanisms are designed to keep the electrode surface clean. The effect of mesh sizes on the calculation of ion temperature is discussed by using simulation studies as well as laboratory experiments. The study suggests that the uniformity of the electric field in the RPA sensor is critical. The manuscript describes the principle of the RPA, the effect of the mesh size using computer simulation studies, and the mechanical design of the sensor sealing to remove electrode contamination.
Key words: Lower ionosphere, ion temperature, electrode contamination, mesh size effect.