The polarized Gamma-ray Observer (PoGOLite) is a balloon-borne experiment that will measure the polarization of soft gamma rays in the energy range 25 keV-80 keV. PoGOLite will carry an auroral diagnostics package, ALBERT, to measure the auroral emissions that will enhance the background level.
The spectrophotometers of the Alfven Laboratory Balloon ExpeRimenT consists of a photo multiplying tube (PMT), lenses and a Fabry-Perot etalon, to measure auroral emissions as well as surrounding background emissions. The etalon requires a temperature stabilized environment. In this thesis a thermal analysis of ALBERT has been performed and a control system has been designed.
ALBERT has a power budget of 28 W and to meet the thermal requirements the pressure vessel will be insulated with 15 mm of Aerogel Spaceloft on the inside and 5 mm on the outside. A Peltier element is used to heat or cool the vessel.
At times when heating with a Peltier element is not efficient, due to too high temperature difference, a 12 W air heater will be used in instead. The air heater and the Peltier element will be upported by a 12 W bench heater, which by heating the optical setup ensures a correct temperature of the Fabry-Perot etalons.
The control system will consist of one PID for the air heater and one for the Peltier element. The bench heater will be controlled by a PD regulator with feed forward. The PMT has a built in Peltier element and this will be controlled by a PID regulator with feed forward.
Source: KTH
Author: Magnus Söderquist
