Abstract
Thermal performance of an O-shaped Oscillating Heat pipe (OHP) for balloon-borne General Anti-Particle Spectrometer (GAPS) experiment has been investigated. The developed OHP is a closed type and O-shaped for using the gravity assist. R410A is selected as the working fluid for the use at low temperatures. At -50 deg-C, we achieved a thermal conductance of 20 W/K for 150 W heat input with 32 loops and -40 deg-C heating section. We also found for the first time that this large-scale OHP can be operated at low temperatures. It is found that this OHP can satisfy the GAPS thermal control requirement.