The Prototype GAPS (pGAPS) Experiment

TL;DR

The pGAPS experiment demonstrated the feasibility of using lithium drifted silicon detectors on a balloon for cosmic ray antiparticle detection, validating key technologies and background characterization for future GAPS missions.

Contribution

This paper reports the successful flight of a prototype GAPS instrument, testing detector operation, thermal management, and background measurement at high altitude.

Findings

Lithium drifted silicon detectors operated successfully at balloon altitude.

Thermal model and cooling system were validated during flight.

Over one million cosmic ray triggers recorded, meeting all flight goals.

Abstract

The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS experiment (pGAPS) was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 hours, with over 3 hours at float altitude (~33 km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded.