Development of a balloon-borne radioactivity detector for space weather measurements

Measurement of space weather is key to understanding, preventing, and mitigating the adverse effects of space weather events. Ground-based detectors and satellite sensors provide coverage of energetic particles in their respective domains, however, there remains scope for intermediary devices and instrumentation.

We present a novel energetic particle detector which has undergone development and deployment on radiosonde systems. The small form-factor and light weight instrument is composed of a CsI(Tl) scintillator coupled to a PiN photodiode and is capable of count rate and energy discrimination. Recent energy calibrations suggest the instrument is sensitive to a range of energies from 30 keV to 9.4 MeV. The microscintillator detector is therefore an ideal instrument for space weather investigations.

During previous flights, the microscintillator detector responded to low energy particles in the stratosphere, particularly observing energetic electron precipitation events. Recent research however has focussed on understanding and improving the detector performance at temperatures comparable to the atmospheric environment, and modifying the internal microcontroller system for interfacing with the new industry standard Vaisala RS41 radiosonde system.

We present the low temperature (0 °C to -50 °C) response of the detector to terrestrial background radiation, and progress in interfacing with the new radiosonde system, both obtained in a controlled laboratory setting. Future deployments of the detector are planned over the coming year as we approach solar maximum in 2025.