Manuscript

Testing Low-Cost Geiger Counters for Potential Use on Stratospheric Ballooning Missions

---

Abstract

Stratospheric weather balloons can ascend above 25 kilometers, passing the Regener-Pfotzer maximum, where the cosmic radiation environment transitions from a flux of secondary particles to fewer-but-more-energetic primary cosmic rays. During the spring of 2025, the Solar Max Ballooning Initiative sought to characterize the Forbush decrease: an observed dip in cosmic ray intensity striking the Earth following coronal mass ejections (CMEs), when the Sun’s magnetic field carried by the solar wind deflects incoming galactic cosmic rays. As informal participants in this multi-team effort, the ballooning team at the U of MN Twin Cities purchased several low-cost, commercially-available Geiger counters to test them for potential use on stratospheric balloon missions. Historically, our team has flown RM-60 and RM-80 Geiger counters from Aware Electronics, as well as Neulog Geiger counter modules. However, these products are longer available, so this study is seeking viable replacements capable of operating in stratospheric conditions. We purchased, ground tested, and flew several new-to-us Geiger counters including “MightyOhm”, “DFRobot: Gravity”, “Shkalacar”, and “GQ GMC-500+”. Of these, the “GQ GMC-500+” and “DFRobot: Gravity” units have shown the most promise during stratospheric balloon flights, with consistent high-altitude performance, adequate sensitivity to altitude-dependent radiation changes, and ease of data collection using microcontrollers or built-in logging systems. We are also in the process of characterizing how the orientation of asymmetrical Geiger counters influences their efficiency in detecting cosmic radiation levels. Preliminary results suggest that there is a slight orientation dependence for the counters we have tested at different angles in flight, especially below the Regener-Pfotzer max altitude, but that the sensitivity variation between supposedly-identical units might be an even-larger effect.

Keywords: Geiger counter, stratosphere, stratospheric ballooning, weather balloon

How to Cite:

Shin, J., Margosian, D. & Flaten, J., (2025) “Testing Low-Cost Geiger Counters for Potential Use on Stratospheric Ballooning Missions”, Academic High Altitude Conference 2025(1). doi: https://doi.org/10.31274/ahac.20147