We’re experimenting with a new particle detector, based on a special light-sensitive “PIN” diode. We’ve adapted a circuit from Elektor, and we’ve started to experiment with it. We’re hoping to develop an inexpensive, low-power detector that works as well as or better than the Geiger-Müller tubes we’ve been using in all the pixels. If we can achieve reliable operation (not yet, but we’re trying), we’ll build a prototype board with an array of PIN diodes, trying to achieve a sensitive area similar in size to the G-M tubes.
Additional experimentation is being done to see if we can shield the G-M tubes to reduce their sensitivity to Earth-based radiation. That might reduce the number of event detections that aren’t really cosmic-ray muons.