his detector design is an experiment in using a summing amplifier for measuring coincidence between multiple ionizing radiation detectors. In this example four Geiger–Müller tubes. The output would be used to drive different colours and sounds based on the voltage level of each pulse. It would also display background radiation as a specific colour/sound which would be ~1/4V pulse. Where a muon strike (cosmic ray) being either ~1/2V ~3/4V and ~1V.
Note the pulse height clearly increasing when the tubes are oriented from vertical to horizontal. This is a result of an ionizing particle traversing through more than one GMT originating from the sky.