Editing Explorer 2 (section)

=== Geiger counter ===
An Anton 314 omnidirectional Geiger tube detector was used to measure the flux of energetic [[charged particle]]s (protons E>30 MeV and electrons E>3 MeV). The instrument consisted of a single [[Geiger–Müller tube|Geiger-Mueller tube]], a scaling circuit to reduce the number of pulses, and a telemetry system to transmit the data to ground receiving stations. The Geiger-Mueller tube was a type 314 Anton halogen quenched counter with stainless steel (approximately 75% iron, 25% chromium) wall of approximately {{cvt|0.12|cm}} thickness. The instrument was mounted within the spacecraft hull, which had {{cvt|0.58|mm}} thick stainless steel walls. The counter was {{cvt|10.2|cm}} long by {{cvt|2.0|cm}} diameter and the internal wire was {{cvt|10|cm}} in length. The tube had a very small variation in counting efficiency over the range -55° to +175&nbsp;°C. It had approximately 85% counting efficiency for [[cosmic ray]]s, and about 0.3% counting efficiency for [[photon]]s of energy 660 keV. The "dead time" (time to reset to record the next count) of the counters was about 100 microseconds. The counter was connected to a [[Amplifier|current amplifier]], which directly fed a scaler stage, a bistable transistor multivibrator that could operate over a wide range of voltages and a temperature range of -15° to +85&nbsp;°C, limited primarily by the supply batteries. The scaler resolving time was 250 microseconds. For pulse counts higher than 4000 per second, the scaler indicated a count of 4000. Results were sent to the ground through the telemetry system in real time. The experiment had no onboard data storage device, and could only send telemetry to the ground when it was passing over an Earth receiving station, so some regions had no coverage during the flight.<ref name="Instrument1">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1958-001A-01|title=Experiment: Geiger counter|publisher=NASA|date=14 May 2020|access-date=13 February 2021}} {{PD-notice}}</ref>