Word: geigers
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Cosmic Counter. The degree of cosmic radiation in space is a bafflement that earth satellites have so far only deepened. Geiger counters aboard Explorers I and III were so swamped that they choked up. The new Explorer IV, equipped with more specialized counters, reports that radiation doubles for every 60 miles over a threshold 250 miles beyond earth...
...where magnetic deflection is greatest), and strongest near the magnetic poles. At 1,200 miles above South America, the radiation hit Explorer IV at a heavy ten roentgens an hour-enough to give the human space traveler his top weekly X-ray dosage in about two minutes. And one Geiger counter inside the satellite, though coated with lead 1/16 in. thick, recorded 60% as many impacts as its unshielded mate, which in turn reported radiation almost as intense as that reported by two scintillation counters outside the vehicle. Nobody knows where this radiation comes from or what gives it such...
Little is known about the radiation belt. Explorer III, with a single Geiger counter, reported only that the radiation was strong enough to jam the counter's tube. The more sophisticated instruments of Explorer IV, two Geiger counters and two scintillation counters, are designed to measure the radiation accurately and tell what kind it is. They will report over two radio transmitters, a high-powered one on 108.03 megacycles, a low-powered one at 108 megacycles, both with chemical batteries. Explorer IV has no solar battery, no magnetic tape, no mouse...
...came from a team of cosmic ray experts at the State University of Iowa headed by Dr. James A. Van Allen. Both Explorer I and Explorer III, said Van Allen, ran into a belt of intense radiation at about 600 miles elevation. Each of the satellites carries a single Geiger tube to count cosmic rays. The radio transmitter of Explorer I sends a signal whenever the tube has made 128 counts. Explorer III has a magnetic tape that records the tube's counts during each circuit of the earth and reports to a ground station...
...Allen was sure that no ray-free belt could exist between the earth and space. The only reasonable explanation, he decided, was that the silenced Geiger tubes had been knocked out temporarily by radiation too intense for them to handle. So he subjected a spare tube to X-ray bombardment in the laboratory. After studying its behavior, he decided that the tubes carried by the satellites must have passed through radiation equivalent to 35,000 counts per second, but were so choked up that they could not report their experience...