Word: magnetization
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Dates: during 1930-1939
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...cyclotron of Ernest Orlando Lawrence neatly finesses such troubles by making a comparatively small voltage act on a particle repeatedly until it attains a speed corresponding to extremely high voltage, thus dispensing with a discharge tube altogether. Most conspicuous feature of the apparatus is an 85-ton electro-magnet whose poles face each other vertically across an 8-in. gap. In the gap is placed a shallow cylindrical tank, pumped out to a high vacuum so that particles inside may move freely without interference from air molecules. Ions such as deuterons (nuclei of heavy hydrogen...
...means of a radio-frequency oscillator a rapidly alternating potential of 50,000 volts is maintained across the tank. Under this influence the deuterons in the centre start to move outward. The effect of the big magnet is to pull them in circles. Just as they complete a half-circle the voltage is reversed, so that they get a kick of 50,000 volts to boost them around the other side of the circle at higher speed. After another half-circle the reversed voltage hits them again, and so on. The deuterons go spiraling outward, faster and faster, toward...
...Breaks." Lawrence conceived the basic idea of the cyclotron in 1929 when he read a paper by an obscure German on the behavior of ions in a magnetic field. Next year he and three co-workers -Niels Edlefsen, M. Stanley Livingston and David Sloan-built the first cyclotron with a tank six inches across and a small magnet. It worked, but Lawrence pined for a bigger magnet...
When Dr. Leonard Fuller, head of electrical engineering at the university, heard of this he asked Lawrence how an 85-ton magnet would suit him. Lawrence gasped. Dr. Fuller also happened to be vice-president of Federal Telegraph Co., which had built four 85-ton magnets for round-the-world radio transmission during the War. Peace came before this particular magnet could be shipped to China and ever since it had lain idle at Palo Alto. Dr. Fuller and Dr. Lawrence jumped into an automobile and roared down to Palo Alto. Soon the big magnet was installed at Berkeley...
...Carnegie Institution's seismograph station on Mt. Wilson in California, Dr. Hugo Benioff has built recorders which work by electromagnetism. The weight is a magnet hung so that its poles are a tiny fraction of an inch from the armature. When an earth tremor twitches the armature, the distance between it and the magnet changes slightly, altering the magnetic field and creating a tiny electric current which is amplified by vacuum tubes. This current fluctuates the light beam which makes the record, also twitches a galvanometer needle. In the Benioff seismograph, earth movements are magnified 200,000 times...