John Call Cook

In 1951 Cook was the first PhD in Geophysics to graduate from Penn State University. By this time he had produced three articles which challenged existing thinking of the time, "Laboratory Tests of Electrolog Resistivity Interpretation", "Characteristics of Reservoir Models by Resistivity Logging", and "Can Gravity Be Abolished?". His doctoral dissertation, "An Analysis of Airborne Surveying for Surface Radioactivity", was also published in the primary journal for the field, Geophysics.

His education nearly complete, Cook wrote letters offering his services to several oil companies and other labs (the natural employers of geophysicists) located in the subtropical Southwest, as wife Vi needed warmer climate. He received five invitations to interviews in the Spring of 1951.

The Geophysics department had just bought a small, portable geiger counter, which did respond well to the gamma rays coming from rock samples Cook had gathered from the Mauch Chunk camotite outcrop. One could get crude quantitative data by counting the audible "clicks" it produced over a minute's time. In this way, a gamma-ray "profile" of an ore stockpile at a uranium refinery at Rifle, Colorado was obtained during Cook's trip West in the summer of 1950. The ore was clearly detectable at a distance of a quarter-mile. However, it was known that equipment of much greater sensitivity would be needed for a practical airborne survey. In fact, scintillation detectors having both a much larger cross- section and much higher detection efficiency were already in airborne use in Canada and by the U.S. Geological Survey, although many of the details were secret.

Cook attempted to cast a large sodium iodide crystal in a glass baking dish, using one of the Department ovens, with poor results. (it's an art) With limited funds, he secured a large geiger-mueller tube 18 inches long, one inch in diameter, which was adequate for his thesis experiments. He developed the needed accessory circuits (high-voltage source and amplifiers, all battery-powered, a borrowed mechanical pulse counter, and 400 ft of lightweight, high-voltage twin cable on a portable reel). With this equipment Cook found the effect of height on the gamma ray field from the soil (using flagpoles). He also ran fairly accurate (1.5%) radiation profiles at various heights over several gamma-ray sources: boxes of ore, the Mauch Chunk uranium deposit, and 0.1 gram of pure radium borrowed from a hospital! Heights up to 300 ft. were achieved using 6-foot hydrogen-filled balloons from the Meteorology department to lift the detector, preamplifier and cable. This work occupied much of the Winter and Spring of 1950–51. Cook wrote a careful thesis of over 100 pages, with 29 figures, which wife Vi typed in 3 copies, and was approved by the committee.

In the Winter of 1949 Cook attempted to complete an experiment begun during his master's work: to detect a tangential gravitational field purportedly produced around a rotating body (according to certain published theories). He had not found it with the small centrifuge in the Mineral Processing lab, so arranged to work with the massive turbine rotors at the Westinghouse Plant Apparatus Division, Atomic Power Plant Equipment, east of Pittsburgh, Pa. He drove to the plant several times with the Eötvös torsion balance in the back, and set it up close to one of the newly made rotors while it was being balanced at 3,600rpm on the giant factory floor. The balance needed to settle for an hour, and Cook needed one reading with the rotor stationary, then another with it turning at full speed; however random vibrations, the starting and stopping for tuning, and heating and cooling to simulate operating conditions made stable readings difficult. Westinghouse engineers showed Cook blueprints of the building, which had a floor of great cast-iron plates 6" thick, resting on brick piers on bedrock. It could hardly be more sturdy, yet still vibrated from the machinery. Cook tried damping spurious modes by filling the delicate instrument with alcohol, but this induced more instabilities, possibly from thermal currents. During his final attempt at Westinghouse Cook was told that a famous engineer in the research lab wanted to see him, Joseph Slepian, who asked about the theoretical basis of a tangential gravitational field, and proceeded to cast doubt as it's not an effect predicted by Einstein's General Relativity. Cook could not debate the matter and so gave up the pursuit.

Pirson then arranged for Cook to take over a research project for the Penn Grade Crude Association (a small group of oil firms in northwest Pennsylvania) with a salary of $300/mo and promotion to Research Associate. Another Research Associate, Bacon, and Cook were left with teaching all of the Geophysics courses; Bacon taught most, while Cook taught General Geochemistry for Fall-Winter, 1948-9 and worked in research. At the end of the school year, Pirson left the university for a better paying job with an oil company in Tulsa, OK. All in the department were sorry to see this professor go.

During the Winter-Spring of 1948-9 Cook did field work in the oilfields around Bradford in northwestern Pennsylvania as part of the Penn Grade research. These fields are famous for producing high-grade petroleum which is refined into Quaker State, Pennzoil and other superior brands. Cook saw the actual drilling and logging processes, although most wells were 30–50 years old with decrepit and rusty pumping equipment. A central engine running on natural gas (from the wells) in a shack, with steel rods radiating out to wells all around (as much as 500' away), rocking back and forth on the ground or on stands. Here, Cook conceived an improvement in electric logging technique: a thin-sheet current path controlled by 'shielding-current' electrodes, analogous to the Kelvin potential shields he had learned about at the University of Utah. He built a model, which did indeed greatly improve the vertical resolution of the resistivity logging. Cook considered getting a patent, but soon learned that a similar system had been developed by another sole inventor and Schlumberger Well Surveying Corp, who were involved in patent litigation with one another.

Graduated in 1947 at age 29. Somewhat in shock from the experiences of his Master's, Cook drove home. He met L.V.S. Roos of Texaco, who headed a crew doing seismic prospecting for oil in the Utah area, and was hired on as Assistant Recorder at $300/month. Early each morning their crew of 8 would drive out with the recording truck, a drill-hole rig, and a water tanker to various sites marked by a survey crew. The drill crew made a 3" hole up to 150' deep and emplaced a dynamite charge. They laid out numerous cables 1,000' around the radius of the recorder truck and attached geophones connected at intervals. Then a preliminary charge would be set off to 'spring' the hole, and then the main shot was made, requiring many switches to be thrown in a special order. This all required concentration and care as, once blown the hole could not be used anymore, and Cook was soon promoted for getting good data. Having a master's degree, Cook was treated as someone special by visiting Texaco officials and Mr. Roos, and it was suggested that he could be a Crew Chief or could be asked to join the laboratory staff in Houston. These successes and being with family, had restored Cook's confidence.

In late Fall, 1947 Cook received a telegram from Prof. Pirson at Penn State offering him a job in the Geophysics Department as a Research Assistant for $170/mo, to work on a PhD in Geophysics. Tuition would be only a nominal fee, and colder weather meant working on the field crew would be unpleasant, so Cook immediately accepted the opportunity. On arrival at Penn State he moved back into the Graduate Club and was accepted into the PhD program. Cook was made responsible for the earthquake seismograph station so learned how to run it, read the records, and send reports to Washington. At Prof. Pirson's request he built their first vertical-component seismometer and arranged for visible-ink recording of its output upstairs in their offices, so they no longer had to develop photographic records to know when an earthquake was happening anywhere on Earth.

In spring 1945 they received news of the German V-2 rocket-propelled ballistic missiles striking Britain. The German Rocket Society, with their government's support, had continued the work of American Robert Goddard and were far ahead of the U.S. However, their large, successful rockets had been applied at once to military purposes. Cook was disgusted with this and so lost interest in rockets until NASA was formed. When it also developed that he would soon be leaving Cambridge, he resigned as president of the MIT Rocket Research Society and turned it over to Robert Kraichnan, who would later become prominent in relativity.

In the Fall of 1945 Cook applied for and received a graduate assistantship at Penn State and began work on a master's degree. During his second year there he was appointed to teach Prof. Weber's junior year Thermal Laboratory course. Cook read extensively in the Physics Library on gravitational topics, developed a thesis plan, and performed a program of experiments using an Eötvös torsion balance (an extremely sensitive gravity-sensing instrument) owned by the Geophysics Department in the Mineral Industries building. Prof. Sylvain Pirson there was pleased with the modifications Cook had made to improve the sensitivity of the balance, and with his administration of the course. However Prof. Duncan, the department head, advised Cook that as he'd had serious difficulty with some important mathematical physics courses, it was recommended that he leave with the MS and not come back.

Cook initially studied at Brigham Young University then enrolled with the University of Utah to study Physics. In the Spring of 1941 Cook began work as lab assistant at the university, and graduated that same year.

John Call Cook (April 7, 1918 – October 12, 2012) was an American geophysicist who played a crucial role in establishing the field of ground-penetrating radar and is generally regarded as contributing the fundamental research to develop the field. Cook is also known for demonstrating that aerial surveys can map surface radioactivity to enable much more efficient prospecting for uranium ore, for inventing electrostatic detection of hazardous ice crevasses, and for developing other novel techniques in remote sensing.

John Call Cook was born on April 7, 1918 in Afton, Wyoming, to Carl and Ella Cook. Carl made his living as an attorney and farmer, and was himself the son of Phineas Wolcott Cook and number 4 wife, Johanna.