Interview with Thomas A. Tombrello - Caltech Oral Histories

Tombrello–70
slightly older grad student, working on photoemission, I believe, which was new. The
photoelectric effect was one of the reasons Einstein got the Nobel Prize. Millikan, too. Millikan
got the Nobel Prize [1923] not just for measuring the electron charge but also for experimental
work on the photoelectric effect, which verified some of Einstein’s predictions about its being a
quantum effect. So Charlie did his thesis on that topic and got his degree in rather short order
[1929].
There’d been a professor occupying the High-Voltage Lab, which is now Sloan, and his
name was Royal Sorensen. During the 1930s, he built some cascade transformers that would go
up to almost 1 million volts. The purpose of this lab was to test components for the Hoover
Dam—then the Boulder Dam—which was just being finished. They were building the electrical
systems for it, and they needed high-voltage testing of the insulators and other components.
Sorensen had a lot to do with that. Charlie Lauritsen saw this as an opportunity to get into a new
field, which was building high-voltage X-ray tubes and getting into high-voltage X-ray therapies.
Kellogg started with a donation from W. K. Kellogg, who had a ranch out in Pomona.
ASPATURIAN: This was a cereal magnate.
TOMBRELLO: That’s a story in its own right, because his brother was the one who invented the
cereal, but W. K. was the one who turned it into a company and made money out of it. The
brother of W. K. had run a sanatorium, and one of the things you fed people were health foods,
and one of the health foods was Kellogg’s cereal. Kellogg was getting older and of course was
getting interested in things like cancer, and so he funded the building of the Kellogg Lab, which
was attached to the High-Voltage Lab. Charlie started building high-voltage X-rays, using X-ray
tubes and optimizing them based on his knowledge about field emission—because one of the
limitations of an X-ray tube is electrons being sucked out of the electrodes and causing problems
inside the tube. Charlie had learned a lot about minimizing such effects. He was able to build
some high-voltage tubes that went up to about 1 million volts. This was done in partnership with
the Huntington Hospital. This is all in 1930-31 to maybe 1933; I’m not sure of the exact time
sequence. A lot of things were going on.
At the same time nuclear physics was appearing. E. O. Lawrence at Berkeley had built a
cyclotron and was doing nuclear physics with it. Merle Tuve had built Van de Graaffs [Van de
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