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Luis Alvarez (1911-1988)

Luis W. Alvarez
A

lvarez and Lawrence first met at the Century of Progress Exhibition at the Chicago World’s Fair in June 1932, where Lawrence had assembled a scale-model cyclotron. Birge hired Alvarez in 1936 but he left the department almost immediately to work at the Rad Lab.


Within a year he had given the first experimental demonstration of the existence of the phenomenon of K-electron capture by nuclei, and soon after developed a method for producing beams of very slow neutrons. During World War II he went to the Radiation Laboratory at MIT and helped develop three important radar systems: the microwave early warning system, the Eagle high altitude bombing system, and a system for landing airplanes safely in fog and other conditions when the runways are obscured. He went to Los Alamos in 1944 where he worked on the high-precision detonators required for exploding the plutonium implosion bomb. In 1945 he flew in the Enola Gay as a scientific observer of the atomic bombing of Hiroshima.


On his return to Berkeley from the war, he developed a proton linear accelerator in 1947 called the Linac. Later, working with the Lab’s Bevatron, Alvarez developed large liquid hydrogen bubble chambers – particle detectors which, working on the principle of bubble formation in a heated liquid, create small bubbles where passing charged particles have ionized atoms in the liquid. He then created high-speed machines for analyzing the millions of photos produced by the devices.


The result of his work was the discovery of a large number of previously unknown fundamental particle resonances, for which he received the Nobel Prize in 1968. Alvarez’s future work crossed disciplines as he found practical applications of physics in archaeology and palentology, helping to develop the theory that there dinosaurs were made extinct by the impact of a giant asteroid striking the early 65 million years ago. He also served on the Warren Commission to investigate the assassination of President Kennedy. Alvarez stayed at Berkeley until 1978.


10" Bubble Chamber Logs,Vols II - III
3/14/56 - 12/20/56

D

aily logbooks from Alvarez's bubble chamber show the day-to-day mess of scientific activity and research which is often left out of the physics textbooks.


Along with their thousands of bubble chamber photographs, the log books contain humorous banter between the researchers, complaints about machinery breaking down and the occasional "sickness" of the Bevatron (a cyclotron that accelerates protons up to several billion electron volts), and, in the end, a wealth of solid scientific data.


10" Bubble Chamber Log Vol. III 10" Bubble Chamber Log Vol. III 10" Bubble Chamber Log Vol. III
10" Bubble Chamber Log Vol. III
pages shown [cover, 80, 81]
[BANC MSS 76/161 c, vol. III 7/31/56-12/20/56]


"Some accelerator!"

I

n response to Alvarez’s proposal for a new type of linear accelerator, almost half a mile long and capable of five times the energies of current cyclotrons, Lawrence wrote back with an enthusiastic letter. Later, in a telephone conversation transcribed from Nov 7, 1945, Lawrence said about Alvarez:


“Alvarez has gotten the idea of putting obsolete radar equipment and incorporating it in a very interesting way in a Linear Accelerator which may make it possible to go to hundreds of millions of volts of all kinds of particles, not only electrons and protons but many ions as well ….


It is wonderful and in the Alvarez style – something that is out of the ordinary. It is bound to lead to very important physics in the future. The schemes of Alvarez and McMillan [the synchrotron] in my judgment is [sic] the outstanding event of their generation….”


Letter from Lawrence to Alvarez Proposing a New Type of Linear Accelerator, 1945 Letter from Lawrence to Alvarez Proposing a New Type of Linear Accelerator, 1945
Letter from Lawrence to Alvarez Proposing a New Type of Linear Accelerator, 1945. pages shown [1, 2]
[BANC MSS 72/117 c]


"I certainly am enthusiastic over your idea of getting a larger number of 268's to drive a linear accelerator... for 500 million volts there would be 500 or more in line, which means a system in overall length of 2000 feet or more. Some accelerator! But Strawberry Canyon is longer than that!"


Correspondence between Alvarez and Lawrence, April 1945

W

hile Lawrence was enthusiastic about Alvarez’s idea for a new accelerator, he persisted in attempting to find ways to modify the machine so that it would reach even higher energies than the very high ones it was already hoping for.


In response, Alvarez carefully explains, with detailed diagrams, why one set of Lawrence’s modifications would not work.


Alvarez to Lawrence, Critiquing Proposed Modifications, 1945 Alvarez to Lawrence, Critiquing Proposed Modifications, 1945
Alvarez to Lawrence, Critiquing Proposed Modifications, 1945
pages shown [1, 3] additional [2, 4]
[BANC MSS 72/117 c, Ctn. 28:1]


Ground Controlled Approach System (GCA)

"The Winner of the Collier Trophy," Collier's, December 21, 1946
"The Winner of the Collier Trophy," Collier's, December 21, 1946

[BANC MSS 84/82 cz, Ctn. 71]


At age 35, Alvarez won the National Aeronautical Association's Collier Trophy in 1946 for his conception and development of the GCA, the first successful bad-weather landing system for airplanes. President Truman presented the award in a White House ceremony.