John Alexander Simpson

John Alexander Simpson (November 3, 1916 – August 31, 2000) was an American physicist and science educator.

He was deeply committed to educating the public and political leaders about science and its implications, most notably as a principal founder of the Bulletin of the Atomic Scientists and a long-time member of the organizations Board of Sponsors.

He is known for inventions such as the gas flow α-particle proportional counter (for measuring plutonium yields in the presence of high intensity fission products), and the neutron monitor, and for having several of the instruments he created launched into space, such a dust flux monitor aboard the Stardust spacecraft.

Simpson spent his career as an instructor and researcher for the University of Chicago's Enrico Fermi Institute and Department of Physics, where he conducted experiments in nuclear physics and with cosmic rays.

His research continued up until a few weeks prior to his death.

He died of pneumonia which he contracted in the hospital following a successful heart surgery.

The year he died, his instruments in space had been sending data back for nearly 40 years.

Born in Portland, Oregon, Simpson was an accomplished clarinetist and saxophonist in his early years, receiving an award in high school for his virtuosity.

He received an AB degree from Reed College in 1940, where he became interested in the history of science and technology from the Greeks to the Middle Ages to the most recent discoveries in astronomy and physics.

He obtained an MS from New York University in 1943, and a Ph.D a year later.

It was at New York University in 1943 when Simpson was invited to be employed at University of Chicago.

Volney Wilson, an administrator at the university's Metallurgical Laboratory asked him to help invent instruments for measuring high levels of radioactivity.

It took much convincing, but Simpson finally agreed to help.

Simpson began his professional career as a physicist in 1943 where he acted as a group leader on the Manhattan Project.

The Manhattan Project was the codename for a United States project with the United Kingdom and Canada conducted during World War II to develop the first atomic bombs.

It was common for governments to recruit physicists during World War II for such tasks.

Simpson had taken up the offer after recognizing the social and human implications of nuclear energy and wanted to partake in its development.

Because of this, Simpson became a founding member and first chairman of the Atomic Scientists of Chicago in August 1945, a day after the United States dropped the atomic bomb on Hiroshima and two years after the start of his career.

He was also a co-founder that same year of the Bulletin of the Atomic Scientists.

The bulletin's aim was to spell out the implications of the atomic bomb and provide rational courses of action in response to the implications.

In the October 29, 1945, issue of Life, Simpson, along with Eugene Rabinowitch, spoke about their involvement with nuclear energy, and said that scientists for the first time had recognized a moral responsibility to warn of the danger of any further use of nuclear weapons.

Simpson felt that scientists and engineers could no longer remain aloof from the consequences of their work.

In 1945, he also worked as an unofficial adviser to Connecticut Senator Brien McMahon after taking a leave of absence from the university.

As part of the university faculty, Simpson invented and patented a "gas flow α-particle proportional counter for measuring plutonium yields in the presence of high intensity fission products" by piping the plutonium-bearing gas through the counter itself.

Simpson has 15 patents under his name, which include the multiwire proportional counter, a device that improves accuracy and reading speed of radiation, and the neutron monitor.

Nancy Farley Wood worked with Simpson and is credited with the development and production of the radiation detectors for the laboratory.

Simpson was a pioneer in the study of cosmic rays.

Beginning in 1946 with investigations into cosmic ray neutrons in the lower atmosphere (developed from pre-World War II work by Serge Korff), he contributed significantly throughout the years to the field's development with his scientific investigations.

Simpson's contributions were unique in that he accomplished his work in a way that boosted the accomplishments and careers of others around him.

In 1949, Simpson contributed to the discovery that the latitude effect seen with neutrons is around 20 times greater than with ionization chambers; in 1951, he found that the time variations are much greater as well.

He had recognized the potential of neutrons and lower energy cosmic ray particles for exploring the causes of the time variations.

That year he also invented the neutron monitor to fulfill the need for a stable ground-based neutron detector.

In doing so, he established neutron monitor stations at various locations including Huancayo, Peru; Mexico City, Mexico; Sacramento Peak, New Mexico; Climax, Colorado; and Chicago, Illinois.

In 1954 and 1955, Simpson explored the global and time variations of cosmic rays at these neutron monitor stations around the world.

In 1955, he gave Eugene N. Parker a job as a research associate in the Enrico Fermi Institute of the University of Chicago, and his progress was largely a consequence of Simpson's continued support.

In 1956, a giant cosmic ray flare provided the first direct glimpse of composition of interplanetary space.

At this point, the scientific community surrounding cosmic rays and solar activity had grown large.

Simpson was one of 12 scientists responsible for organizing and coordinating the International Geophysical Year (1957–58), helping to make it a huge success.

At the end of 1957, after the launch of Sputnik by the Soviet Union, Simpson, realizing the necessity for the US to send instruments into space, outlined the scientific situation and his plans for such activity to University Chancellor Lawrence Kimpton.

This same year Simpson began his tenure as a faculty member at the University of Chicago as a physics instructor, and remained there throughout his career, partaking in research until shortly before his death in August 2000.