Samuel King Allison (November 13, 1900 – September 15, 1965) was an American physicist, most notable for his role in the Manhattan Project, for which he was awarded the Medal for Merit.

He graduated in 1921, and then embarked on his PhD in chemistry under the supervision of William Draper Harkins, writing his thesis on "Atomic Stability III, the Effects of Electrical Discharge and High Temperatures", a topic closely related to experimental physics.

At the time x-rays were an important means of investigating atomic structures, but the concept that light had both wave and particle properties, as demonstrated by Arthur Compton, was not universally accepted.

[13] He became head of the Metallurgical Laboratory's chemistry section in January 1942,[11] and in March, his small experimental reactor using beryllium came closer to criticality than the graphite-moderated design of Enrico Fermi's group at Columbia University.

The Director of the Manhattan Project, Brigadier General Leslie R. Groves, Jr., told them that time was more important than money, and if two approaches looked promising, they should build both.

[11] [17] By late 1944, the locus of the Manhattan Project had shifted to the Los Alamos Laboratory in New Mexico, and Allison went there in November 1944 as the chairman of the Technical and Scheduling Committee.

Allison formed part of the "Cowpuncher Committee" that "rode herd" on the implosion project, ensuring that it stayed on track and on schedule.

He was a strong opponent of secrecy in science, and, in an influential speech announcing the creation of the Enrico Fermi Institute said:We are determined to return to free research as before the war.

If secrecy is imposed on scientific research in physics, we will find all first-rate scientists working on subjects as innocuous as the colors of butterfly wings.

The name was a reference to the massive bevatron being built at the Lawrence Berkeley Laboratory, which was planned to accelerate particles to billions of electron volts.

[22] Later, Allison acquired a 2 MeV Van de Graaff generator, and he recalled an old paper on producing lithium ions from minerals like Eucryptite.

[23] Allison died of complications following an aortic aneurism on September 15, 1965, while attending the Plasma Physics and Controlled Nuclear Fusion Research Conference in Culham, England.