After World War II, Huizenga attended famous lectures given in Chicago by Fermi and soon began a half-century of atomic sleuthing.
"John Huizenga conducted research at the forefront of nuclear physics and contributed a host of exceptional insights," said Wolf-Udo Schröder, a professor of chemistry and physics at the University of Rochester and a protégé of Huizenga's. The discoveries stimulated "vigorous research," he added, and remain central to the field.
John Robert Huizenga was born in Fulton, Ill., on the Mississippi River, on April 21, 1921. His father was a farmer, and until high school John learned his lessons in a one-room schoolhouse.
He graduated in early 1944 from Calvin College in Grand Rapids, Mich., where a teacher got him hooked on chemistry. He entered graduate school in physical chemistry at the University of Illinois and was soon drafted into the Manhattan Project to build the atom bomb.
The recruiters, he recalled in a memoir for the American Institute of Physics, a federation of physical science societies, "convinced me of the importance" of using his scientific training "in an exciting and militarily important secret project."
In Oak Ridge, Tenn., he supervised teams analyzing the purity of enriched uranium coming out of sprawling production lines. Robert S. Norris, a nuclear historian, said the purified uranium fueled the weapon that leveled Hiroshima in August 1945.
After the war, Huizenga received his Ph.D. from the University of Illinois and took a job in nuclear chemistry at the Argonne National Laboratory, which was then on the University of Chicago campus. It was there that he met Fermi. His research focused on uncovering the secrets of atomic interactions, especially with the subatomic particles known as neutrons.
His first big moment came soon after the government detonated the world's first hydrogen bomb in the Pacific in 1952. The bomb vaporized an atoll. In sifting through the radioactive debris, Huizenga and his Argonne peers, as well as teams in Berkeley, Calif., and Los Alamos, N.M., found that two new elements - highly radioactive and unknown in nature - had formed when uranium atoms in the nuclear blast captured speeding neutrons.
The discoveries, of einsteinium and fermium, were initially kept secret for security reasons, then unveiled in 1955, not long after the scientists they had been named after had died.
In 1966, Huizenga received the government's Lawrence Award for outstanding accomplishments in illuminating the intricacies of nuclear fission, the fracturing of atoms into pieces. That same year, he accompanied the first American scientific delegation to be sent to the Soviet Union.
He accepted a professorship at the University of Rochester in 1967 and stayed there for the rest of his career. His 1973 textbook, "Nuclear Fission," written with Robert Vandenbosch, remains a standard in the field. He was elected to the National Academy of Sciences in 1976.
Huizenga lectured in China after its opening to the West. After one visit, in 1979, the nation's leader, Deng Xiaoping, sent his youngest son, Deng Zhifang, to study in Huizenga's department at the University of Rochester.
In 1989, Huizenga was appointed co-chairman of a Department of Energy panel that investigated and debunked the highly publicized "cold fusion" claims of two University of Utah chemists, who said they had achieved nuclear fusion at room temperature in a jar of water. If their claims had been true, the discovery would have flooded the world with energy cheap enough to supplant all rivals.
Huizenga lectured widely on the topic and in 1992 published "Cold Fusion: The Scientific Fiasco of the Century." On the claim's 10th anniversary, in 1999, as true believers around the globe kept looking for glimmers of hope that cold fusion could be realized, he accused them of chasing a ghost.