William Duane (February 17, 1872 – March 7, 1935) was an American physicist who conducted research on radioactivity and X-rays and their usage in the treatment of cancer.

He worked with Pierre and Marie Curie in their University of Paris laboratory for six years and developed a method for generating quantities of radon-222 "seeds" from radium for usage in early forms of brachytherapy.

Duane received his doctorate degree from the University of Berlin after his dissertation Uber elektrolytische Thermoketten was accepted by Max Planck.

He spent a one-year sabbatical with Pierre and Marie Curie in their radium research laboratory at the University of Paris in 1906[4] and was then invited to work with them from 1907 to 1912.

Although none of the papers were in direct collaboration with the Curies, he worked closely with them and it was reported that when Marie Curie visited America years later, she stated that she most wanted to see "Niagara Falls, The Grand Canyon and William Duane"[3] Duane refined a technique for extracting radon-222 gas from radium sulfate solutions.

[5] Duane made important contributions to the technical details of measuring X-ray dosage in terms of the ionization of air.

[10] He developed the Duane-Hunt law, relating the minimum wavelength of X-rays to the threshold voltage of the cathode rays that excite them; and Duane's hypothesis of quantized translative momentum transfer.

[11] In 1925, Arthur Compton demonstrated that the scattering of 130,000-volt X-rays from the first sixteen elements in the periodic table (hydrogen through sulfur) were polarized.

[17] He received the John Scott Medal[18] and the Comstock Prize in Physics from the National Academy of Sciences, of which he was a member, in 1922.