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National Museum of Nuclear Science & History

Chicago Pile-1 Participants

49 scientists and workers witnessed Chicago Pile-1, the world’s first controlled, self-sustaining nuclear chain reaction, going critical on December 2, 1942. Four years later, 15 of those participants posed for an iconic photograph on the steps of Eckhart Hall at the University of Chicago. Below is a list of the men and women in that image, along with their years of birth and death. It is followed by a full list of the people who were present when CP-1 went critical.

Document Type:
Chicago Pile-1 reunion, December 2, 1946. Photo courtesy of the University of Chicago Photographic Archive, [apf3-00232], Special Collections Research Center, University of Chicago Library.

Left to right, back row:
Norman Hilberry, 1899-1986
Samuel Allison, 1900-1965
Thomas Brill, 1920-1998
Robert Nobles, 1917-2007
Warren Nyer, 1922-2016
Marvin Wilkening, 1918-2006

Left to right, middle row:
Harold Agnew, 1921-2013
William Sturm, 1918-1999
Harold Lichtenberger, 1920-1993
Leona Woods, 1919-1986
Leo Szilard, 1898-1964

Left to right, front row:
Enrico Fermi, 1901-1954
Walter Zinn, 1907-2000
Albert Wattenberg, 1917-2007
Herbert Anderson, 1914-1988


List of Chicago Pile-1 Witnesses

  1. Harold M. Agnew
  2. Samuel K. Allison
  3. Herbert L. Anderson
  4. Wayne Arnold
  5. Hugh M. Barton
  6. Thomas Brill
  7. Robert F. Christy
  8. Arthur H. Compton
  9. Enrico Fermi
  10. Richard J. Fox
  11. Stewart Fox
  12. Carl C. Gamertsfelder
  13. Alvin C. Graves
  14. Crawford H. Greenewalt
  15. Norman Hilberry
  16. David L. Hill
  17. William H. Hinch
  18. Robert E. Johnson
  19. W.R. Kanne
  20. August C. Knuth
  21. Phillip Grant Koontz
  22. Herbert E. Kubitschek
  23. Harold V. Lichtenberger
  24. George M. Maronde
  25. Anthony J. Matz
  26. George Miller
  27. George S. Monk
  28. Henry W. Newson
  29. Robert G. Nobles
  30. Warren E. Nyer
  31. Wilcox P. Overbeck
  32. J. Howard Parsons
  33. Gerard S. Pawlicki
  34. Theodore Petry
  35. David P. Rudolph
  36. Leon Sayvetz
  37. Leo Seren
  38. Louis Slotin
  39. Frank H. Spedding
  40. William J. Sturm
  41. Leo Szilard
  42. Albert Wattenberg
  43. Richard J. Watts
  44. George L. Weil
  45. Eugene P. Wigner
  46. Marvin H. Wilkening
  47. Volney C. (Bill) Wilson
  48. Leona Woods (Marshall Libby)
  49. Walter H. Zinn


[Thanks to David Wargowski for his help in compiling these lists.]