The Scientific Legacy of the Manhattan Project

By Vince Cianciolo

Susan Seestrom from Los Alamos National Laboratory (LANL) started the session on the Manhattan Project Scientific Legacy (cosponsored by the DNP and FPS) with a talk on "Accelerator Based Tools of Stockpile Stewardship". Susan’s talk started by emphasizing the importance of the fundamental science knowledge that formed the basis for the Manhattan project’s success, and pointed out the under-recognized role of female scientists in the development of that knowledge. Susan discussed how the urgency of the war effort necessitated a more empirical approach that, during the cold war, developed into an extensive live-testing program which demonstrated successful weapon design and fabrication by detonating a subset of those weapons. Today the Los Alamos, Livermore and Sandia Laboratory Directors must certify the readiness of the nation’s nuclear stockpile without the certainty given by that testing program, a task that becomes more difficult as the stockpile ages. In order to fulfill this mission there has been a renewed emphasis on the development of fundamental scientific knowledge – Science-Based Stockpile Stewardship. Susan’s talk focused on modern accelerator-based techniques pioneered at LANL, such as proton, neutron and x-ray radiography.

Ed Hartouni from Lawrence Livermore National Laboratory (LLNL) concluded the session with a talk on "The Quest for Fusion at the National Ignition Facility (NIF)". Ed provided an interesting historical overview of nuclear fusion, pointing out that fusion was recognized as a physical process two decades before nuclear fission, with Arthur Eddington correctly identifying it as the Sun’s power source. Eddington also recognized that fusion is a double-edged sword, "…it seems to bring a little nearer to fulfilment our dream of controlling this latent power for the well-being of the human race — or for its suicide." Hydrogen bombs ("uncontrolled" nuclear fusion) were successfully detonated in 1952. The laser was invented in 1960, and Ed noted that very soon after the laser was recognized by both US and Soviet scientists as a possible path to "controlled" nuclear fusion using inertial confinement. NIF uses an array of 192 lasers to compress fuel pellets containing a mixture of deuterium and tritium. New diagnostic techniques have been and continue to be implemented to provide a better understanding of the data and of how to push forward to ignition — current "shots" are within a factor of two of that goal.

The results of experiments described by both speakers are used to validate and improve computer simulations that in turn provide confidence in the stockpile’s integrity. The development of all the associated scientific techniques and scientists is a testament to the vision for the role of science in the service of the nation laid out in Vannevar Bush’s hugely influential 1945 report "Science: The Endless Frontier."

The articles in this issue represent the views of their authors and are not necessarily those of the Forum or APS.