Reinvestigation of the yield of the trinity device

Previous published analyses of trinitite to determine the yield of the Trinity nuclear explosion used various estimates of the fraction of fission products that became incorporated in trinitite. Furthermore, these studies utilized nuclear data that has subsequently been revised. Utilizing a planar germanium detector, we observed gamma rays produced by the decays of both ¹³⁷Cs and ²³⁹Pu from four samples of trinitite. From the observed ¹³⁷Cs/²³⁹Pu ratios of and a simple analysis method based on current nuclear data and weapons debris studies, we find an average yield of 9.1 ± 4.5 kilotons from our four samples. While this result is substantially lower than the established total yield of 21 kilotons, it is in reasonable agreement that attributable to fissions in the ²³⁹Pu core alone.