Instead, Dok measured the gamma radiation emitted by americium-~-a daughter product of plutonium. Americium results from radioactive decay of plutonium, and its gamma emissions are sufficiently energetic to penetrate several inches of soil. To accomplish this measurement in the difficult environment on Enewetak, DoE designed and built special tracked vehicles which could operate in the soft sands, equipped them with boom-mounted, highly sensitive germanium detectors (cooled by liquid nitrogen), and installed analysis and counting equipment in the vehicle. The vehicle itself was air conditioned to provide a controlled environment for this delicate equiprnent. These mobile measuring systems measured the intensity of gamma radiation in the energy spectrum characteristic of americium. Readings were taken at every intersection of a 50-meter grid surveyed on each island which coarser aerial and in-situ surveys had shown to have significant transuranic contamination. At each location of van readings, soil samples from several depths were obtained and were analyzed for plutoniurn-americium ratio by the radiological laboratories. In areas of higher or irregular contamination, additional van readings and soil samples were taken at intervals of 25, 12%, or 6% meters. Sophisticated computer programs were developed to produce radiation contour maps of plutonium contamination, which were then used by cleanup teams to guide soil excision. After each removal of soil, the area was re-surveyed, new van readings and new soil samples were taken, until acceptable limits. residual plutonium contamination had reached The U.S. forces which accomplished the radiological cleanup and rehabilitation throughout 1978 and 1979 typically were present in about the following groups and strengths: Joint Task Group Staff (DINA) 35 Army Element 430 Navy Element 5 Air Force Element 75 Support Contractor 165 Army & Air Force Exchange System 5 DoE 5 Rad-Lab Contractors 10 Mid-Pacific Research Laboratory 10 Dol and TTPI 5 Rehabilitation Contractor Micronesian Labor 100 10 965