Sidney Niemeyer served in various scientific leadership roles at Lawrence Livermore National Laboratory (LLNL) for twenty-seven years. Shortly after becoming the Nuclear Chemistry Division Leader, the end of the Nuclear Test Program thrust him into the role of program development. He began to articulate the need for the country to develop a nuclear forensics capability to address the new reality of a post-Cold-War world. In 1995 he chaired an International Conference on Nuclear Smuggling Forensic Analysis, which led to the formation of the Nuclear Forensics International Technical Working Group (ITWG). He co-chaired the ITWG for its first twelve years, giving it a culture and organizational structure that has served it well to this day.

After he briefed numerous U.S. government officials over eight years, the U.S. began to invest in developing its nuclear forensics capability. During the first three years of the Department of Homeland Security, he served as a detailee for RadNuc Forensics. In this role he served as Thrust Area Leader for the research and development program and as the point-of-contact with the interagency to develop a national capability in nuclear forensics. He served on an Attribution Working Group, commissioned by the National Security Council, which eventually led to the formation of the National Technical Nuclear Forensics Center (NTNFC). During the first year of the NTNFC, he served as its Scientific Advisor.

Since retiring from LLNL in 2007, he has been a member of NTNFC’s Nuclear Forensics Science Panel (NFSP). He participated in annual reviews of various U.S. nuclear forensics R&D programs, and he also served on a number of NFSP subcommittees to provide special reports to U.S. agencies on specific issues.

In 2019 he retired from a second career and decided to embrace the challenge of writing a novel. Within a year he completed the first draft of Atomic Peril, and since then he has completed three more drafts with the help of an independent editor and a dozen beta readers. This thriller makes the same basic point he made in an Arms Control Today article he wrote in 2007, but by making the point in a much more compelling manner, he hopes to gain wider recognition for the importance of nuclear forensics for national security.

In earlier research work, beginning with his physics PhD thesis work at the University of California at Berkeley, he emphasized the application of isotopic measurements in multi-disciplinary studies.  His research initially focused on the origin of the solar system by studies of meteorites and lunar samples. Subsequently he conducted geochemical research on the evolution of the earth’s crust and mantle, as well as applying geochemical tracing techniques to hydrological and environmental issues.