36Kr

36Kr
36Kr · Public domain · source
Name	36Kr
Mass number	36
Atomic number	36
Protons	36
Half life	Stable (primordial)
Natural abundance	~0.337%

36Kr is a stable isotope of the noble gas element krypton, notable for its role in geochemical tracing, atmospheric studies, and nuclear forensics. Discovered through mass spectrometric work that paralleled investigations in laboratories such as those at Los Alamos National Laboratory, Lawrence Berkeley National Laboratory, and Royal Society-affiliated research, it features in investigations alongside isotopes studied at institutions like Harvard University, Massachusetts Institute of Technology, Stanford University, and California Institute of Technology. Because of its inert chemical character, 36Kr has been measured in contexts ranging from studies by National Aeronautics and Space Administration missions to analyses performed at Max Planck Society, Smithsonian Institution, and national laboratories including Oak Ridge National Laboratory and Argonne National Laboratory.

Overview

36Kr is one of six stable isotopes of krypton and one of many isotopes routinely reported in geochemical and cosmochemical surveys by teams from University of Cambridge, University of Oxford, ETH Zurich, Imperial College London, and University of Tokyo. It is detected and reported in work connected to agencies and projects such as European Space Agency, Japan Aerospace Exploration Agency, National Oceanic and Atmospheric Administration, and research collaborations like those at Woods Hole Oceanographic Institution and Scripps Institution of Oceanography. The isotope’s abundance and isotopic ratios are compared in datasets maintained by organizations including International Atomic Energy Agency, United Nations Educational, Scientific and Cultural Organization, and national standards bodies such as National Institute of Standards and Technology.

Isotopic Properties

36Kr has 36 protons and no additional proton-neutron asymmetry beyond its 36-nucleon proton count; its nuclear spin is 0, making it diamagnetic in nuclear magnetic resonance contexts considered in studies at Rutherford Appleton Laboratory, CERN, and research groups at Princeton University. Isotopic masses and atomic mass evaluations cite measurements from collaborations involving National Physical Laboratory (UK), Bureau International des Poids et Mesures, and metrology work at Physikalisch-Technische Bundesanstalt. Comparative isotopic studies place 36Kr alongside isotopes like those of argon and xenon when teams at Columbia University, Yale University, and University of Chicago examine noble-gas fractionation in planetary samples returned by missions planned with Jet Propulsion Laboratory input.

Production and Detection

36Kr in terrestrial and extraterrestrial samples arises from primordial nucleosynthesis and cosmogenic production via spallation from cosmic-ray interactions; such processes are modeled in frameworks used by researchers at California Institute of Technology, University of California, Berkeley, and Institute for Nuclear Research (Russia). Production methods in laboratory contexts include gas separation and cryogenic distillation implemented by industrial partners and research centers like Air Liquide, Linde plc, and university gas labs at University of Minnesota and University of Michigan. Detection relies on mass spectrometry techniques—static mass spectrometers, multi-collector inductively coupled plasma mass spectrometers, and noble gas mass spectrometers—employed at facilities such as Argonne National Laboratory, Pacific Northwest National Laboratory, and university centers at University of Washington and University of California, Davis. Interdisciplinary teams from MIT, Harvard, Cambridge, Oxford, and ETH Zurich have advanced ultra-trace detection, often cross-referencing methods used in Lawrence Livermore National Laboratory nuclear forensics.

Occurrence and Abundance

36Kr is present in the Earth’s atmosphere, constituting a small fraction of atmospheric krypton measured by monitoring networks coordinated with World Meteorological Organization and Global Atmosphere Watch. It is also identified in extraterrestrial materials analyzed by groups at Smithsonian Institution, Natural History Museum, London, and planetary science divisions at NASA centers including Johnson Space Center and Ames Research Center. Studies by research teams at University of Arizona, University of Hawaiʻi, and Brown University report 36Kr signatures in meteorites, lunar samples, and cometary material, often compared to isotopic records from Voyager program, Galileo (spacecraft), and Cassini–Huygens mission datasets.

Applications and Uses

36Kr is used as a tracer in atmospheric circulation and paleoclimate studies conducted by groups at Scripps Institution of Oceanography, ETH Zurich, University of Bern, and National Oceanic and Atmospheric Administration. It is used in groundwater dating and deep-seated fluid studies by teams at US Geological Survey, Geological Survey of Canada, and academic groups at University of Cambridge and Stockholm University. In nuclear forensics and treaty verification contexts, laboratories such as Comprehensive Nuclear-Test-Ban Treaty Organization-affiliated facilities and national labs (Los Alamos National Laboratory, Lawrence Livermore National Laboratory) analyze 36Kr ratios to attribute sources, often in collaboration with agencies like Department of Energy (United States), Defence Science and Technology Laboratory (UK), and international research consortia.

Safety and Handling

As an inert noble gas, 36Kr poses low chemical hazard but shares asphyxiation risk and pressurized-gas concerns typical of industrial gas handling addressed in standards by Occupational Safety and Health Administration, European Chemicals Agency, and safety protocols at institutions such as National Institutes of Health and Centers for Disease Control and Prevention. Storage and transport practices follow regulations overseen by International Air Transport Association and United Nations Economic Commission for Europe model rules, with handling guidelines applied in laboratories at Johns Hopkins University, Mayo Clinic, and corporate research facilities at BASF and Siemens. Monitoring and detection equipment developed at Sandia National Laboratories and Pacific Northwest National Laboratory support safe use in scientific and industrial settings.

Category:Isotopes