The International Noble Gas Experiment (INGE) was formed in 1999 as an informal expert's group of developers of radioactive xenon measurement systems for the International Monitoring System for the Comprehensive Nuclear-Test-Ban Treaty (CTBT) (signed in 1997, but which has not entered into force). The group originally consisted of research and development groups from Germany, France, Russia, Sweden, and the United States, as well as personnel from Provisional Technical Secretariat of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization CTBTO.
The INGE group was formed to test aspects of measuring xenon fission product radionuclides released by nuclear explosions. The systems developed and participating in the INGE measure xenon isotopes in the atmosphere and includes 131mXe, 133Xe, 133mXe, and 135Xe.
Since the INGE was formed in 1999, the group has expanded somewhat and now includes R&D and operational groups from many locations around the world. Although there is no official list of INGE members, the group is informally composed of scientists, engineers, and others from Argentina, Austria, Australia, Canada, China, France, Germany, Japan, Norway, South Korea, Sweden, Russia, the United States, and several other countries. These members regularly contribute to better understanding radioactive xenon measurements through operation of samplers, measurements of background at various locations, creation of data analysis routines, etc.
Staff from the preparatory commission of the CTBTO oversaw the experiment, with technical assistance from a German group of noble gas experts from the BfS in Freiburg, Germany. As of 2009, the experiment was still on-going, and so far it had consisted of 3 phases: