OSIRIS Gamma-Ray Spectrometer for Nuclear On-Site Inspections under the CTBT

Nuclear Explosion Evidence: The OSIRIS Gamma-Ray Spectrometer for Nuclear On-Site Inspections under the CTBT

The Challenge
The On-Site Inspection RadioIsotopic Spectroscopy (OSIRIS) system was designed to collect evidence of nuclear explosions, under the provisions of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). 

The Approach
The On-Site Inspection RadioIsotopic Spectroscopy (OSIRIS) system uses a measurement-restriction approach to limit information displayed on radioisotopes to a select set of 17 fission products.*

These radioisotopes, with half-lives ranging from days to years, have been identified by a group of international technical experts as being relevant to the detection and identification of a nuclear explosion when their presence is detected during a CTBT on-site inspection.

Other OSIRIS features include:
  • Automatic spectral data interpretation, in real time.
  • Only summary information presented to the operators. Raw spectral data files are stored to hard disk after encryption using the Advanced Encryption Standard-128.
  • Automatic energy calibration from Eu-152, Th-228, or natural background gamma rays.
  • No liquid nitrogen required.
  • Seven-hour spectrometer battery lifetime, battery may be “hot-swapped” while the spectrometer is in operation.
  • OSIRIS software works with Windows 7 and Windows 10 operating systems.
OSIRIS was developed and tested jointly by Idaho National Laboratory, Lawrence Livermore National Laboratory, and Pacific Northwest National Laboratory. Further information can be found in a recent peer-reviewed technical publication.**

The Solution
OSIRIS is now a commercial product available from ORTEC. 

*The 17 fission products identified by OSIRIS are 140Ba, 141Ce, 144Ce, 134Cs, 137Cs, 131I, 132I, 140La, 99Mo, 95Nb, 147Nd, 144Pr, 106Rh, 103Ru, 99mTc, 132Te, and 95Zr. Presence of one or more of these radionuclides in the inspection area, when coupled with the presence of additional indicators of a nuclear explosion, can be extremely helpful in determining whether a nuclear explosion has occurred.

**Caffrey, A. J., T. W. Bowyer, A. E. Egger, J. C. Hall, S. M. Kelly, K. M. Krebs, S. A. Kreek, D. V. Jordan, B. D. Milbrath, S. W. Padgett, C. J. Wharton, and N. G. Wimer, 2015, Osiris—Gamma-ray spectroscopy software for on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty, Nuclear Instruments & Methods in Physics Research, 784, 405–411, doi:10.1016/j.nima.2014.10.066 
OSIRIS Gamma-Ray Spectrometer for Nuclear On-Site Inspections under the CTBT
The OSIRIS spectrometer, a modified ORTEC IDM-200-R and toughbook computer. The ruggedized computer functions as the OSIRIS control panel and display.


OSIRIS Gamma-Ray Spectrometer for Nuclear On-Site Inspections under the CTBT
A prototype OSIRIS gamma-ray spectrometer being set up during the Comprehensive Nuclear-Test-Ban Treaty Integrated Field Exercise-14, Jordan, 2014.


OSIRIS Gamma-Ray Spectrometer for Nuclear On-Site Inspections under the CTBT
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