Accelerator Mass Spectrometry at ANL and ORNL

Application/instrumentation: Accelerator Mass Spectrometry at ANL and ORNL
Developed at: Argonne National Laboratory (ANL), Oak Ridge National Laboratory (ORNL)
Developed in: Current
Result of NP research: Basic NP research
Application currently being supported by: DOE NP
Impact/benefit to spin-off field: Provide conclusive evidence of the source of confiscated materials, especially actinides and transuranic elements. Other applications include oceanography, hydrology, actinides for geophysical studies, and medical studies.

Facilities such as Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory (ANL) and Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratories (ORNL)offer exciting opportunities as prototype facilities to aid in the development of new Accelerator Mass Spectrometry (AMS) methods with many applications including Stewardship Science. AMS is the analytical technique with the highest sensitivity known in physics.

Images of the MeV tanden accelerator at HRIBF Images of the 25 MeV tanden accelerator at HRIBF
Figure1:Images of the MeV tanden accelerator at HRIBF
The technique of AMS is used to perform ultra-sensitive measurements of concentration of rare isotopes in samples placed in the ion source of an accelerator system. A key advantage of the technique is that it requires only very small samples of material. Such isotope 'fingerprints' can be used for a wide variety of applications.

Atmospheric and underground nuclear weapons tests have introduced into the environment a variety of long-lived radionuclides. Other nuclear activities, including fuel reprocessing and waste disposal have contributed as well. To limit the proliferation of nuclear weapons manufacture and testing requires the highest sensitivity techniques possible to detect radionuclides in the environment that serve as a signature of clandestine activities. AMS measurements of 36Cl together with 14C and 129I can offer a valuable tool to monitor safeguard policies. AMS can also be used for the characterization of weapons grade material via the determination of 240Pu/239Pu ratios.

An important application of AMS measurements of the naturally occurring 36Cl/Cl ratio in water (as opposed to the one created by atmospheric and underground nuclear weapons test) is for dating underground water. Dating allows the determination of water flow and accumulation in underground reservoirs. HFRIB has successfully demonstrated the ability to execute measurements requiring the highest sensitivity, with 36Cl/Cl ratios as low as a few times 10-16.

Reference:

[1] A. Galindo-Uribarri et al. / Nucl. Instr. and Meth. in Phys. Res. B 259 (2007) 123–130