Evaluation of Ultra-Low Background Materials for Uranium and Thorium Using ICP-MS
An increasing number of physics experiments require low background materials for their construction. The presence of Uranium and Thorium and their progeny in these materials present a variety of unwanted background sources for these experiments. The sensitivity of the experiments continues to drive the necessary levels of detection ever lower as well. This requirement for greater sensitivity has rendered direct radioassay impractical in many cases requiring large quantities of material, frequently many kilograms, and prolonged counting times, often months. Other assay techniques have been employed such as Neutron Activation Analysis but this requires access to expensive facilities and instrumentation and can be further complicated and delayed by the formation of unwanted radionuclides. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a useful tool and recent advancements have increased the sensitivity particularly in the elemental high mass range of U and Th. Unlike direct radioassay, ICP-MS is a destructive technique since it requires the sample to be in liquid form which is aspirated into a high temperature plasma. But it benefits in that it usually requires a very small sample, typically about a gram. Here we will discuss how a variety of low background materials such as copper, polymers, and fused silica are made amenable to ICP-MS assay and how the arduous task of maintaining low backgrounds of U and Th is achieved.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1149242
- Report Number(s):
- PNNL-SA-96462; 830403000
- Resource Relation:
- Conference: Proceedings of the IV International Workshop in Low Radioactivity Techniques (LRT2013), April 10-12, 2013, Assergi, Italy. AIP Conference Proceedings, 1549:58-65
- Country of Publication:
- United States
- Language:
- English
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