Speaker
Eric Hoppe
(Pacific Northwest National Laboratory)
Description
The variety of next generation highly sensitive radiation detectors searching for trace radioactive isotopes, dark matter, and neutrinoless double beta decay must be constructed using ultra-low background materials. Because of the cost and complexity of these new detector systems, foreseeable backgrounds can no longer merely be discovered when the detector is first operated, essentially allowing the detector to be the primary assay tool, and then hopefully mitigated later. Rather, backgrounds must be anticipated and eliminated in the design phase. Inductively coupled plasma mass spectrometry is an analytical tool with the sensitivity necessary to assay materials in a timely and cost effective manner before their use as a construction material. Assay methods employed for a few of the metals used in detector and shielding construction are presented. Although necessary in many applications for their high strength, the relatively high concentrations of thorium and uranium found in currently available stainless steel and titanium are reviewed. Assay of lead and commercial copper used for shielding and some detector components is also discussed. Finally assay of electroformed copper of extreme purity is shown.
Summary
Assay of several metals for uranium and thorium content ranging from micrograms/gram to femtograms/gram using inductively coupled plasma mass spectrometry is presented. The materials are used in a variety of low background detector systems.
Primary author
Eric Hoppe
(Pacific Northwest National Laboratory)
Co-authors
Brian LaFerriere
(Pacific Northwest National Laboratory)
Isaac Arnquist
(Pacific Northwest National Laboratory)
Tapas Maiti
(Pacific Northwest National Laboratory)
