Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8175729 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2014 | 6 Pages |
Abstract
Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These materials are also important for use in high-purity germanium spectrometers used in screening materials for radiopurity. The next-generation science applications require materials with radiopurity levels at or below 1 μBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below ~10 μBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure 232Th and 238U near the desired purity levels. An assay of electroformed copper at a μBq/kg level has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
E.W. Hoppe, C.E. Aalseth, O.T. Farmer, T.W. Hossbach, M. Liezers, H.S. Miley, N.R. Overman, J.H. Reeves,