404 research outputs found
A Review and Outlook for the Removal of Radon-Generated Po-210 Surface Contamination
The next generation low-background detectors operating deep underground aim
for unprecedented low levels of radioactive backgrounds. The deposition and
presence of radon progeny on detector surfaces is an added source of energetic
background events. In addition to limiting the detector material's radon
exposure in order to reduce potential surface backgrounds, it is just as
important to clean surfaces to remove inevitable contamination. Such studies of
radon progeny removal have generally found that a form of etching is effective
at removing some of the progeny (Bi and Pb), however more aggressive
techniques, including electropolishing, have been shown to effectively remove
the Po atoms. In the absence of an aggressive etch, a significant fraction of
the Po atoms are believed to either remain behind within the surface or
redeposit from the etching solution back onto the surface. We explore the
chemical nature of the aqueous Po ions and the effect of the oxidation state of
Po to maximize the Po ions remaining in the etching solution of contaminated Cu
surfaces. We present a review of the previous studies of surface radon progeny
removal and our findings on the role of oxidizing agents and a cell potential
in the preparation of a clean etching technique.Comment: Proceedings of the Low Radioactivity Techniques (LRT) 2017, Seoul,
South Korea, May 24-26, 201
Uptake and efflux of copper-64 in Menkes'-disease and normal continuous lymphoid cell lines
Low Background Signal Readout Electronics for the MAJORANA DEMONSTRATOR
The MAJORANA DEMONSTRATOR is a planned 40 kg array of Germanium detectors
intended to demonstrate the feasibility of constructing a tonne-scale
experiment that will seek neutrinoless double beta decay () in
. Such an experiment would require backgrounds of less than 1
count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of
the decay. Designing low-noise electronics, which must be placed
in close proximity to the detectors, presents a challenge to reaching this
background target. This paper will discuss the MAJORANA collaboration's
solutions to some of these challenges
Contamination Control and Assay Results for the Majorana Demonstrator Ultra Clean Components
The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment
utilizing enriched Ge-76 detectors in 2 separate modules inside of a common
solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has
utilized world leading assay sensitivities to develop clean materials and
processes for producing ultra-pure copper and plastic components. This
experiment is now operating, and initial data provide new insights into the
success of cleaning and processing. Post production copper assays after the
completion of Module 1 showed an increase in U and Th contamination in finished
parts compared to starting bulk material. A revised cleaning method and
additional round of surface contamination studies prior to Module 2
construction have provided evidence that more rigorous process control can
reduce surface contamination. This article describes the assay results and
discuss further studies to take advantage of assay capabilities for the purpose
of maintaining ultra clean fabrication and process design.Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul
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