The Enriched Xenon Observatory (EXO) will search for double beta decays of 136 Xe. We report the results of a systematic study of trace concentrations of radioactive impurities in a wide range of raw materials and finished parts considered for use in the construction of EXO-200, the first stage of the EXO experimental program. Analysis techniques employed, and described here, include direct gamma counting, alpha counting, neutron activation analysis, and high-sensitivity mass spectrometry. r
Experimental results from equimolar PEG and protein standards samples are presented from a MALDI-TOF mass spectrometer equipped with both ionizing detectors and the novel single molecule sensitive cryodetectors. The data are consistent with a model hypothesis suggesting that the observed decrease in signal strength in conventional ionizing detector MALDI-TOF mass spectrometers can be explained by the exponentially decreasing quantum efficiency of ionizing detectors. Cryodetectors, in contrast, have a mass independent detection efficiency of 100% on impact and provide additional information on the molecule state owing to the calorimetric nature of the detection mechanism.
The design, construction, and performance of a linear radio-frequency ion
trap (RFQ) intended for use in the Enriched Xenon Observatory (EXO) are
described. EXO aims to detect the neutrinoless double-beta decay of $^{136}$Xe
to $^{136}$Ba. To suppress possible backgrounds EXO will complement the
measurement of decay energy and, to some extent, topology of candidate events
in a Xe filled detector with the identification of the daughter nucleus
($^{136}$Ba). The ion trap described here is capable of accepting, cooling, and
confining individual Ba ions extracted from the site of the candidate
double-beta decay event. A single trapped ion can then be identified, with a
large signal-to-noise ratio, via laser spectroscopy.Comment: 18 pages, pdflatex, submitted to NIM
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