Xenon purity analysis for EXO-200 via mass spectrometry Dobi, A.; Hall, C.; Slutsky, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2012, Volume:
675
Journal Article
Peer reviewed
Open access
We describe purity measurements of the natural and enriched xenon stockpiles used by the EXO-200 double beta decay experiment based on a mass spectrometry technique. The sensitivity of the ...spectrometer is enhanced by several orders of magnitude by the presence of a liquid nitrogen cold trap, and many impurity species of interest can be detected at the level of one part-per-billion or better. We have used the technique to screen the EXO-200 xenon before, during, and after its use in our detector, and these measurements have proven useful. This is the first application of the cold trap mass spectrometry technique to an operating physics experiment.
SETTING: Municipalities of Baerum and Oslo, Norway.OBJECTIVES: To examine the effectiveness of tuberculosis (TB) screening in asylum seekers 1987-1995, and to describe TB incidence rates after ...arrival.DESIGN: Register-based, retrospective cohort study of 19912 asylum seekers
with a mean follow-up of 6.3 years.RESULTS: Seventy-six persons were diagnosed with TB, of whom 43 (57%) had pulmonary TB. Twenty-two cases (17 pulmonary) were found through screening at entry. Eleven persons had abnormal mass miniature X-rays (MMRs), but had inadequate follow-up and were
diagnosed later through passive case finding. MMR itself had a sensitivity of 96% and a specificity of 98% for pulmonary TB, diagnosed within 1 year after arrival. TB prevalence at entry was 110/100000; for Somalis it was 577/100000. Incidence rates were stable in the total cohort after arrival,
whereas rates for extra-pulmonary TB in Somalis increased.CONCLUSIONS: Screening on entry should continue, but follow-up of abnormal MMRs must be improved. There should be more emphasis on treatment of latent infection.
A linear RFQ ion trap for the Enriched Xenon Observatory Flatt, B.; Green, M.; Wodin, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2007, Volume:
578, Issue:
2
Journal Article
Peer reviewed
Open access
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
136Xe to
136Ba. 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 (
136Ba). 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.
An inverted-geometry, high voltage polarized electron gun with UHV load lock
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/1994
Journal Article
A liquid xenon ionization chamber in an all-fluoropolymer vessel LePort, F.; Pocar, A.; Bartoszek, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2007, Volume:
578, Issue:
2
Journal Article
Peer reviewed
Open access
A novel technique has been developed to build vessels for liquid xenon ionization detectors entirely out of an ultra-clean fluoropolymer. One such detector was operated inside a welded, He leak ...tight, all-fluoropolymer chamber. The measured energy resolution for 570
keV gamma rays is
σ
/
E
=
5.1
%
at a drift field of 1.5
kV/cm, in line with the best values obtained for ionization only detectors run in LXe using conventional, metal vessels.
It is still unclear whether the reported increase in the prevalence of asthma is real or due to changes in diagnostic criteria. The objectives of this study were to compare the prevalence of ...diagnosed asthma with the prevalence of respiratory symptoms, and to compare the association between asthma and other atopic diseases in 1981 and 1994. The study populations comprised randomly selected school classes in Oslo in 1981 (n=1,772) and 1994 (n=2,577). The main outcomes in these comparable cross-sectional studies of children, 6-16 yrs of age, were parent-reported prevalence of diagnosed asthma, respiratory symptoms, eczema and hay fever. The questionnaire was identical in 1981 and 1994. The response rates were 94% (1,674 out of 1,772) in 1981 and 85% (2,188 out of 2,577) in 1994. The lifetime prevalence of asthma increased from 3.4% in 1981 to 9.3% in 1994; odds ratio (OR) 2.9 (95% confidence interval (95% CI) 2.1-4.0) comparing 1994 to 1981. The prevalence of occasional wheezing increased from 9.0 to 10.8%; OR 1.2 (95% CI 1.0-1.5), and attacks of wheezing from 3.7 to 6.8%; OR 1.8 (95% CI 1.3-2.5). Survival analyses for 3 year birth cohorts showed that asthma was more readily diagnosed in the latest birth cohort (1985-1988). The association between asthma and other atopic diseases decreased during the period under study. The increase in diagnosed asthma and respiratory symptoms supports a true increase in asthma. However, the larger increase in diagnosed asthma than wheezing and a reduced association between asthma and other atopic diseases suggest that the increase in asthma may be explained, in part, by changes in diagnostic criteria.
In 1993, 4521 schoolchildren in Oslo, Norway, participated in a European study on air pollution and respiratory health. Incorporated in the primary questionnaire were five questions taken from a ...study performed 12 years earlier on 1772 schoolchildren in the same city. The response rate was 85% in 1993 vs 95% in 1981. The current and cumulative prevalences of doctor-diagnosed asthma in 1993 were 4.2% and 8.0%, respectively, compared to 2.2% (P < 0.01) and 3.4% (P < 0.01) in 1981. Attacks of breathlessness during the last 3 years were experienced by 7.1% in 1993 and 3.3% in 1981 (P < 0.05). Wheezing or breathlessness on exposure to pollen in 1993 and 1981 was reported by 6.1% and 3.7% (P < 0.01), respectively; to animals by 4.0% and 2.8% (P < 0.05); and to exercise by 10.2% and 4.8% (P < 0.01). The prevalence of occasional wheezing and the cumulative prevalence of doctor-diagnosed eczema, urticaria, and hay fever were not significantly altered. To summarize, a higher prevalence of both doctor-diagnosed asthma and symptoms of obstructive airways disease was reported by children attending primary school in Oslo in 1993 than 12 years earlier. No increase was observed in the prevalence of other atopic diseases.
Initial impact parameter resolution of the new SLD vertex detector Sinev, N.B; Brau, J.E; Abe, K ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Volume:
409, Issue:
1-3
Journal Article
Peer reviewed
Open access
During 1996 the SLD collaboration completed the construction of, and began the operation of, a new vertex detector (VXD3). This detector, based on 96 CCD’s each of 13cm2 area, is an upgrade of the ...original vertex detector of SLD (VXD2), and is made possible by advances in the technology of CCD detectors. New front-end electronics and a new data acquisition system were developed for this upgrade. Its improved characteristics will enhance many SLD measurements, and open the possibility to observe Bs0-mixing. More than 50000 Z events obtained with the new vertex detector have been analyzed. Results on the new detector performance (including resolution evaluation) from this first data are presented.
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