148 research outputs found
Spatially uniform calibration of a liquid xenon detector at low energies using 83m-Kr
A difficult task with many particle detectors focusing on interactions below
~100 keV is to perform a calibration in the appropriate energy range that
adequately probes all regions of the detector. Because detector response can
vary greatly in various locations within the device, a spatially uniform
calibration is important. We present a new method for calibration of liquid
xenon (LXe) detectors, using the short-lived 83m-Kr. This source has
transitions at 9.4 and 32.1 keV, and as a noble gas like Xe, it disperses
uniformly in all regions of the detector. Even for low source activities, the
existence of the two transitions provides a method of identifying the decays
that is free of background. We find that at decreasing energies, the LXe light
yield increases, while the amount of electric field quenching is diminished.
Additionally, we show that if any long-lived radioactive backgrounds are
introduced by this method, they will present less than 67E-6 events/kg/day in
the next generation of LXe dark matter direct detection searchesComment: 9 pages, 9 figures. Accepted to Review of Scientific Instrument
CONTRIBUTIONS OF CABIN RELATED AND GROUND OPERATION TECHNOLOGIES TOWARDS FLIGHTPATH 2050
Abstract The vision of the European Commission (EC) for 2050 is a 75% reduction in carbon dioxide (CO2) emissions per passenger kilometer relative to the capabilities of conventional aircraft in 2000. This paper focuses on airframe related contributions to a reduction of CO2 emissions in terms of structural changes of the cabin and fuselage design. Furthermore, thus far disregarded emissions during the on-block time at the airport are considered and ground operation enhancements are presented to reduce these. For the methodical approach several separate sensitivity analyses were performed to assess the CO2 impact of cabin and fuselage modifications, in terms of higher passenger density, reduced interior weight or usage of Carbon Fiber Reinforced Plastic (CFRP) for the fuselage structure, on the basis of a narrow-body medium-to-short haul reference aircraft. Moreover, the impact of electric taxiing and reduced onblock Auxiliary Power Unit (APU) running time are investigated. The result of the investigated airframe related technologies is a 6.5% CO2 emission reduction compared to the reference aircraft and a 6.2% reduction for the ATM and ground operation. However, the reduction potential of the presented strategies is insufficient to reach to target Flightpath 2050 goals solely from the investigated areas. Hence, further studies have to be conducted to improve cabin related designs and ground operation based processes to ensure the fulfillment of the released targets
Dark Matter Results from 100 Live Days of XENON100 Data
We present results from the direct search for dark matter with the XENON100
detector, installed underground at the Laboratori Nazionali del Gran Sasso of
INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg
liquid xenon target. Interaction vertex reconstruction in three dimensions with
millimeter precision allows to select only the innermost 48 kg as ultra-low
background fiducial target. In 100.9 live days of data, acquired between
January and June 2010, no evidence for dark matter is found. Three candidate
events were observed in a pre-defined signal region with an expected background
of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter
interactions today, excluding spin-independent elastic WIMP-nucleon scattering
cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90%
confidence level.Comment: 5 pages, 5 figures; matches accepted versio
Implications on Inelastic Dark Matter from 100 Live Days of XENON100 Data
The XENON100 experiment has recently completed a dark matter run with 100.9
live-days of data, taken from January to June 2010. Events in a 48kg fiducial
volume in the energy range between 8.4 and 44.6 keVnr have been analyzed. A
total of three events have been found in the predefined signal region,
compatible with the background prediction of (1.8 \pm 0.6) events. Based on
this analysis we present limits on the WIMP-nucleon cross section for inelastic
dark matter. With the present data we are able to rule out the explanation for
the observed DAMA/LIBRA modulation as being due to inelastic dark matter
scattering off iodine at a 90% confidence level.Comment: 3 pages, 3 figure
ASSESSMENT OF PROTECTIVE PROPERTIES OF GLASSES WITH THE USE OF GOLMIUM OXIDE AGAINST GAMMA RADIATION
Presents the results of calculating the protective properties of glass from gamma radiation using holmium oxide in its composition for the energy range 0,122-1,408 MeV
Clinical practice: Noninvasive respiratory support in newborns
The most important goal of introducing noninvasive ventilation (NIV) has been to decrease the need for intubation and, therefore, mechanical ventilation in newborns. As a result, this technique may reduce the incidence of bronchopulmonary dysplasia (BPD). In addition to nasal CPAP, improvements in sensors and flow delivery systems have resulted in the introduction of a variety of other types of NIV. For the optimal application of these novelties, a thorough physiological knowledge of mechanics of the respiratory system is necessary. In this overview, the modern insights of noninvasive respiratory therapy in newborns are discussed. These aspects include respiratory support in the delivery room; conventional and modern nCPAP; humidified, heated, and high-flow nasal cannula ventilation; and nasal intermittent positive pressure ventilation. Finally, an algorithm is presented describing common practice in taking care of respiratory distress in prematurely born infants
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