Search results for " Radon"
showing 10 items of 20 documents
Absolutely continuous variational measures of Mawhin's type
2011
Abstract In this paper we study absolutely continuous and σ-finite variational measures corresponding to Mawhin, F- and BV -integrals. We obtain characterization of these σ-finite variational measures similar to those obtained in the case of standard variational measures. We also give a new proof of the Radon-Nikodým theorem for these measures.
Results from a calibration of XENON100 using a source of dissolved radon-220
2017
A Rn 220 source is deployed on the XENON100 dark matter detector in order to address the challenges in calibration of tonne-scale liquid noble element detectors. We show that the Pb 212 beta emission can be used for low-energy electronic recoil calibration in searches for dark matter. The isotope spreads throughout the entire active region of the detector, and its activity naturally decays below background level within a week after the source is closed. We find no increase in the activity of the troublesome Rn 222 background after calibration. Alpha emitters are also distributed throughout the detector and facilitate calibration of its response to Rn 222 . Using the delayed coincidence of R…
Evaluation of radon levels in indoor gymnasia of palermo (Sicily) and Sassari (Sardinia)
2012
<p><strong>Background</strong>: In the last decades, there has been increased worldwide interest in the management of health risks from indoor radon.</p><p><strong>Methods</strong>: From 2006 to 2008, a survey on air radon levels was carried out in a total of 57 indoor gymnasia respectively located in the urban area of Palermo (Sicily) and Sassari (Sardinia).</p><p><strong>Results</strong>: The indoor radon levels were generally low with different geometric means in the two geographic areas (14.3 Bq/m3 in Palermo and 36 Bq/m3 in Sassari, respectively). Overall, in both groups increasing values of radon were found during the n…
RADEMACHER'S THEOREM IN BANACH SPACES WITHOUT RNP
2017
Abstract We improve a Duda’s theorem concerning metric and w *-Gâteaux differentiability of Lipschitz mappings, by replacing the σ-ideal 𝓐 of Aronszajn null sets [ARONSZAJN, N.: Differentiability of Lipschitzian mappings between Banach spaces, Studia Math. 57 (1976), 147–190], with the smaller σ-ideal 𝓐 of Preiss-Zajíček null sets [PREISS, D.—ZAJÍČEK, L.: Directional derivatives of Lipschitz functions, Israel J. Math. 125 (2001), 1–27]. We also prove the inclusion C̃ o ⊂ 𝓐, where C̃ o is the σ-ideal of Preiss null sets [PREISS, D.: Gâteaux differentiability of cone-monotone and pointwise Lipschitz functions, Israel J. Math. 203 (2014), 501–534].
A variational henstock integral characterization of the radon-nikodým property
2009
A characterization of Banach spaces possessing the Radon-Nikodym property is given in terms of finitely additive interval functions. We prove that a Banach space X has the RNP if and only if each X-valued finitely additive interval function possessing absolutely continuous variational measure is a variational Henstock integral of an X-valued function. Due to that characterization several X-valued set functions that are only finitely additive can be represented as integrals.
Radon–Nikodym Property and Area Formula for Banach Homogeneous Group Targets
2013
We prove a Rademacher-type theorem for Lipschitz mappings from a subset of a Carnot group to a Banach homogeneous group, equipped with a suitably weakened Radon-Nikodym property. We provide a metric area formula that applies to these mappings and more generally to all almost everywhere metrically differentiable Lipschitz mappings defined on a Carnot group. peerReviewed
Operator martingale decomposition and the Radon-Nikodym property in Banach spaces
2010
Abstract We consider submartingales and uniform amarts of maps acting between a Banach lattice and a Banach lattice or a Banach space. In this measure-free setting of martingale theory, it is known that a Banach space Y has the Radon–Nikodým property if and only if every uniformly norm bounded martingale defined on the Chaney–Schaefer l-tensor product E ⊗ ˜ l Y , where E is a suitable Banach lattice, is norm convergent. We present applications of this result. Firstly, an analogues characterization for Banach lattices Y with the Radon–Nikodým property is given in terms of a suitable set of submartingales (supermartingales) on E ⊗ ˜ l Y . Secondly, we derive a Riesz decomposition for uniform …
Optimal recovery of a radiating source with multiple frequencies along one line
2020
We study an inverse problem where an unknown radiating source is observed with collimated detectors along a single line and the medium has a known attenuation. The research is motivated by applications in SPECT and beam hardening. If measurements are carried out with frequencies ranging in an open set, we show that the source density is uniquely determined by these measurements up to averaging over levelsets of the integrated attenuation. This leads to a generalized Laplace transform. We also discuss some numerical approaches and demonstrate the results with several examples.
Design and realization of a radon chamber as a secondary standard
2010
The air-radon mixture is the most significant source of natural radiation in workplaces and within dwellings. Despite some uncertainty in the risk estimates, it is widely believed that greater the exposure to radon, greater the risk of developing lung cancer. To assess the radiological hazard, accurate measurements of radon concentrations are necessary. A large variety of radon monitoring instruments have been developed in the last years, usually calibrated in radon chambers containing a known radon concentration released within the chamber by a specific solid radium-226 source. Radon calibration chamber has been constructed to test and calibrate radon and radon progeny detectors at various…
$^{222}$Rn emanation measurements for the XENON1T experiment
2021
The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the $^{222}$Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a $^{222}$Rn activity concentration of 10 $\mu$Bq/kg in 3.2 t of xenon. The knowledge of the distribut…