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Benitez-Medina, C.

Publications and source records attributed to Benitez-Medina, C..

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

The EXO-200 detector, part II: auxiliary systems

The EXO-200 experiment searched for neutrinoless double-beta decay of 136 Xe with a single-phase liquid xenon detector. It used an active mass of 110 kg of 80.6%-enriched liquid xenon in an ultra-low background time projection chamber with ionization and scintillation detection and readout. Here, this paper describes the design and performance of the various support systems necessary for detector operation, including cryogenics, xenon handling, and controls. Novel features of the system were driven by the need to protect the thin-walled detector chamber containing the liquid xenon, to achieve high chemical purity of the Xe, and to maintain thermal uniformity across the detector.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Investigation of radioactivity-induced backgrounds in EXO-200

The search for neutrinoless double-beta decay ( 0 ν β β ) requires extremely low background and a good understanding of their sources and their influence on the rate in the region of parameter space relevant to the 0 ν β β signal. We report on studies of various β and γ backgrounds in the liquid-xenon-based EXO- 200 0 ν β β experiment. With this work we try to better understand the location and strength of specific background sources and compare the conclusions to radioassay results taken before and during detector construction. Finally, we discuss the implications of these studies for EXO-200 as well as for the next-generation, tonne-scale nEXO detector.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Spectroscopy of Ba andBa+deposits in solid xenon for barium tagging in nEXO

Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra for deposits of barium atoms and ions in solid xenon matrices are presented. Excitation spectra for prominent emission lines, temperature dependence, and bleaching of the fluorescence reveal the existence of different matrix sites. A regular series of sharp lines observed in Ba + deposits is identified with some type of barium hydride molecule. Lower limits for the fluorescence quantum efficiency of the principal Ba emission transition are reported. Under current conditions, an image of fewer than or equal to 10 4 Ba atoms can be obtained. Prospects for imaging single Ba atoms in solid xenon are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

An RF-only ion-funnel for extraction from high-pressure gases

An RF ion-funnel technique has been developed to extract ions from a high-pressure (10 bar) noble-gas environment into a vacuum (10 -6 mbar). Detailed simulations have been performed and a prototype has been developed for the purpose of extracting 136 Ba ions from Xe gas with high efficiency. With this prototype, ions have been extracted for the first time from high-pressure xenon gas and argon gas. Systematic studies have been carried out and compared to simulations. This demonstration of extraction of ions, with mass comparable to that of the gas generating the high-pressure, has applications to Ba tagging from a Xe-gas time-projection chamber for double-beta decay, as well as to the general problem of recovering trace amounts of an ionized element in a heavy (m > 40 u) carrier gas.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Improved measurement of the 2 ν β β half-life of 136 Xe with the EXO-200 detector

In this work, we report on an improved measurement of the 2 ν β β half-life of 136 Xe performed by EXO-200. The use of a large and homogeneous time-projection chamber allows for the precise estimate of the fiducial mass used for the measurement, resulting in a small systematic uncertainty. We also discuss in detail the data-analysis methods used for double- β decay searches with EXO-200, while emphasizing those directly related to the present measurement. The 136 Xe 2 ν β β half-life is found to be T 1 / 2 2 ν β β = 2.165 ± 0.016 ( stat ) ± 0.059 ( sys ) × 10 21 yr. Finally, this is the most precisely measured half-life of any 2 ν β β decay to date.

136Xe↗