37 research outputs found
Constraints on the electron-hole pair creation energy and Fano factor below 150 eV from Compton scattering in a Skipper-CCD
Fully-depleted thick silicon Skipper-charge-coupled devices (Skipper-CCDs)
are an important technology to probe neutrino and light-dark-matter
interactions due to their sub-electron read-out noise. However, the successful
search for rare neutrino or dark-matter events requires the signal and all
backgrounds to be fully characterized. In particular, a measurement of the
electron-hole pair creation energy below 150 eV and the Fano factor are
necessary for characterizing the dark matter and neutrino signals. Moreover,
photons from background radiation may Compton scatter in the silicon bulk,
producing events that can mimic a dark matter or neutrino signal. We present a
measurement of the Compton spectrum using a Skipper-CCD and a Am
source. With these data, we estimate the electron-hole pair-creation energy to
be eV at 130 K in the energy range between 99.3 eV
and 150 eV. By measuring the widths of the steps at 99.3 eV and 150 eV in the
Compton spectrum, we introduce a novel technique to measure the Fano factor,
setting an upper limit of 0.31 at 90% C.L. These results prove the potential of
Skipper-CCDs to characterize the Compton spectrum and to measure precisely the
Fano factor and electron-hole pair creation energy below 150 eV
First results from a multiplexed and massive instrument with sub-electron noise Skipper-CCDs
We present a new instrument composed of a large number of sub-electron noise
Skipper-CCDs operated with a two stage analog multiplexed readout scheme
suitable for scaling to thousands of channels. New, thick, Mpix sensors,
from a new foundry, are glued into a Multi-Chip Module (MCM) printed circuit
board on a ceramic substrate which has 16 sensors each. The instrument, that
can hold up-to 16 MCMs, a total of 256 Skipper-CCD sensors (called a
Super-Module with grams of active mass and Mpix), is part
of the RD effort of the OSCURA experiment which will have
super-modules. Experimental results with MCMs and Skipper-CCDs
sensors are presented in this paper. This is already the largest ever build
instrument with single electron sensitivity CCDs using nondestructive readout,
both, in terms of active mass and number of channels.Comment: Corrected minor typo
Results of the engineering run of the coherent neutrino nucleus interaction experiment (CONNIE)
The CONNIE detector prototype is operating at a distance of 30 m from the core of a 3.8 GWth nuclear reactor with the goal of establishing Charge-Coupled Devices (CCD) as a new technology for the detection of coherent elastic neutrino-nucleus scattering. We report on the results of the engineering run with an active mass of 4 g of silicon. The CCD array is described, and the performance observed during the first year is discussed. A compact passive shield was deployed around the detector, producing an order of magnitude reduction in the background rate. The remaining background observed during the run was stable, and dominated by internal contamination in the detector packaging materials. The in-situ calibration of the detector using X-ray lines from fluorescence demonstrates good stability of the readout system. The event rates with the reactor ON and OFF are compared, and no excess is observed coming from nuclear fission at the power plant. The upper limit for the neutrino event rate is set two orders of magnitude above the expectations for the standard model. The results demonstrate the cryogenic CCD-based detector can be remotely operated at the reactor site with stable noise below2 e RMS and stable background rates. The success of the engineering test provides a clear path for the upgraded 100 g detector to be deployed during 2016.Fil: Aguilar Arevalo, A.. Universidad Nacional Autónoma de México; MéxicoFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Fundación José A. Balseiro; ArgentinaFil: Bonifazi, C.. Universidade Federal do Rio de Janeiro; BrasilFil: Butner, M.. Fermi National Accelerator Laboratory; Estados UnidosFil: Cancelo, G.. Fermi National Accelerator Laboratory; Estados UnidosFil: Castañeda Vazquez, A.. Universidad Nacional Autónoma de México; MéxicoFil: Cervantes Vergara, B.. Universidad Nacional Autónoma de México; MéxicoFil: Chavez, C. R.. Universidad Nacional de Asunción; ParaguayFil: Da Motta, H.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: D'Olivo, J. C.. Universidad Nacional Autónoma de México; MéxicoFil: Dos Anjos, J.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Estrada, J.. Fermi National Accelerator Laboratory; Estados UnidosFil: Fernández Moroni, Guillermo. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ford, R.. Fermi National Accelerator Laboratory; Estados UnidosFil: Foguel, A.. Centro Brasileiro de Pesquisas Físicas; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Hernandez Torres, K. P.. Universidad Nacional Autónoma de México; MéxicoFil: Izraelevitch, F.. Fermi National Accelerator Laboratory; Estados UnidosFil: Kavner, A.. University of Michigan; Estados UnidosFil: Kilminster, B.. Universitat Zurich; SuizaFil: Kuk, K.. Fermi National Accelerator Laboratory; Estados UnidosFil: Lima Jr, H. P.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Makler, M.. Centro Brasileiro de Pesquisas Físicas; BrasilFil: Molina, J.. Universidad Nacional de Asunción; ParaguayFil: Moreno Granados, G.. Universidad Nacional Autónoma de México; MéxicoFil: Moro, Juan Manuel. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paolini, Eduardo Emilio. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto ; ArgentinaFil: Sofo Haro, Miguel Francisco. Comision Nacional de Energia Atomica. Gerencia D/area de Energia Nuclear; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tiffenberg, Javier Sebastian. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trillaud, F.. Universidad Nacional Autónoma de México; MéxicoFil: Wagner, S.. Centro Brasileiro de Pesquisas Físicas; Brasil. Pontificia Universidade Católica do Rio Grande do Sul; Brasi
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB
We present results of a dark matter search performed with a 0.6 kg day
exposure of the DAMIC experiment at the SNOLAB underground laboratory. We
measure the energy spectrum of ionization events in the bulk silicon of
charge-coupled devices down to a signal of 60 eV electron equivalent. The data
are consistent with radiogenic backgrounds, and constraints on the
spin-independent WIMP-nucleon elastic-scattering cross section are accordingly
placed. A region of parameter space relevant to the potential signal from the
CDMS-II Si experiment is excluded using the same target for the first time.
This result obtained with a limited exposure demonstrates the potential to
explore the low-mass WIMP region (<10 GeV/) of the upcoming DAMIC100, a
100 g detector currently being installed in SNOLAB.Comment: 11 pages, 11 figure
SENSEI: Characterization of Single-Electron Events Using a Skipper-CCD
We use a science-grade Skipper Charge Coupled Device (Skipper-CCD) operating
in a low-radiation background environment to develop a semi-empirical model
that characterizes the origin of single-electron events in CCDs. We identify,
separate, and quantify three independent contributions to the single-electron
events, which were previously bundled together and classified as ``dark
counts'': dark current, amplifier light, and spurious charge. We measure a dark
current, which depends on exposure, of (5.89+-0.77)x10^-4 e-/pix/day, and an
unprecedentedly low spurious charge contribution of (1.52+-0.07)x10^-4 e-/pix,
which is exposure-independent. In addition, we provide a technique to study
events produced by light emitted from the amplifier, which allows the
detector's operation to be optimized to minimize this effect to a level below
the dark-current contribution. Our accurate characterization of the
single-electron events allows one to greatly extend the sensitivity of
experiments searching for dark matter or coherent neutrino scattering.
Moreover, an accurate understanding of the origin of single-electron events is
critical to further progress in ongoing R&D efforts of Skipper and conventional
CCDs.Comment: 9 pages, 6 figures, 4 table
SENSEI: Direct-Detection Results on sub-GeV Dark Matter from a New Skipper CCD
We present the first direct-detection search for sub-GeV dark matter using a new ∼2-gram high-resistivity Skipper CCD from a dedicated fabrication batch that was optimized for dark matter searches. Using 24 days of data acquired in the MINOS cavern at the Fermi National Accelerator Laboratory, we measure the lowest rates in silicon detectors of events containing one, two, three, or four electrons, and achieve world-leading sensitivity for a large range of sub-GeV dark matter masses. Data taken with different thicknesses of the detector shield suggest a correlation between the rate of high-energy tracks and the rate of single-electron events previously classified as "dark current."We detail key characteristics of the new Skipper CCDs, which augur well for the planned construction of the ∼100-gram SENSEI experiment at SNOLAB.Fil: Barak, Liron. Universitat Tel Aviv; IsraelFil: Bloch, Itay M.. Universitat Tel Aviv; IsraelFil: Cababie, Mariano Ruben. Universidad de Buenos Aires; Argentina. Fermi National Accelerator Laboratory; Estados UnidosFil: Cancelo, Gustavo Indalecio. Fermi National Accelerator Laboratory; Estados UnidosFil: Chaplinsky, Luke. Stony Brook University; Estados UnidosFil: Chierchie, Fernando. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Crisler, Michael. Fermi National Accelerator Laboratory; Estados UnidosFil: Drlica Wagner, Alex. University of Chicago; Estados Unidos. Fermi National Accelerator Laboratory; Estados UnidosFil: Essig, Rouven. Stony Brook University; Estados UnidosFil: Estrada, Juan. Fermi National Accelerator Laboratory; Estados UnidosFil: Etzion, Erez. Universitat Tel Aviv; IsraelFil: Fernández Moroni, Guillermo. Fermi National Accelerator Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Gift, Daniel. Stony Brook University; Estados UnidosFil: Munagavalasa, Sravan. Stony Brook University; Estados UnidosFil: Orly, Aviv. Universitat Tel Aviv; IsraelFil: Rodrigues, Dario. Fermi National Accelerator Laboratory; Estados Unidos. Universidad de Buenos Aires; ArgentinaFil: Singal, Aman. Stony Brook University; Estados UnidosFil: Sofo Haro, Miguel Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fermi National Accelerator Laboratory; Estados Unidos. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Stefanazzi, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Fermi National Accelerator Laboratory; Estados UnidosFil: Tiffenberg, Javier Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fermi National Accelerator Laboratory; Estados UnidosFil: Uemura, Sho. Universitat Tel Aviv; IsraelFil: Volansky, Tomer. Universitat Tel Aviv; IsraelFil: Yu, Tien Tien. University of Oregon; Estados UnidosFil: SENSEI collaboration. No especifíca