arXiv subjects

J. Tiffenberg

Publications and source records attributed to J. Tiffenberg.

At least 19 recordsLinked to original sources

arXiv2025

Community Report from the 2025 SNOLAB Future Projects Workshop

SNOLAB hosts a biannual Future Projects Workshop (FPW) with the goal of encouraging future project stakeholders to present ideas, concepts, and needs for experiments or programs that could one day be hosted at SNOLAB. The 2025 FPW was held in the larger context of a 15-year planning exercise requested by the Canada Foundation for Innovation. This report collects input from the community, including both contributions to the workshop and contributions that could not be scheduled in the workshop but nonetheless are important to the community.

hep-ex↗

arXiv2024

A multi-channel silicon package for large-scale skipper-CCD experiments

The next generation of experiments for rare-event searches based on skipper Charge Coupled Devices (skipper-CCDs) presents new challenges for the sensor packaging and readout. Scaling the active mass and simultaneously reducing the experimental backgrounds in orders of magnitude requires a novel high-density silicon-based package that must be massively produced and tested. In this work, we present the design, fabrication, testing, and empirical signal model of a multi-channel silicon package. In addition, we outline the chosen specifications for the ongoing production of 1500 wafers that will add up to a 10 kg skipper-CCD array with 24000 readout channels.

astro-ph.IM↗

arXiv2024

Studying single-electron traps in newly fabricated Skipper-CCDs for the Oscura experiment using the pocket-pumping technique

Understanding and characterizing very low-energy ($\sim$eV) background sources is a must in rare-event searches. Oscura, an experiment aiming to probe electron recoils from sub-GeV dark matter using a 10-kg skipper-CCD detector, has recently fabricated its first two batches of sensors. In this work, we present the characterization of defects/contaminants identified in the buried-channel region of these newly fabricated skipper-CCDs. These defects/contaminants produce deferred charge from trap emission in the images next to particle tracks, which can be spatially resolved due to the sub-electron resolution achieved with these sensors. Using the trap-pumping technique, we measured the energy and cross section associated to these traps in three Oscura prototype sensors from different fabrication batches which underwent different gettering methods during fabrication. Results suggest that the type of defects/contaminants is more closely linked to the fabrication batch rather than to the gettering method used. The exposure-dependent single-electron rate (SER) of one of these sensors was measured $\sim$100~m underground, yielding $(1.8\pm 0.3)\times10^{-3}~e^-$/pix/day at 131K. The impact of the identified traps on the measured exposure-dependent SER is evaluated via a Monte Carlo simulation. Results suggest that the exposure-dependent SER of Oscura prototype sensors would be lower in lower background environments as expected.

physics.ins-det↗

arXiv2024

Interferometry with few photons

Optical phase determination is an important and established tool in diverse fields such as astronomy, biology, or quantum optics. There is increasing interest in using a lower number of total photons. However, different noise sources, such as electronic readout noise in the detector, and shot noise, hamper the phase estimation in regimes of very low illumination. Here we report a study on how the quality of phase determination is affected by these two sources of noise. To that end, we experimentally reconstruct different wavefronts by means of a point diffraction interferometer for different mean intensities of illumination, up to $15\ \mathrm{phot/px}$. Our interferometer features a Skipper-CCD sensor, which allows us to reduce the readout noise arbitrarily, thus enabling us to separate the effect of these two sources of noise. For two cases of interest: a spatial qudit encoding phase, consisting of d = 6 uniform phase regions, and a more general continuous phase, we see that reducing the readout noise leads to a clear improvement in the quality of reconstruction. This can be explained by a simple noise model that allows us to predict the expected fidelity of reconstruction and shows excellent agreement with the measurements.

quant-ph↗

arXiv2024

Deployment and performance of a Low-Energy-Threshold Skipper-CCD inside a nuclear reactor

Charge Coupled Devices (CCD) are used for reactor neutrino experiments and already shown their potential in constraining new physics models. The prospect of a Skipper-CCD experiment looking for standard and beyond standard model physics (BSM) in a nuclear reactor has been recently evaluated for different benchmark scenarios. Here we report the installation of the first 2 g Skipper-CCD inside the containment building of a 2 GW$_{th}$ nuclear power plant, positioned 12 meters from the center of the reactor core. We discuss the challenges involved in the commissioning of the detector and present data acquired during reactor ON and reactor OFF periods, with the detector operating with a sub-electron readout noise of 0.17 e-. The ongoing efforts to improve sensitivities to CEvNS and BSM interaction are also discussed.

hep-ex↗

arXiv2023

Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs

We present results from a 3.25 kg-day target exposure of two silicon charge-coupled devices (CCDs), each with 24 megapixels and skipper readout, deployed in the DAMIC setup at SNOLAB. With a reduction in pixel readout noise of a factor of 10 relative to the previous detector, we investigate the excess population of low-energy events in the CCD bulk previously observed above expected backgrounds. We address the dominant systematic uncertainty of the previous analysis through a depth fiducialization designed to reject surface backgrounds on the CCDs. The measured bulk ionization spectrum confirms the presence of an excess population of low-energy events in the CCD target with characteristic rate of ${\sim}7$ events per kg-day and electron-equivalent energies of ${\sim}80~$eV, whose origin remains unknown.

astro-ph.CO↗

arXiv2023

Infrared photon-number-resolving imager using a Skipper-CCD

Imaging in a broad light-intensity regime with a high signal-to-noise ratio is a key capability in fields as diverse as Quantum Metrology and Astronomy. Achieving high signal-to-noise ratios in quantum imaging leads to surpassing the classical limit in parameter estimation. In astronomical detection, the search for habitable exoplanets demands imaging in the infrared its atmospheres looking for biosignatures. These optical applications are hampered by detection noise, which critically limits their potential, and thus demands photon-number and spatial resolution detectors. Here we report an imaging device in the infrared wavelength range able to arbitrarily reduce the readout noise. We built a Measured Exposure Skipper-CCD Sensor Instrument equipped with a thick back-illuminated sensor, with photon-number-resolving capability in a wide dynamic range, spatial resolution, high quantum efficiency in the near-infrared and ultra-low dark counts. This device allows us to image objects in a broad range of intensities within the same frame and, by reducing the readout noise to less than 0.2e$^-$, to distinguish even those shapes with less than two photons per pixel, unveiling what was previously hidden in the noise. These results pave the way for building high-standard infrared imagers based on Skipper-CCDs.

physics.ins-det↗

arXiv2022

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, $1.35$ 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 $\approx 130$ grams of active mass and $346$ Mpix), is part of the R$\&$D effort of the OSCURA experiment which will have $\approx 94$ super-modules. Experimental results with $10$ MCMs and $160$ 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.

physics.ins-det↗

arXiv2022

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 $^{241}$Am source. With these data, we estimate the electron-hole pair-creation energy to be $\left(3.71 \pm 0.08\right)$ 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.

physics.ins-det↗

arXiv2021

Characterization of the background spectrum in DAMIC at SNOLAB

We construct the first comprehensive radioactive background model for a dark matter search with charge-coupled devices (CCDs). We leverage the well-characterized depth and energy resolution of the DAMIC at SNOLAB detector and a detailed GEANT4-based particle-transport simulation to model both bulk and surface backgrounds from natural radioactivity down to 50 eV$_{\text{ee}}$. We fit to the energy and depth distributions of the observed ionization events to differentiate and constrain possible background sources, for example, bulk $^{3}$H from silicon cosmogenic activation and surface $^{210}$Pb from radon plate-out. We observe the bulk background rate of the DAMIC at SNOLAB CCDs to be as low as $3.1 \pm 0.6$ counts kg$^{-1}$ day$^{-1}$ keV$_{\text{ee}}^{-1}$, making it the most sensitive silicon dark matter detector. Finally, we discuss the properties of a statistically significant excess of events over the background model with energies below 200 eV$_{\text{ee}}$.

hep-ex↗

arXiv2020

Measurement of the bulk radioactive contamination of detector-grade silicon with DAMIC at SNOLAB

We present measurements of bulk radiocontaminants in the high-resistivity silicon CCDs from the DAMIC at SNOLAB experiment. We utilize the exquisite spatial resolution of CCDs to discriminate between $\alpha$ and $\beta$ decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. Using spatially-correlated $\beta$ decays, we measure a bulk radioactive contamination of $^{32}$Si in the CCDs of $140 \pm 30$ $\mu$Bq/kg, and place an upper limit on bulk $^{210}$Pb of $< 160~\mu$Bq/kg. Using similar analyses of spatially-correlated bulk $\alpha$ decays, we set limits of $< 11$ $\mu$Bq/kg (0.9 ppt) on $^{238}$U and of $< 7.3$ $\mu$Bq/kg (1.8 ppt) on $^{232}$Th. The ability of DAMIC CCDs to identify and reject spatially-coincident backgrounds, particularly from $^{32}$Si, has significant implications for the next generation of silicon-based dark matter experiments, where $\beta$'s from $^{32}$Si decay will likely be a dominant background. This capability demonstrates the readiness of the CCD technology to achieve kg-scale dark matter sensitivity.

physics.ins-det↗

arXiv2020

Results on Low-Mass Weakly Interacting Massive Particles from an 11 kg-day Target Exposure of DAMIC at SNOLAB

We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg-day target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies $>$200 eV$_{\rm ee}$ in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50 eV$_{\rm ee}$. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections $\sigma_{\chi-n}$ as low as $3\times 10^{-41}$ cm$^2$ for WIMPs with masses $m_{\chi}$ from 7 to 10 GeV$c^{-2}$ . These results are the strongest constraints from a silicon target on the existence of WIMPs with $m_{\chi}$$<$9 GeV$c^{-2}$ and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.

astro-ph.CO↗

arXiv2019

Proceedings of The Magnificent CE$\nu$NS Workshop 2018

The Magnificent CE$\nu$NS Workshop (2018) was held November 2 & 3 of 2018 on the University of Chicago campus and brought together theorists, phenomenologists, and experimentalists working in numerous areas but sharing a common interest in the process of coherent elastic neutrino-nucleus scattering (CE$\nu$NS). This is a collection of abstract-like summaries of the talks given at the meeting, including links to the slides presented. This document and the slides from the meeting provide an overview of the field and a snapshot of the robust CE$\nu$NS-related efforts both planned and underway.

hep-ex↗

arXiv2019

Constraints on Light Dark Matter Particles Interacting with Electrons from DAMIC at SNOLAB

We report direct-detection constraints on light dark matter particles interacting with electrons. The results are based on a method that exploits the extremely low levels of leakage current of the DAMIC detector at SNOLAB of 2-6$\times$10$^{-22}$ A cm$^{-2}$. We evaluate the charge distribution of pixels that collect $<10~\rm{e^-}$ for contributions beyond the leakage current that may be attributed to dark matter interactions. Constraints are placed on so-far unexplored parameter space for dark matter masses between 0.6 and 100 MeV$c^{-2}$. We also present new constraints on hidden-photon dark matter with masses in the range $1.2$-$30$ eV$c^{-2}$.

astro-ph.CO↗

arXiv2017

A measurement of the ionization efficiency of nuclear recoils in silicon

We have measured the ionization efficiency of silicon nuclear recoils with kinetic energy between 1.8 and 20 keV. We bombarded a silicon-drift diode with a neutron beam to perform an elastic-scattering experiment. A broad-energy neutron spectrum was used and the nuclear recoil energy was reconstructed using a measurement of the time of flight and scattering angle of the scattered neutron. The overall trend of the results of this work is well described by the theory of Lindhard et al. above 4 keV of recoil energy. Below this energy, the presented data shows a deviation from the model. The data indicates a faster drop than the theory prediction at low energies.

physics.ins-det↗

arXiv2017

Measurement of low energy ionization signals from Compton scattering in a CCD dark matter detector

An important source of background in direct searches for low-mass dark matter particles are the energy deposits by small-angle scattering of environmental $γ$ rays. We report detailed measurements of low-energy spectra from Compton scattering of $γ$ rays in the bulk silicon of a charge-coupled device (CCD). Electron recoils produced by $γ$ rays from $^{57}$Co and $^{241}$Am radioactive sources are measured between 60 eV and 4 keV. The observed spectra agree qualitatively with theoretical predictions, and characteristic spectral features associated with the atomic structure of the silicon target are accurately measured for the first time. A theoretically-motivated parametrization of the data that describes the Compton spectrum at low energies for any incident $γ$-ray flux is derived. The result is directly applicable to background estimations for low-mass dark matter direct-detection experiments based on silicon detectors, in particular for the DAMIC experiment down to its current energy threshold.

physics.ins-det↗

arXiv2017

First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter with DAMIC at SNOLAB

We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30 eV$c^{-2}$ with the DAMIC experiment at SNOLAB. Under the assumption that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter $κ$ is competitive with constraints from solar emission, reaching a minimum value of 2.2$\times$$10^{-14}$ at 17 eV$c^{-2}$. These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses 3-12 eV$c^{-2}$ and the first demonstration of direct experimental sensitivity to ionization signals $<$12 eV from dark matter interactions.

astro-ph.CO↗

arXiv2016

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/$c^{2}$) of the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.

astro-ph.CO↗