Abstract
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 ≈ 130 grams of active mass and
346 Mpix), is part of the R&D effort of the OSCURA experiment
which will have ≈ 94 super-modules. Experimental results
with 10 MCMs and 160 Skipper-CCDs sensors are presented in this
paper. This is already the largest ever built instrument with single
electron sensitivity CCDs using nondestructive readout, both, in
terms of active mass and number of channels.
We present results of a dark matter search performed with a 0.6 kg d 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) with the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.
The CONNIE experiment Aguilar-Arevalo, A.; Bertou, X.; Bonifazi, C. ...
Journal of physics. Conference series,
10/2016, Letnik:
761, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos ...from a nuclear reactor with silicon nuclei. This talk, given at the XV Mexican Workshop on Particles and Fields (MWPF), discussed the potential of CONNIE to perform this measurement, the installation progress at the Angra dos Reis nuclear power plant, as well as the plans for future upgrades.
The CONNIE detector prototype is operating at a distance of 30 m from the core of a 3.8 GW sub(th) 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 below 2 e super(-) 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.
Abstract
With Skipper-CCD detectors it is possible to take multiple samples of the charge packet collected on each pixel. After averaging the samples, the noise can be extremely reduced allowing the ...exact counting of electrons per pixel. In this work we present an analog circuit that, with a minimum number of components, applies a double slope integration (DSI) and at the same time averages the multiple samples, producing at its output the pixel value with sub-electron noise. For this purpose, we introduce the technique of using the DSI integrator capacitor to add the skipper samples. An experimental verification using discrete components is presented, together with an analysis of its noise sources and limitations. After averaging 400 samples it was possible to reach a readout noise of 0.18 e
-
rms
/pix, comparable to other available readout systems. Due to its simplicity and significant reduction of the sampling requirements, this circuit technique is of particular interest in particle experiments and cameras with a high density of Skipper-CCDs.
We present a position-sensitive neutron detection technique based on a Commercial Off-The-Shelf CMOS image sensor (CIS) covered with nanoparticles of sodium gadolinium fluoride (NaGdF4). The ...synthesis procedure and characterization of the NaGdF4 nanoparticles are detailed, as well as the deposition method of the conversion layers over the surface of the chips. We also present a manufacture method of test patterns made with neutron-absorbing materials. These patterns were designed to evaluate the performance of the proposed technique. Analyzing the obtained neutron images we conclude that the intrinsic spatial resolution of the developed method is better than (15±6) μm, this upper bound for the spatial resolution is comparable with that obtained with the best neutron position-sensitive detectors available nowadays.
Abstract
In this paper we present a method for obtention of neutron
images with Commercial-Off-The-Shelf (COTS) CMOS image sensors
through the activation of indium foils. This detection method has
...been designed specifically for the acquisition of thermal and
epitermal neutron images in mixed beams with a high gamma flux, and
also for the study of high radioactive samples that are usually
placed into research reactor pools. We also present a technique to
obtain multi-spectral neutron images taking advantage of the high
neutron absorption cross-section of this material in the thermal
energy range, as well as around the 1.45 eV resonance. Measurements
performed in a neutron beam of the RA6 nuclear research reactor
located in Bariloche, Argentina, confirm the capability of the
proposed technique.
Ionizing radiation detection devices have been widely used in recent years in various applications and experimental fields, such as high-energy physics, nuclear physics, and medical imaging. Detailed ...description of their operational properties and their characterization by means of numerical modelling, as simulations, are key issue to understand the characteristics of radiation detectors in terms of efficiency, resolution and signal-to-noise ratio, since they allow optimising parameters that will be further used. The modelling processes, as the simulations, are routinely carried out using various tools, like Monte Carlo approaches, for instance: PENELOPE, FLUKA or GEANT4 are used to study the interaction of the radiation with the detector accounting for the whole physical processes. However, transporting electron/hole pairs, as generated through the device sensor to conform the corresponding electronic signals uses tools based on the finite element method, such as TCAD (Technology Computer Aided Design), which are developed mainly to help the microelectronics industry to design products. Usually, modelling approaches for radiation transport and electronic signal production are not integrated, thus performing the simulation process by splitting the problem into successive independent phases. Within this framework, the present study proposes, implements, and reports on a novel methodology that allows combining the two approaches aimed at integrating the complete simulation, thus achieving astep-by-step integrated modelling flow to describe the interaction of ionizing radiation with the sensor along with thetransport of the generated charge to the photodiodes and, finally, to the generation of electronic signals.
Abstract
The Dark Matter Daily Modulation experiment (DMSQUARE) seeks for dark matter interactions with a Skipper CCD. It is currently running at surface level in Bariloche, Argentina, and will be ...moved to a shallow underground site at Sierra Grande, Argentina in November 2021. The low threshold achieved by Skipper CCDs allows to search for electron recoil events with an ionization energy down to 1.2 eV. In order to extract a potential dark matter signal from noise at the single electron level, we propose to search for a diurnal modulation of events, resulting from the potential interaction of the dark matter wind with the particles in the Earth. Depending on the model, mass and cross-section, this modulation can be maximum at 40deg of latitude in the Southern Hemisphere, where DMSQUARE is operated. In this article we present the experiment, report preliminary results with a prototype Skipper CCD taking data at surface level and comment on future prospects.
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