Skipper-CCD Sensors for the Oscura Experiment: Requirements and Preliminary Tests
Brenda A. Cervantes-Vergara, Santiago Perez, Juan Estrada, Ana Botti, Claudio R. Chavez, Fernando Chierchie, Nathan Saffold, Alexis Aguilar-Arevalo, Fabricio Al… 展开作者
Brenda A. Cervantes-Vergara, Santiago Perez, Juan Estrada, Ana Botti, Claudio R. Chavez, Fernando Chierchie, Nathan Saffold, Alexis Aguilar-Arevalo, Fabricio Alcalde-Bessia, Nicolás Avalos, Oscar Baez, Daniel Baxter, Xavier Bertou, Carla Bonifazi, Gustavo Cancelo, Nuria Castelló-Mor, Alvaro E. Chavarria, Juan Manuel De Egea, Juan Carlos D'Olivo, Cyrus Dreyer, Alex Drlica-Wagner, Rouven Essig, Ezequiel Estrada, Erez Etzion, Paul Grylls, Guillermo Fernandez-Moroni, Marivi Fernández-Serra, Santiago Ferreyra, Stephen Holland, Agustín Lantero Barreda, Andrew Lathrop, Ian Lawson, Ben Loer, Steffon Luoma, Edgar Marrufo Villalpando, Mauricio Martinez Montero, Kellie McGuire, Jorge Molina, Sravan Munagavalasa, Danielle Norcini, Alexander Piers, Paolo Privitera, Dario Rodrigues, Richard Saldanha, Aman Singal, Radomir Smida, Miguel Sofo-Haro, Diego Stalder, Leandro Stefanazzi, Javier Tiffenberg, Michelangelo Traina, Sho Uemura, Pedro Ventura, Rocío Vilar Cortabitarte, Rachana Yajur
发表信息：
Journal of Instrumentation, Volume 18, August 2023
Oscura是一项拟开展的多千克级skipper-CCD实验，旨在进行暗物质（DM）直接探测搜索，其10千克探测器阵列将对亚GeV暗物质-电子相互作用达到前所未有的灵敏度。Oscura计划在SNOLAB运行，上覆岩层厚度为2070米，目标是在30千克·年的总曝光量下，在2-10个电子的电离信号区域的每个电子 bin 中，背景事件数少于1个，辐射本底率为0.01 dru。为实现这一目标，Oscura必须解决每一种潜在的背景事件来源，包括仪器本底。在本研究中，我们讨论了主要的仪器本底来源以及控制这些本底的策略，对传感器的性能参数设定了一系列约束条件。我们展示了首批制造的Oscura原型传感器的测试结果，在已设定的约束条件下评估了它们的性能，并基于这些结果估算了Oscura的仪器本底。
英文摘要：
Oscura is a proposed multi-kg skipper-CCD experiment designed for a dark matter (DM) direct detection search that will reach unprecedented sensitivity to sub-GeV DM-electron interactions with its 10 kg detector array. Oscura is planning to operate at SNOLAB with 2070 m overburden, and aims to reach a background goal of less than one event in each electron bin in the 2-10 electron ionization-signal region for the full 30 kg-year exposure, with a radiation background rate of 0.01 dru. In order to achieve this goal, Oscura must address each potential source of background events, including instrumental backgrounds. In this work, we discuss the main instrumental background sources and the strategy to control them, establishing a set of constraints on the sensors' performance parameters. We present results from the tests of the first fabricated Oscura prototype sensors, evaluate their performance in the context of the established constraints and estimate the Oscura instrumental background based on these results.
This work briefly discusses the potential applications of the Skipper-CCD technology in astronomy and reviews its current use in dark matter and neutrino experiments. An overview of the ongoing efforts to build multi-kilogram experiments with these sensors is given, in the context of the Oscura experiment. First results from the characterization of Oscura sensors from the first 200 mm wafer-fabrication run with a new vendor are presented. The overall yield of the electron counting capability of these sensors is 71%. A noise of 0.087 e$^-$ RMS, with 1225 samples/pix, and a dark current of (0.03…
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 $\appro…
The Skipper CCD-in-CMOS Parallel Read-Out Circuit (SPROCKET) is a mixed-signal front-end design for the readout of Skipper CCD-in-CMOS image sensors. SPROCKET is fabricated in a 65 nm CMOS process and each pixel occupies a 50$μ$m $\times$ 50$μ$m footprint. SPROCKET is intended to be heterogeneously integrated with a Skipper-in-CMOS sensor array, such that one readout pixel is connected to a multiplexed array of nine Skipper-in-CMOS pixels to enable massively parallel readout. The front-end includes a variable gain preamplifier, a correlated double sampling circuit, and a 10-bit serial successi…
The skipper CCD is a special type of charge coupled device in which the readout noise can be reduced to sub-electron levels by averaging independent measurements of the same charge. Thus the charge in the pixels can be determined by counting the exact number of electrons. The total readout time is proportional to the number of measurements of the charge in each pixel. For some applications this time may be too long; however, researchers usually are interested only on certain region within the matrix of pixels. In this paper we present the development of a smart skipper readout technique that a…
Skipper-CCD can achieve deep sub-electron readout noise making possible the absolute determination of the exact number of ionized electrons in a large range, from 0 to above 1900 electrons. In this work we present a novel technique that exploits this unique capability to allow self-calibration and the ultimate determination of silicon properties. We performed an absolute measurement of the variance and the mean number of the charge distribution produced by $^{55}$Fe X-rays, getting a Fano factor absolute measurement in Si at 123K and 5.9 keV. A value of 0.119 $\pm$ 0.002 was found and the elec…
The development of the Skipper Charge Coupled Devices (Skipper-CCDs) has been a major technological breakthrough for sensing very weak ionizing particles. The sensor allows to reach the ultimate sensitivity of silicon material as a charge signal sensor by unambiguous determination of the charge signal collected by each cell or pixel, even for single electron-hole pair ionization. Extensive use of the technology was limited by the lack of specific equipment to operate the sensor at the ultimate performance. In this work a simple, single-board Skipper-CCD controller is presented, aimed for the o…
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, it averages the multiple samples producing at its output the pixel value with sub-electron noise. For this prupose, we introduce the technique of using the DSI integrator capacitor to add the skipper samples. An experiment…
A Sub-electron-noise Skipper-CCD Readout ASIC with Improved Channel-to-channel Isolation and an Integrated Cryogenic Voltage Reference
Instituto Balseiro（巴尔塞罗研究所）；Instituto de Nanociencia y Nanotecnología INN (CNEA-CONICET)（纳米科学与技术研究所（CNEA-CONICET））；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Universidad Nacional de Córdoba（科尔多瓦国立大学）；Comisión Nacional de Energía Atómica (CNEA)（国家原子能委员会）；CONICET（阿根廷国家科学研究委员会）
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, prod…
Characterization of Spurious Charge in SENSEI Skipper-CCDs
C.N. Yang Institute for Theoretical Physics, Stony Brook University（纽约州立大学石溪分校杨振宁理论物理研究所）；Department of Physics and Astronomy, Stony Brook University（纽约州立大学石溪分校物理与天文学系）；Department of Physics and Institute for Fundamental Science, University of Oregon（俄勒冈大学物理与基础科学研究所）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Département de Physique, Université de Montréal（蒙特利尔大学物理系）；Instituto de Inv. en Ing. Eléctrica (IIIE), Dpto. de Ingeniería Eléctrica y de Computadoras (DIEC), Universidad Nacional del Sur (UNS)-CONICET（国立苏尔大学电气与计算机工程系电气研究研究所（IIIE）-阿根廷科学与技术研究委员会）；Department of Astronomy and Astrophysics, University of Chicago（芝加哥大学天文与天体物理学系）；Brookhaven National Laboratory（布鲁克海文国家实验室）；School of Physics and Astronomy, Tel-Aviv University（特拉维夫大学物理与天文学学院）
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 ima…
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)…
We present the first direct-detection search for eV-to-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-en…
We present new direct-detection constraints on eV-to-GeV dark matter interacting with electrons using a prototype detector of the Sub-Electron-Noise Skipper-CCD Experimental Instrument. The results are based on data taken in the MINOS cavern at the Fermi National Accelerator Laboratory. We focus on data obtained with two distinct readout strategies. For the first strategy, we read out the Skipper-CCD continuously, accumulating an exposure of 0.177 gram-days. While we observe no events containing three or more electrons, we find a large one- and two-electron background event rate, which we attr…
Searches for CEνNS and Physics beyond the Standard Model using Skipper-CCDs at CONNIE
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）；Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO)（巴里洛切原子中心与巴尔塞罗研究所，阿根廷国家原子能委员会（CNEA），阿根廷国家科学研究委员会（CONICET），门多萨国立大学（UNCUYO））；International Center for Advanced Studies & Instituto de Ciencias Físicas, ECyT-UNSAM and CONICET（高级研究中心与物理科学研究所，阿根廷国立萨米恩托理工大学及阿根廷国家科学研究委员会（CONICET））；Instituto de Física, Universidade Federal do Rio de Janeiro（里约热内卢联邦大学物理研究所）；Fermi National Accelerator Laboratory（费米国家加速器实验室）
We have developed a non-destructive readout system that uses a floating-gate amplifier on a thick, fully depleted charge coupled device (CCD) to achieve ultra-low readout noise of 0.068 e- rms/pix. This is the first time that discrete sub-electron readout noise has been achieved reproducibly over millions of pixels on a stable, large-area detector. This allows the precise counting of the number of electrons in each pixel, ranging from pixels with 0 electrons to more than 1500 electrons. The resulting CCD detector is thus an ultra-sensitive calorimeter. It is also capable of counting single pho…
Experiments aiming to directly detect dark matter through particle recoils can achieve energy thresholds of $\mathcal{O}(1\,\mathrm{eV})$. In this regime, ionization signals from small-angle Compton scatters of environmental $γ$-rays constitute a significant background. Monte Carlo simulations used to build background models have not been experimentally validated at these low energies. We report a precision measurement of Compton scattering on silicon atomic shell electrons down to 23$\,$eV. A skipper charge-coupled device (CCD) with single-electron resolution, developed for the DAMIC-M experi…
The DAMIC experiment employs large-area, thick charge-coupled devices (CCDs) to search for the interactions of low-mass dark matter particles in the galactic halo with silicon atoms in the CCD target. From 2017 to 2019, DAMIC collected data with a seven-CCD array (40-gram target) installed in the SNOLAB underground laboratory. We report dark-matter search results, including a conspicuous excess of events above the background model below 200 eV$_{\rm ee}$, whose origin remains unknown. We present details of the published spectral analysis, and update on the deployment of skipper CCDs to perform…
The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called "hidden sector." A prototype…
