Modern Skipper CCD technology has been used in particle physics experiments since its first successful demonstration in 2017. This technology has been demonstrated to achieve extremely low readout noise (0.039 e-rms/pix), while maintaining the benefits of conventional CCD detectors. The extremely low noise of Skipper CCDs presents a very interesting potential for certain astronomical applications where photon shot noise does not dominate, and the ability of Skipper CCDs to be tuned for a desired readout noise allows for a wide range of applications. In the current paper, we focus on the engineering work performed in cryo-mechanics and electronics (Dewar, detector mount, preamplifier, etc.) at NOIRLab-CTIO in order to perform on-sky testing of a mosaic of 4 Skipper CCDs using the SOAR Integral Field Spectrograph (SIFS). This work was performed in the context of a NOIRLab/LNA/Fermilab/U.Chicago/LBNL collaboration for testing Skipper devices for astronomy. We also present the mosaic characterization results of the detectors from the laboratory, as well as the final engineering performance results from on sky observations.
The Skipper is a special type of charge-coupled device (CCD) that allows pixel measurements with sub-electron noise levels due to its non-destructive readout operation. Over the last decade, these sensors have been used as particle detectors on a variety of experiments, such as the direct detection of galactic dark matter and neutrino experiments. Skipper CCD achieves low-noise by reading multiple times, and sequentially, the pixel charge packet, which translates to longer readout times. This becomes a limiting factor for those applications that require sub-electron detection and faster readout speeds. A novel analysis method for reducing the total pixel readout time is presented in this work. The method relies on analyzing the time-domain properties of the video signal including the clock feedthroughs and their shapes to optimize the clock transitions that define the pixel. The analysis technique is experimentally demonstrated using a standard scientific detector and also with a Skipper CCD with single photon sensitivity. In both cases the sensors are operated and readout using the Low Threshold Acquisition (LTA) controller with an updated firmware for faster clock sequencing. A good compromise between noise performance and total readout time was achieved. This will allows the use of the Skipper CCD and/or the LTA for astronomy, quantum imaging, and other applications that require faster readout times than previous uses of the sensor and the controller.
We present the development of a Skipper Charge-Coupled Device (CCD) focal plane prototype for the SOAR Telescope Integral Field Spectrograph (SIFS). This mosaic focal plane consists of four 6k × 1k, 15 μm pixel Skipper CCDs mounted inside a vacuum dewar. We describe the process of packaging the CCDs so that they can be easily tested, transported, and installed in a mosaic focal plane. We characterize the performance of ∼ 650μm thick, fully-depleted engineering-grade Skipper CCDs in preparation for performing similar characterization tests on science-grade Skipper CCDs which will be thinned to 250μm and backside processed with an antireflective coating. We achieve a single-sample readout noise of 4.5 e− rms/pix for the best performing amplifiers and subelectron resolution (photon counting capabilities) with readout noise σ ∼ 0.16 e− rms/pix from 800 measurements of the charge in each pixel. We describe the design and construction of the Skipper CCD focal plane and provide details about the synchronized readout electronics system that will be implemented to simultaneously read 16 amplifiers from the four Skipper CCDs (4-amplifiers per detector). Finally, we outline future plans for laboratory testing, installation, commissioning, and science verification of our Skipper CCD focal plane.
We characterize the response of a novel 250 µm thick, fully-depleted Skipper Charged-Coupled Device (CCD) to visible/near-infrared light with a focus on potential applications for astronomical observations. We achieve stable, single-electron resolution with readout noise σ 0.18 e− rms/pix from 400 non-destructive measurements of the charge in each pixel. We verify that the gain derived from photon transfer curve measurements agrees with the gain calculated from the quantized charge of individual electrons to within < 1%. We also perform relative quantum efficiency measurements and demonstrate high relative quantum efficiency at optical/near- infrared wavelengths, as is expected for a thick, fully depleted detector. Finally, we demonstrate the ability to perform multiple non-destructive measurements and achieve sub-electron readout noise over configurable sub- regions of the detector. This work is the first step toward demonstrating the utility of Skipper CCDs for future astronomical and cosmological applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.