An introduction to some imperfections of CCD sensors

Astier, P.

doi:10.1088/1748-0221/10/05/c05013

Cited by 6 publications

(4 citation statements)

References 19 publications

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“…Other effects known or expected for thick CCDs, e.g., notable charge diffusion, resistivity variations in the bulk Si (a.k.a. 'tree-ring pattern', see, e.g., Astier 2015), or wavelength dependent defocus from the increased absorption depth of infrared photons, are not present in LDSS-3C.…”

Section: An Introduction To Ldss-3cmentioning

confidence: 94%

A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C

Stevenson

Bean

Seifahrt

et al. 2016

ApJ

105

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The characterization of a physically-diverse set of transiting exoplanets is an important and necessary step towards establishing the physical properties linked to the production of obscuring clouds or hazes. It is those planets with identifiable spectroscopic features that can most effectively enhance our understanding of atmospheric chemistry and metallicity. The newly-commissioned LDSS-3C instrument on Magellan provides enhanced sensitivity and suppressed fringing in the red optical, thus advancing the search for the spectroscopic signature of water in exoplanetary atmospheres from the ground. Using data acquired by LDSS-3C and the Spitzer Space Telescope, we search for evidence of water vapor in the transmission spectrum of the Neptune-mass planet HAT-P-26b. Our measured spectrum is best explained by the presence of water vapor, a lack of potassium, and either a high-metallicity, cloud-free atmosphere or a solar-metallicity atmosphere with a cloud deck at ∼10 mbar. The emergence of multi-scale-height spectral features in our data suggests that future observations at higher precision could break this degeneracy and reveal the planet's atmospheric chemical abundances. We also update HAT-P-26b's transit ephemeris, t 0 = 2455304.65218(25) BJD TDB , and orbital period, p = 4.2345023(7) days.

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Section: An Introduction To Ldss-3cmentioning

confidence: 94%

A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C

Stevenson

Bean

Seifahrt

et al. 2016

ApJ

105

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show abstract

“…Thick, high-resistivity CCDs have been used by other widefield imagers such as the Dark Energy Camera (DECam, Flaugher et al 2015) and the Hyper Suprime-Cam (HSC, Miyazaki et al 2018), in part due to their high quantum efficiency (QE) at longer wavelengths (near-infrared). However, these types of detectors have been found to imprint subtle but significant undesirable characteristics that impact centroid, photometric, flux, and shape measurements (Stubbs 2014;Astier 2015;Mandelbaum 2015). Study and characterization of any source of systematic errors will be crucial to achieving the required accuracy to achieve the scientific goals of a survey such as the LSST.…”

Section: Introductionmentioning

confidence: 99%

Photometry, Centroid and Point-spread Function Measurements in the LSST Camera Focal Plane Using Artificial Stars

Esteves,

Utsumi,

Snyder

et al. 2023

PASP

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The Vera C. Rubin Observatory’s LSST Camera (LSSTCam) pixel response has been characterized using laboratory measurements with a grid of artificial stars. We quantify the contributions to photometry, centroid, point-spread function size, and shape measurement errors due to small anomalies in the LSSTCam CCDs. The main sources of those anomalies are quantum efficiency variations and pixel area variations induced by the amplifier segmentation boundaries and “tree-rings”—circular variations in silicon doping concentration. This laboratory study using artificial stars projected on the sensors shows overall small effects. The residual effects on point-spread function (PSF) size and shape are below 0.1%, meeting the ten-year LSST survey science requirements. However, the CCD mid-line presents distortions that can have a moderate impact on PSF measurements. This feature can be avoided by masking the affected regions. Effects of tree-rings are observed on centroids and PSFs of the artificial stars and the nature of the effect is confirmed by a study of the flat-field response. Nevertheless, further studies of the full-focal plane with stellar data should more completely probe variations and might reveal new features, e.g., wavelength-dependent effects. The results of this study can be used as a guide for the on-sky operation of LSSTCam.

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“…(3) Astier certified static image distortions on deep-depleted CCD sensors and presented a summary of the results of CCD sensor characterization and mitigation methods. (4) Xia et al proposed that, compared with traditional industrial sensor signals, machine vision systems can quickly understand manufacturing scenarios and provide the extracted semantic information to manufacturing ontologies developed by experts or ML-enabled network systems. (5) Leary used machine vision technology to monitor the entire metal rolling process and realized visual feedback control of the entire system through a high-speed data transmission network.…”

Section: Introductionmentioning

confidence: 99%

Design of Automatic Test System for Dynamic Performance of Magnetic Head Based on Machine Vision

Long¹,

Bian²,

Wang³

2022

Sensors and Materials

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The dynamic performance test of a hard disk head is the most effective method of evaluating hard disk performance, but it must be conducted in a dust-and electrostatic discharge (ESD)-free environment. With the rapid development of perpendicular magnetic recording (PMR) technology, the flying height of a magnetic head is reduced from 18 nm to less than 2 nm, which makes the testing conditions increasingly demanding, and the traditional way of manual testing by an operator cannot match the requirement of production testing. To meet the technical requirement of the dynamic performance test of a hard disk head, an automatic test system is developed using a CCD image sensor and an Epson robot. In this system, the vision system of the robot can accomplish, in real time and accurately, the image acquisition and image processing of the object in the magnetic head testing process and calculate the actual position of the object after hand-eye calibration. Visual guidance is provided to the robot to grasp and place the target accurately, and related sensors provide various state data during the system operation. Thus, the difficult problem in the development process from manual operation to robot automation in the dynamic performance test of a magnetic head is successfully solved. The results show that the consumption of test materials is considerably reduced, and the test precision and efficiency are markedly improved.

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An introduction to some imperfections of CCD sensors

Cited by 6 publications

References 19 publications

A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C

A SEARCH FOR WATER IN THE ATMOSPHERE OF HAT-P-26b USING LDSS-3C

Photometry, Centroid and Point-spread Function Measurements in the LSST Camera Focal Plane Using Artificial Stars

Design of Automatic Test System for Dynamic Performance of Magnetic Head Based on Machine Vision

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