A comparison of charge transfer efficiency measurement techniques on proton damaged n-channel CCDs for the Hubble Space Telescope Wide-Field Camera 3

Waczynski, Augustyn; Polidan, Elizabeth; Marshall, P.W.; Reed, Robert A.; Johnson, Scott D.; Hill, Robert J.; Delo, Gregory; Wassell, E. J.; Cheng, E. S.

doi:10.1109/23.983134

Cited by 25 publications

(39 citation statements)

References 9 publications

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“…As the signal level increases, both the density of the charge packet and the volume occupied by it increase. Assuming bulk traps are uniformly distributed, there will be a larger number of traps per electron at small signal levels which may cause the commonly reported increase in CTI at small signal levels 8,9 .…”

Section: Charge Packet Modelsmentioning

confidence: 99%

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Pixel-level modelling and verification for the EUCLID VIS CCD

et al. 2013

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Euclid is an M-class mission selected for the next phase of ESA's long-term Cosmic Vision programme. The mission's primary aim is to provide insight into the physical cause of the accelerating universe which will be achieved by investigating the nature of dark energy, dark matter and gravity. The investigation will involve the measurement of the effects of intervening gravitational potentials on visible light from distant galaxies, a process known as weak gravitational lensing.The CCD273 was designed by e2v for the Euclid mission, and is based on an older design for the CCD204, with changes designed and implemented to improve operation under irradiation. These changes include a narrower buried channel in the serial register to reduce trap interactions during readout. Pixel level models have been developed to improve knowledge of charge packet distribution within the CCD273 and CCD204 using Silvaco TCAD, enabling more effective predictions to be made about device functionality before and after irradiation which can be immediately tested on both devices. This paper is focussed on latest results, with particular reference to the on-going model verification, designed to build confidence in the device models and provide feedback to further improve the modelling effort.

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Section: Charge Packet Modelsmentioning

confidence: 99%

“…A large portion of proton interactions will result in no damage to the detector where the displaced silicon atom finds its way back to its lattice site. However in a few instances the vacancy may migrate away from the initial lattice position until it becomes stable 9 .…”

Section: Radiation Damagementioning

confidence: 99%

Pixel-level modelling and verification for the EUCLID VIS CCD

et al. 2013

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Section: Charge Diffusion and Charge Transfer Efficiency Measurementmentioning

confidence: 99%

“…Other proposed solutions, including the summation of the charges in adjacent pixels, serve to destroy the information about short time constant traps. LSST will be using the 'extended pixel edge response' method that is well documented in the literature 12 . Work on other methods continues.…”

Section: Charge Diffusion and Charge Transfer Efficiency Measurementmentioning

confidence: 99%

“…The standard tool for measurement of CTE in CCDs is the analysis of the peak pixel intensity of 55 Fe x-ray generated charge packets collected in the silicon. We will not describe the process in detail here as it is well documented in the literature 2,12,14 .For relatively thin devices which present relatively little opportunity for charge to diffuse while moving from the conversion point to the collection point, there is a high probability that all the electrons in a charge packet will be captured in a single pixel, allowing for a direct measure of the system gain as well as a determination of CTE by measurement of the peak pixel signal as a function of the position of the pixel in which the charge was collected and therefore the amount of signal that was lost from the pixel as it was transferred to the output node. Note that this technique is sensitive to charge that is lost due to capture in both short and long time constant traps as it excludes all signal not found in the brightest pixel.…”

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confidence: 99%

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Electro-optical testing of fully depleted CCD image sensors for the Large Synoptic Survey Telescope camera

et al. 2014

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The LSST Camera science sensor array will incorporate 189 large format Charge Coupled Device (CCD) image sensors. Each CCD will include over 16 million pixels and will be divided into 16 equally sized segments and each segment will be read through a separate output amplifier.The science goals of the project require CCD sensors with state of the art performance in many aspects. The broad survey wavelength coverage requires fully depleted, 100 micrometer thick, high resistivity, bulk silicon as the imager substrate. Image quality requirements place strict limits on the image degradation that may be caused by sensor effects: optical, electronic, and mechanical.In this paper we discuss the design of the prototype sensors, the hardware and software that has been used to perform electro-optic testing of the sensors, and a selection of the results of the testing to date. The architectural features that lead to internal electrostatic fields, the various effects on charge collection and transport that are caused by them, including charge diffusion and redistribution, effects on delivered PSF, and potential impacts on delivered science data quality are addressed. INTRODUCTIONThe Large Synoptic Survey Telescope (LSST) will combine an 8.4 meter telescope with a light-gathering power among the largest in the world and a camera made up of more than 3 billion pixels. Data on billions of galaxies will be used to create a three dimensional map of the Universe with unprecedented depth and detail. This map will then be used to tomographically map dark matter, chart the clustering of galaxies, and to characterize the properties of dark energy. In addition, a wide range of other topics in astrophysics will be probed using the 15 Terabytes of imaging data that the system will produce each night.Of particular importance in executing the LSST science mission is the fidelity of both the photometric and astrometric measurements that can be made using the data that the instrument produces. As example, the detection and distribution mapping of dark matter via the analysis of subtle geometric distortion of galactic shapes caused by gravitational lensing ("weak lensing") requires precision in both photometric and astrometric measurement.The science goals of the project 1 require CCD sensors with state of the art performance in many aspects. The telescope plate scale and expected image quality require a sensor pixel size of no more than 10 micrometers square. The broad survey wavelength coverage and sensitivity requirements at long wavelengths (~1000 nm) dictate the use of thick, fully depleted, high resistivity bulk silicon as the imager substrate. Data throughput requirements impose a cadence of 15-second exposures and two-second imager read times. Survey optical depth goals require a per-pixel amplifier read noise PROTOTYPE LSST CCDS AND TEST FACILITIES Baseline CCD architectureIn order to meet the various requirements outlined above, a nominal sensor architecture and design was established. The features and specifications of the ...

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Simultaneous assessment of peak-locking and CCD readout errors through a multiple Δt strategy

et al. 2011

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The multiple Dt strategy is an inexpensive procedure that can be implemented with any usual particle image velocimetry (PIV) set up. The only requirement is acquiring different series of PIV image pairs, setting a different time between laser pulses for each series. With this additional information, robust procedures for error assessment are possible. Within this strategy, this paper offers new discoveries that correct and complement previous works by the authors. Nogueira et al. (Meas Sci Technol 20-7:074001, 2009) addressed the tasks of assessing CCD readout and peak-locking bias errors separately. In this paper, a new approach, of general application to PIV, is proposed for assessing both errors simultaneously. Additionally, it unveils the effect of the flow variability on the local amplitude of the peak-locking bias. In a different work, Nogueira et al. (Exp Fluids. doi: 10.1007/s00348-011-1094-2, 2011) have focused on assessing peak-locking rms error. That paper achieved only order of magnitude estimations of the rms error because one of its components was overlooked. Here, the new term is included and the assessment obtained is good enough to correct rms systematic errors, improving the measurement of the turbulent kinetic energy or similar flow magnitudes. After describing the strategies, the application to selected synthetic and real cases is presented, validating the modeling of the errors behavior when dealing with turbulent flows. The results indicate the possibility to assess bias errors in the range from 0.01 to 0.2 pixels for both sources (peak locking and CCD readout) simultaneously. Furthermore, the previous works simply assessed the magnitude of the errors, but the results of the new procedures proposed here, in some cases, are good enough to correct the measurement itself. In addition, the determination of zones where these errors are not the dominant ones is presented.

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A comparison of charge transfer efficiency measurement techniques on proton damaged n-channel CCDs for the Hubble Space Telescope Wide-Field Camera 3

Cited by 25 publications

References 9 publications

Pixel-level modelling and verification for the EUCLID VIS CCD

Pixel-level modelling and verification for the EUCLID VIS CCD

Electro-optical testing of fully depleted CCD image sensors for the Large Synoptic Survey Telescope camera

Simultaneous assessment of peak-locking and CCD readout errors through a multiple Δt strategy

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