Characterization of a photon counting EMCCD for space-based high contrast imaging spectroscopy of extrasolar planets

Wilkins, Ashlee; McElwain, Michael W.; Norton, Timothy; Rauscher, Bernie J.; Rothe, J.; Malatesta, M.; Hilton, G. C.; Bubeck, James R.; Grady, C. A.; Lindler, Don J.

doi:10.1117/12.2055346

“…The level of CIC is higher for devices operated in inverted mode and is independent of the operating temperature of the CCD. Problems with CICs are typically reported for electron multiplying charged-coupled devices (EMCCDs) due to the use of multiplication gain registers, which amplify CICs (Wilkins et al, 2014). However, dark signal that arises from CICs may also not be neglected for the Aeolus ACCDs as the memory section is operated in inverted mode and special clocking is applied in the on-chip accumulation process.…”

Section: Dark Current Signals and Anomaliesmentioning

confidence: 99%

Characterization of dark current signal measurements of the ACCDs used on board the Aeolus satellite

Weiler

¹

,

Kanitz

²

,

Wernham

³

et al. 2021

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Abstract. Even just shortly after the successful launch of the European Space Agency satellite Aeolus in August 2018, it turned out that dark current signal anomalies of single pixels (so-called “hot pixels”) on the accumulation charge-coupled devices (ACCDs) of the Aeolus detectors detrimentally impact the quality of the aerosol and wind products, potentially leading to wind errors of up to several meters per second. This paper provides a detailed characterization of the hot pixels that occurred during the first 1.5 years in orbit. The hot pixels are classified according to their characteristics to discuss their impact on wind measurements. Furthermore, mitigation approaches for the wind retrieval are presented and potential root causes for hot pixel occurrence are discussed. The analysis of the dark current signal anomalies reveals a large variety of anomalies ranging from pixels with random telegraph signal (RTS)-like characteristics to pixels with sporadic shifts in the median dark current signal. Moreover, the results indicate that the number of hot pixels almost linearly increased during the observing period between 2 September 2018 and 20 May 2020 with 6 % of the ACCD pixels affected in total at the end of the period leading to 9.5 % at the end of the mission lifetime. This work introduces dedicated instrument calibration modes and ground processors, which allowed for a correction shortly after a hot pixel occurrence. The achieved performance with this approach avoids risky adjustments to the in-flight hardware operation. It is demonstrated that the success of the correction scheme varies depending on the characteristics of each hot pixel itself. With the herein presented categorization, it is shown that multi-level RTS pixels with high fluctuation are the biggest challenge for the hot pixel correction scheme. Despite a detailed analysis in this framework, no conclusion could be drawn about the root cause of the hot pixel issue.

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“…In this context, the challenge of detecting very faint photon fluxes (photon s −1 cm −2 ) can be addressed using an electron-multiplying charge-coupled device camera (EM-CCD). Schematically, the electron-multiplication gain provides the so-called sub-electron readout noise necessary to detect single photons despite noisy output amplifiers 2,[6][7][8][9][10] . However, electron-multiplication is a stochastic phenomenon that comes with a gain noise characterized by an excess noise factor (ENF) that typically reaches √ 2 at high gains.…”

Section: Detectivity Optimization To Detect Of Ultraweak Light Fluxesmentioning

confidence: 99%

Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

Khaoua

¹

,

Graciani

²

,

Kim

³

et al. 2021

Sci Rep

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For a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

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“…A directed pre-phase-A activity was created to advance the technologies needed for CGI. This included coronagraph masks and architecture, in particular Hybrid Lyot [19], Shaped Pupil [20], Phase-Induced Amplitude Apodization [21] coronagraphs, low-order wavefront sensing and control [22], and electronmultiplying CCD detectors [23]. The projects maturing these technologies through TDEM-funded activities were folded into the technology activity and a technology development plan created a series of nine milestones to bring these technologies to TRL 5.…”

Section: Metrics and Resultsmentioning

confidence: 99%

A decade of NASA strategic astrophysics technology investments: technology maturation, infusion, and other benefits

Pham

¹

,

Ganel

²

,

Valinia

³

et al. 2020

Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV

0

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NASA's Astrophysics Division (APD) funds development of cutting-edge technology to enable its missions to achieve ambitious and groundbreaking science goals. These technology development efforts are managed by the Physics of the Cosmos (PCOS), Cosmic Origins (COR), and Exoplanet Exploration (ExE) Programs. The NASA Strategic Astrophysics Technology (SAT) Program was established in 2009 as a new technology maturation program to fill the gap in the Technology Readiness Level (TRL) range from 3 to 6. Since program inception, 100 SAT grants have been openly competed and awarded, along with dozens of direct-funded projects, leading to a host of technologies advancing their TRLs and/or being infused into space and suborbital missions and ground-based projects. We present the portfolio distribution in terms of specific technology areas addressed, including optics, detectors, coatings, coronagraphs, starshades, lasers, electronics, cooling systems, and micro-thruster subsystems. We show an analysis of the rate of TRL advances, infusion success stories, and other benefits such as training the future astrophysics workforce, including students and postdoctoral fellows hired by projects. Finally, we present APD's current strategic technology maturation priorities for investment, enabling a range of future strategic astrophysics missions.

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Characterization of a photon counting EMCCD for space-based high contrast imaging spectroscopy of extrasolar planets

Cited by 15 publications

References 16 publications

Characterization of dark current signal measurements of the ACCDs used on board the Aeolus satellite

Characterization of dark current signal measurements of the ACCDs used on board the Aeolus satellite

Detectivity optimization to measure ultraweak light fluxes using an EM-CCD as binary photon counter array

A decade of NASA strategic astrophysics technology investments: technology maturation, infusion, and other benefits

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