CETUS: an innovative UV probe-class mission concept

Heap, Sara R.; Danchi, W. C.; Burge, James H.; Dodson, Kelly; Hull, Anthony B.; Kendrick, Steven; McCandliss, Stephan R.; Mehle, Gregory V.; Purves, Lloyd; Sheikh, David; Valente, M.; Woodruff, Robert A.

doi:10.1117/12.2274202

Cited by 3 publications

(5 citation statements)

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“…The science themes include Cosmic Evolution of Galaxies, Stars, and Exo-Planets, The Modern Universe: What It's Made of; How It Works, Transients, and Deep Surveys. 1,2 To fit within a $1 billion budget, a moderate size of 1.5-m diameter OTA aperture size is proposed. Observations of a large sample of objects are provided by multipixel detectors and parallel observing.…”

Section: Design Overview 21 Science Goals Determine Cetus Designmentioning

confidence: 99%

“…3,4 CETUS observes and records spectrally filtered images, as well as low-and high-resolving power spectroscopy of galaxies, in the vacuum UV spectral region. Highly efficient photon detection design is enabled by (1) using an all-reflective optical design of the OTA and the instruments, (2) using Lyman-α-optimized [or as an option predicated on successful technology development, Lyman UV (LUV)-optimized protected Al + LiF coating] reflective mirror coatings, (3) minimizing the number of reflections in each optical path, (4) using field-sharing that permits simultaneous observation by SIs, and (5) using detectors with minimum number of windows and high quantum efficiency. Table 1 summarizes the top-level requirements of the OTA and SIs.…”

Section: Design Overview 21 Science Goals Determine Cetus Designmentioning

confidence: 99%

“…The Cosmic Evolution through UV Spectroscopy (CETUS) mission concept, if approved and implemented, will partially fill this void. 1,2 CETUS is a NASA headquarters-selected probe-class mission concept which includes a 1.5-m aperture diameter large field of view (FOV) optical telescope assembly (OTA) optimized for imaging and spectroscopy with three science instruments (SIs) that observe within the 100-to 400-nm spectral region. The CETUS design enables simultaneous far UV/near UV (FUV/NUV) wide-field imaging, NUV multiobject spectroscopy, and LUV/FUV long-slit spectroscopy and NUV point source spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…a) ESRWs at the TMA focus for each instrument and (b) the "effective diffraction-limited wavelength" if the value for w is the FWHM of an effective Airy pattern.Journal of Astronomical Telescopes, Instruments, and Systems 024006-15Apr-Jun 2019 • Vol. 5(2) …”

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confidence: 99%

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Optical design for CETUS: a wide-field 1.5-m aperture UV payload being studied for a NASA probe class mission study

Woodruff

Danchi

Heap

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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As part of a study funded by NASA headquarters, we are developing a probe-class mission concept called the Cosmic Evolution through UV Spectroscopy (CETUS). CETUS includes a 1.5-m aperture diameter telescope with a large field of view (FOV). CETUS includes three scientific instruments: a far ultraviolet (FUV) and near ultraviolet (NUV) imaging camera (CAM); a NUV multiobject spectrograph (MOS); and a dual-channel point/slit spectrograph (PSS) in the Lyman ultraviolet (LUV), FUV, and NUV spectral regions. The large FOV three-mirror anastigmatic (TMA) optical telescope assembly (OTA) simultaneously feeds the three separate scientific instruments. That is, the instruments view separate portions of the TMA image plane, enabling parallel operation by the three instruments. The field viewed by the MOS, whose design is based on an Offner-type spectrographic configuration to provide wide FOV correction, is actively configured to select and isolate numerous field sources using a next-generation micro-shutter array. The two-channel CAM design is also based on an Offner-like configuration. The PSS performs high spectral resolution spectroscopy on unresolved objects over the NUV region with spectral resolving power, R ∼ 40;000, in an echelle mode. The PSS also performs long-slit imaging spectroscopy at R ∼ 20;000 in the LUV and FUV spectral regions with two aberration-corrected, blazed, holographic gratings used in a Rowland-like configuration. The optical system also includes two fine guidance sensors, and wavefront sensors that sample numerous locations over the full OTA FOV. In-flight wavelength calibration is performed by a wavelength calibration system, and flat-fielding is also performed, both using inflight calibration sources. We describe the current optical design of CETUS and the major trade studies leading to the design.

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Section: Design Overview 21 Science Goals Determine Cetus Designmentioning

confidence: 99%

Section: Design Overview 21 Science Goals Determine Cetus Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Optical design for CETUS: a wide-field 1.5-m aperture UV payload being studied for a NASA probe class mission study

Woodruff

Danchi

Heap

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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“…NASA's Cosmic Origins Program 1 identifies photon-counting large-format ultraviolet detectors as a top priority technology for future ultraviolet and optical astronomy missions. This technology is seen as a key enabler of both future large aperture space telescopes such as LUVOIR, 2 and moderate aperture survey missions such as CETUS 3 and CASTOR. 4,5 The desired performance requirements are: high quantum efficiency (>70%), large-format (>2k × 2k) detector arrays for operation at 90 to 350 nm wavelength or broader and ideally with red leak (longer wavelength) suppression.…”

Section: Introductionmentioning

confidence: 99%

Quantum yield estimation for an electron-multiplying charge-coupled device from photon counting test data

Gleisinger

Rowlands

Scott

et al. 2020

J. Astron. Telesc. Instrum. Syst.

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Electron-multiplying charge-coupled devices (EMCCDs) allow for subelectron effective read noise and thus for imaging at extremely low flux levels. In the ultraviolet, quantum yield creates an additional source of stochastic gain variation, which can be difficult to quantify using existing techniques. We propose a method for measuring the quantum yield gain of these devices, independent of existing methods, using images that are part of the existing test regimen for new EMCCDs. With this method, we were able to recover the quantum yield used to create simulated images within an accuracy of ∼5% and the method provided consistent results with test images after only minor modifications. However, the measured quantum yield remains anomalously low, consistent with other measurements on Teledyne-e2v devices. We hypothesize that this discrepancy is due to lateral transfer of secondary electrons between pixels at the surface explained by the band structure and crystal geometry of typical silicon wafers used in array detector manufacture. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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