Design and production of DESI slit assemblies

Tyas, Luke; Besuner, Robert; Bramall, David; Edelstein, Jerry; Jelinsky, Patrick; Poppett, Claire; Schmoll, J.; Sharples, R. M.

doi:10.1117/12.2312034

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…One end of each fiber cable bundle terminates at the slithead (Tyas et al 2018), which consists of 500 fibers in a linear array that is grouped into 20 blocks of 25 fibers each. Each block has 25 parallel V-grooves machined in fused silica that hold the fiber ends, and consequently each block points at a slightly different angle along the linear slit.…”

Section: Fiber Cables and Slit Headsmentioning

confidence: 99%

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Abareshi

Aguilar

Ahlen

et al. 2022

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129

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The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360–980 nm with a spectral resolution that ranges from 2000–5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the [O ii] doublet at 8 × 10−17 erg s−1 cm−2 in 1000 s for galaxies at z = 1.4–1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned.

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Section: Fiber Cables and Slit Headsmentioning

confidence: 99%

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Abareshi

Aguilar

Ahlen

et al. 2022

Self Cite

129

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“…The petal/fiber/spectrograph system is modular: a fiber cable from each petal carries the 500 optical fibers to a slithead, which is installed in one spectrograph. The fiber cables 15 and slitheads 16 were designed and built by Durham University (United Kingdom). The petals are mounted to the corrector via a cone-shaped adapter (the FPD, from Fermilab), which bolts to the end flange of the corrector and presents a circular mounting ring (FPR) to which the petals are attached.…”

Section: Mock Petal Installationmentioning

confidence: 99%

Installation of the Dark Energy Spectroscopic Instrument at the Mayall 4-meter telescope

Besuner¹,

Allen²,

Baltay³

et al. 2020

Ground-Based and Airborne Instrumentation for Astronomy VIII

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The Dark Energy Spectroscopic Instrument (DESI) is a Stage IV ground-based dark energy experiment that will measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 square degrees will be measured during the life of the experiment. We describe the installation of the major elements of the instrument at the Mayall 4m telescope, completed in late 2019. The previous prime focus corrector, spider vanes, and upper rings were removed from the Mayall's Serrurier truss and replaced with the newlyconstructed DESI ring, vanes, cage, hexapod, and optical corrector. The new corrector was optically aligned with the primary mirror using a laser tracker system. The DESI focal plane system was integrated to the corrector, with each of its ten 500-fiber-positioner petal segments installed using custom installation hardware and the laser tracker. Ten DESI spectrographs with 30 cryostats were installed in a newly assembled clean room in the Large Coude Room. The ten cables carrying 5000 optical fibers from the positioners in the focal plane were routed down the telescope through cable wraps at the declination and hour angle axes, and their integral slitheads were integrated with the ten spectrographs. The fiber view camera assembly was installed to the Mayall's primary mirror cell. Servers for the instrument control system replaced existing computer equipment. The fully integrated instrument has been commissioned and is ready to start its operations phase.

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“…The slit, which is the input to the spectrograph, consists of 500 fiber end-faces arranged into a fiber slit 2 . The fibers are arranged in a radius of 468 mm, near the collimator focus.…”

Section: Optical Componentsmentioning

confidence: 99%

The DESI spectrograph system and production

Edelstein¹,

Jelinsky²,

Levi

et al. 2018

Ground-Based and Airborne Instrumentation for Astronomy VII

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The Dark Energy Spectroscopic Instrument (DESI) is a project in construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs covering a 360-980 nm passband with a spectral resolution (λ/Δλ) between 1500 and 4000. The spectrograph uses two dichroic beam splitters to separate the flux among three spectral cameras, each with a volume phase holographic grating and lens system that focuses onto a charge coupled device detector. We describe the spectrograph, its system requirements, design and construction.

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Design and production of DESI slit assemblies

Cited by 4 publications

References 2 publications

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Installation of the Dark Energy Spectroscopic Instrument at the Mayall 4-meter telescope

The DESI spectrograph system and production

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