Integration and testing of the DESI multi-object spectrograph: performance tests and results for the first unit out of ten

Sandrine Perruchot (1) , Julien Guy (2) , Laurent Le Guillou (3) , Pierre-Eric Blanc (1) , Samuel Ronayette (4) , X. Regal (4) , Gérard Castagnoli (4) , Eduardo Sepulveda (3) , Auguste Le van Suu (5) , Eric Jullo (6) , Jean-Gabriel Cuby (6) , Sonia Karkar (5) , Patrick Ghislain (3) , Philippe Repain (3) , Pierre-Henri Carton (7) , Christophe Magneville (8) , Anne Ealet (5) , Stéphanie Escoffier (5) , A. Secroun (5) , M.-C Cousinou (5) , Klaus Honscheid (9) , Ann Elliot (5) , Patrick Jelinsky (10) , D. Brooks (2) , Gregory Tarlè (11)

1 OHP - Observatoire de Haute-Provence
2 UCL - University College of London [London]
3 LPNHE (UMR_7585) - Laboratoire de Physique Nucléaire et de Hautes Énergies
4 OSU PYTHEAS - Institut Pythéas
5 CPPM - Centre de Physique des Particules de Marseille
6 LAM - Laboratoire d'Astrophysique de Marseille
7 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
8 DPhP - Département de Physique des Particules (ex SPP)
9 OSU - Ohio State University [Columbus]
10 SSL - Space Sciences Laboratory [Berkeley]
11 Department of Physics [Ann Arbor]

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 deg² 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. A consortium of Aix-Marseille University (AMU) and CNRS laboratories (LAM, OHP and CPPM) together with LPNHE (CNRS, Universities Pierre et Marie Curie and Paris-Diderot) and the WINLIGHT Systems company based in Pertuis (France), are in charge of integrating and validating the performance requirements of the full spectrographs. This includes the cryostats, shutters and other mechanisms. The first spectrograph of the series of ten has been fully tested and the performance requirements verified for the following items: focus, image quality, straylight, stability, detector properties and throughput. We present the experimental setup, the test procedures and the results.

Mots clés: performance; DESI; Dark energy; multi-object spectrograph; integration; qualification

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Optique / photonique

Sandrine Perruchot, Julien Guy, Laurent Le Guillou, Pierre-Eric Blanc, Samuel Ronayette, et al.. Integration and testing of the DESI multi-object spectrograph: performance tests and results for the first unit out of ten. Ground-based and Airborne Instrumentation for Astronomy VII, Jun 2018, Austin, TX, United States. pp.107027K, ⟨10.1117/12.2311996⟩. ⟨hal-02003974⟩