Testing the 10 spectrograph units for DESI: approach and results

TL;DR

This paper details the approach and results of testing and validating ten spectrograph units for the DESI project, ensuring they meet performance requirements for large-scale cosmic measurements.

Contribution

It introduces a systematic approach for integrating and validating multiple spectrographs efficiently within a tight schedule for the DESI experiment.

Findings

Successful validation of all ten spectrographs' performance

Identification of key benefits and limitations of the testing approach

Enhanced readiness of spectrographs for deployment in DESI

Abstract

The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sqdeg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope delivers 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, IN2P3, Sorbonne Universit\'e and Universit\'e de Paris) and the WINLIGHT Systems company based in Pertuis (France), were in charge of integrating and validating the performance requirements of the ten full spectrographs, equipped with their cryostats, shutters and other mechanisms. We present a summary of our activity which allowed an efficient validation of the systems in a short-time schedule. We detail the main results. We emphasize the benefits of our approach and also its limitations.