iLocater is a new, near-infrared, extreme precision radial velocity (EPRV) spectrograph under construction for the dual 8.4m diameter Large Binocular Telescope (LBT). The instrument uses single-mode fibers (SMFs) injected with adaptive optics for illumination. We present the integration process for the spectrograph and cryostat systems, and the laboratory performance testing that has been completed. Testing has included optical performance characterization at ambient and cryogenic temperatures, assessment of cryogenic thermal control of the system (80-100K) at sub-mK level, and instrument detector performance (an H4RG-10). The optimized spectrograph and cryostat system will be delivered to the LBT in 2024.
The Gemini Planet Imager (GPI) is a dedicated high-contrast imaging facility instrument. After six years, GPI has helped establish that the occurrence rate of Jovian planets peaks near the snow. GPI 2.0 is expected to achieve deeper contrasts, especially at small inner working angles, to extend GPI’s operating range to fainter stars, and to broaden its scientific capabilities. GPI shipped from Gemini South in 2022 and is undergoing an upgrade as part of a relocation to Gemini North. We present the status of the upgrades including replacing the current wavefront sensor with an EMCCD-based pyramid wavefront sensor, adding a broadband low spectral resolution prism, new apodized-pupil Lyot coronagraph designs, upgrades of the calibration wavefront sensor and increased queue operability. Further we discuss the progress of reintegrating these components into the new system and the expected performance improvements in the context of GPI 2.0’s enhanced science capabilities.
The Gemini Planet Imager (GPI), is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. After spending 2013 - 2020 at Gemini South, the instrument is currently undergoing maintenance and upgrades before its transition to Gemini North as GPI 2.0. Among the upgrades are significant changes to the Integral Field Spectrograph (IFS), including the installation of new prisms, Lyot stops/apodizers, and filters. The upgrades are expected to improve overall performance in the relevant wavelengths and angular separations needed for GPI 2.0.
The Gemini Planet Imager (GPI) is a high-contrast imaging instrument designed to directly detect and characterize young, Jupiter-mass exoplanets. After six years of operation at Gemini South in Chile, the instrument is being upgraded and relocated to Gemini North in Hawaii as GPI 2.0. GPI helped establish that Jovian-mass planets have a higher occurrence rate at smaller separations, motivating several sub-system upgrades to obtain deeper contrasts (up to 20 times improvement to the current limit), particularly at small inner working angles. This enables access to additional science areas for GPI 2.0, including low-mass stars, young nearby stars, solar system objects, planet formation in disks, and planet variability. The necessary instrumental changes required toenable these new scientific goals are to (i) the adaptive optics system, by replacing the current Shack-Hartmann Wavefront Sensor (WFS) with a pyramid WFS and a custom EMCCD, (ii) the integral field spectrograph, by employing a new set of prisms to enable an additional broadband (Y-K band) low spectral resolution mode, as well as replacing the pupil viewer camera with a faster, lower noise C-RED2 camera (iii) the calibration interferometer, by upgrading the low-order WFS used for internal alignment and on-sky target tracking with a C-RED2 camera and replacing the calibration high-order WFS used for measuring and correcting non-common path aberrations with a self coherent camera, (iv) the apodized-pupil Lyot coronagraph designs and (v) the software, to enable high-efficiency queue operations at Gemini North. GPI 2.0 is expected to go on-sky in early 2024. Here I will present the new scientific goals, the key upgrades, the current status and the latest timeline for operations.
The Gemini Planet Imager (GPI) is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. After several years of successful operations on sky at Gemini South, GPI is undergoing an upgrade at the University of Notre Dame and is being moved to Gemini North. We present the current performance results, from in-lab testing, for several of the upgraded components to the Integral Field Spectrograph (IFS) and the Calibration Wavefront Sensor (CAL) for GPI 2.0. These upgrades include changes to the IFS dispersion prisms, changes to the pupil viewing cameras, and changes to the low order wavefront sensor. These improvements are designed to improve the magnitude and contrast range of GPI. We describe the alignment of several components, their noise characteristics, and their performance in the GPI environment.
GPI is a facility instrument designed for the direct detection and characterization of young Jupiter mass exoplanets. GPI has helped establish that the occurrence rate of Jovian planets peaks near the snow line (~3 AU), and falls off toward larger separations. This motivates an upgrade of GPI to achieve deeper contrasts, especially at small inner working angles, to extend GPI’s operating range to fainter stars, and to broaden its scientific capabilities, all while leveraging its historical success. GPI was packed and shipped in 2022, and is undergoing a major science-driven upgrade. We present the status and purpose of the upgrades including an EMCCD-based pyramid wavefront sensor, broadband low spectral resolution prisms, new apodized-pupil Lyot coronagraph designs, upgrades of the calibration wavefront sensor and increased queue operability. We discuss the expected performance improvements and enhanced science capabilities to be made available in 2024.
Extremely precise radial velocity (EPRV) measurements are critical for characterizing nearby terrestrial worlds. EPRV instrument precisions of σRV = 1−10 cm/s are required to study Earth-analog systems, imposing stringent, sub-mK, thermo-mechanical stability requirements on Doppler spectrograph designs. iLocater is a new, high resolution (R = 190, 500 median) near infrared (NIR) EPRV spectrograph under construction for the dual 8.4 m diameter Large Binocular Telescope (LBT). The instrument is one of the first to operate in the diffraction-limited regime enabled by the use of adaptive optics and single-mode fibers. This facilitates affordable optomechanical fabrication of the spectrograph using intrinsically stable materials. We present the final design and performance of the iLocater cryostat and thermal control system which houses the instrument spectrograph. The spectrograph is situated inside an actively temperature-controlled radiation shield mounted inside a multi-layer-insulation (MLI) lined vacuum chamber. The radiation shield provides sub-mK thermal stability, building on the existing heritage of the Habitable-zone Planet Finder (HPF) and NEID instruments. The instrument operating temperature (T = 80−100 K) is driven by the requirement to minimize detector background and instantaneous coefficient of thermal expansion (CTE) of the materials used for spectrograph fabrication. This combination allows for a reduced thermomechanical impact on measurement precision, improving the scientific capabilities of the instrument.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.