MAJIS (Moons And Jupiter Imaging Spectrometer) is the visible and infrared imaging spectrometer of the ESA L-Class mission JUICE (JUpiter Icy moons Explorer). MAJIS plays a major role for achieving the JUICE main scientific objectives, which include the compositional study of the Galilean moons, their past and present activity, and its relation with observed surface features. It will also study the composition, structure, chemistry and dynamics of the Jovian atmosphere. MAJIS is composed of two spectral channels: the VIS-NIR (0.5µm-2.35µm), and the IR (2.25µm-5.54µm). Both channels are equipped with a Focal Plane Unit (FPU) mainly including a Teledyne H1RG Focal Plan Array (FPA), one Focal Plane electronics (FPE) and one filter. A dedicated facility was developed at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) for the characterization of the Flight (FM) and Spare (SM) models of the MAJIS VIS-NIR FPU. The radiometric capabilities of the facility include: (1) the tuning of the monochromatic flux provided to the detector over a four-decade range of intensity, (2) optical configurations for dark conditions, uniform light beam or convergent light beam with the same focal ratio as MAJIS, and (3) relative and absolute radiometric scales at the FPA plane. This work describes the radiometric characterization campaign of the MAJIS VIS-NIR SM FPU and the respective data analysis methods used to derive some of the detector key parameters such as the gain, the dark current, the linearity, the full-well capacity and the operability. A comparison with the performances of the FM VIS-NIR FPU is also provided.
We describe the IR focal plane filters of the MAJIS imaging spectrometer for the JUICE mission to the Jupiter System. The focal plane filters provided by Viavi Solutions are integrated into a filter holder placed above the IR channel focal plane array, enclosed in a baffle and cooled to cryogenic temperatures. The filters comprise two segments bonded together on a sapphire substrate: a broad-band, low-pass filter and a narrow-band linear variable filter (LVF) in the MWIR. We present the justification for using such filters, their architecture, the measurement facilities that were implemented for assessing their performances and the derived optical performances. The filters have been fully qualified and integrated into MAJIS and are within the performance specifications.
We describe the IR focal plane unit of the MAJIS imaging spectrometer for the JUICE mission to the Jupiter Sys tem. Optical light from the telescope and spectrometer is focalized on the IR Focal plane unit which compris es a Teledyne Imaging Sensors H1RG detector overlain by a Viavi Solutions filter assembly. Both components are baffled and work at cryogenic temperatures. We describe the IR focal plane architecture, the measurement facilities and the main performance-critical specifications. The IR channel of MAJIS offers strong versatility with the capability to acquire high resolution spectra from the Jupiter atmosphere to organic matter on icy moon surfaces, over a wide spectral and dynamical range.
MAJIS (Moons And Jupiter Imaging Spectrometer) is the VIS-IR imaging spectrometer of the ESA/JUICE mission that will explore the Jovian system. It covers the spectral range 0.5 to 2.35 μm and 2.26 to 5.56 μm using two channels. The MAJIS Optical Head (OH) consists in a TMA telescope shared between the two channels, as well as a slit and collimator, then a dichroic filter that splits the light between the channels, each one being equipped with its own grating and focusing lens. The same type of detector is used for both spectrometers (apart from the order sorting filter), being a 400 pixels × 508 spectels with 36 µm pitch. We will present the characterization of the OH performed at Leonardo Company at cold operational temperatures (from 110K to 150K). The test set-up with a specific emphasis of the Optical Ground Support Equipment (OGSE) used during that characterization campaign will be shortly described. Then, the main performances (spatial, spectral) of the OH will be presented and a comparison with the requirements will be provided.
The JUICE (JUpiter ICy moons Explorer) mission by ESA aims to explore the emergence of habitable worlds around gas giants and the Jupiter system as an archetype of gas giants. MAJIS (Moons and Jupiter Imaging Spectrometer) is the visible to near-infrared imaging spectrometer onboard JUICE which will characterize the surfaces and exospheres of the icy moons and perform monitoring of the Jupiter atmosphere. The launch is scheduled for 2023 with the first MAJIS observations inside the Jovian system occurring more than 8 years later. The MAJIS optical head is equipped with two Teledyne H1RG detectors, one for each of the two spectrometer channels (VIS-NIR and IR). This paper describes the characterization of the VIS-NIR Focal Plane Unit. These detectors will be operated in a non-standard way, allowing near/full-frame retrieval over short integration times (<< 1 sec) while maintaining good noise performance. After a quick description of the characterization strategy that was designed to evaluate the performances of the VIS-NIR detector according to the MAJIS operational specifications, the paper will address the data analyses and the main results of the characterization campaign. The major performance parameters such as dark current, linearity, noise, quantum efficiency, and operability will be presented and compared with the requirements.
KEYWORDS: Sensors, Frequency modulation, Fermium, Jupiter, Radiometry, Radio optics, Quantum efficiency, Data modeling, Temperature metrology, Spectroscopy
MAJIS is part of the science payload of the ESA L-Class mission JUICE to be launched in 2022 with an arrival at Jupiter in 2030. MAJIS will perform imaging spectroscopy through two channels: VIS-NIR (0.50 µm - 2.35 µm) and IR (2.25 µm - 5.54 µm). The Royal Belgian Institute for Space Aeronomy (BIRA-IASB) and the Royal Observatory of Belgium (ROB) contribute to MAJIS with the characterization and calibration of the VIS-NIR Flight Model (FM) and Spare Model (SM) detectors, including the design, development, and validation of the setup, as well as the data processing pipeline. The FM and SM detectors are characterized under different illumination conditions (along four decades of dynamical range), temperature (125 K - 144 K), beam uniformities, exposure times, and/or data acquisition rates. In this paper, we describe the optical performances of the facility, which can be configurable for dark conditions, uniform light beam, and convergent beam with same focal ratio as MAJIS convergence optics. We provide a relative radiometry scale for the typical characterization measurements, as well as a fully characterized flux that will allow us to perform characterization measurements in an absolute radiometry scale, such as quantum efficiency (QE). In addition, we describe the thermal performances provided by the bench reaching different temperature scenarios, including the expected operating temperature of the detector at 132 K. The characterization facility was completed and subjected to validation tests in early 2020. The MAJIS VIS-NIR FM detector was delivered for its complete characterization in June 2020.
MAJIS (Moons And Jupiter Imaging Spectrometer) is one of the science instruments of the ESA L-Class mission JUICE (Jupiter ICy Moons Explorer) to be launched in 2022 with an arrival at Jupiter in 2030. MAJIS will perform imaging spectroscopy through two channels: VIS-NIR (0.50 um - 2.35 um) and IR (2.25 μm - 5.54 μm). The Royal Belgian Institute for Space Aeronomy (BIRA-IASB) and the Royal Observatory of Belgium (ROB) contribute to MAJIS with the characterization of the VIS-NIR Flight Model (FM) and Spare Model (SM) detectors, including the design, development and validation of the setup, and the data processing pipeline. Typical detector characterization measurements were performed during the campaigns but also calibrated measurements such as Quantum Efficiency (QE). Since some of the characterization measurements require different illumination conditions, temperature, beam uniformity, exposure time, and/or data acquisition procedure, the characterization setup is configurable for dark conditions, uniform light beam, and convergent beam with same focal ratio as MAJIS convergence optics. The thermal-vacuum characterization facility was completed at BIRA-IASB premises and was subjected to validation tests on late 2019 and early 2020. MAJIS VIS-NIR FM detector was delivered for its complete characterization in June 2020; SM characterization shall be performed after time of meeting. In this paper, we summarize the optical and thermal performances of the facility, the detector's mechanical integration method and its optical alignment into the setup, the security system implemented, the general operation of the setup during the characterization campaign, and FM preliminary result analyses.
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