arXiv subjects

Benoît Serra

Publications and source records attributed to Benoît Serra.

7 recordsLinked to original sources

arXiv2026

Charge migration characterization in the METIS H2RG detectors

The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the first-light instruments of the Extremely Large Telescope (ELT). For the L and M band, the instrument makes use of Teledyne's H2RG detectors, known to be affected by charge migration, also known as the brighter-fatter effect (BFE). In the H2RG detectors this manifests as photo-electrons moving from a central bright pixel to neighboring pixels as the depletion region of the central pixel shrinks with accumulated charge. Due to its effect of `blurring' information, it especially affects direct imaging, transit, and high-resolution spectroscopy applications. We aim to characterize its effect in the METIS H2RG detectors, such that we can remove it without losing information.

astro-ph.IM↗

arXiv2026

Direct Imaging Discovery of Giant Exoplanet $β$ Pictoris d: A Decade-Long Game of Hide-and-Seek

We report the direct imaging discovery of a third exoplanet in the $β$ Pictoris system. We detect $β$ Pictoris d ($β$ Pic d) in non-coronagraphic observations obtained with VLT/ERIS as well as multi-epoch archival datasets from JWST/NIRCam and VLT/SPHERE. Astrometric measurements over an 11-year baseline demonstrate that it is consistent with a gravitationally-bound source with orbital motion. Joint multi-planet orbit fits of all three planets in the system yield a semi-major axis of $26.0^{+2.2}_{-6.1}$ au and inclination $89.0^{+0.7}_{-0.6}$ deg for planet d. $β$ Pic d has a larger orbital semi-major axis than the other known planets in the system, but is coplanar with the inner two planets, and its orbit is consistent with sculpting the inner edge of the debris disk. $β$ Pic d has a contrast of $ΔL^{\prime}=12.11\pm0.15$ mag, with colors and luminosity that closely match those of 51 Eri b, another exoplanet in the $β$ Pictoris moving group. Its VLT/ERIS and JWST/NIRCam colors are distinct from those of free-floating planetary-mass objects of a similar age and temperature. Its red $F410M-F444W$ color indicates strong CO$_2$ absorption in its atmosphere and suggests significant enhancement in metals compared to free-floating objects. From the ATMO hot-start evolutionary models, we estimate an effective temperature of $600^{+45}_{-60}$ K and mass of $2.4\pm0.6$ $M_{\rm Jup}$, which also closely matches similar estimates for 51 Eri b. $β$ Pic d is among the lowest-mass exoplanets imaged from the ground. This discovery highlights the deep sensitivity achievable with ground-based imaging in the mid-infrared and the discovery potential of future high-contrast observations with the Extremely Large Telescope.

astro-ph.EP↗

arXiv2026

An Analysis of Large Astronomical Detector Controller Systems and Implications for Future ESO Detector Systems

Large astronomical instruments using tens to hundreds of optical or infrared science detectors pose specific challenges for detector control, where, in addition to performance, other engineering aspects like scalability, power consumption, size, weight and programmatic aspects such as cost and sustainability need to be considered. In this paper we analyze the approach existing instruments have taken for detector control. We focus this analysis on recent ground based astronomical instruments using 10 or more detectors for science imaging or spectrography. From this analysis we identify key technologies, like cryogenic electronics, Ethernet based interfaces and fully-digital detectors, for implementing efficient control of many detectors. We also propose a concept joining all identified technologies that could be considered for future large ESO instruments as a complement of ESO's general detector controller, NGCII.

astro-ph.IM↗

arXiv2020

Detector Systems Engineering for Extremely Large Instruments

The scientific detector systems for the ESO ELT first-light instruments, HARMONI, MICADO, and METIS, together will require 27 science detectors: seventeen 2.5 $μ$m cutoff H4RG-15 detectors, four 4K x 4K 231-84 CCDs, five 5.3 $μ$m cutoff H2RG detectors, and one 13.5 $μ$m cutoff GEOSNAP detector. This challenging program of scientific detector system development covers everything from designing and producing state-of-the-art detector control and readout electronics, to developing new detector characterization techniques in the lab, to performance modeling and final system verification. We report briefly on the current design of these detector systems and developments underway to meet the challenging scientific performance goals of the ELT instruments.

astro-ph.IM↗

arXiv2020

Characterisation, performance, and operational aspects of the H4RG-15 near infrared detectors for the MOONS instrument

MOONS is a multi-object spectrograph for the ESO VLT covering a simultaneous wavelength range of 0.6-1.8 microns using approximately 1000 fibres. It uses four Teledyne Imaging Systems H4RG-15 4K x 4K detectors with 2.5 $μ$m cut-off material for the two longer wavebands (YJ and H). Since the spectrographs utilize an extremely fast modified Schmidt camera design, then the detectors are situated in the optical beam and hence required the development of a novel 64- channel cryogenic differential cryogenic preamplifier, minimized for optical footprint which will be reported on. We have operated the Engineering Grade H4RG detector at a range of temperatures from 90K to 40K and we will report on the advantages of the lower operational temperature. We have completed a full persistence analysis and are able to model it reasonably well and will offer a correction for it in our data pipeline. We have also configured the detector for use with both unbuffered and buffered outputs and report on the differences in performance between the two output types. We have also seen some programming issues with the detector type and will report on our work-around for this, we will also describe the use of the column-deselect feature and row skipping to minimize the effects of PEDs. We have also measured charge injection per read and report on this, likewise we have also measured the inter-pixel capacitance in different regions of the detector. We will present all these results together with a summary of the complete performance characteristics of this detector family.

astro-ph.IM↗

arXiv2020

Performance advantages of buffered mode operation of HxRG near infrared detectors

The Teledyne HxRG detectors have versatile and programmable output options to allow operation of them in a variety of configurations such as slow unbuffered, slow buffered, fast buffered or unbuffered modes to optimise the detector performance for a given application. Normally at ESO, for low noise operation, the detectors are operated in slow unbuffered mode. Whilst the slow unbuffered mode offers a simple interface to the external preamplifier electronics, the detector operation in this mode can suffer from reduced pixel frequency response and higher electrical crosstalk between the readout channels. In the context of the detector systems required for the first generation instruments of the ELT (MICADO, HARMONI and METIS), an exercise was undertaken to evaluate the noise, speed and crosstalk performance of the detectors in the slow buffered mode. A test preamplifier has been designed with options to operate a H2RG detector in buffered or unbuffered and with or without using the reference output, so a direct performance comparison can be made between different modes. This paper presents the performance advantages such as increased pixel frequency response, elimination of electrical crosstalk between the readout channels and the noise performance in the buffered mode operation. These improvements allow us to achieve the same frame readout time using half the detector cryogenic electronics and detector controller electronics for the ELT instruments, which significantly reduces the associated cryomechanical complexities in the instrument.

astro-ph.IM↗

arXiv2020

Pyxel: the collaborative detection simulation framework

Pyxel is a novel python tool for end-to-end detection chain simulation i.e. from detector optical effects to readout electronics effects. It is an easy-to-use framework to host and pipeline any detector effect model. It is suited for simulating both Charge-Coupled Devices, CMOS Image Sensors and Mercury Cadmium Telluride hybridized arrays. It is conceived as a collaborative tool to promote reusability, knowledge transfer, and reliability in the instrumentation community. We provide a demonstration of Pyxel's basic principles, describe newly added capabilities, and give examples of more advanced applications.

astro-ph.IM↗