83 research outputs found
Nondissipative Addressing for Time-Division SQUID Multiplexing
International audienceRecent and future astronomical instruments are based on a focal plane mapped by a large array of superconducting bolometers. Cryogenic analog multiplexing readout techniques, based on superconducting quantum interference devices (SQUIDs), are currently developed to achieve the readout of large arrays of this kind of low noise background-limited detectors. To effectively reduce the number of cryogenic wires (particularly, SQUID biasing), line/column addressing is currently used in time-division multiplexing, i.e., same biasing is applied to a few SQUIDs (on a line) of different columns. This technique should dramatically increase power consumption if parallel biasing is applied via resistors to isolate each column; the power budget is particularly limited on this kind of front-end cryogenic readout. A design with one transformer per SQUID is also used to read out SQUID biased in series with no excess of consumption and crosstalk. We propose here a new biasing technique using simple surface-mounted capacitors, which is easier to implement. These capacitors are used to parallel bias SQUIDs without additional Joule effect while minimizing crosstalk. However, capacitors do not allow dc biasing and need a current mean value equal to zero to avoid biasing source saturation. We have then tested square current biasing through capacitors on a commercial SQUID. This measurement shows that capacitors are able to proper bias SQUID and then to perform a nondissipative addressing for time-division SQUID multiplexing
The Gamma Cube: a new way to explore the gamma-ray sky
International audienceWe propose a new concept to allow the tracking of electrons in a gamma-ray telescope operating in the 5â100 MeV band. The idea of this experiment is to image the ionizing tracks that charged particles produce in a scintillator. It is a pair creation telescope at high energy and a Compton telescope with electron tracking at low energy. The telescope features a large scintillator transparent to the scintillation light, an ad-hoc optical system and a high resolution and highly sensitive imager. The performance perspectives and the advantages of such a system are outstanding but the technical difficulties are serious. A few years of research and development within the scientific community are required to reach the TRL level appropriate to propose the Gamma Cube in response to a flight opportunity
On-ground calibration of the X-ray, gamma-ray, and relativistic electron detector onboard TARANIS
Wada Yuuki, Laurent Philippe, Pailot Damien, et al. On-ground calibration of the X-ray, gamma-ray, and relativistic electron detector onboard TARANIS. Journal of Astronomical Telescopes, Instruments, and Systems 10(2), 7 May 2024 ; https://doi.org/10.1117/1.JATIS.10.2.026005.We developed the X-ray, gamma-ray, and relativistic electron detector (XGRE) onboard the Tool for the Analysis of RAdiation from lightNIngs and Sprites (TARANIS) satellite, to investigate high-energy phenomena associated with lightning discharges such as terrestrial gamma-ray flashes and terrestrial electron beams. XGRE consisted of three sensors. Each sensor has one layer of LaBr3 crystals for X-ray/gamma-ray detections and two layers of plastic scintillators for electron and charged-particle discrimination. Since 2018, the flight model of XGRE was developed, and validation and calibration tests, such as a thermal cycle test and a calibration test with the sensors onboard the satellite, were performed before the launch of TARANIS on 17 November 2020. The energy range of the LaBr3 crystals sensitive to X-rays and gamma rays was determined to be 0.04 to 11.6Â MeV, 0.08 to 11.0Â MeV, and 0.08 to 11.3Â MeV for XGRE1, 2, and 3, respectively. The energy resolution at 0.662Â MeV (full width at half maximum) was 20.5%, 25.9%, and 28.6%, respectively. The results from the calibration test were then used to validate a simulation model of XGRE and TARANIS. By performing Monte Carlo simulations with the verified model, we calculated effective areas of XGRE to X-rays, gamma rays, electrons, and detector responses to incident photons and electrons coming from various elevation and azimuth angles
QUBIC: The QU Bolometric Interferometer for Cosmology
One of the major challenges of modern cosmology is the detection of B-mode
polarization anisotropies in the CMB. These originate from tensor fluctuations
of the metric produced during the inflationary phase. Their detection would
therefore constitute a major step towards understanding the primordial
Universe. The expected level of these anisotropies is however so small that it
requires a new generation of instruments with high sensitivity and extremely
good control of systematic effects. We propose the QUBIC instrument based on
the novel concept of bolometric interferometry, bringing together the
sensitivity advantages of bolometric detectors with the systematics effects
advantages of interferometry. Methods: The instrument will directly observe the
sky through an array of entry horns whose signals will be combined together
using an optical combiner. The whole set-up is located inside a cryostat.
Polarization modulation will be achieved using a rotating half-wave plate and
interference fringes will be imaged on two focal planes (separated by a
polarizing grid) tiled with bolometers. We show that QUBIC can be considered as
a synthetic imager, exactly similar to a usual imager but with a synthesized
beam formed by the array of entry horns. Scanning the sky provides an
additional modulation of the signal and improve the sky coverage shape. The
usual techniques of map-making and power spectrum estimation can then be
applied. We show that the sensitivity of such an instrument is comparable with
that of an imager with the same number of horns. We anticipate a low level of
beam-related systematics thanks to the fact that the synthesized beam is
determined by the location of the primary horns. Other systematics should be
under good control thanks to an autocalibration technique, specific to our
concept, that will permit the accurate determination of most of the systematics
parameters.Comment: 12 pages, 10 figures, submitted to Astronomy and Astrophysic
Large bolometer arrays with superconducting NbSi sensors for future space experiments
International audienceNew techniques in microelectronics allow to build large arrays of bolometers filling the focal plane of submillimeter and millimeter telescopes. The expected sensitivity increase is the key for the next generation of space experiments in this wavelength range. Superconducting bolometers offer currently the best prospects in terms of sensitivity and multiplexed readout. We present here the developments led in France based on NbSi alloy thermometers. The manufacturing process of a 23 pixel array and the test setup are described
QUBIC: the Q&U Bolometric Interferometer for Cosmology
The primordial B-mode polarisation of the Cosmic Microwave Background is the imprints of the gravitational wave background generated by inflation. Observing the B-mode is up to now the most direct way to constrain the physics of the primordial Universe, especially inflation. To detect these B-modes, high sensitivity is required as well as an exquisite control of systematics effects. To comply with these requirements, we propose a new instrument called QUBIC (Q and U Bolometric Interferometer for Cosmology) based on bolometric interferometry. The control of systematics is obtained with a close-packed interferometer while bolometers cooled to very low temperature allow for high sensitivity. We present the architecture of this new instrument, the status of the project and the self-calibration technique which allows accurate measurement of the instrumental systematic effects
Planck early results: first assessment of the High Frequency Instrument in-flight performance
The Planck High Frequency Instrument (HFI) is designed to measure the
temperature and polarization anisotropies of the Cosmic Microwave Background
and galactic foregrounds in six wide bands centered at 100, 143, 217, 353, 545
and 857 GHz at an angular resolution of 10' (100 GHz), 7' (143 GHz), and 5'
(217 GHz and higher). HFI has been operating flawlessly since launch on 14 May
2009. The bolometers cooled to 100 mK as planned. The settings of the readout
electronics, such as the bolometer bias current, that optimize HFI's noise
performance on orbit are nearly the same as the ones chosen during ground
testing. Observations of Mars, Jupiter, and Saturn verified both the optical
system and the time response of the detection chains. The optical beams are
close to predictions from physical optics modeling. The time response of the
detection chains is close to pre-launch measurements. The detectors suffer from
an unexpected high flux of cosmic rays related to low solar activity. Due to
the redundancy of Planck's observations strategy, the removal of a few percent
of data contaminated by glitches does not affect significantly the sensitivity.
The cosmic rays heat up significantly the bolometer plate and the modulation on
periods of days to months of the heat load creates a common drift of all
bolometer signals which do not affect the scientific capabilities. Only the
high energy cosmic rays showers induce inhomogeneous heating which is a
probable source of low frequency noise.Comment: Submitted to A&A. 22 pages, 6 tables, 21 figures. One of a set of
simultaneous papers for the Planck Missio
The Large Imaging Spectrometer for Solar Accelerated Nuclei (LISSAN): A next-generation solar Îł-ray spectroscopic imaging instrument concept
Models of particle acceleration in solar eruptive events suggest that roughly equal energy may go into accelerating electrons and ions. However, while previous solar X-ray spectroscopic imagers have transformed our understanding of electron acceleration, only one resolved image of Îł-ray emission from solar accelerated ions has ever been produced. This paper outlines a new satellite instrument conceptâthe large imaging spectrometer for solar accelerated nuclei (LISSAN)âwith the capability not only to observe hundreds of events over its lifetime, but also to capture multiple images per event, thereby imaging the dynamics of solar accelerated ions for the first time. LISSAN provides spectroscopic imaging at photon energies of 40 keVâ100 MeV on timescales of âČ10 s with greater sensitivity and imaging capability than its predecessors. This is achieved by deploying high-resolution scintillator detectors and indirect Fourier imaging techniques. LISSAN is suitable for inclusion in a multi-instrument platform such as an ESA M-class mission or as a smaller standalone mission. Without the observations that LISSAN can provide, our understanding of solar particle acceleration, and hence the space weather events with which it is often associated, cannot be complete
Matthew Flinders et la mise en cartes dâun nouvel espace indo-pacifique
At the turn of the nineteenth century, the Royal Navy captain Matthew Flinders concluded a circumnavigation and hydrographical survey of Australia. He drew most of the charts of his voyage when, returning to England during the Napoleonic wars, he was detained for more than six years in Mauritius, which at that time was the French Isle de France. Against a background of commercial ambitions and maritime and colonial rivalries between European nations, governments and institutions increasingly relied on maps as one of their fundamental form of knowledge to shape their enterprise.The paper investigates how Flindersâs charts participated in the construction of a new maritime space that connected Australia to the Indian Ocean and the world maritime space. It reflects that the making up of Flindersâs maps was influenced by their spatial and local contexts. It highlights the network of institutions and individuals above and beyond Flindersâs maps that controlled or informed them
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