75 research outputs found
A demonstrator for bolometric interferometry
Bolometric Interferometry (BI) is one of the most promising techniques for
precise measurements of the Cosmic Microwave Background polarization. In this
paper, we present the results of DIBO (Demonstrateur d'Interferometrie
Bolometrique), a single-baseline demonstrator operating at 90 GHz, built to
proof the validity of the BI concept applied to a millimeter-wave
interferometer. This instrument has been characterized in the laboratory with a
detector at room temperature and with a 4 K bolometer. This allowed us to
measure interference patterns in a clean way, both (1) rotating the source and
(2) varying with time the phase shift among the two interferometer's arms.
Detailed modelisation has also been performed and validated with measurements.Comment: 15 pages, 14 figure
Probing neutrino masses with CMB lensing extraction
We evaluate the ability of future cosmic microwave background (CMB)
experiments to measure the power spectrum of large scale structure using
quadratic estimators of the weak lensing deflection field. We calculate the
sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and
PLANCK to the non-zero total neutrino mass M_nu indicated by current neutrino
oscillation data. We find that these experiments greatly benefit from lensing
extraction techniques, improving their one-sigma sensitivity to M_nu by a
factor of order four. The combination of data from PLANCK and the SAMPAN
mini-satellite project would lead to sigma(M_nu) = 0.1 eV, while a value as
small as sigma(M_nu) = 0.035 eV is within the reach of a space mission based on
bolometers with a passively cooled 3-4 m aperture telescope, representative of
the most ambitious projects currently under investigation. We show that our
results are robust not only considering possible difficulties in subtracting
astrophysical foregrounds from the primary CMB signal but also when the minimal
cosmological model (Lambda Mixed Dark Matter) is generalized in order to
include a possible scalar tilt running, a constant equation of state parameter
for the dark energy and/or extra relativistic degrees of freedom.Comment: 13 pages, 4 figures. One new figure and references added. Version
accepted for publicatio
Four dof Piezoelectric Microgripper Equipped with a Smart CMOS Camera.
International audienceThis paper deals with the design of a micro-eyein- hand architecture. It consists of a smart camera embedded on a gripper. The camera is a high speed (10 000 fps) CMOS sensor of 64 64 pixels. Each pixel measures 35 m 35 m and includes a photodiode, an amplifier, two storage capacitors, and an analog arithmetic unit. The gripper consists of a 4 dof (degrees-of-freedom) (y+, y-, z+, z-) microprehensile based on piezoelectric actuators
Polarization experiments
Possible instrumental set--ups for the measurement of CMB polarization are
reviewed in this article. We discuss existing and planned instruments, putting
special emphasis on observational, instrumental, and data processing issues for
the detection of very low polarization signals of prime cosmological interest.
A short prospective summary is included
Development of MKIDs in the Optical and Near-infrared Bands for SPIAKID
SpectroPhotometric Imaging in Astronomy with Kinetic Inductance Detectors
(SPIAKID) aims at designing, building, and deploying on the sky a
spectrophotometric imager based on microwave kinetic inductance detectors
(MKIDs) in the optical and near-infrared bands. MKIDs show a fast response and
the ability to resolve photon energy compared to the conventional
Charge-coupled Devices (CCDs). In this paper, we present the design and
simulation of the MKID arrays for SPIAKID. The detectors consist of four arrays
with each array of 20,000 lumped-element pixels, and each array will be read
with 10 readout lines. %The array is designed to have resonances between 4-8GHz
with a frequency spacing of 2 MHz and a coupling quality factor (Qc) of about
50000. The meander material of the resonators is trilayer TiN/Ti/TiN to have
better uniformity of the critical temperature across the array. We also present
the measurement result for a test array with pixels which is a
subset of the designed 2000-pixel array to verify the design and fabrication.
The current measured best energy resolving power is 2.4 at
nm and the current medium R is around 1.7. We have also
observed the response of the TiN/Ti/TiN is much smaller than expected.Comment: 9 pages, 6 figures. Accepted by the Journal of Low Temperature
Physic
Modeling of Planck-high frequency instrument bolometers using non-linear effects
Abstract The Planck satellite, which is planned to be launched in 2007, is dedicated to surveying the Cosmic Microwave Background (CMB) to a high precision. Aboard this mission, the High-Frequency Instrument (HFI) will use 52 NTD Ge spiderweb bolometers made by Caltech-JPL and cooled to 100 mK by a dilution cooler. In this paper, we present a model of these detectors that includes non-linear effects seen in NTD Ge thermometers: electron-phonon decoupling and electrical field effect. We show that this model leads to consider only electrical field effect. Furthermore, the optical characterization of the HFI bolometers clearly shows a non-ideal behavior that is explained by non-linear effects in the thermometer. We finally show that these effects have to be taken into account for optimized CMB observations and to fully understand the physics of semi-conducting bolometers. r 2005 Elsevier B.V. All rights reserved. PACS: 95.55.J
PRISM (Polarized Radiation Imaging and Spectroscopy Mission): A White Paper on the Ultimate Polarimetric Spectro-Imaging of the Microwave and Far-Infrared Sky
PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to
ESA in response to the Call for White Papers for the definition of the L2 and
L3 Missions in the ESA Science Programme. PRISM would have two instruments: (1)
an imager with a 3.5m mirror (cooled to 4K for high performance in the
far-infrared---that is, in the Wien part of the CMB blackbody spectrum), and
(2) an Fourier Transform Spectrometer (FTS) somewhat like the COBE FIRAS
instrument but over three orders of magnitude more sensitive. Highlights of the
new science (beyond the obvious target of B-modes from gravity waves generated
during inflation) made possible by these two instruments working in tandem
include: (1) the ultimate galaxy cluster survey gathering 10e6 clusters
extending to large redshift and measuring their peculiar velocities and
temperatures (through the kSZ effect and relativistic corrections to the
classic y-distortion spectrum, respectively) (2) a detailed investigation into
the nature of the cosmic infrared background (CIB) consisting of at present
unresolved dusty high-z galaxies, where most of the star formation in the
universe took place, (3) searching for distortions from the perfect CMB
blackbody spectrum, which will probe a large number of otherwise inaccessible
effects (e.g., energy release through decaying dark matter, the primordial
power spectrum on very small scales where measurements today are impossible due
to erasure from Silk damping and contamination from non-linear cascading of
power from larger length scales). These are but a few of the highlights of the
new science that will be made possible with PRISM.Comment: 20 pages Late
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10â»ÂčⶠW/âHz
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10â»ÂčⶠW/âHz
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