[Show abstract][Hide abstract] ABSTRACT: High resolution observations of the thermal Sunyaev-Zel'dovich (tSZ) effect
are necessary to allow the use of clusters of galaxies as a probe for large
scale structures at high redshifts. With its high resolution and dual-band
capability at millimeter wavelengths, the NIKA camera can play a significant
role in this context. NIKA is based on newly developed Kinetic Inductance
Detectors (KIDs) and operates at the IRAM 30m telescope, Pico Veleta, Spain. In
this paper, we give the status of the NIKA camera, focussing on the KID
technology. We then present observations of three galaxy clusters: RX
J1347.5-1145 as a demonstrator of the NIKA capabilities and the recent
observations of CL J1226.9+3332 (z = 0.89) and MACS J0717.5+3745 (z = 0.55). We
also discuss prospects for the final NIKA2 camera, which will have a 6.5
arcminute field of view with about 5000 detectors in two bands at 150 and 260
[Show abstract][Hide abstract] ABSTRACT: The New IRAM KID Array (NIKA) is a dual-band camera operating with frequency
multiplexed arrays of Lumped Element Kinetic Inductance Detectors (LEKIDs)
cooled to 100 mK. NIKA is designed to observe the intensity and polarisation of
the sky at 1.25 and 2.14 mm from the IRAM 30 m telescope. We present the
improvements on the control of systematic effects and astrophysical results
made during the last observation campaigns between 2012 and 2014.
[Show abstract][Hide abstract] ABSTRACT: The New IRAM KID Array (NIKA) instrument is a dual-band imaging camera
operating with Kinetic Inductance Detectors (KID) cooled at 100 mK. NIKA is
designed to observe the sky at wavelengths of 1.25 and 2.14 mm from the IRAM
30m telescope at Pico Veleta with an estimated resolution of 13 arcsec and 18
arcsec respectively. This work presents the performance of the NIKA camera
prior to its opening to the astrophysical community as an IRAM common user
facility in early 2014. NIKA is a test-bench for the final NIKA2 instrument to
be installed at the end of 2015. The last NIKA observation campaigns on
November 2012 and June 2013 have been used to evaluate this performance and to
improve the control of systematic effects. We discuss here the dynamical tuning
of the readout electronics to optimize the KID working point with respect to
background changes and the new technique of atmospheric absorption correction.
These modifications improve significantly the overall linearity, sensitivity
and absolute calibration performance of NIKA. This is proved on observations of
point-like sources for which we obtain a best sensitivity (averaged over all
valid detectors) of 40 and 14 mJy.s^1/2 for optimal weather conditions for the
1.25 and 2.14 mm arrays, respectively. NIKA observations of well known extended
sources (DR21 complex and the Horsehead nebula) are presented. This performance
makes the NIKA camera a competitive astrophysical instrument.
[Show abstract][Hide abstract] ABSTRACT: The next generations of cosmic microwave background (CMB) instruments will be dedicated to the detection and characterisation of CMB B-modes. To measure this tiny signal, instruments need to control and minimise systematics. Signal modulation is one way to achieve such a control. New generation of focal planes will include the entire detection chain on chip. In this context, we present a superconducting coplanar switch driven by DC current. It consists of a superconducting micro-bridge which commutes between its on (superconducting) and off (normal metal) states, depending on the amplitude of the current injection. To be effective, we have to use a high normal state resistivity superconducting material with a gap frequency higher than the frequencies of operation (millimeter waves). Several measurements were made at low temperature on NbN and yielded very high resistivities. Preliminary results of components dc behavior is shown. Thanks to its low power consumption, fast modulation and low weight, this component is a perfect candidate for future CMB space missions.
Journal of Low Temperature Physics 01/2014; 176(5-6). · 1.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The New IRAM KIDs Array (NIKA) is a pathfinder instrument devoted to
millimetric astronomy. In 2009 it was the first multiplexed KID camera on the
sky; currently it is installed at the focal plane of the IRAM 30-meters
telescope at Pico Veleta (Spain). We present preliminary data from the last
observational run and the ongoing developments devoted to the next NIKA-2
kilopixels camera, to be commissioned in 2015. We also report on the latest
laboratory measurements, and recent improvements in detector cosmetics and
read-out electronics. Furthermore, we describe a new acquisition strategy
allowing us to improve the photometric accuracy, and the related automatic
[Show abstract][Hide abstract] ABSTRACT: We present the first detection of the thermal Sunyaev-Zel'dovich (tSZ) effect
from a cluster of galaxies performed with a KIDs (Kinetic Inductance Detectors)
based instrument. The tSZ effect is a distortion of the black body CMB (Cosmic
Microwave Background) spectrum produced by the inverse Compton interaction of
CMB photons with the hot electrons of the ionized intra-cluster medium. The
massive, intermediate redshift cluster RX J1347.5-1145 has been observed using
NIKA (New IRAM KIDs arrays), a dual-band (140 and 240 GHz) mm-wave imaging
camera, which exploits two arrays of hundreds of KIDs: the resonant frequencies
of the superconducting resonators are shifted by mm-wave photons absorption.
This tSZ cluster observation demonstrates the potential of the next generation
NIKA2 instrument, being developed for the 30m telescope of IRAM, at Pico Veleta
(Spain). NIKA2 will have 1000 detectors at 140GHz and 2x2000 detectors at
240GHz, providing in that band also a measurement of the linear polarization.
NIKA2 will be commissioned in 2015.
[Show abstract][Hide abstract] ABSTRACT: Clusters of galaxies provide precious informations on the evolution of the
Universe and large scale structures. Recent cluster observations via the
thermal Sunyaev-Zel'dovich (tSZ) effect have proven to be a powerful tool to
detect and study them. In this context, high resolution tSZ observations (about
tens of arcsec) are of particular interest to probe intermediate and high
redshift clusters. Such observations will be carried out with the millimeter
dual-band NIKA2 camera, based on Kinetic Inductance Detectors (KIDs) and to be
installed at the IRAM 30-meter telescope in 2015. To demonstrate the potential
of such an instrument, we present tSZ observations with the NIKA camera
prototype, consisting of two arrays of 132 and 224 detectors observing at 140
and 240 GHz with a 18.5 and 12.5 arcsec angular resolution, respectively. The
cluster RX J1347.5-1145 was observed simultaneously at 140 and 240 GHz. We used
a spectral decorrelation technique to remove the atmospheric noise and obtain a
map of the cluster at 140 GHz. The efficiency of this procedure has been
characterized through realistic simulations of the observations. The obtained
140 GHz map presents a decrement at the cluster position consistent with the
tSZ nature of the signal. We used this map to study the pressure distribution
of the cluster by fitting a gNFW model to the data. Subtracting this model from
the map, we confirm that RX J1347.5-1145 is an ongoing merger, in agreement
with and complementary to previous tSZ and X-ray observations. For the first
time, we demonstrate the tSZ capability of KIDs based instruments. The NIKA2
camera, with about 5000 detectors and a 6.5 arcmin field of view, will be a
well-suited instrument for in-depth studies of the Intra Cluster Medium from
intermediate to distant clusters and so for the follow-up of recently detected
clusters by the Planck satellite.
[Show abstract][Hide abstract] ABSTRACT: NIKA (New IRAM KID Arrays) is a dual-band imaging instrument installed at the
IRAM (Institut de RadioAstronomie Millimetrique) 30-meter telescope at Pico
Veleta (Spain). Two distinct Kinetic Inductance Detectors (KID) focal planes
allow the camera to simultaneously image a field-of-view of about 2 arc-min in
the bands 125 to 175 GHz (150 GHz) and 200 to 280 GHz (240 GHz). The
sensitivity and stability achieved during the last commissioning Run in June
2013 allows opening the instrument to general observers. We report here the
latest results, in particular in terms of sensitivity, now comparable to the
state-of-the-art Transition Edge Sensors (TES) bolometers, relative and
absolute photometry. We describe briefly the next generation NIKA-2 instrument,
selected by IRAM to occupy, from 2015, the continuum imager/polarimeter slot at
the 30-m telescope.
[Show abstract][Hide abstract] ABSTRACT: In many papers, compact band-reject filters are realized by associating microstrip lines with complementary split ring resonators (CSRR). These studies assume that the periodicity of CSRR is perfect. However, a margin of error, related to the precision of manufacturing techniques, appears when operating these filters. In this paper, the robustness of the behavior of these filters is studied according to the degree of disturbance of the periodicity.
Antennas and Propagation Conference (LAPC), 2013 Loughborough; 01/2013
[Show abstract][Hide abstract] ABSTRACT: We are developing a detection system based on a NbSi Transition Edge Sensor (TES) bolometer array. A thermo-mechanical architecture accomodates the array and the cryogenic stage of the readout. We model the coupling of the TES bolometer to the radiation by means of twin slot antenna. We present the latest design of the cryogenic readout which includes a BiCMOS SiGe integrated circuit at 4 K controlling a Superconducting Quantum Interference Device (SQUID) amplifier.
IEEE Transactions on Applied Superconductivity 07/2011; · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microbolometers are at present the most sensitive detectors for mm and sub-mm Astronomy. They are in use in most of the present
instruments in that bandwidth. We have developed filled arrays of NbSi-based planar antenna coupled microbolometers. The fabrication
details are given, together with characterization of the NbSi thermometers and optical results. The optical performances are
potentially good for ground-based mm-wave astronomy applications, while the overall detectors performances are limited by
low-frequency excess noise in the thermometric NbSi high-impedance sensors (Anderson insulator).
[Show abstract][Hide abstract] ABSTRACT: The achievement of the Planck and Herschel space missions in the submillimeter and millimeter range was made possible by a continuous effort on detector developments. Now limited by the intrinsic fluctuations of the radiation coming from the astronomical sources themselves, the sensitivity improvement requires the development of large arrays of detectors filling the focal plane of the telescopes. We present here the development of a TES array using NbSi sensors on SiN membranes. The readout electronics is based on SQUIDs and a cooled SiGe ASIC multiplexer. The detector is coupled with the input radiation by means of antenna. The present goal performance is adapted for the realisation of a ground based millimeter camera.
[Show abstract][Hide abstract] ABSTRACT: To enhance systematics cleaness of a new advanced detection architecture for B‐modes detection of the Cosmic Microwave Background polarization and in the framework of the ground based instrument QUBIC (Q and U Bolometric Interferometer for Cosmology), we study planar superconducting devices. Waveguide to microstrip transition, orthomode transducer and phase switches are therefore investigated as well as their cryogenic characterization at millimeter waves. We also show design and nanotechnology fabrication process of these devices.
[Show abstract][Hide abstract] ABSTRACT: Instrumental progress allowed the development of bolometric detectors adapted to submillimeter and millimeter wavelengths. Superconducting transition-edge sensors (TESs) are currently under heavy development to be used as ultra sensitive bolometers. In addition to good performance, the choice of material depends on long term stability (both physical and chemical) along with a good reproducibility and uniformity in fabrication. For this purpose we are investigating the properties of NbSi thin films and have already developed arrays of NbSi TES. NbSi is a well-known alloy for use in resistive thermometers. We present a low temperature characterization of the NbSi films on a 23-pixel array. In order to tune the critical temperature of the NbSi thermometers down to the desired range, we have to adjust the concentration of Niobium in the NbSi alloy. In this experiment, we set for a Niobium concentration of 15 percent, to be able to run tests at a convenient temperature larger than 300 miliKelvin. Tests are made using Helium4-cooled cryostats, 300 miliKelvin Helium3 mini-fridges, resistance bridge and a commercial SQUID with its readout circuit. Parameters being measured are: critical temperature, resistance, sharpness of the transition given by the alpha parameter and noise measurements. The multiplexing is also developed to prepare the final chain for noise measurements on 23 pixel bolometers array.
IEEE Transactions on Applied Superconductivity 07/2009; · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To further increase the sensitivity of future telescope projects dedicated to photometric astronomy observation at millimeter and sub-millimeter wavelengths, large number of bolometer is currently developed. In this context, The DCMB (Dévelopement Concerté de Matrice de Bolomètre) French collaboration makes an R&D effort to develop large bolometer arrays. This paper concentrates on a first demonstration of NbSi TES (Transition-Edge Sensors) array development: a 23 NbSi superconducting thermometer array. Firstly, the NbSi thin film alloy is described then the 23 TES array topology is presented. The readout of large TES arrays requires ultra low noise amplification and multiplexing electronics. The use of a first stage transducer such as a SQUID (Superconducting QUantum Interference Device) allows ultimate performances in terms of noise. However, the linearization of the SQUID characteristic requires a Low Noise Amplifier (LNA) to generate a Flux Lock Loop (FLL). We implement this component in a cryogenic SiGe Integrated Circuit (IC) that could also contains the control of the multiplexing. Using this readout chain, a one-pixel operation using NbSi thermometer readout by SQUID and a cryogenicLNAis demonstrated. Finally, the development of a specific cryogenic IC including amplifiers, addressing and switching current sources needed for a 24 to 1 time domain SQUID multiplexer is presented
IEEE Transactions on Applied Superconductivity 07/2009; · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the framework of the DCMB (Développement Concerté de Matrices de Bolomètres) collaboration we develop low temperature bolometer arrays for large field, high resolution imaging in astrophysics. DCMB is a R&D effort funded by CNES and CNRS involving a number of French laboratories. Two parallel developments have been made in this collaboration based on the NbSi alloy either semi-conducting or superconducting depending on the Nb concentration. Multiplexing schemes have been developed and demonstrated for these two options. Here we focus on high impedance bolometers and present two examples of array developments in progress: first, a 23 pixels array for the balloon-borne instrument OLIMPO and, second, 204 pixels for ground based observations with the 30m IRAM telescope.
[Show abstract][Hide abstract] ABSTRACT: Future ground and space astronomy experiments will require large arrays of sensitive detectors in the submillimeter and millimeter ranges. Superconducting Transition Edge Sensors (TES) are currently under development in many institutes to be used as ultra sensitive bolometers. We are investigating co-evaporated NbSi thin films TES arrays. We present here the characterisation and laboratory performances of an array and its readout electronics.
[Show abstract][Hide abstract] ABSTRACT: Bolometers cooled to very low temperature are currently the most sensitive detectors for low spectral resolution detection of millimetre and sub-millimetre wavelengths. The best performances of the state-of-the-art bolometers allow to reach sensitivities below the photon noise of the Cosmic Microwave Background for example. Since 2003, a french R&D effort called DCMB ("Developpement Concerte de Matrices de Bolometres") has been organised between different laboratories to develop large bolometers arrays for astrophysics observations. Funded by CNES and CNRS, it is intended to get a coherent set of competences and equipments to develop very cold bolometers arrays by microfabrication. Two parallel developments have been made in this collaboration based on the NbSi alloy either semi-conductive or superconducting depending on the proportion of Nb. Multiplexing schemes have been developed and demonstrated for these two options. I will present the latest developments made in the DCMB collaboration and future prospects.
[Show abstract][Hide abstract] ABSTRACT: Future space experiments will require large arrays of sensitive detectors in the submillimeter and millimeter range. Superconducting transition-edge sensors (TESs) are currently under heavy development to be used as ultra sensitive bolometers. In addition to good performance, the choice of material depends on long term stability (both physical and chemical) along with a good reproducibility and uniformity in fabrication. For this purpose we are investigating the properties of co-evaporated NbSi thin films. NbSi is a well-known alloy for use in resistive thermometers. We present a full low temperature characterization of superconductive NbSi films. In order to tune the critical temperature of the NbSi thermometers down to the desired range, we have to adjust the concentration of niobium in the NbSi alloy. Tests are made using 4He-cooled cryostats, 300mK 3He mini-fridges, Resistance Bridges and commercial SQUID. Measured parameters are the critical temperature, the sharpness of the transition. Noise measurements are on-going.
[Show abstract][Hide abstract] ABSTRACT: Access to new microelectronics facilities allows the development of large bolometer arrays for astronomy. The expected sensitivity increase is the key for the next generation of cameras at the focal plane of submillimeter and millimeter telescopes. We present here the research led in France in this domain.
Millimeter Waves, 2008. GSMM 2008. Global Symposium on; 05/2008