L’article a pour objet de mieux cerner ce que recouvre le concept d’accompagnement methodologique dans l’enseignement superieur. La premiere partie propose une typologie des dispositifs d’accompagnement methodologique en s’inspirant des travaux de Romainville et Noel (1998). Deux dispositifs contrastes d’aide methodologique, tous deux experimentes a l’universite Joseph-Fourier (UJF) de Grenoble, sont ensuite analyses afin d’identifier les logiques sur lesquelles ils sont construits et les pratiques effectives qui y sont developpees. Apres avoir discute les resultats, nous detaillons en quoi ces pratiques relevent d’une activite d’accompagnement impliquant un changement par rapport a une activite traditionnelle d’enseignement. La conclusion insiste sur la necessite d’adopter egalement une approche institutionnelle et politique des dispositifs d’accompagnement methodologique.

Context. We have developed a dual-band (140 and 220 GHz) mm-wave imaging camera based on superconducting kinetic inductance detector (KID) arrays. Each array contains 132 superconducting resonators whose resonant frequencies are shifted by mm-wave photons absorption. The read out is achieved with a single electronics chain per band, taking advantage of the intrinsic KID frequency-domain multiplexability. The arrays are easily scalable and well adapted for future large format focal plane instruments. NIKA (formerly Neel IRAM KID Array, now New IRAM KID Array) has been specifically designed for the IRAM 30 m telescope at Pico Veleta, and is one of the first instruments using KIDs to have made measurements of astronomical sources.Aims. In this Letter we describe the solutions adopted to improve the calibration accuracy and the sensitivity of the instrument, and we report on the outcome of the 3rd NIKA observing run of October, 2011.Methods. We use a fast electronic modulation of the readout tone for each KID pixel in order to linearize the instrument calibration, which we track with measurements of planets. We also adopt a new design of the KIDs, sensitive to both polarizations, to increase the amount of radiation absorbed and thus the optical efficiency of the system.Results. We measured an average sensitivity on the sky of 21 mJys(0.5) per beam at 140 GHz and 140 mJys(0.5) at 220 GHz in the best observing conditions (tau(220) similar or equal to 0.2) after atmospheric noise decorrelation. The sensitivity at 220 GHz was limited by the atmospheric attenuation and loading as well as a reduction in the spectral bandwidth due to a misplaced filter. We found the repeatability in the photometry over the entire observing run to be better than 10% in both bands, thus demonstrating a significant improvement over the previous runs. We also find good agreement between NIKA measurements of faint astronomical sources and previous measurements of the same sources.

We are developing an instrument based on Kinetic Inductance Detectors (KID) known as the Néel IRAM KID Array (NIKA). Leveraging the experience gained from the first generation NIKA in 2009, an improved, dual-band (150 GHz and 240 GHz) instrument has been designed and tested at the Institut of RadioAstronomie Millimetrique (IRAM) 30-meter telescope in October 2010. The performances, in terms of sensitivity on-the-sky at 150 GHz, are already comparable to existing state-of-the-art bolometer-based instruments. NIKA represents thus the first real proof that KID are a viable technology for ground-based Astronomy. We will describe the instrument, the most recent results and the future plans for building a large resident mm-wave camera.

We present millimeter-wave Stationary-Waves Integrated Fourier Transform Spectrometry (SWIFTS) using the nascent Kinetic Inductance Detector (KID) technology. SWIFTS operation consists in converting a stationary-wave spatial sampling into the frequency domain; our SWIFTS devices are designed to operate in the sub-THz region. Millimeter wave power is probed using KIDs, high-quality superconducting resonators deemed to be the next generation millimetric photon detectors for large array astronomy cameras. We expect KIDs to be sensitive enough to sense the stationary wave without altering its properties. Moreover, KID multiplexing capabilities will allow the use of many detectors on a single transmission line, facilitating cryogenic measurements.The SWIFTS concept, already validated in the optical and microwave (< 20 GHz) bands, will be useful in any applications where integrated and broadband spectral analysis is needed. We discuss SWIFTS device structure, its measurement operation and some preliminary results.

We present latest developments of the millimetric Stationary Waves Integrated Fourier Transform Spectrometer (SWIFTS) that uses the Kinetic Inductance Detectors (KID) technology. SWIFTs are on-chip autocorrelator spectrometers where the incoming signal forms an interferogram by reflection in a short-circuited coplanar wave-guide. By collecting electromagnetic (EM) energy along the guide, one can retrieve this interference pattern. A subsequent offline Fourier transform gives spectral information with a moderate resolution (~500-1000). SWIFTS concept has already been proven to work in the optical and microwave (<20 GHz) bands. It will be useful in any application where integrated and broadband spectral analysis is needed, as an example it will be a practical alternative to Martin-Pupplet interferometer. In practice, fabrication of such a device is very challenging mostly because the set of detectors has to collect energy without destroying the interference pattern. As a consequence, design of the coupling parts is a crucial problem that has to be tackled with the help of EM simulation tools. We present here the SWIFTS principle of operation, details of fabrication, and the latest simulations results.

The Neel Iram Kids Array (NIKA) is a prototype instrument devoted to millimetric astronomy that has been designed to be mounted at the focal plane of the IRAM 30m telescope at Pico Veleta (Spain). After the runs of 2009 and 2010, we carried a third technical run in October 2011. In its latest configuration, the instrument consists of a dual-band camera, with bands centered at 150 GHz and 220 GHz, each of them equipped with 116 pixels based on Lumped Element Kinetic Inductance Detectors. During the third run we tested many improvements that will play a crucial role in the development of the final, kilopixel sized camera. In particular, a new geometry based on a Hilbert curve has been adopted for the absorbing area of the LEKIDs, that makes the detectors dual-polarization sensitive. Furthermore, a different acquisition strategy has been adopted, which has allowed us to increase the photometric accuracy of the measurements, a fundamental step in order to get scientifically significant data. In this paper we describe the main characteristics of the 2011 NIKA instrument and outline some of its key features, discusse the results we obtained and give a brief outlook on the future NIKA camera which will be installed permanently on site.

Context. The Neel IRAM KIDs Array (NIKA) is a fully-integrated measurement system based on kinetic inductance detectors (KIDs) currently being developed for millimeter wave astronomy. In a first technical run, NIKA was successfully tested in 2009 at the Institute for Millimetric Radio Astronomy (IRAM) 30-meter telescope at Pico Veleta, Spain. This prototype consisted of a 27-42 pixel camera imaging at 150 GHz. Subsequently, an improved system has been developed and tested in October 2010 at the Pico Veleta telescope. The instrument upgrades included dual-band optics allowing simultaneous imaging at 150 GHz and 220 GHz, faster sampling electronics enabling synchronous measurement of up to 112 pixels per measurement band, improved single-pixel sensitivity, and the fabrication of a sky simulator to replicate conditions present at the telescope. Results. The new dual-band NIKA was successfully tested in October 2010, performing in-line with sky simulator predictions. Initially the sources targeted during the 2009 run were re-imaged, verifying the improved system performance. An optical NEP was then calculated to be around 2 \dot 10-16 W/Hz1/2. This improvement in comparison with the 2009 run verifies that NIKA is approaching the target sensitivity for photon-noise limited ground-based detectors. Taking advantage of the larger arrays and increased sensitivity, a number of scientifically-relevant faint and extended objects were then imaged including the Galactic Center SgrB2(FIR1), the radio galaxy Cygnus A and the NGC1068 Seyfert galaxy. These targets were all observed simultaneously in the 150 GHz and 220 GHz atmospheric windows.

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).

Current generation millimeter wavelength detectors suffer from scaling limits imposed by complex cryogenic readout electronics. To circumvent this it is imperative to investigate technologies that intrinsically incorporate strong multiplexing. One possible solution is the kinetic inductance detector (KID). In order to assess the potential of this nascent technology, a prototype instrument optimized for the 2 mm atmospheric window was constructed. Known as the N\'eel IRAM KIDs Array (NIKA), it was recently tested at the Institute for Millimetric Radio Astronomy (IRAM) 30-meter telescope at Pico Veleta, Spain. The measurement resulted in the imaging of a number of sources, including planets, quasars, and galaxies. The images for Mars, radio star MWC349, quasar 3C345, and galaxy M87 are presented. From these results, the optical NEP was calculated to be around $1 \times 10^{-15}$ W$ / $Hz$^{1/2}$. A factor of 10 improvement is expected to be readily feasible by improvements in the detector materials and reduction of performance-degrading spurious radiation.

Throughout the last decades, development of low-temperature detectors focused mainly on the design of high-sensitivity, single-pixel devices. This includes such devices as semiconductor-based photodetectors and bolometers, Magnetic Metallic Calorimeters (MMC), Superconducting Tunnel Junctions (STJ), and Transition Edge Sensors (TES). However, these devices have had limited success in achieving the simultaneous large-scale array sizes and large-bandwidth operation necessary for high-speed, high-resolution detection. To overcome this performance limitation, it is advisable to focus on low-temperature detectors which are intrinsically adapted to giant-array multiplexing and ultra-fast readout. To adopt large scale frequency-domain multiplexing for low-temperature detectors, it is necessary to find detectors which "broadcast" at microwave frequencies. Superconducting microwave resonators naturally lend themselves to this task. One recent demonstration is an implementation known as Kinetic Inductance Detectors (KIDs). This detection mechanism can be adopted for low-energy EM radiation (radio, min, THz) in continuous mode, or in pulsed mode for higher energy radiation and particles. We present an ongoing development for a KIDs instrument dedicated to millimetric ground-based observations at the 30m IRAM telescope at Pico Veleta. The Neel IRAM KIDs Array (NIKA) project is coordinated in Grenoble and involves groups in Holland (SRON), UK (Cardiff) and Italy (Roma).

Low‐temperature physics and astronomy have traditionally focused on developing exquisitely sensitive single‐pixel detectors. While this has yielded considerable results, these technologies almost uniformly suffer from an inability to scale to large array sizes. In order to circumvent this barrier, frequency‐multiplexing techniques have recently emerged as a suitable solution. Here we present a detailed description of a measurement platform based on frequency‐multiplexed superconducting resonators along with the results from two distinct measurements that leverage this nascent technology to achieve multiple‐device readout. The first application discussed is a seven‐pixel array sensor of the permittivity of liquid helium suitable for quantum hydrodynamic experiments. The second implementation described is a prototype 16‐channel mm‐wavelength detector optimized for ground‐based astronomical detection at the 30 meter Institute for Millimeter‐Wave Radio Astronomy (IRAM) telescope in Pico Veleta, Spain.

We present the design and the present development status of a 204 pixels mm-wave bolometric camera compatible with the 30 meter IRAM telescope at Pico Veleta. Sequential and non-sequential ray-tracing and physical optics simulations have been performed with ZEMAX, taking into account the IRAM mirrors and the telecentric camera. The focal plane is made by an array of antenna-coupled NbSi microbolometers, described in brief. We present the cryostat design, and then more in details the optics and the baffling system. We conclude with a brief discussion on the future perspectives toward the multi-thousands pixels bolometric mm-wave camera at IRAM.

The use of a multiplexing readout for an array of bolometers simplifies the electronics and wiring, so making the readout of large arrays of bolometers (>100) feasible. Here we describe a time domain multiplexing technique and its performance based on the use of quantum-point-contact high-electron-mobility-transistors as low temperature (to approximately 100 mK) switches for measuring high impedance (5...70 MOmega) resistances and sensors. The presented system is well matched to ground based millimetric astronomy demands.

New 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.

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 ("Development 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.