5,450 research outputs found
NIKEL: Electronics and data acquisition for kilopixels kinetic inductance camera
A prototype of digital frequency multiplexing electronics allowing the real
time monitoring of microwave kinetic inductance detector (MKIDs) arrays for
mm-wave astronomy has been developed. Thanks to the frequency multiplexing, it
can monitor simultaneously 400 pixels over a 500 MHz bandwidth and requires
only two coaxial cables for instrumenting such a large array. The chosen
solution and the performances achieved are presented in this paper.Comment: 21 pages, 14 figure
Bi-layer Kinetic Inductance Detectors for space observations between 80-120 GHz
We have developed Lumped Element Kinetic Inductance Detectors (LEKID)
sensitive in the frequency band from 80 to 120~GHz. In this work, we take
advantage of the so-called proximity effect to reduce the superconducting gap
of Aluminium, otherwise strongly suppressing the LEKID response for frequencies
smaller than 100~GHz. We have designed, produced and optically tested various
fully multiplexed arrays based on multi-layers combinations of Aluminium (Al)
and Titanium (Ti). Their sensitivities have been measured using a dedicated
closed-circle 100 mK dilution cryostat and a sky simulator allowing to
reproduce realistic observation conditions. The spectral response has been
characterised with a Martin-Puplett interferometer up to THz frequencies, and
with a resolution of 3~GHz. We demonstrate that Ti-Al LEKID can reach an
optical sensitivity of about ~ (best pixel), or
~ when averaged over the whole array. The optical
background was set to roughly 0.4~pW per pixel, typical for future space
observatories in this particular band. The performance is close to a
sensitivity of twice the CMB photon noise limit at 100~GHz which drove the
design of the Planck HFI instrument. This figure remains the baseline for the
next generation of millimetre-wave space satellites.Comment: 7 pages, 9 figures, submitted to A&
Microfabrication technology for large LEKID arrays : from NIKA2 to future applications
The Lumped Element Kinetic Inductance Detectors (LEKID)demonstrated full
maturity in the NIKA (New IRAM KID Arrays)instrument. These results allow
directly comparing LEKID performance with other competing technologies (TES,
doped silicon) in the mm and sub-mm range. A continuing effort is ongoing to
improve the microfabrication technologies and concepts in order to satisfy the
requirements of new instruments. More precisely, future satellites dedicated to
CMB (Cosmic Microwave Background) studies will require the same focal plane
technology to cover, at least, the frequency range of 60 to 600 GHz. Aluminium
LEKID developed for NIKA have so far demonstrated, under real telescope
conditions, performance approaching photon-noise limitation in the band 120-300
GHz. By implementing superconducting bi-layers we recently demonstrated LEKID
arrays working in the range 80-120 GHz and with sensitivities approaching the
goals for CMB missions. NIKA itself (350 pixels) is followed by a more
ambitious project requiring several thousands (3000-5000) pixels. NIKA2 has
been installed in October 2015 at the IRAM 30-m telescope. We will describe in
detail the technological improvements that allowed a relatively harmless
10-fold up-scaling in pixels count without degrading the initial sensitivity.
In particular we will briefly describe a solution to simplify the difficult
fabrication step linked to the slot-line propagation mode in coplanar
waveguide
Two-Scale Kirchhoff Theory: Comparison of Experimental Observations With Theoretical Prediction
We introduce a non-perturbative two scale Kirchhoff theory, in the context of
light scattering by a rough surface. This is a two scale theory which considers
the roughness both in the wavelength scale (small scale) and in the scales much
larger than the wavelength of the incident light (large scale). The theory can
precisely explain the small peaks which appear at certain scattering angles.
These peaks can not be explained by one scale theories. The theory was assessed
by calculating the light scattering profiles using the Atomic Force Microscope
(AFM) images, as well as surface profilometer scans of a rough surface, and
comparing the results with experiments. The theory is in good agreement with
the experimental results.Comment: 6 pages, 8 figure
The NIKA instrument: results and perspectives towards a permanent KID based camera for the Pico Veleta observatory
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
tuning procedure.Comment: 24th International Symposium on Space Terahertz Technology, ISSTT
2013, April 8 to 10, 2013, Groningen, the Netherland
Latest NIKA results and the NIKA-2 project
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.Comment: Proceedings of Low Temperature Detectors 15 (LTD-15), Pasadena, June
201
NIKA2: a mm camera for cluster cosmology
Galaxy clusters constitute a major cosmological probe. However, Planck 2015
results have shown a weak tension between CMB-derived and cluster-derived
cosmological parameters. This tension might be due to poor knowledge of the
cluster mass and observable relationship.
As for now, arcmin resolution Sunyaev-Zeldovich (SZ) observations ({\it e.g.}
SPT, ACT and Planck) only allowed detailed studies of the intra cluster medium
for low redshift clusters () high
resolution and high sensitivity SZ observations are needed. With both a wide
field of view (6.5 arcmin) and a high angular resolution (17.7 and 11.2 arcsec
at 150 and 260 GHz), the NIKA2 camera installed at the IRAM 30-m telescope
(Pico Veleta, Spain) is particularly well adapted for these observations. The
NIKA2 SZ observation program will map a large sample of clusters (50) at
redshifts between 0.5 and 0.9. As a pilot study for NIKA2, several clusters of
galaxies have been observed with the pathfinder, NIKA, at the IRAM 30-m
telescope to cover the various configurations and observation conditions
expected for NIKA2.
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