87 research outputs found
Performance-related payments in local governments: do they improve performance or only increase salary?
Personnel policies in public sector organizations are fundamental to improving public services, since they have an impact on both individual and organizational performance. Within the broad area of Human Resources Management (HRM), Performance-Related Pay Systems (PRPSs) are widely considered one of the cornerstones of public sector managerial reforms. Monetary incentives should be paid for performance achievements of single employees and/or teams, according to a defined set of objectives. While the role and appropriateness of PRPSs in the public sector have been widely discussed in the literature, in some countries monetary incentives have been used as a tool to increase individual salaries, without considering them as a motivating instrument in a wider HRM system. A small number of studies have been conducted to understand the limitations of this form of incentives and to investigate whether it can be replaced by different and more effective incentives in order to avoid the de-motivating effect caused by money, as recognized in the literature. This study tries to fill this gap investigating, through twenty-five interviews to informed respondents the effectiveness of existing PRPSs at Local government level in Italy both in terms of performance and motivation and the possibility to substitute monetary with non-monetary incentives. The findings suggest that the limitations of monetary incentives have been widely recognized, but it is still difficult to replace them with different and more effective alternatives
Prototype high angular resolution LEKIDs for NIKA2
The current resolution of the NIKA2 260 GHz arrays is limited by the
inductor size on the individual pixels. In view of future
updates of the instrument, we have developed a prototype array with smaller
pixels that is experimentally compared to the current pixel design. We find an
in-lab improvement increase of the angular resolution of 8%, promising an
on-sky FWHM resolution of 10.2" using this new pixel design.Comment: 6 pages, 4 figures, submitted to Journal of Low Temperature Detecto
High-impedence NbSi TES sensors for studying the cosmic microwave background radiation
Precise measurements of the cosmic microwave background (CMB) are crucial in
cosmology, because any proposed model of the universe must account for the
features of this radiation. Of all CMB measurements that the scientific
community has not yet been able to perform, the CMB B-mode polarization is
probably the most challenging from the instrumental point of view. The
signature of primordial gravitational waves, which give rise to a B-type
polarization, is one of the goals in cosmology today and amongst the first
objectives in the field. For this purpose, high-performance low-temperature
bolometric cameras, made of thousands of pixels, are currently being developed
by many groups, which will improve the sensitivity to B-mode CMB polarization
by one or two orders of magnitude compared to the Planck satellite HFI
detectors. We present here a new bolometer structure that is able to increase
the pixel sensitivities and to simplify the fabrication procedure. This
innovative device replaces delicate membrane-based structures and eliminates
the mediation of phonons: the incoming energy is directly captured and measured
in the electron bath of an appropriate sensor and the thermal decoupling is
achieved via the intrinsic electron-phonon decoupling of the sensor at very low
temperature. Reported results come from a 204-pixel array of NbSi
transition edge sensors with a meander structure fabricated on a 2-inch silicon
wafer using electron-beam co-evaporation and a cleanroom lithography process.
To validate the application of this device to CMB measurements, we have
performed an optical calibration of our sample in the focal plane of a dilution
cryostat test bench. We have demonstrated a light absorption close to 20% and
an NEP of about 7 W/, which is highly encouraging
given the scope for improvement in this type of detectors.Comment: 6 pages, 10 figures. arXiv admin note: text overlap with
arXiv:1005.0555 by other author
A horn-coupled millimeter-wave on-chip spectrometer based on Lumped Element Kinetic Inductance Detectors
Context. Millimetre-wave astronomy is an important tool for both general
astrophysics studies and cosmology. A large number of unidentified sources are
being detected by the large field-of-view continuum instruments operating on
large telescopes.
Aims. New smart focal planes are needed to bridge the gap between large
bandwidth continuum instruments operating on single dish telescopes and the
high spectral and angular resolution interferometers (e.g. ALMA in Chile, NOEMA
in France). The aim is to perform low-medium spectral resolution observations
and select a lower number of potentially interesting sources, i.e.
high-redshift galaxies, for further follow-up.
Methods. We have designed, fabricated and tested an innovative on-chip
spectrometer sensitive in the 85-110~GHz range. It contains sixteen channels
selecting a frequency band of about 0.2 GHz each. A conical horn antenna
coupled to a slot in the ground plane collects the radiation and guides it to a
mm-wave microstrip transmission line placed on the other side of the
mono-crystalline substrate. The mm-wave line is coupled to a filter-bank. Each
filter is capacitively coupled to a Lumped Element Kinetic Inductance Detector
(LEKID). The microstrip configuration allows to benefit from the high quality,
i.e. low losses, mono-crystalline substrate, and at the same time prevents
direct, i.e. un-filtered, LEKID illumination.
Results. The prototype spectrometer exhibit a spectral resolution R = lambda
/ Delta_lambda = 300. The optical noise equivalent power is in the low
1E-16W/sqrt(Hz) range for an incoming power of about 0.2pW per channel. The
device is polarisation-sensitive, with a cross-polarisation lower than 1% for
the best channels.Comment: Submitted to Astronomy & Astrophysic
Spectrométrie de Fourier intégrée pour l'astronomie millimétrique
Au cours des dernières décennies, l observation du ciel dans les longueurs d onde millimétriques a permis de faire grandement progresser notre compréhension de l univers, notamment à travers l étude du fond diffus cosmologique. Pour répondre aux besoins actuels des astronomes, nous proposons dans ce rapport un instrument intégré permettant de réaliser des mesures spectrales large-bande dans le domaine millimétrique. Celui-ci se base sur le concept de SWIFTS (Stationary-Wave Fourier-Transform Spectrometer :spectromètre de Fourier à ondes stationnaire), un instrument opérationnel aux longueurs d onde visibles et infrarouges. Notre dispositif " SWIFTS millimétrique " utilise des détecteurs à inductance cinétique (KID pour Kinetic Inductance Detectors) comme détecteurs de lumière. Différents aspects de la conception du SWIFTS millimétrique sont abordés dans ce rapport. Le dimensionnement des éléments clés du dispositif est réalisé à l aide de simulations électromagnétiques. Nous proposons aussi un procédé de fabrication en technologie silicium permettant le dépôt d antennes sur membrane de nitrure de silicium SiN. Les premières caractérisations permettent de confirmer un fonctionnement adapté des détecteurs en configuration SWIFTS et démontre l existence d un couplage entre l antenne et un des détecteurs aux longueurs d onde millimétriques ce qui ouvre la voie à un futur démonstrateur. Parallèlement, la technologie développée pour le SWIFTS millimétrique a rendu possible la fabrication de KID sur membrane. L intérêt est ici d évaluer la membrane comme un moyen de réduire l interaction entre les rayons cosmiques et le détecteur dans la perspective d une utilisation des KID dans l espace. Des mesures comparatives effectuées sur KID déposés sur membrane et sur substrat démontrent des taux d'événements identiques dans les deux cas. La membrane est donc inefficace pour l application envisagée. Le temps de relaxation présente en revanche une dépendance avec la présence du substrat.For the last decades, millimeter wavelength observations allowed a large improvement of our knowledge of the universe in particular with the study of the Cosmic Microwave Background. To meet today astronomers needs, we propose hereby an integrated instrument able to perform wide-band spectral measurements in the millimeter spectrum. It is based on the SWIFTS concept (Stationary-Wave Fourier-Transform Spectrometer) an instrument already demonstrated in the optical and infrared bands. Our device "the millimeterSWIFTS" makes use of Kinetic Inductance Detectors (KID) as light detectors. Multiples aspects of the millimeter SWIFTS development are presented in this report. Design of the key-parts of the device is done with the help of electromagnetic simulations. We also propose a process of fabrication allowing the deposition of an antenna on a silicon nitride membrane SiN. First measurements confirm an adapted behavior of the KID in a SWIFTS design and demonstrate a coupling between the antenna and one of the detectors in themillimeter waves. This opens the way to a future demonstrator. In parallel, the technology developed for the millimeter SWIFTS allowed the deposition of KID on membrane. Main goal here is to assess membranes as a mean to reduce the interaction between cosmic rays and the detector in the case of a space application. Comparative measurements performed on KID deposited on membrane and on substrate demonstrate the same rate of events in both cases. Thus, membrane is not an option for the desired application. However, relaxation time shows a dependency with the presence of substrate.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF
WSPEC: A waveguide filter-bank focal plane array spectrometer for millimeter wave astronomy and cosmology
Imaging and spectroscopy at (sub-)millimeter wavelengths are key frontiers in
astronomy and cosmology. Large area spectral surveys with moderate spectral
resolution (R=50-200) will be used to characterize large scale structure and
star formation through intensity mapping surveys in emission lines such as the
CO rotational transitions. Such surveys will also be used to study the SZ
effect, and will detect the emission lines and continuum spectrum of individual
objects. WSPEC is an instrument proposed to target these science goals. It is a
channelizing spectrometer realized in rectangular waveguide, fabricated using
conventional high-precision metal machining. Each spectrometer is coupled to
free space with a machined feed horn, and the devices are tiled into a 2D array
to fill the focal plane of the telescope. The detectors will be aluminum
Lumped-Element Kinetic Inductance Detectors (LEKIDs). To target the CO lines
and SZ effect, we will have bands at 135-175 GHz and 190-250 GHz, each
Nyquist-sampled at R~200 resolution. Here we discuss the instrument concept and
design, and successful initial testing of a WR10 (i.e. 90 GHz) prototype
spectrometer. We recently tested a WR5 (180 GHz) prototype to verify that the
concept works at higher frequencies, and also designed a resonant backshort
structure that may further increase the optical efficiency. We are making
progress towards integrating a spectrometer with a LEKID array and deploying a
prototype device to a telescope for first light.Comment: 7 pages, 4 figures, submitted to Journal of Low Temperature Physic
Study of systematic effects in beta decay measurements with AgReO4 calorimeters
AgReO4 microcalorimeters are planned to be used again in the next generation
of calorimetric neutrino mass experiments with sensitivity down to 0.2 eV. The
understanding and characterization of all possible sources of systematic
uncertainties is crucial. In this work we focus on two of these sources, which
have been studied in the 10 detectors of the Milano AgReO4 array experiment
(MIBETA): a) the solid-state Beta Environmental Fine Structure (BEFS) observed
for the first time in AgReO4; b) the detector energy response for internal beta
events, which has been investigated with a dedicated measurement using a 44Ti
gamma source. The possible effects on neutrino mass experiments due to the
incomplete understanding of these two aspects are discussed.Comment: 3 pages, 2 figures Accepted, Nucl. Instr. Meth. Phys. A, proc. LTD11
Workshop, Tokyo, 200
Lumped Element Kinetic Inductance Detectors for space applications
Kinetic Inductance Detectors (KID) are now routinely used in ground-based
telescopes. Large arrays, deployed in formats up to kilopixels, exhibit
state-of-the-art performance at millimeter (e.g. 120-300 GHz, NIKA and NIKA2 on
the IRAM 30-meters) and sub-millimeter (e.g. 350-850 GHz AMKID on APEX)
wavelengths. In view of future utilizations above the atmosphere, we have
studied in detail the interaction of ionizing particles with LEKID (Lumped
Element KID) arrays. We have constructed a dedicated cryogenic setup that
allows to reproduce the typical observing conditions of a space-borne
observatory. We will report the details and conclusions from a number of
measurements. We give a brief description of our short term project, consisting
in flying LEKID on a stratospheric balloon named B-SIDE.Comment: To appear in the SPIE 2016 Proceeding
Quasiparticle dynamics in granular aluminum close to the superconductor to insulator transition
Superconducting high kinetic inductance elements constitute a valuable
resource for quantum circuit design and millimeter-wave detection. Granular
aluminum (GrAl) in the superconducting regime is a particularly interesting
material since it has already shown a kinetic inductance in the range of
nH and its deposition is compatible with conventional Al/AlOx/Al
Josephson junction fabrication. We characterize microwave resonators fabricated
from GrAl with a room temperature resistivity of cm, which is a factor of 3 below the superconductor to
insulator transition, showing a kinetic inductance fraction close to unity. The
measured internal quality factors are on the order of
in the single photon regime, and we demonstrate that non-equilibrium
quasiparticles (QP) constitute the dominant loss mechanism. We extract QP
relaxation times in the range of 1 s and we observe QP bursts every
s. The current level of coherence of GrAl resonators makes them attractive for
integration in quantum devices, while it also evidences the need to reduce the
density of non-equilibrium QPs.Comment: 5 pages, 4 figures, supplementary materia
Probing Neutrino low energy and mass scales
Low energy neutrino processes are ideal probes for new Physics beyond the
Standard Model. Cosmological observations and rare nuclear processes can test
neutrino mass scales and give definite answers to unsolved basic questions like
the Majorana/Dirac nature of the neutrino.Comment: 6 Pages, summary of the ``Probing low energy and mass scales''
session during the Neutrino Oscillation Workshop NOW2006, Otranto, Italy,
September 9-16 200
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