Achieving a percentage-level precision measurement of the coherent elastic neutrino nucleus scattering (CE
ν
NS) spectrum requires a robust data processing pipeline which can be characterised with ...great precision. To fulfil this goal, we present hereafter a new Python-based data processing pipeline specifically designed for temporal data analysis and pulse amplitude estimation. This pipeline features a data generator allowing to accurately simulate the expected data stream from the
Ricochet
experiment at the Institut Laue Langevin nuclear reactor, including both background and CE
ν
NS signals. This data generator is pivotal to fully understand and characterise the data processing overall efficiency, its reconstruction biases, and to properly optimise its configuration parameters. We show that thanks to this optimised data processing pipeline, the CryoCube detector array will be able to achieve a 70 eV energy threshold combined with electronic/nuclear recoil discrimination down to
∼
100 eV, hence fulfilling the
Ricochet
targeted performance.
Optimum amplification in surface enhanced Raman scattering (SERS) from individual nanoantennas is expected when the excitation is slightly blue-shifted with respect to the localized surface plasmon ...resonance (LSPR), so that the LSPR peak falls in the middle between the laser and the Stokes Raman emission. Recent experiments have shown when moving the excitation from the visible to the near-infrared that this rule of thumb is no more valid. The excitation has to be red-shifted with respect to the LSPR peak, up to 80 nm, to obtain highest SERS. Such discrepancy is usually attributed to a near-field (NF) to far-field (FF) spectral shift. Here we critically discuss this hypothesis for the case of gold nanocylinders. By combining multiwavelength-excitation SERS experiments with numerical calculations, we show that the red-shift of the excitation energy does not originate from a spectral shift between the extinction (FF) and the near-field distribution (NF), which is found to be not larger than 10 nm. Rather, it can be accounted for by looking at the peculiar spectral dependence of the near-field intensity on the cylinders diameter, characterized by an initial increase, up to 180 nm diameter, followed by a decrease and a pronounced skewness.
There is an increasing interest for tower concentrated solar power (CSP) systems which can work at temperatures higher than 1073 K to optimize the efficiency. One of the challenges is to design the ...receiver that will be heated at high temperatures in air. On the contrary to coatings in gas turbine engine, the coating/substrate system must have a high thermal conductivity to ensure a good heat transfer to the fluid. Aluminum nitride (AlN) coating, deposited by chemical vapor deposition at 1373 K at a growth rate of 10–50 μm h−1, is selected for its high thermal conductivity, low thermal expansion coefficient, high temperature stability and its ability to develop stable alumina scales above 1273 K. Cast and ODS (Oxide Dispersion Strengthened) FeCrAl alloys, also alumina-formers, are chosen as model substrates to reduce the influencing parameters in real-life receivers and to study the potential of these coatings. Accelerated cyclic oxidation tests and emissivity measurements allow the evaluation of AlN coatings as materials for high temperature CSP receivers. The multilayered systems show low degradation after hundreds of thermal cycles at 1073 K in air and can support higher temperatures (1373 K) for 100 to 500 h depending on the coating thickness. Nevertheless the fast cyclic oxidations in solar furnace generated cracks through the coatings. The measurement of the optical properties also revealed a decrease of the absorptivity after oxidation.
•Thick AlN coatings (15-40 μm) were deposited on Fe-Cr-Al alloys by chemical vapor deposition.•Their microstructure can be controlled by the N/Al ratio of gaseous precursors.•Their oxidation in the 1073-1373 K temperature range showed that a porous alumina layer is growing.•Optical measurements reveal that the development of the alumina layer degrades the absorptivity of the initial layer.•The lifetime of 40 μm AlN coatings can be estimated to be several years in the 1073-1173 K temperature range.
The necessity to increase exposure in rare event search experiments by maintaining a low energy threshold and a good energy resolution leads to segmented detectors as in EDELWEISS (Dark Matter), ...CUORE (0
ν
β
β
) or Ricochet (CENNS) for example. However, the large number of sub-elements can dramatically increase the complexity of such detector arrays. In this work we report on our progress towards designing a flexible detector technology based on Kinetic Inductance Detector (KID) resonators evaporated on massive target crystals readout by a contact-less feedline. Providing that we achieve
O
(
100
)
eV energy threshold, such approach could easily be scaled to tens of kilogram detector arrays thanks to the intrinsic multiplexing capability of KIDs. Using a 30 g silicon target absorber with Al/Ti multi layers for the KID resonator, we report a significant improvement of our detector response exhibiting a keV-scale energy resolution combined with the absence of position dependence on the event location. Indeed, compared to our previous work, we are now able to properly identify calibration lines from surface (20 keV X-rays) and bulk events (60 keV gamma rays). This significant improvement is an important step towards a better understanding of phonons and quasiparticles dynamics, which is pivotal in optimizing this technology.
Cystic fibrosis is a disease caused by a mutation on the CFTR gene coding for a chloride channel. The dominant mutation F508del eliminates the CFTR protein at the surface of epithelial cells, causing ...an accumulation of viscous mucus in the airways. In advanced stages of the disease, respiratory failure is associated with cellular hypoxia. Our project aims not only to describe the impact of hypoxia on ion channels and to highlight the underlying signaling pathways involved, but also to test the effectiveness of current CF treatments under the above-mentioned conditions.
The
Ricochet
reactor neutrino observatory is planned to be installed at Institut Laue–Langevin starting in mid-2022. The scientific goal of the
Ricochet
collaboration is to perform a low-energy and ...percentage precision CENNS measurement in order to explore exotic physics scenarios beyond the standard model. To that end,
Ricochet
will host two cryogenic detector arrays: the CryoCube (Ge target) and the Q-ARRAY (Zn target), both with unprecedented sensitivity to
O
(10) eV nuclear recoils. The CryoCube will be composed of 27 Ge crystals of 38 g instrumented with NTD-Ge thermal sensor as well as aluminum electrodes operated at 10 mK in order to measure both the ionization and the heat energies arising from a particle interaction. To be a competitive CENNS detector, the CryoCube array is designed with the following specifications: a low-energy threshold (
∼
50
eV), the ability to identify and reject with a high efficiency the overwhelming electromagnetic backgrounds (gamma, beta, and X-rays), and a sufficient payload (
∼
1
kg). After a brief introduction of the future
Ricochet
experiment and its CryoCube, the current works and first performance results on the optimization of the heat channel, and the electrode designs will be presented. We conclude with a preliminary estimation of the CryoCube sensitivity to the CENNS signal within
Ricochet
.
•The potential of the Kanthal Super ER (KSER) for solar applications is evaluated.•KSER is oxidized in muffle or solar furnaces at 1373, 1600, 1850 or 2100 K.•The oxidation in air in temperature ...follows semi-parabolic or subparabolic kinetics.•The radiative properties are not drastically affected by the oxidation.
The oxidation resistance of receivers is a critical point in the development of plants using solar tower technology. Intermetallics in MoSiAl system present oxidation maximum temperature and creep resistance superior to the ones of the currently used Ni-based alloys. We followed here the oxidation resistance of such intermetallic exposed to different treatments in air: long-term oxidation (up to 700 h) at 1373 K, and for several cycles of 20 min in solar furnace. The normal spectral emissivity is measured up to 1640 K in air, and our main positive conclusion is this property is not degraded by the oxidation.
The sensitivities of light Dark matter particle searches with cryogenic detectors are mostly limited by large backgrounds of events that do not produce ionization signal. The CRYOSEL project develops ...a new technique, where this background in a germanium cryogenic detector is rejected by using the signals from a superconducting single electron device (SSED) sensor designed to detect the phonons emitted through the Neganov–Trofimov–Luke effect by the e
-
h
+
pairs as they drift in a nearby very high-field region. A tag on signals from this device should suppress the heat-only background. The measurement of the response to IR laser pulses of the first CRYOSEL prototype show the relevance of such sensor technology.
The aim of the SELENDIS project within the EDELWEISS collaboration is to observe single e
-
h
+
pairs in lightweight (3.3 g) cryogenic germanium bolometers with charge and phonon readout at biases up ...to
∼
100
V. These devices are ideal to characterize in detail the mechanism of charge creation and collection in cryogenic germanium detectors. Electron–hole pairs are produced in the bulk of the detector either by the injection of pulsed IR laser or by neutron activation of germanium inducing the
K
,
L
and
M
lines from
71
Ge electron capture decays. Low-energy laser pulses are also used to probe the single e
-
h
+
pair sensitivity of Ge bolometers. Preliminary results are used to compare these two modes of charge creation, an important step toward a detailed characterization of Ge bolometers for their use in sub-MeV dark matter searches.
PDF
