44 research outputs found
First demonstration of 30 eVee ionization energy resolution with Ricochet germanium cryogenic bolometers
The future Ricochet experiment aims to search for new physics in the
electroweak sector by measuring the Coherent Elastic Neutrino-Nucleus
Scattering process from reactor antineutrinos with high precision down to the
sub-100 eV nuclear recoil energy range. While the Ricochet collaboration is
currently building the experimental setup at the reactor site, it is also
finalizing the cryogenic detector arrays that will be integrated into the
cryostat at the Institut Laue Langevin in early 2024. In this paper, we report
on recent progress from the Ge cryogenic detector technology, called the
CryoCube. More specifically, we present the first demonstration of a 30~eVee
(electron equivalent) baseline ionization resolution (RMS) achieved with an
early design of the detector assembly and its dedicated High Electron Mobility
Transistor (HEMT) based front-end electronics. This represents an order of
magnitude improvement over the best ionization resolutions obtained on similar
heat-and-ionization germanium cryogenic detectors from the EDELWEISS and
SuperCDMS dark matter experiments, and a factor of three improvement compared
to the first fully-cryogenic HEMT-based preamplifier coupled to a CDMS-II
germanium detector. Additionally, we discuss the implications of these results
in the context of the future Ricochet experiment and its expected background
mitigation performance.Comment: 10 pages, 5 figures, 1 tabl
Fast neutron background characterization of the future Ricochet experiment at the ILL research nuclear reactor
The future Ricochet experiment aims at searching for new physics in the
electroweak sector by providing a high precision measurement of the Coherent
Elastic Neutrino-Nucleus Scattering (CENNS) process down to the sub-100 eV
nuclear recoil energy range. The experiment will deploy a kg-scale
low-energy-threshold detector array combining Ge and Zn target crystals 8.8
meters away from the 58 MW research nuclear reactor core of the Institut Laue
Langevin (ILL) in Grenoble, France. Currently, the Ricochet collaboration is
characterizing the backgrounds at its future experimental site in order to
optimize the experiment's shielding design. The most threatening background
component, which cannot be actively rejected by particle identification,
consists of keV-scale neutron-induced nuclear recoils. These initial fast
neutrons are generated by the reactor core and surrounding experiments
(reactogenics), and by the cosmic rays producing primary neutrons and
muon-induced neutrons in the surrounding materials. In this paper, we present
the Ricochet neutron background characterization using He proportional
counters which exhibit a high sensitivity to thermal, epithermal and fast
neutrons. We compare these measurements to the Ricochet Geant4 simulations to
validate our reactogenic and cosmogenic neutron background estimations.
Eventually, we present our estimated neutron background for the future Ricochet
experiment and the resulting CENNS detection significance.Comment: 14 pages, 14 figures, 1 tabl
Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications
Coherent elastic neutrino-nucleus scattering (CENS) is a process in which neutrinos scatter on a nucleus which acts as a single particle. Though the total cross section is large by neutrino standards, CENS has long proven difficult to detect, since the deposited energy into the nucleus is keV. In 2017, the COHERENT collaboration announced the detection of CENS using a stopped-pion source with CsI detectors, followed up the detection of CENS using an Ar target. The detection of CENS has spawned a flurry of activities in high-energy physics, inspiring new constraints on beyond the Standard Model (BSM) physics, and new experimental methods. The CENS process has important implications for not only high-energy physics, but also astrophysics, nuclear physics, and beyond. This whitepaper discusses the scientific importance of CENS, highlighting how present experiments such as COHERENT are informing theory, and also how future experiments will provide a wealth of information across the aforementioned fields of physics
Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications
Coherent elastic neutrino-nucleus scattering (CENS) is a process inwhich neutrinos scatter on a nucleus which acts as a single particle. Thoughthe total cross section is large by neutrino standards, CENS has longproven difficult to detect, since the deposited energy into the nucleus is keV. In 2017, the COHERENT collaboration announced the detection ofCENS using a stopped-pion source with CsI detectors, followed up thedetection of CENS using an Ar target. The detection of CENS hasspawned a flurry of activities in high-energy physics, inspiring newconstraints on beyond the Standard Model (BSM) physics, and new experimentalmethods. The CENS process has important implications for not onlyhigh-energy physics, but also astrophysics, nuclear physics, and beyond. Thiswhitepaper discusses the scientific importance of CENS, highlighting howpresent experiments such as COHERENT are informing theory, and also how futureexperiments will provide a wealth of information across the aforementionedfields of physics.<br
An experimental study of the efficiency of new cutting fluids during turning hardened 35NiCrMo 16.6 steel
The present paper deals with the application of new water-based semi-synthetic cutting fluids when machining hardened steels and more generally high strength alloys. A qualification test is defined on the basis of a longitudinal turning operation, and as a part of a study absolutely necessary to be engaged in view to choose an alternative new cutting fluid in accordance to the current French legislation and statutory regulations concerning the environment. The effectiveness of ten commercially available cutting fluids is studied, in relation with the technical objectives to be achieved in terms of quality: dimensional accuracy, surface finish, tool damage and tool life, chip breaking and disposal.Measured and calculated values of cutting force, tool wear, surface roughness, apparent coefficient of friction on the tool face, are compared to those obtained when machining is performed without application of cutting fluid (dry cutting), with application of a 6-bar compressed air jet (air cutting), and with application of two “reference cutting fluids”: a well known cutting fluid of the previous generation, and a water solution containing 3% triethanolamine by volume
Host factors determine the evolution of infection with Staphylococcus aureus to gangrenous mastitis in goats
The online version of this article (10.1186/s13567-018-0564-4) contains supplementary material, which is available to authorized users.International audienceStaphylococcus aureus is the major cause of very severe mastitis of dairy goats. The initial objective of our study was to fine-tune an experimental model of infection of the goat mammary gland with two strains of S. aureus and two lines of goats (low and high somatic cell score lines). Following the challenge, the 10 infected goats divided in two clear-cut severity groups, independently of the S. aureus strain and the goat line. Five goats developed very severe mastitis (of which four were gangrenous) characterized by uncontrolled infection (UI group), whereas the other five kept the infection under control (CI group). The outcome of the infection was determined by 18 h post-infection (hpi), as heralded by the bacterial milk concentration at 18 hpi: more than 107/mL in the UI group, about 106/mL in the CI group. Leukocyte recruitment and composition did not differ between the groups, but the phagocytic killing at 18 hpi efficiency did. Contributing factors involved milk concentrations of α-toxin and LukMF' leukotoxin, but not early expression of the genes encoding the pentraxin PTX3, the cytokines IL-1α and IL-1β, and the chemokines IL-8 and CCL5. Concentrations of TNF-α, IFN-γ, IL-17A, and IL-22 rose sharply in the milk of UI goats when infection was out of control. The results indicate that defenses mobilized by the mammary gland at an early stage of infection were essential to prevent staphylococci from reaching critical concentrations. Staphylococcal exotoxin production appeared to be a consequent event inducing the evolution to gangrenous mastitis
Optimization and performance of the CryoCube detector for the future RICOCHET low-energy neutrino experiment
International audienceThe 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 38g instrumented with NTD-Ge thermal sensor as well as aluminum electrodes operated at 10mK 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 (eV), the ability to identify and reject with a high efficiency the overwhelming electromagnetic backgrounds (gamma, betas, X-rays) and a sufficient payload (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