372 research outputs found
Tagger design optimization
This note presents the simulations and tests performed at LPSC Grenoble for the optimization of the DVCS tagger paddles. The choice of the wrapping material and the addition of a light guide with a specific triangular cut are discussed and confronted to experimental measurements. This study led to the final configuration of the DVCS tagger
SPIRAL 2 coupler preparation and RF conditioning
Proc. On LineInternational audienceFive radiofrequency coupler prototypes have been manufactured. Three of them will be mounted in the cryomodules of the SPIRAL 2 superconducting LINAC (LINear ACcelerator). This paper describes the coupler preparation and the first results of their conditioning
Status of the GRANIT facility
The GRANIT facility is a follow-up project, which is motivated by the recent
discovery of gravitational quantum states of ultracold neutrons. The goal of
the project is to approach the ultimate accuracy in measuring parameters of
such quantum states and also to apply this phenomenon and related experimental
techniques to a broad range of applications in particle physics as well as in
surface and nanoscience studies. We overview the current status of this
facility, the recent test measurements and the nearest prospects.Comment: 11 pages, 20 figures, Proceedings of the GRANIT-2014 WORKSHOP
"Quantum gravitational spectroscopy with ultracold systems"(Les Houches
Experimental study of a liquid Xenon PET prototype module
A detector using liquid Xenon in the scintillation mode is studied for
Positron Emission Tomography (PET). The specific design aims at taking full
advantage of the liquid Xenon properties. It does feature a promising
insensitive to any parallax effect. This work reports on the performances of
the first LXe prototype module, equipped with a position sensitive PMT
operating in the VUV range (178 nm).Comment: Proc. of the 7th International Workshops on Radiation Imaging
Detectors (IWORID-7), Grenoble, France 4-7 July 200
Directional detection of meV dark photons with Dandelion
This paper presents Dandelion, a new dish antenna experiment searching for
dark photons (DPs) with masses around the meV that will start acquiring data by
the end of 2023. A spherical mirror acts as a conversion surface between DPs
and standard photons that converge to a matrix of 418 Kinetic Inductance
Detectors cooled down to 150 mK. A tilt of the mirror at 1 Hz moves the
expected signal over the pixels thus enabling a continuous background
measurement. The expected signal has two modulations: a spatial modulation
providing a directional signature for the unambiguous discovery of a DP, and an
intensity modulation allowing the determination of the polarization of the DP.
For masses near the meV, the inflationary production of longitudinal and
transverse DPs are mutually excluded, thus the polarization determination by
Dandelion could shed a new light on the inflation phase of the early universe.
A first Dandelion prototype operating for 30 days would improve by more than
one order of magnitude the current exclusion limits on DPs at the meV mass
scale and would probe this region with an unprecedented discovery potential
based on directional detection.Comment: 17 pages, 7 figure
Quantum view of Li-ion high mobility at carbon-coated cathode interfaces
: Lithium-ion batteries (LIBs) are among the most promising power sources for electric vehicles, portable electronics and smart grids. In LIBs, the cathode is a major bottleneck, with a particular reference to its low electrical conductivity and Li-ion diffusivity. The coating with carbon layers is generally employed to enhance the electrical conductivity and to protect the active material from degradation during operation. Here, we demonstrate that this layer has a primary role in the lithium diffusivity into the cathode nanoparticles. Positron is a useful quantum probe at the electroactive materials/carbon interface to sense the mobility of Li-ion. Broadband electrical spectroscopy demonstrates that only a small number of Li-ions are moving, and that their diffusion strongly depends on the type of carbon additive. Positron annihilation and broadband electrical spectroscopies are crucial complementary tools to investigate the electronic effect of the carbon phase on the cathode performance and Li-ion dynamics in electroactive materials
Ultracold-neutron infrastructure for the gravitational spectrometer GRANIT
The gravitational spectrometer GRANIT will be set up at the Institut Laue
Langevin. It will profit from the high ultracold neutron density produced by a
dedicated source. A monochromator made of crystals from graphite intercalated
with potassium will provide a neutron beam with 0.89 nm incident on the source.
The source employs superthermal conversion of cold neutrons in superfluid
helium, in a vessel made from BeO ceramics with Be windows. A special
extraction technique has been tested which feeds the spectrometer only with
neutrons with a vertical velocity component v < 20 cm/s, thus keeping the
density in the source high. This new source is expected to provide a density of
up to 800 1/cm3 for the spectrometer.Comment: accepted for publication in Proceedings International Workshop on
Particle Physics with Slow Neutron
Power couplers for Spiral 2
http://accelconf.web.cern.ch/AccelConf/SRF2011/papers/frioa04.pdf Due to its success, we intend to have a PRST-AB SRF2011 special edition.International audienc
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