19 research outputs found
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
Design and test of a compact and high-resolution time-of-flight measurement device for cold neutron beams
A time-of-flight device was developed to characterize wavelength distribution and uniformity of a cold neutron beam. This device is very compactâthe distance of flight is 60 cmâbut achieves very high resolutionâthe intrinsic resolution Îλ/λ=2.4Ă10^{-3} at λ=0.89âânm. The time-of-flight device is composed of a fixed slit, a disk rotating up to 216 Hz, and a neutron detector with a thin spherical conversion layer with the chopper slit in its focus. The device accepts the complete angular divergence of the initial neutron beam. The efficiency of neutron detection is constant over the detector area. Systematic corrections caused by neutron scattering in air are minimized due to the reduction of the time-of-flight length. Measurements have been performed on the beamline of the GRANIT experiment at ILL (part of the H172 beamline) on level C, and the first order diffraction peak of the crystal monochromator used for the GRANIT beamline was found to be at λ=0.8961(11)âânm, and having a width of Ï=0.0213(13)âânm
Manipulation of gravitational quantum states of a bouncing neutron with the GRANIT spectrometer
The bouncing neutron is one of the rare system where gravity can be studied
in a quantum framework. To this end it is crucial to be able to select some
specific gravitational quantum state (GQS). The GRANIT apparatus is the first
physics experiment connected to a superthermal helium UCN source. We report on
the methods developed for this instrument showing how specific GQS can be
favored using a step between mirrors and an absorbing slit. We explore the
increase of GQS separation efficiency by increasing the absorber roughness
amplitude, and find it is feasible but requires a high adjustment precision. We
also quantify the transmission of the absorbing slit leading to a measurement
of the spatial extension of the neutron vertical wave function m.Comment: 5 pages, 3 figure
Manipulation of gravitational quantum states of a bouncing neutron with the GRANIT spectrometer
The bouncing neutron is one of the rare system where gravity can be studied in a quantum framework. To this end it is crucial to be able to select some specific gravitational quantum state (GQS). The GRANIT apparatus is the first physics experiment connected to a superthermal helium UCN source. We report on the methods developed for this instrument showing how specific GQS can be favored using a step between mirrors and an absorbing slit. We explore the increase of GQS separation efficiency by increasing the absorber roughness amplitude, and find it is feasible but requires a high adjustment precision. We also quantify the transmission of the absorbing slit leading to a measurement of the spatial extension of the neutron vertical wave function m
Manipulation of gravitational quantum states of a bouncing neutron with the GRANIT spectrometer
The bouncing neutron is one of the rare system where gravity can be studied in a quantum framework. To this end it is crucial to be able to select some specific gravitational quantum state (GQS). The GRANIT apparatus is the first physics experiment connected to a superthermal helium UCN source. We report on the methods developed for this instrument showing how specific GQS can be favored using a step between mirrors and an absorbing slit. We explore the increase of GQS separation efficiency by increasing the absorber roughness amplitude, and find it is feasible but requires a high adjustment precision. We also quantify the transmission of the absorbing slit leading to a measurement of the spatial extension of the neutron vertical wave function m
The PolarKID project: polarization measurements with KIDs for the next generation of CMB telescopes
International audienceThe goal of the PolarKID project is testing a new method for the measurement of polarized sources, in order to identify all the possible instrumental systematic effects that could impact the detection of CMB B-modes of polarization. It employs the KISS (KIDs Interferometer Spectrum Survey) instrument coupled to a sky simulator and to sources such as point-like black bodies (simulating planets), a dipole (extended source) and a polarizer. We use filled-arrays Lumped Element Kinetic Inductance Detectors (LEKIDs) since they have multiple advantages when observing both in a photometry and in a polarimetry configuratio
Design, assembly and validation of the Filter Exchange System of LSSTCam
International audienceThe Filter Exchange System (FES) of the Legacy Survey of Space and Time camera (LSSTCam) for the Vera C. Rubin Observatory has been integrated into the camera assembly before shipping to Chile. It holds five 75-cm filters weighing 25.5 to 38 kg. The main requirement for the FES is to perform each exchange in under 90s, with 100-ÎŒm positioning in the focal plane, while operating within the envelope of the camera body. The FES is split into three motorized subsystems: the Carousel stores the filters and rotates the selected filter to the standby position, the Autochanger moves the filter between the standby position and the focal plane, and the Loader can be mounted on the camera body to swap filters in and out during daytime, allowing the use of the full 6-filter set of LSSTCam. The locking mechanisms are also motorized, and their designs and qualifications account for seisms up to magnitude 7. Additional design constraints come from the temperature range at the Observatory and the cleanliness requirements for the filters and lenses. Programmable Logic Controllers enforce the safety equations of the system, and the control of the FES has been integrated into the overall Camera Control System software. After assembly of a full-scale prototype, the FES has been assembled and tested in France on a test-stand simulating telescope attitude, then integrated into the camera body at SLAC National Accelerator Laboratory. It meets its required performances, including an average exchange time of 83s
Ătonnante physique
International audienceDiscipline multimillĂ©naire, la physique explore lâespace et le temps. De lâimmensitĂ© des amas de galaxies Ă lâinfinie petitesse des particules Ă©lĂ©mentaires, des Ă©chelles humaines â du mĂštre au centimĂštre â jusquâau nanomonde, de lâextrĂȘme briĂšvetĂ© du mouvement de lâĂ©lectron jusquâau fond des Ăąges dâoĂč nous parviennent les premiĂšres lumiĂšres de lâUniversâ: les domaines couverts par cette discipline nâont pas fini de nous Ă©tonner.Cette science est celle de lâexpĂ©rimentation mĂ©thodique qui met au point des instruments originaux pour observer la matiĂšre, inerte ou vivante, en laboratoire ou Ă distance. Celle qui pose encore de grandes questions fondamentales. Mais aussi celle qui accompagne notre vie quotidienne avec ses dĂ©veloppements dans les domaines des matĂ©riaux, de la santĂ©, de lâĂ©nergie, du climatâŠPour montrer toute sa richesse, cet ouvrage rĂ©unit 70 contributions de physiciennes et de physiciens rĂ©cemment rĂ©compensĂ©s par une mĂ©daille du CNRS pour lâoriginalitĂ© et lâimportance de leurs travaux. Abondamment illustrĂ©, accessible Ă tout amateur de science, Ătonnante Physique lĂšve un voile sur les recherches les plus actuelles