Submillimetre/TeraHertz Astronomy at Dome C with CEA filled bolometer array

Submillimetre/TeraHertz (e.g. 200, 350, 450 microns) astronomy is the prime technique to unveil the birth and early evolution of a broad range of astrophysical objects. A major obstacle to carry out submm observations from ground is the atmosphere. Preliminary site testing and atmospheric transmission models tend to demonstrate that Dome C could offer the best conditions on Earth for submm/THz astronomy. The CAMISTIC project aims to install a filled bolometer-array camera with 16x16 pixels on IRAIT at Dome C and explore the 200-$\mu$m windows for potential ground-based observations.Comment: 6 page

The ArT\'eMiS wide-field submillimeter camera: preliminary on-sky performances at 350 microns

ArTeMiS is a wide-field submillimeter camera operating at three wavelengths simultaneously (200, 350 and 450 microns). A preliminary version of the instrument equipped with the 350 microns focal plane, has been successfully installed and tested on APEX telescope in Chile during the 2013 and 2014 austral winters. This instrument is developed by CEA (Saclay and Grenoble, France), IAS (France) and University of Manchester (UK) in collaboration with ESO. We introduce the mechanical and optical design, as well as the cryogenics and electronics of the ArTeMiS camera. ArTeMiS detectors are similar to the ones developed for the Herschel PACS photometer but they are adapted to the high optical load encountered at APEX site. Ultimately, ArTeMiS will contain 4 sub-arrays at 200 microns and 2x8 sub-arrays at 350 and 450 microns. We show preliminary lab measurements like the responsivity of the instrument to hot and cold loads illumination and NEP calculation. Details on the on-sky commissioning runs made in 2013 and 2014 at APEX are shown. We used planets (Mars, Saturn, Uranus) to determine the flat-field and to get the flux calibration. A pointing model was established in the first days of the runs. The average relative pointing accuracy is 3 arcsec. The beam at 350 microns has been estimated to be 8.5 arcsec, which is in good agreement with the beam of the 12 m APEX dish. Several observing modes have been tested, like On-The-Fly for beam-maps or large maps, spirals or raster of spirals for compact sources. With this preliminary version of ArTeMiS, we concluded that the mapping speed is already more than 5 times better than the previous 350 microns instrument at APEX. The median NEFD at 350 microns is 600 mJy.s1/2, with best values at 300 mJy.s1/2. The complete instrument with 5760 pixels and optimized settings will be installed during the first half of 2015.Comment: 11 pages, 11 figures. Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII, June 24, 2014. To be published in Proceedings of SPIE Volume 915

直結腸癌細胞線粒體超微結構與細胞凋亡的關系.

Non destructive testing (NDT) has been widely developed in numerous industrial fields. All the classical techniques - ultrasonics, eddy currents, radiography- are nowadays currently used either for production tests or for facility inspection

CEA Program for Multiple-Technique Non Destructive Testing: The CIVASystem

Non destructive testing (NDT) has been widely developed in numerous industrial fields. All the classical techniques - ultrasonics, eddy currents, radiography- are nowadays currently used either for production tests or for facility inspection.</p

Optical design for the 450, 350, and 200 µm ArTeMiS camera

ArTeMiS is a submillimeter camera planned to work simultaneously at 450 mum, 350 mum and 200 mum by use of 3 focal planes of, respectively, 8, 8 and 4 bolometric arrays, each one made of 16 x18 pixels. In July 2013, with a preliminary setting reduced to 4 modules and to the 350 mum band, ArTeMiS was installed successfully at the Cassegrain focus of APEX, a 12 m antenna located on the Chajnantor plateau, Chile. After the summary of the scientific requirements, we describe the main lines of the ArTeMiS nominal optical design with its rationale and performances. This optical design is highly constrained by the room allocation available in the Cassegrain cabin. It is an all-reflective design including a retractable pick off mirror, a warm Fore Optics to image the focal plane of the telescope inside the cryostat, and the cold optics. The large size of the field of view at the focal plane of the telescope, 72 mm x 134 mm for the 350 mum and 450 mum beams, leads to the use of biconical toroidal mirrors. In this way, the nominal image quality obtained on the bolometric arrays is only just diffraction limited at some corners of the field of view. To keep a final PSF as much uniform as possible across the field of view, we have used the technic of manufacturing by diamond turning to machine the mirrors. This approach, while providing high accuracy on the shape of the mirrors, made easier the control of the two sub units, the Fore Optics and the cold optics, in the visible domain and at room temperature. Moreover, the use of the similar material (Aluminium alloy 6061) for the optical bench and the mirrors with their mount ensures a homothetic shrinking during the cooling down. The alignment protocol, drew up at the early step of the study, is also presented. It required the implementation of two additional mechanisms inside the cryostat to check the optical axis of the cold optics, in the real conditions of operation of ArTeMiS. In this way, it was possible to pre-align the Fore Optics sub unit with respect to the cold optics. Finally, despite the high constraints of the operating conditions of APEX, this protocol allowed to align ArTeMiS with respect to the telescope in a single adjustment. The first images obtained on the sky, Saturn with its rings, are give

Voyage dans les lumières de l’Univers

Pendant longtemps, les astrophysiciens n’ont eu à leur disposition que la lumière visible pour observer l'Univers. Aujourd’hui, grâce aux observatoires spatiaux, ils disposent d’une panoplie d’instruments capables de capter toutes les lumières de l’Univers, des ondes radio aux rayonnements gamma

Expansion of Circulating CD49b+LAG3+ Type 1 Regulatory T Cells in Human Chronic Graft-Versus-Host Disease

International audienceNo abstract availabl