30 research outputs found
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
Swell Prediction Off the Belgian Coast - An Operational Application of Supercomputing
Two swell prediction models are compared amongst various machines in terms of their implementation and optimazation and results of the models are given. The importance of a suitable implementation for an optimal performance is demonstrated
Mossbauer-spectra of Some Low Symmetry Compounds Containing a Tin Manganese Bond
info:eu-repo/semantics/publishe
CRANIAL BASE ANGULATION AND PROGNATHISM RELATED TO CRANIAL AND GENERAL SKELETAL MATURATION IN HUMAN FETUSES.
A new method for the oxidation of 1, 4-dihydropyridine derivatives by guanidinium nitrate in the presence of silica sulfuric acid under mild, heterogeneous and metal-free conditions
The A1 Pillaring of Clays .1. Pillaring With Dilute and Concentrated A1 Solutions
Saponite, hectorite, and laponite have been pillared with cationic Al clusters, and special attention has been given to the solution chemistry of Al. Pillared saponite is obtained after exchange with refluxed Al solutions; while for hectorite, Al solutions treated with ammonium acetate give a pillared product with 1.8-1.9 nm spacing and thermal stability up to 873 K. In both types of solutions, the Keggin ion Al cluster is a minority species or totally absent. The typical 1.8-1.9 nm spacing is only obtained after washing. The quality of the pillared material can be judged From its thermal stability, its surface area, and the width of the d001 line before and after pillaring. The width should not exceed 0.3 nm before calcination and 0.5 nm after calcination. The latter criterion reflects the importance of the crystallinity of the parent clay for successful pillaring. Pillaring in concentrated conditions occurs by a combination of ion exchange and precipitation of Al and gives materials that exhibit poor thermal stability
Polymorphous/crystalline single heterojunction and double heterojunction solar cells optimisation on p type monocrystalline silicon
International audienc