Cohen S.,BIRA |
East G.W.,IUCEEM |
2010 Beam Instrumentation Workshop, BIW 2010 - Proceedings | Year: 2010
A four-channel magnet-power-supply ramp controller has been designed and deployed at the new ALPHA (Advanced Electron Photon Facility) at the Indiana University Center for Exploration of Energy and Matter (IUCEEM). The first application is a power-supply controller. For all practical purposes, the system is a versatile arbitrary voltage-waveform-generator with full DAQ (data acquisition) capabilities that can be used in a variety of beam instrumentation settings. The real-time controller can generate four arbitrary independently-triggerable ramp profiles. A normalized wave-form vector is encoded as a Process Variable array and is uploaded and stored by the real-time controller as required. Each ramp array element is clocked out to a 16-bit DAC (Digital to Analog Converter) via a DMA FIFO and built-in FPGA. The duration of the waveform is programmable with a minimum time resolution of 20 μsec between profile values. Four bipolar DACs have an output range of +/- 10V. Eight digital I/O control bits are allocated for each control channel. Typically, these bits are used to monitor and control the power-supply operational state. The control-system interface uses the EPICS Channel-Access server accessible on Labview RT 2009.
Portafaix T.,University of Reunion Island |
Godin-Beekmann S.,LATMOS |
Payen G.,University of Reunion Island |
De Maziere M.,BIRA |
And 8 more authors.
EPJ Web of Conferences | Year: 2016
A DIAL lidar system performing stratospheric ozone profile measurements from 15 to 45 km is installed at Reunion Island (southwest of Indian Ocean). The purpose of this communication is to present this DIAL system mounted now at the new Maido Observatory since February 2013, and the ozone profile retrieval. The first stratospheric ozone profiles obtained during 2013 and 2014 will be presented and discussed. Inter-comparison and differences observed with other high vertical resolution ozone profiles performed by ECC ozonesonde will be shown. Finally, comparisons with low vertical resolution ozone profiles retrieved from microwave and FTIR remote sensing measurements performed at Maido will be carried out, making appropriate use of the associated averaging kernels. © 2016 Owned by the authors, published by EDP Sciences.
Jiggens P.T.A.,European Space Agency |
Gabriel S.B.,University of Southampton |
Heynderickx D.,DH Consultancy |
Crosby N.,BIRA |
And 2 more authors.
Proceedings of the European Conference on Radiation and its Effects on Components and Systems, RADECS | Year: 2011
A new modelling methodology for the prediction of the solar proton environment a 1 AU is presented. This new method named Virtual Timelines is applied to the SEPEM Reference Event List derived from a long flu time series of space-based measurements to produce the SEPEM model for proton peak flux and fluence at 1 AU. There are several new components including the use of the Lévy distribution for time distributions and the accounting for the non-poin-like nature of SEP events. © 2011 IEEE.
Roscoe H.K.,British Antarctic Survey |
Brough N.,British Antarctic Survey |
Jones A.E.,British Antarctic Survey |
Wittrock F.,University of Bremen |
And 3 more authors.
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2014
Tropospheric BrO was measured by a ground-based remote-sensing spectrometer at Halley in Antarctica in spring 2007, and BrO was measured by satellite-borne remote-sensing spectrometers using similar spectral regions and similar Differential Optical Absorption Spectroscopy (DOAS) analyses. Near-surface BrO was simultaneously measured in situ at Halley by Chemical Ionisation Mass Spectrometer (CIMS), and in an earlier year near-surface BrO was measured at Halley over a long path by a ground-based DOAS spectrometer. During enhancement episodes, total amounts of tropospheric BrO from the ground-based remote-sensor were similar to those from space, but if we assume that the BrO was confined to the mixed layer they were very much larger than values measured by either near-surface technique. This large apparent discrepancy can be resolved if substantial amounts of BrO were in the free troposphere during most enhancement episodes. Amounts observed by the ground-based remote sensor at different elevation angles, and their formal inversions to vertical profiles, demonstrate that much of the BrO was indeed often in the free troposphere. This is consistent with the ~5 day lifetime of Bry and with the enhanced BrO observed during some Antarctic blizzards. © 2014 The Authors.
Schlappi B.,University of Bern |
Altwegg K.,University of Bern |
Balsiger H.,University of Bern |
Calmonte U.,University of Bern |
And 11 more authors.
3rd AIAA Atmospheric Space Environments Conference | Year: 2011
For critical optical surfaces and sensitive instrumentation, contamination due to spacecraft outgassing is a nuisance. To avoid or minimize the resulting, limiting factors in the future, a comprehensive understanding of the outgassing mechanisms is necessary. Here we summarize findings from outgassing studies using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) on the Rosetta spacecraft. Data are available for a flight time of more than six years, a large range of heliocentric distances, and a variety of different test scenarios. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.