Performance of solar concentrator made of an achromatic Fresnel doublet measured with a continuous solar simulator and comparison with a singlet

in Solar Energy Materials & Solar Cells (2013), 190

The SWAP EUV Imaging Telescope Part I: Instrument Overview and Pre-Flight Testing

in Solar Physics (2012)

The Sun Watcher with Active Pixels and Image Processing (SWAP) is an EUV solar telescope onboard ESA’s Project for Onboard Autonomy 2 (PROBA2) mission launched on 2 November 2009. SWAP has a spectral ... [more ▼]

The Sun Watcher with Active Pixels and Image Processing (SWAP) is an EUV solar telescope onboard ESA’s Project for Onboard Autonomy 2 (PROBA2) mission launched on 2 November 2009. SWAP has a spectral bandpass centered on 17.4 nm and provides images of the low solar corona over a 54 × 54 arcmin field-of-view with 3.2 arcsec pixels and an imaging cadence of about two minutes. SWAP is designed to monitor all space-weatherrelevant events and features in the low solar corona. Given the limited resources of the PROBA2 microsatellite, the SWAP telescope is designed with various innovative technologies, including an off-axis optical design and a CMOS–APS detector. This article provides reference documentation for users of the SWAP image data. [less ▲]

Experimental Results of Hybrid and Refractive Achromatic Doublets Made of PC and PMMA

Conference (2012)

Flat Fresnel doublets made of PMMA and PC: combining low cost production and very high concentration ratio for CPV

in Optics Express (2011), 19(S3), 280-294

The linear chromatic aberration (LCA) of several combinations of polycarbonates (PCs) and poly (methyl methacrylates) (PMMAs) as singlet, hybrid (refractive/diffractive) lenses and doublets operating with ... [more ▼]

The linear chromatic aberration (LCA) of several combinations of polycarbonates (PCs) and poly (methyl methacrylates) (PMMAs) as singlet, hybrid (refractive/diffractive) lenses and doublets operating with wavelengths between 380 and 1600 nm – corresponding to a typical zone of interest of concentrated photovoltaics (CPV) – are compared. Those comparisons show that the maximum theoretical concentration factor for singlets is limited to about 1000 × at normal incidence and that hybrid lenses and refractive doublets present a smaller LCA increasing the concentration factor up to 5000 × and 2 × 106 respectively. A new achromatization equation more useful than the Abbé equation is also presented. Finally we determined the ideal position of the focal point as a function of the LCA and the geometric concentration which maximizes the flux on the solar cell. [less ▲]

First light of SWAP on-board PROBA2

in Proceedings of SPIE (2010), 7732

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space ... [more ▼]

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space weather sentinel from a low Earth orbit, providing images at 174 nm of the solar corona. The instrument concept has been adapted to the PROBA2 mini-satellite requirements (compactness, low power electronics and a-thermal opto-mechanical system). It also takes advantage of the platform pointing agility, on-board processor, Packetwire interface and autonomous operations. The key component of SWAP is a radiation resistant CMOS-APS detector combined with onboard compression and data prioritization. SWAP has been developed and qualified at the Centre Spatial de Liège (CSL) and calibrated at the PTB-Bessy facility. After launch, SWAP has provided its first images on 14th November 2009 and started its nominal, scientific phase in February 2010, after 3 months of platform and payload commissioning. This paper summarizes the latest SWAP developments and qualifications, and presents the first light results. [less ▲]

CMOS-APS Detectors for Solar Physics: Lessons Learned during the SWAP Preflight Calibration

in Solar Physics (2008)

Assessment of space radiation effects on solid-state Brillouin phase conjugate mirrors

in Applied Optics (2007), 46(22), 5329-5335

Optical phase conjugation (OPC) provides a means of dynamical correction of thermally induced aberrations in high-power laser systems. This method is particularly interesting for space applications ... [more ▼]

Optical phase conjugation (OPC) provides a means of dynamical correction of thermally induced aberrations in high-power laser systems. This method is particularly interesting for space applications because it is passive, mechanically simple, and allows for improved beam quality with only a small loss in power. To exploit it one has to assess the effect of the space environment, and in particular of space radiation, on the properties of the materials that are suitable for phase-conjugating mirrors (PCMs). We have investigated both materials providing OPC via stimulated Brillouin scattering and actual PCMs with regard to their radiation hardness. Proton- and gamma-irradiated PCMs in the form of 30-cm long silica rods and 5-cm long TeO2 crystals were tested in a single frequency flash-lamp pumped Nd:YAG system delivering up to 220 mJ pulses with a 20 ns duration at a 50 Hz repetition rate. The difference in the reflectivity between irradiated and nonirradiated components was found to be within the measurement errors. Gamma irradiation of TeO2 resulted in a decrease of the laser-induced damage threshold, while for silica possible changes were below the detection limit. Our results show that synthetic fused silica, and Lithosil in particular, can be used for generating the OPC in laser systems operating in a space radiation environment. [less ▲]

SWAP: Sun watcher with a new EUV telescope on a technology demonstration platform

in 5th International Conference on Space Optics (2004, June 01)

SWAP (SWAP (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument that has been selected to fly on the PROBA-2 technology demonstration platform, a program of the European ... [more ▼]

SWAP (SWAP (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument that has been selected to fly on the PROBA-2 technology demonstration platform, a program of the European Space Agency (ESA) to be launched in 2006. SWAP is based on an off-axis degraded Ritchey Chretien telescope that will image the EUV solar corona at 19.5 nm on a specifically fabricated extreme ultraviolet (EUV) sensitivity enhanced CMOS APS detector. The optical design and the optical coatings are derived from the Extreme Ultraviolet Imaging Telescope (EIT) operating on-board SOHO since 1995. It has been adapted for a single wavelength telescope with off-axis optics. It allows to use smaller optics and filters, with simple internal baffles avoiding external protruding parts. The superpolished optics will receive a multilayer coating that provides spectral selection centred on 19.5 nm and EUV reflectivity in normal incidence. This compact design is specifically adapted for accommodation on PROBA-2, where mass and envelope requirements are very stringent The SWAP PROBA-2 program will be an opportunity to demonstrate this new optical concept, while it will also validate space remote sensing with APS detectors, as well as on-board image processing capabilities. On the science outcomes, SWAP will provide solar corona images in the Fe XII line on a baselined 2-min cadence. Observations with this specific wavelength allow detecting phenomena, such as solar flares or 'EIT-waves', associated with the early phase of coronal mass ejections. The SWAP data will complement the observations provided by SOHO-EIT, and STEREO-SECCHI. [less ▲]

SWAP: Sun watcher using APS detector on-board PROBA-2, a new EUV off-axis telescope on a technology demonstration platform

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2003)

SWAP (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument that has been selected to fly on the PROBA-II technology demonstration platform, a program of the European Space ... [more ▼]

SWAP (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument that has been selected to fly on the PROBA-II technology demonstration platform, a program of the European Space Agency (ESA) to be launched in 2006. This paper presents the instrument concept and its scientific goals. SWAP uses an off-axis Ritchey Chretien telescope that will image the EUV solar corona at 19.5 nm on a specifically fabricated extreme ultraviolet (EUV) sensitivity enhanced CMOS APS detector. This type of detector has advantages that promise to be very profitable for solar EUV imaging. The SWAP design is built on a similar concept as the MAGRITTE instrument suite for the NASA Solar Dynamics Observatory (SDO) mission to be launched in 2007. The optics have been adapted to the detector size. The SWAP PROBA-2 program will be an opportunity to demonstrate and validate the optical concept of MAGRITTE, while it will also validate space remote sensing with APS detectors. On the science outcomes, SWAP will provide solar corona images in the Fe XII line on a baselined 1-min cadence. Observations with this specific wavelength allow detecting phenomena, such as solar flares or 'EIT-waves", associated with the early phase of coronal mass ejections. Image recognition software will be developed that automatically detects these phenomena and sends out space weather warnings. Different modules of this software will run both on the ground system as well as on the onboard computer of PROBA II. The SWAP data will complement the observations provided by SOHO-EIT, and STEREO-SECCHI. [less ▲]