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Populations emerging from armed conflicts often remain threatened by landmines and explosive remnants of war. The international mine action community is concerned with the relief of this threat. The Space Assets for Demining Assistance (SADA) undertaking is a set of activities that aim at developing new services to improve the socio-economic impact of mine action activities, primarily focused on the release of land thought to be contaminated, a process described as land release. SADA was originally initiated by the International Astronautical Federation (IAF). It has been implemented under the Integrated Applications Promotion (IAP) program of the European Space Agency (ESA). Land release in mine action is the process whereby the demining community identifies, surveys and prioritizes suspected hazardous areas for more detailed investigation, which eventually results in the clearance of landmines and other explosives, thereby releasing land to the local population. SADA has a broad scope, covering activities, such as planning (risk and impact analysis, prioritization, and resource management), field operations and reporting. SADA services are developed in two phases: feasibility studies followed by demonstration projects. Three parallel feasibility studies have been performed. They aimed at defining an integrated set of space enabled services to support the land release process in mine action, and at analyzing their added value, viability and sustainability. The needs of the mine action sector have been assessed and the potential contribution of space assets has been identified. Support services have been formulated. To test their fieldability, proofs of concept involving mine action end users in various operational field settings have been performed by each of the study teams. The economic viability has also been assessed. Whenever relevant and cost-effective, SADA aims at integrating Earth observation data, GNSS navigation and SatCom technologies with existing mine action tools and procedures, as well as with novel aerial survey technologies. Such conformity with existing user processes, as well as available budgets and appropriateness of technology based solutions given the field level operational setting are important conditions for success. The studies have demonstrated that Earth observation data, satellite navigation solutions and in some cases, satellite communication, indeed can provide added value to mine action activities if properly tailored based on close user interaction and provided through a suitable channel. Such added value for example includes easy and sustained access to Earth observation data for general purpose mapping, land use assessment for post-release progress reporting, and multi-source data fusion algorithms to help quantify risks and socio-economic impact for prioritization and planning purposes. The environment and boundaries of a hazardous area can also be better specified to support the land release process including detailed survey and clearance operations. Satellite communication can help to provide relevant data to remote locations, but is not regarded as strongly user driven. Finally, satellite navigation can support more precise non-technical surveys, as well as aerial observation with small planes or hand-launched UAV's. To ensure the activity is genuinely user driven, the Geneva International Center for Humanitarian Demining (GICHD) plays an important role as ESA’s external advisor. ESA is furthermore supported by a representative field operator, the Swiss Foundation of Mine Action (FSD), providing ESA with a direct connection to the field level end users. Specifically FSD has provided a shared user needs baseline to the three study teams. To ensure solutions meet with end user requirements, the study teams themselves include mine action representatives and have interacted closely with their pre-existing and newly established contacts within the mine action community.

International audience; In this paper, we present the design of a very precise collimated fiber array that meets requirements for beam combining. Calculations permit to determine the tolerances toward key parameters and specify the components to manufacture. Thus, the collimated fiber array is composed of a high quality commercial microlens array and an especially dedicated fiber holder that we design and realize experimentally. Manufacture techniques for both the microlens and the holder are chosen to be collective and then compatible with a high number of fibers. With the collimated fiber array hence obtained, the individual beam quality was measured to be λ/10 and the pointing accuracy is under 0.6 mrad.

The design and fabrication challenges in the first ever attempt to realize a 1-THz vacuum tube amplifier are described. Implementation of innovative solutions including a slow-wave structure in the form of a double corrugated waveguide, lateral tapered input and output couplers, deep X-ray LIGA fabrication process, and a cascade architecture of the backward wave amplifier are discussed. New knowledge in the field of terahertz vacuum devices brought by intensive simulations and development of advanced fabrication and assembly processes of the micro-structures is highlighted.

Summary form only given. The realization of a 1-THz cascade backward wave amplifier (C-BWA) represents a breakthrough in European technology in the THz vacuum electron device field. The huge design and fabrication obstacles solved by the innovative solutions devised during the three years of the OPTHER project added new knowledge over the state-of the-art1.

A state-of-the-art 1 THz cascade backward wave amplifier was fabricated in the frame of the FP7 European Community OPTHER (Optically driven Terahertz amplifier) project. The huge theoretical and technological effort to realize an amplifier at a frequency of 1 THz has created new knowledge and advancements in the field. A double corrugated waveguide was adopted as the slow wave structure to support a cylindrical micro electron beam. The technique developed while working with the challenging dimensions, the assembly of the parts, and the results of the project represent a big step toward the reliable realization of THz vacuum electron devices.

International audience; The THz frequency range represents a true challenge for designers, fabrication technologies and characterization systems. So far, huge technological obstacles have prohibited any system realization different from laboratory one. Furthermore, most of the applications in the THz frequency range require a level of power not achievable by optoelectronic devices at room temperature or by solid-state technology. The recent availability of three-dimensional simulators and high aspect ratio micro-fabrication techniques has stimulated a class of vacuum electron devices operating in the THz regime, to get a level of output power to enable applications at these frequencies. The OPTHER (Optically driven THz amplifier) project, funded by the European Community, is on the road to realize the first 1 THz vacuum tube amplifier. Technology at the state of the art has been used for the realization of the parts with dimensions supporting THz frequencies. A backward wave amplifier configuration is chosen to make the parts realizable. A carbon nanotube cold cathode has been considered for electron generation. A thermionic micro electron gun is designed to test the tube. A novel slow-wave structure (SWS), the double corrugated rectangular waveguide, is devised to support a cylindrical electron beam and to guarantee high interaction impedance with limited losses. Both LIGA and UV SU-8 photolithography have been tested to realize the SWS.

New measurements of the transport and deposition of artificial heavy particles (glass beads) to a thick 'shelterbelt' of maize (width/height ratio W/H approximate to 1.6) are used to test numerical simulations with a Lagrangian stochastic trajectory model driven by the flow field from a RANS (Reynolds-averaged, Navier-Stokes) wind and turbulence model. We illustrate the ambiguity inherent in applying to such a thick windbreak the pre-existing (Raupach et al. 2001; Atmos. Environ. 35, 3373-3383) 'thin windbreak' theory of particle filtering by vegetation, and show that the present description, while much more laborious, provides a reasonably satisfactory account of what was measured. A sizeable fraction of the particle flux entering the shelterbelt across its upstream face is lifted out of its volume by the mean updraft induced by the deceleration of the flow in the near-upstream and entry region, and these particles thereby escape deposition in the windbreak.

The OPTHER (Optically Driven THz amplifier) project supported by the European Commission within the Seventh Framework Program (FP7) represents the first joint European attempt to realize vacuum electron devices in THz range. The target of the project was to design and realize the first 1 THz vacuum tube amplifier. The challenges of the presented task and the innovative solutions adopted established a new level of knowledge in the field. The main aspects of theOPTHER project are described, focusing on challenges and adopted innovative solutions.

Populations emerging from armed conflicts often remain threatened by landmines and explosive remnants of war. The international mine action community is concerned with the relief of this threat. The Space Assets for Demining Assistance (SADA) undertaking is a set of activities that aim at developing new services to improve the socio-economic impact of mine action activities, primarily focused on the release of land thought to be contaminated, a process described as land release. SADA was originally initiated by the International Astronautical Federation (IAF). It has been implemented under the Integrated Applications Promotion (IAP) program of the European Space Agency (ESA). Land release in mine action is the process whereby the demining community identifies, surveys and prioritizes suspected hazardous areas for more detailed investigation, which eventually results in the clearance of landmines and other explosives, thereby releasing land to the local population. SADA has a broad scope, covering activities, such as planning (risk and impact analysis, prioritization, and resource management), field operations and reporting. SADA services are developed in two phases: feasibility studies followed by demonstration projects. Three parallel feasibility studies have been performed. They aimed at defining an integrated set of space enabled services to support the land release process in mine action, and at analyzing their added value, viability and sustainability. The needs of the mine action sector have been assessed and the potential contribution of space assets has been identified. Support services have been formulated. To test their fieldability, proofs of concept involving mine action end users in various operational field settings have been performed by each of the study teams. The economic viability has also been assessed. Whenever relevant and cost-effective, SADA aims at integrating Earth observation data, GNSS navigation and SatCom technologies with existing mine action tools and procedures, as well as with novel aerial survey technologies. Such conformity with existing user processes, as well as available budgets and appropriateness of technology based solutions given the field level operational setting are important conditions for success. The studies have demonstrated that Earth observation data, satellite navigation solutions and in some cases, satellite communication, indeed can provide added value to mine action activities if properly tailored based on close user interaction and provided through a suitable channel. Such added value for example includes easy and sustained access to Earth observation data for general purpose mapping, land use assessment for post-release progress reporting, and multi-source data fusion algorithms to help quantify risks and socio-economic impact for prioritization and planning purposes. The environment and boundaries of a hazardous area can also be better specified to support the land release process including detailed survey and clearance operations. Satellite communication can help to provide relevant data to remote locations, but is not regarded as strongly user driven. Finally, satellite navigation can support more precise non-technical surveys, as well as aerial observation with small planes or hand-launched UAV's. To ensure the activity is genuinely user driven, the Geneva International Center for Humanitarian Demining (GICHD) plays an important role as ESA’s external advisor. ESA is furthermore supported by a representative field operator, the Swiss Foundation of Mine Action (FSD), providing ESA with a direct connection to the field level end users. Specifically FSD has provided a shared user needs baseline to the three study teams. To ensure solutions meet with end user requirements, the study teams themselves include mine action representatives and have interacted closely with their pre-existing and newly established contacts within the mine action community.