Multi-bunch Feedback Systems

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. We first introduce coupled-bunch instabilities, analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedback systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main components of a feedback system and the related issues will also be analysed. Finally, we shall focus on digital feedback systems, their characteristics, and features, as well as on how they can be concretely exploited for both the optimization of feedback performance and for beam dynamics studies.Comment: 44 pages, contribution to the CAS - CERN Accelerator School: Advanced Accelerator Physics Course, Trondheim, Norway, 18-29 Aug 201

Ports as Drivers of Urban and Regional Growth

AbstractTraded volumes – from raw materials to final consumer goods through intermediary products – are projected to continue growing in the foreseeable future: sheer domestic EU and global competition will impose challenging requirements to providing innovative supply-chain and logistics solutions, including not only smart business models but also smart and foresighted infrastructural planning and management capacities.Public planning and funding face critical limitations, such as: (i) not duly accounting for the induced pressures on inland transportation infrastructure allowing access from/to the port to/from interesting trade links/destinations; (ii) not duly accounting for indirect costs and benefits resulting from either new infrastructural developments or re-deployment of existing infrastructures, and (iii) not duly accounting for the impacts of ports on the cities in which they are localised.Fragmented projections and impact assessments lead to sub-optimal economic performance of multi-modal terminals, the transportation network and the area they impact on increasing the risk of depleting initial investments or requiring on-going/permanent – public support, including to overcome local negative impacts.This article has two main purposes. On the one hand, it strives to identify shortcomings that hinder the achievement of expected benefits on urban and regional growth linked to port activity expansion. It is not based on a comprehensive analysis of case studies but on literature review and for that reason limiting factors mentioned in the article are not necessarily suited to specific situations. On the other hand, the article proposes a reflection on the relevant analytical and policy intervention tools having the potential to tackle and – ideally – resolve shortcomings. It advocates that a wider use of such tools would enhance the efficiency of handling freight volumes through ports and onto surface transport corridors maximizing positive spillover effects while minimizing nuisances and drawbacks for the urban and regional areas concerned.Congestion reduction in and around port areas and enhanced competitiveness are the expected results from balanced multimodal transport solutions. Many benefits are associated with efficient ports yet there tends to be a mismatch with gains spilling over to other regions and negative impacts borne locally.This area of research is expected to become all the more relevant in view of growing size of ships and therefore reduced number of ports/operators capable of handling those as well as higher induced pressure on – often already congested – inland transportation corridors.Conversely, development of the Motorways of the Sea and implementation of Short Sea Shipping foresee the increased use of medium and small ports to relieve the heavy burden on land transport, but this implies revised shipping patterns as well as overcoming fragmentation in transport infrastructure planning

Multi-bunch feedback systems

Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. The advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. The lecture will first introduce coupled-bunch instabilities analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedbacks systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main components of a feedback system and the related issues will also be analysed. Finally, we shall focus on digital feedback systems, their characteristics and features, as well as on how they can be concretely exploited for both the optimization of the feedback performance and for beam dynamics studies

Biomethane as alternative fuel for the EU road sector: analysis of existing and planned infrastructure

The views expressed here are purely those of the authors and may not, under any circumstances, be regarded as an official position of the European Commission

Investigations on the distribution of air transport traffic and CO2 emissions within the European Union

This study analyses the structure of air traffic and its distribution among the different countries in the European Union, as well as traffic with an origin or destination in non-EU countries. Data sources are Eurostat statistics and actual flight information from EUROCONTROL. Relevant variables such as the number of flights, passengers or cargo tonnes and production indicators (RPKs) are used together with fuel consumption and CO2 emissions data. The segmentation of air traffic in terms of distance permits an assessment of air transport competition with surface transport modes. The results show a clear concentration of traffic in the five larger countries (France, Germany, Italy, Spain and UK), in terms of RPKs. In terms of distance the segment between 500 and 1000 km in the EU, has more flights, passengers, RTKs and CO2 emissions than larger distances. On the environmental side, the distribution of CO2 emissions within the EU Member States is presented, together with fuel efficiency parameters. In general, a direct relationship between RPKs and CO2 emissions is observed for all countries and all distance bands. Consideration is given to the uptake of alternative fuels. Segmenting CO2 emissions per distance band and aircraft type reveals which flights contribute the most the overall EU CO2 emissions. Finally, projections for future CO2 emissions are estimated, according to three different air traffic growth and biofuel introduction scenarios

CORSIA: The first internationally adopted approach to calculate life-cycle GHG emissions for aviation fuels

The aviation sector has grown at a significant pace in recent years, and despite improvements in aircraft efficiency, the sector's impact on climate change is a growing concern. To address this concern, the International Civil Aviation Organization (ICAO) established the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) to help reduce aviation greenhouse gas (GHG) emissions. This paper presents a methodology agreed by the 193 ICAO member states to evaluate the life-cycle GHG emissions of sustainable aviation fuels (SAFs), in the CORSIA system. The core life-cycle assessment and induced land use change values of SAFs are presented to determine the GHG savings of certified pathways. The paper aims to present that a number of SAFs can yield significant life-cycle emission reductions compared to petroleum-derived jet fuel. This implies the potentially major role of SAFs in reducing aviation's carbon footprint