New wave form surveillance and diagnostics for the LEP injection kickers

The introduction of the Bunch Train Scheme in LEP requires a more precise and automatic supervision of the stability of the LEP injection kickers in timing and amplitude. Comprehensive and user-friendly diagnostic tools are required for in-depth investigation of equipment behaviour. A new system is currently being prepared using to a large extent commercial data acquisition hardware and hardware independent software products

Outsourcing of the New Wave Form Acquisition, Surveillance and Diagnostic System for the LEP Injection Kickers

In 1996, a project has been launched to improve the acquisition, surveillance and diagnostic system of the LEP injection kickers. The technical solution is formed by a VXI acquisition hardware and a Windows NT / LabVIEW software environment. The realisation has been entirely outsourced to industry. This paper discusses the different phases of the project, from market survey over technical specification to acceptance tests, explains the technical choices and evaluates the results, presents the point of view of both parties on the collaboration and concludes with the experiences learned from this project

Long-Distance Wind-Dispersal of Spores in a Fungal Plant Pathogen: Estimation of Anisotropic Dispersal Kernels from an Extensive Field Experiment

Given its biological significance, determining the dispersal kernel (i.e., the distribution of dispersal distances) of spore-producing pathogens is essential. Here, we report two field experiments designed to measure disease gradients caused by sexually- and asexually-produced spores of the wind-dispersed banana plant fungus Mycosphaerella fijiensis. Gradients were measured during a single generation and over 272 traps installed up to 1000 m along eight directions radiating from a traceable source of inoculum composed of fungicide-resistant strains. We adjusted several kernels differing in the shape of their tail and tested for two types of anisotropy. Contrasting dispersal kernels were observed between the two types of spores. For sexual spores (ascospores), we characterized both a steep gradient in the first few metres in all directions and rare long-distance dispersal (LDD) events up to 1000 m from the source in two directions. A heavy-tailed kernel best fitted the disease gradient. Although ascospores distributed evenly in all directions, average dispersal distance was greater in two different directions without obvious correlation with wind patterns. For asexual spores (conidia), few dispersal events occurred outside of the source plot. A gradient up to 12.5 m from the source was observed in one direction only. Accordingly, a thin-tailed kernel best fitted the disease gradient, and anisotropy in both density and distance was correlated with averaged daily wind gust. We discuss the validity of our results as well as their implications in terms of disease diffusion and management strategy

Automatic high voltage conditioning of the electrostatic LEP separators without conventional programming

The TS Tool Kit is a generic, fully data-driven, and user-configurable software system developed at CERN for supervisory, control, and data acquisition applications. It provides a comprehensive framework to solve fairly complex process control problems requiring response times of the order of a second, without any need for conventional programming. The characteristics and benefits of this approach are discussed at the example of the new high voltage conditioning process for the electrostatic LEP separators

Control of the MKQA tuning and aperture kickers of the LHC

The large hadron collider (LHC) at CERN has been equipped with four fast pulsed kicker magnets in RA43 situated at point 4 which are part of the measurement system for the tune and the dynamic aperture of the LHC beam (Beam 1 and Beam 2). For the tune measurement 'Q', the magnets will excite oscillations in part of the beam. This is achieved by means of a generator producing a 5 µs base half-sine pulse of 1.2 kA [1] amplitude, superimposed with a 3rd harmonic to produce a 2 µs flat top. A kick repetition rate of 2 Hz will be possible. To measure the dynamic aperture 'A' of the LHC at different beam energies, the same magnets will also be driven by a more powerful generator which produces a 43 µs base half-sine current pulse of 3.8 kA. For the 'A' mode a thyristor is used as switching element inside the generator. A final third mode named 'AC dipole' will rely on the beam being excited coherently at a frequency close but outside its Eigen-frequencies by an oscillating dipole field. The beam is expected to oscillate at the exciter frequency of 3 kHz with a phase shift of π/2. The 'AC dipole' will use two 18 kW audio amplifiers capable of driving the magnets at 1 kHz(rms) around 3 kHz or between 2.7 kHz and 4 kHz. The complete system uses supervisory control implemented with Siemens PLC technology with added Siemens PROFIsafe safety feature to treat the various interlocks that have been introduced in the circuits and to assu re a safe functioning and provide 'LOCAL' and 'REMOTE' control (via CCC) of the complete installation

Experience with the LHC beam dump post-operational checks system

After each beam dump in the LHC automatic post-operational checks are made to guarantee that the last beam dump has been executed correctly and that the system can be declared to be ‘as good as new’ before the next injection is allowed. The analysis scope comprises the kicker waveforms, redundancy in kicker generator signal paths and different beam instrumentation measurements. This paper describes the implementation and the operational experience of the internal and external post-operational checks of the LHC beam dumping system during the commissioning of the LHC without beam and during the first days of beam operation