Zamudio, Spain
Zamudio, Spain

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Sanz D.,Technical University of Madrid | Ruiz M.,Technical University of Madrid | Eguiraun M.,University of the Basque Country | Arredondo I.,ESS Bilbao Consortium | And 4 more authors.
Fusion Engineering and Design | Year: 2015

Experimental Physics and Industrial Control System (EPICS) is a software tool that during last years has become relevant as a main framework to deploy distributed control systems in large scientific environments. At the moment, ESS Bilbao uses this middleware to perform the control of their Ion Source Hydrogen Positive (ISHP) project. The implementation of the control system was based on: PXI Real Time controllers using the LabVIEW-RT and LabVIEW-EPICS tools; and RIO devices based on Field-Programmable Gate Array (FPGA) technology. Intended to provide a full compliant EPICS IOCs for RIO devices and to avoid additional efforts on the system maintainability, a migration of the current system to a derivative Red Hat Linux (CentOS) environment has been conducted. This paper presents a real application case study for using the NIRIO EPICS device support (NIRIO-EDS) to give support to the ISHP. Although RIO FPGA configurations are particular solutions for ISHP performance, the NIRIO-EDS has permitted the control and monitoring of devices by applying a well-defined design methodology into the previous FPGA configuration for RIO/FlexRIO devices. This methodology has permitted a fast and easy deployment for the new robust, scalable and maintainable software to support RIO devices into the ISHP control architecture. © 2015 Elsevier B.V. All rights reserved.


Jugo J.,University of the Basque Country | Eguiraun M.,ESS Bilbao Consortium
Proceedings of the 2012 UKACC International Conference on Control, CONTROL 2012 | Year: 2012

Event Based Control (EBC) provides a reduction of mean control rates, which is an important advantage in control systems, specially when network environment gets involved. For this reason, the study of design methodologies for EBC systems that met desired specifications regarding stability and performance issues are a valuable research field. This work presents a control design process applied to a class of EBC systems using LMIs, including stability issues on the light of Asynchronous Dynamical System theory. The application of the proposed methodology is presented by an example, showing good performance in simulation results. © 2012 IEEE.


Asua E.,University of the Basque Country | Feutchwanger J.,ESS Bilbao Consortium | Garcia-Arribas A.,University of the Basque Country | Etxebarria V.,University of the Basque Country
Journal of Intelligent Material Systems and Structures | Year: 2010

The ability of shape memory alloys (SMA) to respond to an external stimulus by modifying their dimensions can be used to generate motion or force in electromechanical devices and micro-machines. It has been often demonstrated that SMA-based devices are serious alternatives to conventional micrometric actuators. We have previously demonstrated that, using a high-quality position sensor, such as a linear variable differential transformer (LVDT), to provide the position feedback, accuracies about 3 μm in position control can be obtained. In this work, we present an actuator prototype based in a SMA wire, conceived to be used in lightweight applications, where the bulky position sensor previously used is replaced with a lighter alternative. The most convenient one, and also the most challenging, is to use the wire's own resistance as a measure of its position, that is, to implement a sensorless control strategy. We propose to use a neural network to characterize the relation between the resistance of the wire and its strain and introduce this correspondence as the position feedback in a simple PID closed loop. The experimental results show that, in this way, accuracies about 70 μm can be obtained. The great advantage of this procedure is that the actuator is reduced to a single SMA element without any additional sensor, which is of great importance when the main goals are to reduce the overall weight, size, and cost of the actuator. © 2010 The Author(s).


Hassanzadegan H.,ESS Bilbao Consortium | Hassanzadegan H.,University of the Basque Country | Garmendia N.,ESS Bilbao Consortium | Garmendia N.,University of the Basque Country | And 5 more authors.
Physical Review Special Topics - Accelerators and Beams | Year: 2011

Design and some performance results of the pulsed digital low level radio frequency (LLRF) for the radio frequency quadrupole (RFQ) systems of Rutherford Appleton Laboratory-front end test stand and the future European Spallation Source Bilbao linac are presented. For rf field regulation, the design is based on direct rf-to-baseband conversion using an analog in-phase quadrature (IQ) demodulator, high-speed sampling of the I/Q components, baseband signal processing in a field-programmable gate array (FPGA), conversion to analog, and IQ modulation. This concept leads to a simple and versatile LLRF system which can be used for a large variety of rf frequencies and virtually any LLRF application including cw, ramping, and pulsed. In order to improve the accuracy of the probe voltage measurement, errors associated with the use of analog IQ demodulators have been identified and corrected by FPGA algorithms and proper setting of the feedback loop parameters. Furthermore, a baseband-equivalent model for the rf plant is developed in MATLAB-Simulink to study the RFQ transient response under beam loading in the presence of phase and delay errors. The effect of the unwanted resonant modes on the feedback loop stability and the LLRF considerations to avoid such instabilities are discussed and compared to some other machines such as the ILC and the European free electron laser. The practical results obtained from tests with a mock-up cavity and an RFQ cold model verify that amplitude and phase stabilities down to a fraction of one percent and one degree and phase margins larger than ±50° can be achieved with this method preserving the linearity and bandwidth of the feedback loops. © 2011 American Physical Society.


Cortazar O.D.,University of Castilla - La Mancha | Megia-Macias A.,ESS Bilbao Consortium | Megia-Macias A.,CERN | Tarvainen O.,University of Jyväskylä | And 2 more authors.
Review of Scientific Instruments | Year: 2016

An experimental study of plasma distributions in a 2.45 GHz hydrogen discharge operated at 100 Hz repetition rate is presented. Ultrafast photography, time integrated visible light emission spectra, time resolved Balmer-alpha emission, time resolved Fulcher Band emission, ion species mass spectra, and time resolved ion species fraction measurements have been implemented as diagnostic tools in a broad range of plasma conditions. Results of plasma distributions and optical emissions correlated with H+, H2 +, and H3 + ion currents by using a Wien filter system with optical observation capability are reported. The magnetic field distribution and strength is found as the most critical factor for transitions between different plasma patterns and ion populations. © 2015 AIP Publishing LLC.


Cortazar O.D.,University of Castilla - La Mancha | Megia-Macias A.,ESS Bilbao Consortium
IEEE Transactions on Plasma Science | Year: 2016

A novel strongly eccentric rotating plasma lamina structure subtending approximately an angle of 120° is reported in a 2.45-GHz driven electron cyclotron resonance hydrogen discharge in the proximity of the chamber wall. Shape and rotation frequencies depend critically on the embedded magnetic field distribution in the plasma chamber as well as on neutral gas pressure and microwave power. The discharge denominated test-bench for ion-sources plasma studies includes a transparent doubled shielded quartz window that keeps the microwave resonance condition. An ultrafast microchannel plate charge-coupled device frame camera is used to obtain four pictures of 1-μs exposure time each during a single plasma pulse in the visible emission range. E × B drift is pointed as that responsible for driving the rotational behavior of a thick plasma sheath, where the scale of the quasi-neutrality breaking is estimated ten times greater than that in a typical plasma sheath. © 2016 IEEE.


Jauberteau J.L.,French National Center for Scientific Research | Jauberteau I.,French National Center for Scientific Research | Cortazar O.D.,University of Castilla - La Mancha | Megia-Macias A.,ESS Bilbao Consortium
Physics of Plasmas | Year: 2016

Time evolution of the Electron Energy Distribution Function (EEDF) is measured in pulsed hydrogen microwave magnetoplasma working at 2.45 GHz. Analysis is performed both in resonance (B = 0.087 T) and off-resonance conditions (B = 0.120 T), at two pressures (0.38 Pa and 0.62 Pa), respectively, and for different incident microwave powers. The important effect of the magnetic field on the electron kinetic is discussed, and a critical analysis of Langmuir probe measurements is given. The Electron Energy Distribution Function is calculated using the Druyvesteyn theory (EEDF) and is corrected using the theory developed by Arslanbekov in the case of magnetized plasma. Three different components are observed in the EEDF, whatever the theory used. They are: (a) a low electron energy component at energy lower than 10 eV, which is ascribed to the electron having inelastic collisions with heavy species (H2, H, ions), (b) a high energy component with a mean energy ranging from 10 to 20 eV, which is generally ascribed to the heating of the plasma by the incident microwave power, and (c) a third component observed between the two other ones, mainly at low pressure and in resonance conditions, has been correlated to the electron rotation in the magnetic field. © 2016 AIP Publishing LLC.


Cortazar O.D.,University of Castilla - La Mancha | Megia-Macias A.,ESS Bilbao Consortium | Tarvainen O.,University of Jyväskylä | Vizcaino-De-Julian A.,ESS Bilbao Consortium | Koivisto H.,University of Jyväskylä
Plasma Sources Science and Technology | Year: 2014

The existence of various spatial distributions of hydrogen plasma in a pulsed 2.45 GHz microwave discharge is demonstrated. The data has been obtained through optical emission diagnostics utilizing an ultra-fast CCD camera system with multi-channel plate (MCP) intensifiers, and a wavelength-filtered photodiode recording temporal light emission signals of hydrogen atoms and molecules. It has been observed that the magnetic field topology and strength are determining the transitions between different plasma patterns and spectral saturation times while neutral gas pressure and microwave power show a weaker influence on the profiles but affect the emitted light intensity. © 2014 IOP Publishing Ltd.


Cortazar O.D.,ESS Bilbao Consortium | Cortazar O.D.,University of Castilla - La Mancha | Komppula J.,University of Jyväskylä | Tarvainen O.,University of Jyväskylä | And 3 more authors.
Plasma Sources Science and Technology | Year: 2013

Temporal evolution of microwave-plasma coupling, vacuum ultraviolet (VUV) light emission and plasma electron temperature and density is reported for a 2.45 GHz microwave hydrogen discharge pulsed at 50 Hz. Directional couplers, a VUV spectrometer and a Langmuir probe are used for the diagnostics of the plasma breakdown. A 5-10 s transient peak of light emission exceeding the steady-state intensity by a factor of 3.3 is observed in coincidence with an abrupt drop in the microwave electric field. Observed light emission intensities combined with cross section data indicate that the electron temperature during the breakdown transient exceeds the steady-state value of 4-6 eV by a factor 3, which is in good agreement with the Langmuir probe data. The estimated magnitude of the electron temperature transient corresponds well with the microwave-plasma coupling characteristics, indicating a drop of 30-40% in the electric field strength due to plasma damping. © 2013 IOP Publishing Ltd.


Cortazar O.D.,University of Castilla - La Mancha | Megia-Macias A.,ESS Bilbao Consortium | Tarvainen O.,University of Jyväskylä | Koivisto H.,University of Jyväskylä
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2015

Plasma distribution transients associated with the breakdown of a 2.45 GHz hydrogen discharge similar to high current microwave ion sources are studied by means of an ultra-fast frame image acquisition system in visible light range. Eight different plasma distributions have been studied by photographing the 2D projections of the discharge through a transparent plasma electrode. The temporal evolution of images in Balmer-alpha and Fulcher band wavelengths have been recorded associated to atomic and molecular excitation and ionization processes. Some unexpected plasma distributions transient behaviors during breakdown are reported. © 2015 Elsevier B.V.

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