A. Combo

The TOFOR neutron spectrometer and its first use at JET

A time-of-flight neutron spectrometer (TOFOR) has been developed to measure the 2.45u2002MeVu2002d+d→3He+n neutron emission from D plasmas. The TOFOR design features the capability to operate at high rates in the 100u2002kHz range, data collection with fast time digitizing and storing, and monitoring of the signals from the scintillation detectors used. This article describes the principles of the instrument and its installation at JET and presents preliminary data to illustrate the TOFOR performance as a neutron emission spectroscopy diagnostic.

New MPRu instrument for neutron emission spectroscopy at JET

The MPRu is an upgrade of the magnetic proton recoil (MPR) neutron spectrometer that has been used for 14MeV DT neutron measurements at JET during the DTE1 (1997) and TTE (2003) campaigns. In this contribution the principles of the MPR and its upgrade will be presented. The MPRu allows measurements of the full range of fusion relevant neutron energies, 1.5–18MeV, including the 14MeV DT neutrons, now with significantly reduced background, and also new high-quality measurements of the 2.5MeV DD neutron component. This improvement is made possible by the use of a new proton recoil detector in combination with custom-built transient recorder cards. The importance of these instrumental improvements for extending the use of the MPRu in diagnosis of D and DT plasmas will be discussed. Results from the first 2.5MeV measurements performed with the MPRu during JET high level commissioning in April 2006 are presented.

An event-driven reconfigurable real-time processing system for the next generation fusion experiments

This article presents a new event-driven processing platform which uses a mixture of digital signal processors and field programmable gate arrays to provide data reduction and real-time processing and control capabilities for long discharge fusion experiments. The architecture and physical implementation aims to provide more processing power, a mathematical algorithm description interface, and an easy integration with existing acquisition systems as well as the seamless integration with an event-driven data acquisition and control system for current and upcoming fusion experiments. A complete framework from the algorithm description to the physical implementation of the new platform in a heterogeneous processing system will be described.

A distributed, hardware reconfigurable and packet switched real-time control and data acquisition system

The architecture of a synchronized event-based control and data acquisition system that aims to improve significantly the performance of actual systems is presented. The design explores recent developments in data transport, signal processing and system synchronization. Data transport between the acquisition, processing and storing devices and at backplane level will be performed by InfiniBand, a low latency packet switched network standard. Data processing algorithms will be performed in a mixture of digital signal processors and reconfigurable field programmable gate arrays. Both devices will be programmed from a descriptive high-level mathematical language. Acquisition synchronization, data stamping and event management will be performed through a specialized low latency synchronous optical network for the time critical signals.

A low cost, fully integrated, event-driven, real-time control and data acquisition system for fusion experiments

A new, real-time, distributed, control and data acquisition system architecture for long duration fusion experiments was developed based on the new optical communications technologies and the “System on a Chip” methodology. The architecture integrates data routing, data storage, real-time data processing and control and data acquisition nodes, interconnected by a switched-packed, gigabit, point-to-point, communications network. The routing nodes provide connections to the autonomous storage and processing nodes through standard network links. The control and data acquisition nodes are connected to the routing nodes by specifically designed optical links which provide both data transport and timing/synchronism support. The acquired data are time stamped and can be dynamically processed for local control or sent to the external storage, the real-time processing or the control nodes. The standard processor and the reconfigurable field programmable gate array included in each node allow the programming of the...

Development and characterization of the proton recoil detector for the MPRu neutron spectrometer

Development and characterization of the proton recoil detector for the MPRu neutron spectrometer

Two fast VME transient recorder systems with 12 bits and multiple differential inputs

This article describes two on-site developed, VME transient recorder systems, with 12 bit resolution, eight (four) differential input channels, sampling frequency up to 1.25 (20) MSPS and 512 (250 or 1000) kWords of memory per channel. Autonomous operation is guaranteed by standard static random access memory, under the control of a programmable logic array device for address generation. This device also manages the external trigger signal and provides the control signals for the analog-to-digital converter in articulation with a programmable timing element that determines the acquisition rate. Software drivers have been developed for the OS-9 operating system. Tests to quantify the channel crosstalk, the common mode noise rejection, and the spectral characterization are presented.

PCI data acquisition and signal processing hardware modules for long pulse operation

A set of PCI instrumentation modules was developed at the EURATOM/IST Association. The modules were engineered around a reconfigurable hardware core which permits one to reduce the development time of instrument for new applications, provide support for long time or even continuous operation, and is able to perform real-time digital signal processing. The core was engineered at low cost and the modules incorporate a high number of channels, which contribute to reduce the total cost per channel. Field results are as expected in terms of performance both in data throughput and input characteristics. Currently, a 2 MSPS, 14-bit, eight channel galvanic isolated transient recorder; a 200 MSPS, 8-bit, four channel pulse digitizer; an eight channel time-to-digital-converter with a resolution of 0.4u2002ns, and a reconfigurable hardware expandable board, are implemented.

Upgrade of the data acquisition and control system of the ASDEX upgrade microwave reflectometer

Microwave reflectometry is an important diagnostic to characterize the plasma electron density in fusion experiments. The broadband frequency swept microwave reflectometry system of the ASDEX upgrade tokamak covers the frequency range of 16 to 100 GHz. In order to fully exploit the diagnostic capabilities it is mandatory to upgrade the data acquisition and control system. It should comply with faster frequency sweep times and improved time resolution as well as accuracy allowing, for example, plasma position and shape measurements for control purposes, as it is foreseen for ITER. A new PCI-based system is under development based on a digitizer card with 2 channels, 12-bit resolution and a waveform generator with one channel, 16-bit resolution. Both cards have 512 Mbytes of memory, a digital signal processor (DSP) for advanced processing modes and a field programmable gate array (FPGA) for real-time algorithms and complex trigger managing modes. The system is able to support multiple cards (digitizers and signal generators) operating synchronously at a maximum rate of 210 MSamples/second