M. Drochner

ANKE, a new facility for medium energy hadron physics at COSY-Jülich

Abstract ANKE is a new experimental facility for the spectroscopy of products from proton-induced reactions on internal targets. It has recently been implemented in the accelerator ring of the cooler synchrotron COSY of the Forschungszentrum Julich (FZ-Julich), Germany. The device consists of three dipole magnets, various target installations and dedicated detection systems. It will enable a variety of hadron-physics experiments like meson production in elementary proton–nucleon processes and studies of medium modifications in proton–nucleus interactions.

Evidence for a narrow resonance at 1530MeV/c2 in the K0p-system of the reaction pp→Σ+K0p from the COSY-TOF experiment

The hadronic reaction pp -->Sigma+ K0 p was measured exclusively at a beam momentum of 2.95 GeV/c using the TOF detector at the COSY storage ring. A narrow peak was observed in the invariant mass spectrum of the K0 p subsystem at 1530 +- 5 MeV/c2 with a significance of 4 - 6 standard deviations, depending on background assumptions. The upper limit of 18 +- 4 MeV/c2 (FWHM) for its width is given by the experimental resolution. The corresponding total cross section is estimated to be about 0.4 +- 0.1(stat) +- 0.1(syst) microbarn. Since a resonance in this subsystem must have strangeness S = + 1 we claim it to be the Theta+ state for which very recently evidence was found in various experiments.

SPHERES, Jülich's high-flux neutron backscattering spectrometer at FRM II

SPHERES is a third-generation neutron backscattering spectrometer, located at the 20 MW German neutron source FRM II and operated by the Jülich Centre for Neutron Science. It offers an energy resolution (fwhm) better than 0.65 μeV, a dynamic range of ± 31 μeV, and a signal-to-noise ratio of up to 1750:1.

Performance Aspects of PROFINET IO

Recently, the complex PROFINET CBA (component based automation) has been supplemented by the simplified PROFINET IO standard. PROFINET CBA defines a vendor-independent engineering model covering plant-wide automation and uses a component/container approach. Contrary to this, PROFINET IO aims at decentral periphery scenarios. Analogous to PROFIBUS DP it is based on a modular device model. Functionally, PROFINET IO can be considered as an Ethernet-based fieldbus. It is expected that PROFINET IO will play a major role on the PLC market since it is a possible replacement for PROFIBUS DP. The paper introduces the PROFINET technology and discusses performance aspects. Measurement results are presented.

Integration of industrial automation equipment in experiment control systems via PROFIBUS-developments and experiences at Forschungszentrum Julich

PROFIBUS, being a national German (DIN 19245) and an European (EN 50170) standard, has become the most widely accepted modern fieldbus technology in Europe. It is expected to take a similar role on the world market, since the IEC standardisation efforts for a common international fieldbus failed recently. A major reason for its success is the technological and functional scalability based on a common core. Now, a wide range of PLCs as well as low cost process I/O is available (also from leading manufacturers like Siemens) which enable easy interfacing. ZEL, the central electronics facility of Forschungszentrum Julich, has decided to use predominantly industrial components (PLCs, I/Os, etc.) in the front end of slow control systems for physics experiments.

The second generation of DAQ-Systems at COSY

At the Julich Cooler Synchrotron COSY several experiments are running based on a modular, flexible system design in hardware and software. Future data acquisition experiments should use PC-technologies as far as possible. For the intelligent units initially passive backplanes with Single Bord Computers (SBCs) have been chosen as defined by the PCI Industrial Computer Manufacturing Group (PICMG). For future applications the CompactPCI is considered which combines the IBM PC electrical and software standards with the Eurocard mechanical standards. Connection of the front-end modular systems (CAMAC, VME, FASTBUS) is performed by transparent controllers with PCI compliant interfaces, already available on the market or home made developments. As far as operating systems are concerned UNIX like systems are used. An object oriented, client-server based Experiment Messaging System (EMS) establishes the communication on the application layer between the experiment control, the event builder and different front-end systems. The design criteria for the second generation DAQ-Systems, a first experiment layout, interconnectivity questions and necessary component developments will be described, as well as the problems we have found turning a PC into a diskless system. Important results of performance measurements concerning the DAQ requirements will be given.

Flexible data acquisition system for experiments at COSY

For the KFA Julich cooler synchrotron COSY a general data acquisition system was developed. Its architecture is based on available standards (VME, FASTBUS, CAMAC, VICbus) and UNIX workstations forming a distributed processor system. Based on this hardware a flexible and modular data acquisition software was designed allowing the configuration of various experiment arrangements. The software design for run control is arranged according to a client server connectivity model as well as to an object oriented structure. It is logically based on MAP/MMS (ISO9506), a powerful application layer protocol for distributed automation systems in industry. In our application servers are implemented on the mProcessor controller boards at the frontend. On the workstation side the experiment control client consists of dedicated processes with access to the configurable experiment data base. The user interface is realized by OSF/Motif. Established software standards for online data analysis high energy physics are employed. We discuss the most important design decisions mainly focusing on the software aspects. >

New synchronisation system for experiments at COSY

To improve existing experiments at COSY a new DAQ system is currently under development. It is also well suited to the requirements of WASA at COSY after its transfer from CELSIUS. The DAQ modules are scattered to about 10..20 crates and are able to digitize and store several thousands events before a computer engagement is required. Therefore we need a purely hardware based synchronisation system. The synchronisation system consists of one master module and several output modules housed in a proprietary LVDS crate. It communicates over point to point links with the crate controllers

Spectator detection for the measurement of proton-neutron interactions at ANKE

Abstract A telescope of three silicon detectors has been installed close to the internal target position of the ANKE spectrometer, which is situated inside the ultra-high vacuum of the COSY-Julich light-ion storage ring. The detection and identification of slow protons and deuterons emerging from a deuterium cluster-jet target thus becomes feasible. A good measurement of the energy and angle of such a spectator proton (psp) allows one to identify a reaction as having taken place on the neutron in the target and then to determine the kinematical variables of the ion–neutron system on an event-by-event basis over a range of c.m. energies. The system has been successfully tested under laboratory conditions. By measuring the spectator proton in the pd→pspdπ0 reaction in coincidence with a fast deuteron in the ANKE Forward Detector, values of the pn→dπ0 total cross-section have been deduced. Further applications of the telescope include the determination of the luminosity and beam polarisation which are required for several experiments.

Tuning the instrument resolution using chopper and time of flight at the small-angle neutron scattering diffractometer KWS-2

Using a double-disc chopper with a variable slit opening in concert with a velocity selector and the time-of-flight data acquisition mode, controlled variation of the wavelength spread Δλ/λ between 2 and 20% has become routinely possible at the KWS-2 SANS diffractometer of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center.