[en] The central tracking device of the OPAL experiment at the LEP e⁺e^--collider consists of a pictorial jet chamber with a diameter of 4 m and 4 m length. The calibration of such a large detector is performed by the help of a UV laser system generating straight tracks even in the presence of magnetic fields. Intensive investigations of the laser calibration power and performance were done at the Full Scale Prototype (FSP) of the OPAL jet chamber. Laser double tracks with a precisely known distance are used to determine the drift velocity with an accuracy of 0.1%. From the measured deviations of a straight laser track electronic time offsets, wire positions and field distortions are derived. These calibration constants were applied to correct the measured drift times of test beam events. The sagitta and momentum resolutions of the thus corrected tracks have been obtained in the range from 6 GeV/c to 50 GeV/c. Extrapolating the results to the final OPAL jet chamber, a momentum resolution of σ-p/p = 6% is expected for 50 GeV/c tracks in a magnetic field of 4 kG. (orig.)

[en] Particle identification techniques by measuring the specific energy loss dE/dx have been widely used in high energy physics experiments for many years. The basics of the energy loss measurements are described briefly. The stability requirements, corrections and, in particular, the non-linear saturation effect are discussed in more detail. The performance of present large detectors such as resolution and particle separation power in the relativistic rise region are reviewed. Typical applications to various physics analyses at LEP are given. (orig.)

No abstract available

[en] Purpose. The use of digital full field mammography for imaging augmented breasts.Methods. Images of a sponge, as a tissue equivalent, partly covered with one of three different implants (silicone, silicone/saline, saline) were obtained using digital and film-screen technique. The visualisation of the sponge structure covered by the implant and next to the implant was evaluated by two radiologists. Results were compared to clinical results from 35 patients with implants.Results. Two images with different parameter settings have to be obtained to visualize the covered sponge structure and the structure around the implant with film-screen technique. Digital mammography allows assessment of both areas using one image at different window settings. The assessability of covered structures depends on the type of implant. These results are in keeping with our clinical experiences.Conclusion. Digital mammography allows equal or better assessment of covered and non-covered tissue in augmented breasts without the need for additional exposures. (orig.)

No abstract available

[en] Data Quality Monitoring (DQM) is an important and integral part of the data taking and data reconstruction of HEP experiments. In an online environment, DQM provides the shift crew with live information beyond basic monitoring. This is used to overcome problems promptly and help avoid taking faulty data. During the off-line reconstruction DQM is used for more complex analysis of physics quantities and its results are used to assess the quality of the reconstructed data. The Data Quality Monitoring software Framework (DQMF) which has been provided for the ATLAS experiment performs analysis of monitoring data through user defined algorithms and relays the summary of the analysis results to the configurable Data Quality output stream. From this stream the results can be stored to a database, displayed on a GUI, or used to make some other relevant actions with respect to the operational environment i.e. sending alarms, stopping the run. This paper describes the implementation of the DQMF and discusses experience from usage and performance of the DQMF during ATLAS commissioning.

[en] The jet chamber of the OPAL experiment at the e⁺e^--collider LEP is designed to measure the momentum of charged particles as well as the specific energy loss in the chamber gas. In this paper, the calibration procedure for the energy loss measurement is described in detail. A resolution of 3-4% has been achieved allowing identification of particles with momenta up to 20 GeV/c in dense particle environments typcial for events from Z⁰ decays. (orig.)

[en] Highlights: • Develop a method for combining sustainability dimensions in to one joint decision support system • Emphasize the relevance of assessing various criteria when choosing your water supply source • Develop and test a decision support system combining two multi-criteria assessments • Demonstrate that freshwater is a limited resource • Show water systems based on rain-& stormwater or groundwater are preferable in our case Utilities in larger cities have to make complex decisions planning future investments in urban water infrastructure. Changes are driven by physical water stress or political targets for environmental water flows e.g. through the implementation of the European water framework directive. To include these environmental, economic and social sustainability dimensions we introduce a novel multi-criteria assessment method for evaluation of water supply technologies. The method is presented and demonstrated for four alternatives for water supply based on groundwater, rain- & stormwater or seawater developed for augmenting Copenhagen's current groundwater based water supply. To identify the most sustainable technology, we applied rank order distribution weights to a multi-criteria decision analysis to combine the impact assessments of environment, economy and society. The three dimensions were assessed using 1) life-cycle assessment, 2) cost calculations taking operation and maintenance into account and 3) the multi-criteria decision analysis method Analytical hierarchy process. Specialists conducted the life-cycle assessment and cost calculations and the multi-criteria decision analyses were based on a stakeholder workshop gathering stakeholders relevant for the specific case. The workshop reached consensus on three sets of ranked criteria. Each set represented stakeholder perspectives with first priority given to one of the three sustainability dimensions or categories. The workshop reached consensus and when the highest weight was assigned to the environmental dimension of sustainability then the alternative of ‘Rain- & stormwater harvesting’ was the most sustainable water supply technology; when the highest weight was assigned to the economy or society dimensions then an alternative with ‘Groundwater abstraction extended with compensating actions’ was considered the most sustainable water supply technology. Across all three sets of ranked weights, the establishment of new well fields is considered the least sustainable alternative.

[en] The design features of the OPAL jet chamber are described, such as the mechanical and electrical structure, the high-voltage system, the readout electronics, the gas system and the laser setup for calibration. Special emphasis is put on the experience gained during the construction and running-in phase of all 24 sectors of the chamber. Results from the first operation are given, during which cosmic ray data were taken and a laser mapping of the entire chamber volume has been performed. (orig.)

[en] In this report we describe the construction and performance of the laser system which was used in Summer 1989 for the initial calibration of the OPAL jet chamber after installation on the LEP beam axis and which has served as a monitoring tool since then. Two Nd:YAG lasers are used to generate 48 high precision double beams which enter the chamber at fixed positions. The main features of the roughly 450 optical components are described and the beam alignment procedures are explained. Results are given for jet chamber calibration constants such as drift velocity, Lorentz angle, and residual sagittas. (orig.)