A Time Projection Chamber with GEM-Based Readout

For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.Comment: 22 pages, 19 figure

Simulation studies for a high resolution time projection chamber at the international linear collider

The International Linear Collider (ILC) is planned to be the next large accelerator. The ILC will be able to perform high precision measurements only possible at the clean environment of electron positron collisions. In order to reach this high accuracy, the requirements for the detector performance are challenging. Several detector concepts are currently under study. The understanding of the detector and its performance will be crucial to extract the desired physics results from the data. To optimise the detector design, simulation studies are needed. Simulation packages like GEANT4 allow to model the detector geometry and simulate the energy deposit in the different materials. However, the detector response taking into account the transportation of the produced charge to the readout devices and the effects ofthe readout electronics cannot be described in detail. These processes in the detector will change the measured position of the energy deposit relative to the point of origin. The determination of this detector response is the task of detailed simulation studies, which have to be carried out for each subdetector. A high resolution Time Projection Chamber (TPC) with gas amplification based on micro pattern gas detectors, is one of the options for the main tracking system at the ILC. In the present thesis a detailed simulation tool to study the performance of a TPC was developed. Its goal is to find the optimal settings to reach an excellent momentum and spatial resolution. After an introduction to the present status of particle physics and the ILC project with special focus on the TPC as central tracker, the simulation framework is presented. The basic simulation methods and implemented processes are introduced. Within this stand-alone simulation framework each electron produced by primary ionisation is transferred through the gas volume and amplified using Gas Electron Multipliers (GEMs). The output format of the simulation is identical to the raw data from a real TPC including readout electronics. Not only detector effects, but also consequences of the reconstruction algorithms can be tested. The results achieved with the simulation are compared to data acquired with a TPC prototype. Good agreement can be reached between simulated and measured data. The framework is then used to carry out some exemplary studies to test the performance of a TPC at the ILC. This includes spatial, momentum and energy resolution. The detailed simulation of the amplification structure using GEMs allows to also address the issue of ion backdrift. The results are compared to the design goals of the TESLA TDR. In future developments, the simulation framework presented here could be used to obtain a parametrisation of the detector response, which can then be incorporated into full detector simulations. A realistic detector response for the simulated energy deposit in the active volume could be achieved

Measurement of Chargino and Neutralino Production at CLIC

We present a study performed for the CLIC CDR on the measurement of chargino and neutralino production at sqrt(s) = 3 TeV. Fully hadronic final states with four jets and missing transverse energy were considered. Results obtained using full detector simulation for the masses and for the production cross sections of the changino and the lightest and next-to-lightest neutralinos are discussed

Überlegungen zur Berechnung der Kosten des Grenzanbieters : Bericht der UAG "Grenzanbieter" für die Extensivierungsreferent:innen des Bundes und der Länder

The following paper deals with the question of what effects a marginal provider approach would have on the derivation of support levels for agri-environmental measures. The background to the considerations is that the EU's Strategic Plan Regulation explicitly stipulates that the intended ambition level should be taken into account when determining the payment levels. Furthermore, in the case of a politically intended high penetration of certain measures, average cost considerations are not adequate to achieve the objectives. Against this background, the economic considerations behind the marginal bidder approach are briefly explained. In a second step, it is explained to what extent corresponding considerations are explicitly included in the current derivation of payment levels for agri-environmental and climate measures in the federal states. This is followed by an outline of various approaches as to how a marginal bidder approach can be integrated into the derivation of payment levels and what prerequisites would be necessary in terms of technology and data in each case. Of the four options presented, only one approach, namely the one based on an ad-hoc definition of the marginal bidder, can be implemented in the short term for the majority of measures. The paper concludes by outlining a work programme that would lay the foundations so that a marginal bidder approach could be more widely applied when deriving payments levels in the next CAP funding period (from 2027

The 1-Megapixel pnCCD detector for the Small Quantum Systems Instrument at the European XFEL: system and operation aspects

The X-ray free-electron lasers that became available during the last decade, like the European XFEL (EuXFEL), place high demands on their instrumentation. Especially at low photon energies below 1 keV, detectors with high sensitivity, and consequently low noise and high quantum efficiency, are required to enable facility users to fully exploit the scientific potential of the photon source. A 1-Megapixel pnCCD detector with a 1024 × 1024 pixel format has been installed and commissioned for imaging applications at the Nano-Sized Quantum System (NQS) station of the Small Quantum System (SQS) instrument at EuXFEL. The instrument is currently operating in the energy range between 0.5 and 3 keV and the NQS station is designed for investigations of the interaction of intense FEL pulses with clusters, nano-particles and small bio-molecules, by combining photo-ion and photo-electron spectroscopy with coherent diffraction imaging techniques. The core of the imaging detector is a pn-type charge coupled device (pnCCD) with a pixel pitch of 75 µm × 75 µm. Depending on the experimental scenario, the pnCCD enables imaging of single photons thanks to its very low electronic noise of 3 e− and high quantum efficiency. Here an overview on the EuXFEL pnCCD detector and the results from the commissioning and first user operation at the SQS experiment in June 2019 are presented. The detailed descriptions of the detector design and capabilities, its implementation at EuXFEL both mechanically and from the controls side as well as important data correction steps aim to provide useful background for users planning and analyzing experiments at EuXFEL and may serve as a benchmark for comparing and planning future endstations at other FELs.ISSN:0909-0495ISSN:1600-577

The Karabo distributed control system

The Karabo distributed control system has been developed to address the challenging requirements of the European X-ray Free Electron Laser facility, including complex and custom-made hardware, high data rates and volumes, and close integration of data analysis for distributed processing and rapid feedback. Karabo is a pluggable, distributed application management system forming a supervisory control and data acquisition environment as part of a distributed control system. Karabo provides integrated control of hardware, monitoring, data acquisition and data analysis on distributed hardware, allowing rapid control feedback based on complex algorithms. Services exist for access control, data logging, configuration management and situational awareness through alarm indicators. The flexible framework enables quick response to the changing requirements in control and analysis, and provides an efficient environment for development, and a single interface to make all changes immediately available to operators and experimentalists.</p