M Zühlsdorf

Goethe-Universität Frankfurt am Main, Frankfurt, Hesse, Germany

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Publications (82)275.78 Total impact

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    ABSTRACT: The design of the Barrel DIRC detector for the future PANDA experiment at FAIR contains several important improvements compared to the successful BABAR MC. such as focusing and fast timing. To Lest those improvements as well as other design options a prototype was build and successfully tested in 2012 with particle beams at CERN. The prototype comprises a radiator bar, focusing lens, mirror, and a prism shaped expansion volume made of synthetic fused silica. An array of micro-channel plate photomultiplier tubes measures the location and arrival time of the Cherenkov photons with sub-nanosecond resolution. The development of a fast reconstruction algorithm allowed to tune construction details of the detector setup with test beam data and Monte-Carlo simulations.
    No preview · Article · Dec 2014 · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
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    ABSTRACT: The aim of this research is to develop a planar DIRC detector showing advantages and performance similar to a classical, barrel shaped ENRC, but at smaller polar angles which cannot be accessed using a cylindrical geometry. The device will complement the PANDA Barrel MC by covering polar angles from 5 degrees to 22 degrees. The envisaged pi/K-separation is >= 3 sigma up to 4 GeVic. A major challenge is the adaption of the device to the PANDA environment including a magnetic field of similar to 1-2 T, high rates and radiation, limited space for optics and sensors as well as the lack of a common first-level trigger. This paper discusses a detector design which forms a compromise between these constraints and available hardware, a specific analytic reconstruction method, a performance estimation based on Geant4 simulations and finally the successful particle identification using a recent R&D prototype.
    No preview · Article · Dec 2014 · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
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    ABSTRACT: The charged particle identification at the PANDA experiment will be mainly performed with MC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of C/cm(2) integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress. (C) 2014 Elsevier By. All rights reserved
    No preview · Conference Paper · Dec 2014
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    ABSTRACT: The PANDA experiment at the new Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt, will study fundamental questions of hadron physics and QCD using high intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c. Efficient Particle Identification for a wide momentum range and the full solid angle is required for reconstructing the various physics channels of the PANDA program. HacIronic Particle Identification in the barrel region of the detector will be provided by a DIRC counter. The design is based on the successful BABAR DIRC with important improvements, such as focusing optics and fast photon Liming. Several of these improvements, including different radiator geometries and optics, were tested in particle beams at GSl and at CERN. The evolution of the conceptual design of the PANDA Barrel DIRC and the performance of complex prototypes in test beam campaigns will be discussed.
    No preview · Article · Dec 2014 · Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment
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    ABSTRACT: Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (πN) TDAs from \(\bar pp \to e^ + e^ - \pi ^0 \) reaction with the future P̄ANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q 2, the amplitude of the signal channel \(\bar pp \to e^ + e^ - \pi ^0 \) admits a QCD factorized description in terms of πN TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring \(\bar pp \to e^ + e^ - \pi ^0 \) with the P̄ANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. \(\bar pp \to \pi ^ + \pi ^ - \pi ^0 \) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q 2 < 4.3 GeV2 and 5 < q 2 GeV2, respectively, with a neutral pion scattered in the forward or backward cone \(\left| {\cos \theta _{\pi ^0 } } \right| > 0.5\) in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the P̄ANDA detector will allow to achieve a background rejection factor of 5 · 107 (1 · 107) at low (high) q 2 for s = 5 GeV2, and of 1 · 108 (6 · 106) at low (high) q 2 for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 fb−1 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with P̄ANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing π TDAs.
    Full-text · Article · Sep 2014 · European Physical Journal A
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    ABSTRACT: The PANDA experiment at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR) at GSI, Darmstadt will study fundamental questions of hadron physics and QCD using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c. Hadronic PID in the barrel region of the PANDA detector will be provided by a DIRC (Detection of Internally Reflected Cherenkov light) counter. The design is based on the successful BABAR DIRC with several key improvements, such as fast photon timing and a compact imaging region. Detailed Monte Carlo simulation studies were performed for DIRC designs based on narrow bars or wide plates with a variety of focusing solutions. The performance of each design was characterized in terms of photon yield and single photon Cherenkov angle resolution and a maximum likelihood approach was used to determine the π/K separation. Selected design options were implemented in prototypes and tested with hadronic particle beams at GSI and CERN. This article describes the status of the design and R&D for the PANDA Barrel DIRC detector, with a focus on the performance of different DIRC designs in simulation and particle beams.
    Full-text · Article · May 2014 · Journal of Instrumentation
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    ABSTRACT: This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM-stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy-loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
    Full-text · Article · Feb 2013 · European Physical Journal A
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    ABSTRACT: This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the $\overline{P}$ ANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole $\overline{P}$ ANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
    Full-text · Article · Feb 2013 · European Physical Journal A
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    ABSTRACT: The PANDA Disc DIRC is a novel type of Cherenkov detector, being developed to improve the charged particle identification of the upcoming PANDA experiment at the future FAIRFacility for antiproton and ion research in Darmstadt, Germany facility. The detector has to cover the endcap region of the target spectrometer, resulting in a geometry that by now has never been applied to a DIRC detector. Additional complications are implied by tight space constraints at the foreseen position, interaction rates of 20 MHz up to 50 MHz and the experiments trigger-less readout scheme. To cope with the lack of experience, the development of detector concepts is driven by the development of computer simulations and dedicated reconstruction methods. The performance analysis of a preceding detector concept, presented at the DIRC workshop in 2009, showed several weaknesses which have been eliminated by revising the detector design. This publication summarizes the current status of the software, the reconstruction method and resulting detector performance of the improved design: the PANDA 3D Disc DIRC.
    Preview · Article · Jan 2012 · Journal of Instrumentation
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    ABSTRACT: A 3D Disc DIRC detector is foreseen to provide particle identification in the endcap region of the PANDA experiment at the future FAIR facility. The 3D-DIRC is a synthesis of the previously proposed FL-DIRC and TOP-DIRC at PANDA. It is based on the measurement of the internally reflected Cherenkov light in a 2 cm thick fused silica plate. Position sensitive single photon detectors — either MCP-PMTs or a SiPMs — are placed in the focal plane of small focussing light guides and will provide a measurement of a projection of the Cherenkov angle. A precise determination of the time-of-propagation of the photons will allow to extract additional information of the Cherenkov angle and it will improve the identification of the signal pattern in a high luminosity, high background environment. Dichroic mirrors will be used to handle dispersion effects in the generation and propagation of the photons. The detector is expected to separate pions and kaons up to a momentum of ~ 4 GeV/c.
    Preview · Article · Jan 2012 · Journal of Instrumentation
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    K Föhl · M Düren · P Koch · M Zühlsdorf
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    ABSTRACT: Two Disc DIRC prototypes have been designed and built and are shortly being tested with proton test beams. Different in design details, both aim to provide the WASA-at-COSY experiment with a particle velocity measurement that improves the missing mass resolution. This paper shows the difference in concept between these two designs and also compares to designs that have been proposed for PANDA.
    Preview · Article · Jan 2012 · Journal of Instrumentation
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    M Düren · I Brodski · K Föhl · A Hayrapetyan · P Koch · B Kröck · O Merle · M Sporleder · M Zühlsdorf
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    ABSTRACT: A novel Cherenkov detector, a time-of-propagation (TOP) disc DIRC, is proposed for particle identification at the PANDA experiment at the future FAIR facility. It measures Cherenkov light that is generated and internally reflected in a 2 cm thick fused silica plate. The Cherenkov angle is reconstructed from a time-of-propagation measurement at the rim of the disc of individual Cherenkov photons with a resolution of better than 50 ps. Dichroic mirrors at the rim of the disc fulfil two purposes. They allow for a selection of certain wavelength bands and thus are used to reduce dispersive smearing, and they enlarge the average photon path length by reflection and thus improve the separation power of the detector. A reconstruction algorithm has been developed to assign the detected photons to a given particle trajectory. Using a likelihood method, the algorithm calculates particle type probabilities for each track. The detector is expected to separate pions and kaons up to a momentum of ~ 4 GeV/c. Additional focussing elements at the rim of the disc are proposed to enhance the signal to background separation of the detector.
    Preview · Article · Dec 2009 · Journal of Instrumentation
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    ABSTRACT: The PANDA experiment at the future FAIR facility requires yet another challenging step in detector technology. The high luminosity of the HESR ring puts strong requirements on Particle Identification for the entire detector acceptance. A proposed novel type of detector, a time-of-propagation DIRC will yield the required separation for charged tracks in the angular range between 5 and 22 degree. The anticipated high luminosity and good timing resolution required by the TOP DIRC puts constraints on the required Front End Electronics.
    Preview · Article · Dec 2009 · Journal of Instrumentation
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    K Föhl · I Brodski · M Düren · A Hayrapetyan · P Koch · B Kröck · O Merle · M Sporleder · M Zühlsdorf
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    ABSTRACT: For the ANDA experiment at the future FAIR facility, charged particle identification is of major importance, and hence one foresees a DIRC detector with a circular radiator disc placing the optical elements for photon readout around the disc rim. To improve detector performance beyond the established BaBar DIRC the design presented here implements focussing optics and chromatic dispersion correction. A simplified disc DIRC at WASA shall serve a dual purpose. For the WASAatCOSY experiment itself the DIRC velocity measurement provides an improved energy resolution. For ANDA this WASA-DIRC is a real-experiment prototype validating essential design parts, and beyond the minimum design can act as a test bench for ANDA technology.
    Preview · Article · Nov 2009 · Journal of Instrumentation
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    O Merle · I Brodski · M Düren · K Föhl · A Hayrapetyan · P Koch · B Kröck · M Sporleder · M Zühlsdorf
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    ABSTRACT: The Time of Propagation (ToP) Disc DIRC is a novel type of Cherenkov detector, proposed for the particle identification system in ANDA. DIRC detectors (detection of internal reflected Cherenkov radiation) are a subtype of ring imaging Cherenkov detectors. Therefore the working principle is also based on spacial angle measurement of emitted Cherenkov photons. The ToP Disc DIRC concept involves two novel approaches. Firstly the radiator is realized in shape of a disc, what has never been done before, and secondly the Cherenkov angle is not measured by a spacial readout but reconstructed from one spacial coordinate and a fast single-photon time signal (σ < 50 ps). Photons are not only total reflected inside the radiator but also partly reflected by dielectric mirrors at the rim of the disc, leading to complicated photon tracks which have to be reconstructed. In addition, ANDA is not able to provide a useable start time for a given incident particle. Therefore measured data includes only the photons time of detection and not time of propagation. Previous approaches to DIRC reconstruction cannot be applied due to the different working principles. New specialized reconstruction methods have been developed and will be presented. Preliminary resolution studies based on Monte Carlo data (Geant4) proof that reconstruction of single tracks as well as multiple tracks is feasible.
    Preview · Article · Sep 2009 · Journal of Instrumentation
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    ABSTRACT: Dear Editor, Solitary primary extramedullary plasmacytoma is rare and found in elderly people with a diagnostic challenge for the clinician. Usually, the tumor originates in the nasal cavity or upper respiratory tract located in bone or in soft tissue with potential visceral organ involvement. The plasmacytoma itself can be defined as a more or less welldefined neoplastic proliferation of plasma cells in the absence of generalized disease. Serum paraproteins are present in some of these patients.
    No preview · Article · Jun 2008 · Annals of Hematology
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    ABSTRACT: Oral mucositis is a frequent problem after high-dose methotrexate (HD-MTX), impairing patient's quality of life, leading to higher rates of infections and delaying subsequent chemotherapy. This report describes the effect of palifermin in patients treated within the GMALL-B-ALL 2002 protocol containing HD-MTX who developed a severe mucositis in cycle A1/B1. Ten patients, all with World Health Organization grades III-IV oral mucositis in cycles A1/B1, obtained palifermin with subsequent similar or identical cycles to reduce mucositis. Thus, patients serve as their own control for efficacy of palifermin. All 10 patients developed grades III-IV mucositis in cycles A1/B1 without palifermin, whereas only two of 10 developed grades III-IV mucositis in corresponding cycles A2/B2 with palifermin. Only four of 10 patients showed infections in the cycles with palifermin compared with 10 of 10 patients without palifermin. The duration of mucositits in patients who acquired a higher grade mucositis despite treatment with palifermin could be reduced from 12.9 days (median) without to 11 days with palifermin. The amount of i.v. opioid analgetics could be significantly reduced. Palifermin might reduce the incidence, severeness and duration of oral mucositis in HD-MTX-based chemotherapy and may influence clinical sequelae such as infection and quality of life.
    Preview · Article · Jun 2008 · Annals of Oncology
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    ABSTRACT: MicroRNAs (miRNAs) play an important role in cellular differentiation and cancer pathogenesis. This study analysed the expression of 154 human miRNAs in acute myeloid leukaemia (AML) and control samples using a stem-loop real-time reverse transcription polymerase chain reaction approach. Global patterns of miRNA expression in AML, normal bone marrow (NBM) and CD34(+) progenitor cells allowed correct class predictions similar to whole genome microarray expression analyses that were performed at the same time. At single miRNA species level, MIRN23B was repressed in AML specimens compared to NBM and purified CD34(+) haematopoietic progenitor cells. In contrast, the MIRN221/MIRN222 cluster and MIRN34A were expressed at significantly higher levels in AML blasts. Patients with high MIRN221/MIRN222 expression showed low levels of KIT RNA and protein expression but the correlation between kit protein and KIT mRNA was significantly stronger than the correlation of either one with MIRN221/MIRN222. A global analysis between miRNA expression levels and mRNA expression of predicted target genes revealed only weak associations in the majority of miRNA species. Nonetheless, the presence of two or more miRNA binding sites within the mRNA was usually associated with a decrease in mRNA levels. Taken together, these findings provide evidence that specific miRNA expression patterns exist in AML.
    Full-text · Article · Feb 2008 · British Journal of Haematology
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    ABSTRACT: The metalloexopeptidase CD13/aminopeptidase N (APN) has been shown to be involved in cancer angiogenesis, invasion, and metastasis. Therefore, a CD13/APN-targeted NGR-peptide was labeled with the cyanine dye Cy 5.5 and applied to image tumor xenografts with different APN-expression levels using both planar and tomographic optical imaging methods. In vitro, the peptide-dye conjugate showed a clear binding affinity to APN-positive HT-1080 cells, while negative MCF-7 cells and predosing with the free NGR-peptide revealed little to no fluorescence. In vivo, tumor xenografts (n>or=5) were clearly visualized by two-dimensional (2-D) planar fluorescence reflectance imaging (FRI) and three-dimensional (3-D) fluorescence mediated tomography (FMT) up to 24 h after injection. FMT also allowed us to quantify fluorochrome distribution in deeper tissue sections, showing an average fluorochrome concentration of 306.7+/-54.3 nM Cy 5.5 (HT-1080) and 116.0+/-18.3 nM Cy 5.5 (MCF-7) in the target tissue after 5 h. Competition with the free NGR-peptide resulted in a reduction of fluorochrome concentration in HT-1080 tumor tissue (195.3+/-21.9 nM; 5 h). We thus conclude that NGR-Cy 5.5 combined with novel tomographic optical imaging methods allows us to image and quantify tumor-associated CD13/APN expression noninvasively. This may be a promising strategy for a sensitive evaluation of tumor angiogenesis in vivo.
    Full-text · Article · Jan 2008 · Journal of Biomedical Optics
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    Preview · Article · Nov 2007 · Journal of Clinical Oncology

Publication Stats

2k Citations
275.78 Total Impact Points

Institutions

  • 2014
    • Goethe-Universität Frankfurt am Main
      • Institute of Nuclear Physics
      Frankfurt, Hesse, Germany
  • 2013-2014
    • GSI Helmholtzzentrum für Schwerionenforschung
      Darmstadt, Hesse, Germany
  • 2009-2012
    • Justus-Liebig-Universität Gießen
      • II. Physikalisches Institut
      Gießen, Hesse, Germany
  • 1991-2008
    • Universitätsklinikum Münster
      • • Medizinische Klinik und Poliklinik A
      • • Institut für Transfusionsmedizin und Transplantationsimmunologie
      Muenster, North Rhine-Westphalia, Germany
  • 1990-2008
    • University of Münster
      • • Department of Medicine, Hematology and Oncology
      • • Department of Internal Medicine
      Muenster, North Rhine-Westphalia, Germany
  • 2005-2007
    • Bayer HealthCare
      • Bayer HealthCare Pharmaceuticals
      Leverkusen, North Rhine-Westphalia, Germany
    • Institut für klinische Pharmakologie
      Stuttgart, Baden-Württemberg, Germany