96 research outputs found

    ROPPERI - A TPC readout with GEMs, pads and Timepix

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    The concept of a hybrid readout of a time projection chamber is presented. It combines a GEM-based amplification and a pad-based anode plane with a pixel chip as readout electronics. This way, a high granularity enabling to identify electron clusters from the primary ionisation is achieved as well as flexibility and large anode coverage. The benefits of this high granularity, in particular for dE/dx measurements, are outlined and the current software and hardware development status towards a proof-of-principle is given.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS2016), Morioka, Japan, 5-9 December 2016. C16-12-05.

    Using an InGrid Detector to Search for Solar Chameleons with CAST

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    We report on the construction, operation experience, and preliminary background measurements of an InGrid detector, i.e. a MicroMegas detector with CMOS pixel readout. The detector was mounted in the focal plane of the Abrixas X-Ray telescope at the CAST experiment at CERN. The detector is sensitive to soft X-Rays in a broad energy range (0.3--10 keV) and thus enables the search for solar chameleons. Smooth detector operation during CAST data taking in autumn 2014 has been achieved. Preliminary analysis of background data indicates a background rate of 1−5×10−5 keV−1cm−2s−11-5\times 10^{-5}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1} above 2 keV and ∼3×10−4 keV−1cm−2s−1\sim 3\times 10^{-4}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1} around 1 keV. An expected limit of βγ≲5×1010\beta_\gamma \lesssim 5\times 10^{10} on the chameleon photon coupling is estimated in case of absence of an excess in solar tracking data. We also discuss the prospects for future operation of the detector.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs, Zaragoza, June 22 to 26, 201

    An InGrid based Low Energy X-ray Detector

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    An X-ray detector based on the combination of an integrated Micromegas stage with a pixel chip has been built in order to be installed at the CERN Axion Solar Telescope. Due to its high granularity and spatial resolution this detector allows for a topological background suppression along with a detection threshold below 1 keV1\,\text{keV}. Tests at the CAST Detector Lab show the detector's ability to detect X-ray photons down to an energy as low as 277 eV277\,\text{eV}. The first background data taken after the installation at the CAST experiment underline the detector's performance with an average background rate of 5×10−5 /keV/cm2/s5\times10^{-5}\,/\text{keV}/\text{cm}^2/\text{s} between 2 and 10 keV10\,\text{keV} when using a lead shielding.Comment: 4 pages, 5 figures, Contributed to the 10th Patras Workshop on Axions, WIMPs and WISPs, CERN, June 29 to July 4, 201

    Charge carrier transfer in the gas electron multiplier at low gas gains

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    Connected to the Linear Collider project TESLA at DESY, studies on the readout of TPCs based on the GEM-technology are ongoing. For particle identication via dE/dx - measurement, a good energy resolution is indispensable, and therefore losses of primary electrons have to be avoided. It turned out, that in the GEM transverse diffusion inside or close to the holes is a not negligible reason for these losses. For Ar-CH4 90:10 and TPC-like field configurations it was found, that when operated in normal amplification mode, the Standard Geometry GEM should not lose primaries, whereas for low gains, also when operated in magnetic fields up to 5T, a GEM with larger pitch and hole diameter would be necessary

    Summary and Conclusions of the First DESY Test Beam User Workshop

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    On October 5/6, 2017, DESY hosted the first DESY Test Beam User Workshop [1] which took place in Hamburg. Fifty participants from different user communities, ranging from LHC (ALICE, ATLAS, CMS, LHCb) to FAIR (CBM, PANDA), DUNE, Belle-II, future linear colliders (ILC, CLIC) and generic detector R&D presented their experiences with the DESY II Test Beam Facility, their concrete plans for the upcoming years and a first estimate of their needs for beam time in the long-term future beyond 2025. A special focus was also on additional improvements to the facility beyond its current capabilities

    A Time Projection Chamber with GEM-Based Readout

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    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
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