Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 10: Gaseous detectors

T 10.1: Vortrag

Montag, 15. März 2021, 16:00–16:15, Tj

A Cherenkov Position Micromegas — •Maximilian Rinnagel, Otmar Biebel, Maximilian Herrmann, Christoph Jagfeld, Felix Klitzner, Katrin Penski, Chrysostomos Valderanis, Fabian Vogel, and Ralf Hertenberger — LMU München

Detectors utilizing the Cherenkov effect have been well established for particle identification of charged particles in detector systems such as LHCb or HADES. In reverse it is possible to determine the momentum of a known particle by measuring the opening angle of the Cherenkov cone in thick Cherenkov media. Our goal with this 10x10 cm² prototype is a proof of principle using cosmic muons. A traversing muon creates around 700 Cherenkov photons in a 1-2 cm thick ulta-violet (UV) transparent LiF, CaF₂ or MgF₂ window with an optical refractive index around 1.5 in the UV range. The conversion to electrons happens in transmission in a photosensitive CsI layer at the bottom of the radiator. High voltage around -300 V, applied to a thin layer of Chromium in between the crystal and the CsI, forces the electrons into the drift region of a Micromegas, i.e. gaseous micro pattern detector, where the electrons are detected with excellent spatial resolution after gas-amplification in the anode-stage of the detector. Overall efficiencies of 7% seem possible at transparencies of 60% through the Chromium layer and conversion efficiencies around 12% in the CsI layer. Thus, good momentum resolution and spatial resolution of an incident muon particle will be achieved. We will present the detector design as well as studies concerning the transmission of the radiator material and the predicted photon yield.