Development of a Position-Sensitive Detector for Positronium Inertial Sensing Measurements

S. Mariazzia, b, R. Caravitab, L. Glögglerc, d, L. Povoloa, b, L. Penasaa, b, S. Sharmab, e, f, P. Moskale, f, R.S. Brusaa, b aDepartment of Physics, University of Trento, via Sommarive 14, 38123 Povo, Trento, Italy bTIFPA/INFN Trento, via Sommarive 14, 38123, Povo, Trento, Italy cPhysics Department, CERN, 1211 Geneva 23, Switzerland dDepartment of Physics, Technical University Berlin, Hardenbergstr. 36, 10623 Berlin, Germany eFaculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Krakow, Poland fCenter for Theranostics, Jagiellonian University, Cracow, Poland

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In the last twenty years, both free fall and interferometry/deflectometry experiments have been proposed for the measurement of the gravitational acceleration on positronium, which is a purely leptonic matter-antimatter atom formed by an electron and its antiparticle (positron). Among the several challenges posed by these experiments is the development of position-sensitive detectors to measure the deflection of positronium in the Earth's gravitational field. In this work, we describe our recent progress in the development of position-sensitive detectors. Two different detection schemes are considered. The first is based on Ps ionization in a strong homogeneous magnetic field and imaging of the freed positron with a microchannel plate. The second scheme is based on scanning the positronium atom distribution on a plane by moving the slit or a material grating with sub-nm accuracy, and counting the atoms crossing the obstacle and those annihilating on it. The possibility of reaching a spatial resolution of around 15 μm using the former detection scheme is shown, and preliminary steps towards the development of a detector following the latter scheme (with potential position sensitivity in the sub-nm range) are described.

DOI:10.12693/APhysPolA.142.319 topics: positronium, antimatter, spatial-sensitive detector