The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high ...interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics--the moiré deflectometer--for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.
The principal aim of the AEgIS experiment at CERN is to measure the acceleration of antihydrogen due to Earth's gravitational field. This would be a test of the Weak Equivalence Principle, which ...states that all bodies fall with the same acceleration independently of their mass and composition. The effect of Earth's gravitational field on antimatter will be determined by measuring the deflection of the path of the antihydrogen from a straight line. The position of the antihydrogen will be found by detecting its annihilation on the surface of a silicon detector. The gravitational measurement in AEgIS will be performed with a gravity module, which includes the silicon detector, an emulsion detector and a scintillating fibre time-of-flight detector. As the experiment attempts to determine the gravitational acceleration with a precision of 1%, a position resolution better than 10 μm is required. Here we present the results of a study of antiproton annihilations in a 3D silicon pixel sensor and compare the results with a previous study using a monolithic active pixel sensor. This work is part of a larger study on different silicon sensor technologies needed for the development of a silicon position detector for the AEgIS experiment. The 3D detector together with its readout electronics have been originally designed for the ATLAS detector at the LHC. The direct annihilation of low energy antiprotons ( ~ 100 keV) takes place in the first few μm of the silicon sensor and we show that the charged products of the annihilation can be detected with the same sensor. The present study also aims to understand the signature of an antiproton annihilation event in segmented silicon detectors and compares it with a GEANT4 simulation model. These results will be used to determine the geometrical and process parameters to be adopted by the silicon annihilation detector to be installed in AEgIS.
We present here a new application of silicon sensors aimed at the direct detection of antinucleons annihilations taking place inside the sensor׳s volume. Such detectors are interesting particularly ...for the measurement of antimatter properties and will be used as part of the gravity measurement module in the AEg¯IS experiment at the CERN Antiproton Decelerator. One of the goals of the AEg¯IS experiment is to measure the gravitational acceleration of antihydrogen with 1% precision. Three different silicon sensor geometries have been tested with an antiproton beam to investigate their properties as annihilation detection devices: strip planar, 3D pixels and monolithic pixel planar. In all cases we were successfully detecting annihilations taking place in the sensor and we were able to make a first characterization of the clusters and tracks.
The AEgIS Experiment Knecht, A.; Aghion, S.; Ahlén, O. ...
Hyperfine interactions,
10/2014, Letnik:
228, Številka:
1-3
Journal Article
Recenzirano
The AEgIS experiment aims at performing the first test of the Weak Equivalence Principle of General Relativity in the antimatter sector by measuring the gravitational acceleration acting on a beam of ...cold antihydrogen to a precision of 1%. The installation of the apparatus is making good progress and large parts were taken into operation. Parasitic detector tests during the beamtime in December 2012 gave essential input for an optimal moiré deflectometer and the detector layout necessary to perform the gravity measurement.
The AEgIS experiment 1 aims at directly measuring the gravitational acceleration g on a beam of cold antihydrogen (H) to a precision of 1%, performing the first test with antimatter of the (WEP) Weak ...Equivalence Principle. The experimental apparatus is sited at the Antiproton Decelerator (AD) at CERN, Geneva, Switzerland. After production by mixing of antiprotons with Rydberg state positronium atoms (Ps), the H atoms will be driven to fly horizontally with a velocity of a few 100 ms super(-1) for a path length of about 1 meter. The small deflection, few tens of mu m, will be measured using two material gratings (of period ~ 80 mu m) coupled to a position-sensitive detector working as a moire deflectometer similarly to what has been done with matter atoms 2. The shadow pattern produced by the H beam will then be detected by reconstructing the annihilation points with a spatial resolution (~ 2 mu m) of each antiatom at the end of the flight path by the sensitive-position detector. During 2012 the experimental apparatus has been commissioned with antiprotons and positrons. Since the AD will not be running during 2013, during the refurbishment of the CERN accelerators, the experiment is currently working with positrons, electrons and protons, in order to prepare the way for the antihydrogen production in late 2014.
Resumen El Instituto de Investigaciones Físicasª (IIF) de la Universidad Mayor de San Andres y el Instituto para la Investigacion de Rayos Cósmicos de Japón (ICRR, por sus siglas en inglés13) de la ...Universidad de Tokio, encabezan una inicia- tiva para construir un observatorio en Bolivia, en las cercanías del monte Chacaltaya. El observatorio planeado no es uno convencional, pues detectaría rayos cosmicos provenientes del espacio exterior en lugar de luz visible. Los objetivos principales de este proyecto serían la astronomía gamma y el estudio de posibles cumulos de materia oscura0 en nuestra galaxia. Los beneficios para nuestro país serían importantes, particularmente en los ambitos de la ciencia, la tecnología y la educacion.
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