Velocity-selected production of 2S3 metastable positronium

Positronium in the 2 3 S metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns), making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, 2 3 S positronium is produced, in the absence of an electric field, via spontaneous radiative decay from the 3 3 P level populated with a 205-nm UV laser pulse. Thanks to the short temporal length of the pulse, 1.5 ns full width at half maximum, different velocity populations of a positronium cloud emitted from a nanochanneled positron-positronium converter were selected by delaying the excitation pulse with respect to the production instant. 2 3 S positronium atoms with velocity tuned between 7 7 10 4 ms 121 and 10 7 10 4 ms 121 were thus produced. Depending on the selected velocity, a 2 3 S production efficiency ranging from 3c0.8% to 3c1.7%, with respect to the total amount of emitted positronium, was obtained. The observed results give a branching ratio for the 3 3 P-2 3 S spontaneous decay of (9.7 \ub1 2.7)%. The present velocity selection technique could allow one to produce an almost monochromatic beam of 3c1 7 10 3 2 3 S atoms with a velocity spread of <10 4 ms 121 and an angular divergence of 3c50 mrad

Development of nuclear emulsions operating in vacuum for the AEgIS experiment

For the first time the AEgIS (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) experiment will measure the Earth\u2019s local gravitational acceleration g on antimatter through the evaluation of the vertical displacement of an antihydrogen horizontal beam. This will be a model independent test of the Weak Equivalence Principle at the base of the general relativity. The initial goal of a g measurement with a relative uncertainty of 1% will be achieved with less than 1000 detected antihydrogens, provided that their vertical position could be determined with a precision of a few micrometers. An emulsion based detector is very suitable for this purpose featuring an intrinsic sub-micrometric spatial resolution. Nevertheless, the AEgIS experiment re- quires unprecedented operational conditions for this type of detector, namely vacuum environment and very low temperature. An intense R&D activity is presently going on to optimize the detector for the AEgIS experimental requirements with rather encouraging results

A 3c100\u202f\u3bcm-resolution position-sensitive detector for slow positronium

In this work we describe a high-resolution position-sensitive detector for positronium. The detection scheme is based on the photoionization of positronium in a magnetic field and the imaging of the freed positrons with a Microchannel Plate assembly. A spatial resolution of (88 \ub1 5) \u3bcm on the position of the ionized positronium \u2013in the plane perpendicular to a 1.0 T magnetic field\u2013 is obtained. The possibility to apply the detection scheme for monitoring the emission into vacuum of positronium from positron/positronium converters, imaging positronium excited to a selected state and characterizing its spatial distribution is discussed. Ways to further improve the spatial resolution of the method are presented

Overview of Recent Work on Laser Excitation of Positronium for the Formation of Antihydrogen

The AEgIS experiment carried out at CERN aims to form a cold antihydrogen beam to perform precision studies on gravity. A key ingredient is the creation of antihydrogen via a charge-exchange process between trapped antiprotons and Rydberg excited positronium atoms (Ps). In the present, the latest results of laser excitation of Ps are reviewed, as well as studies on a possible laser manipulation and cooling of Ps and antiprotons

Detection of low energy antiproton annihilations in a segmented silicon detector

The goal of the AEbar gIS experiment at the Antiproton Decelerator (AD) at CERN, is to measure directly the Earth's gravitational acceleration on antimatter by measuring the free fall of a pulsed, cold antihydrogen beam. The final position of the falling antihydrogen will be detected by a position sensitive detector. This detector will consist of an active silicon part, where the annihilations take place, followed by an emulsion part. Together, they allow to achieve 1% precision on the measurement of bar g with about 600 reconstructed and time tagged annihilations. We present here the prospects for the development of the AEbar gIS silicon position sentive detector and the results from the first beam tests on a monolithic silicon pixel sensor, along with a comparison to Monte Carlo simulations

Characterization of a transmission positron/positronium converter for antihydrogen production

none70This work was supported by the Swiss National Science Foundation Ambizione Grant (No. 154833); Istituto Nazionale di Fisica Nucleare; a Deutsche Forschungsgemeinschaft research grant; an excellence initiative of Heidelberg University; European Research Council under the European Union's Seventh Framework Program FP7/2007-2013 (Grants Nos. 291242 and 277762); Austrian Ministry for Science, Research, and Economy; Research Council of Norway; Bergen Research Foundation; John Templeton Foundation; Ministry of Education and Science of the Russian Federation and Russian Academy of Sciences; and the European Social Fund within the framework of realizing the project, in support of intersectoral mobility and quality enhancement of research teams at Czech Technical University in Prague (Grant No. CZ.1.07/2.3.00/30.0034).Aghion, S.; Amsler, C.; Ariga, T.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Kellerbauer, A.; Krasnickã½, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Mazzotta, Z.; Mã¼ller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacifico, N.; Pagano, D.; Penasa, L.; Petracek, V.; Povolo, L.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Resch, L.; Rienã¤cker, B.; Robert, J.; Rã¸hne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Simon, M.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeskal, J.; Zurlo, N.; Andersen, S. L.; Chevallier, J.; Uggerhã¸j, U. I.; Lyckegaard, F.Aghion, S.; Amsler, C.; Ariga, T.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, Andrea; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Kellerbauer, A.; Krasnickã½, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Mazzotta, Z.; Mã¼ller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacifico, N.; Pagano, D.; Penasa, L.; Petracek, V.; Povolo, L.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Resch, L.; Rienã¤cker, B.; Robert, J.; Rã¸hne, O. M.; Rotondi, Alberto; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Simon, M.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeskal, J.; Zurlo, N.; Andersen, S. L.; Chevallier, J.; Uggerhã¸j, U. I.; Lyckegaard, F

The AEgIS Experiment

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

Particle tracking at 4K: The Fast Annihilation Cryogenic Tracking (FACT) detector for the AEgIS antimatter gravity experiment

The AEgIS experiment is an international collaboration with the main goal of performing the first direct measurement of the Earth's gravitational acceleration on antimatter. Critical to the success of AEgIS is the production of cold antihydrogen (H) atoms. The FACT detector is used to measure the production and temperature of the H atoms and for establishing the formation of a H beam. The operating requirements for this detector are very challenging: it must be able to identify each of the thousand or so annihilations in the 1 ms period of pulsed H production, operate at 4 K inside a 1 T solenoidal field and not produce more than 10 W of heat. The FACT detector consists of two concentric cylindrical layers of 400 scintillator fibres with a 1 mm diameter and a 0.6 mm pitch. The scintillating fibres are coupled to clear fibres which transport the scintillation light to 800 silicon photomultipliers. Each silicon photomultiplier signal is connected to a linear amplifier and a fast discriminator, the outputs of which are sampled continuously by Field Programmable Gate Arrays (FPGAs). In the course of the developments for the FACT detector we have established the performance of scintillating fibres at 4 K by means of a cosmic-ray tracker operating in a liquid helium cryostat. The FACT detector was installed in the AEgIS apparatus in December 2012 and will be used to study the H formation when the low energy antiproton physics programs resume at CERN in the Summer of 2014. This paper presents the design requirements and construction methods of the FACT detector and provides the first results of the detector commissioning

Measuring with , progress and perspectives

Aegis experiment's main goal is to measure the local gravitational acceleration of antihydrogen g and thus perform a direct test of the weak equivalence principle with antimatter. In the first phase of the experiment the aim is to measure g with 1% relative precision. This paper presents the antihydrogen production method and a description of some components of the experiment, which are necessary for the gravity measurement. Current status of the Aegis experimental apparatus is presented and recent commissioning results with antiprotons are outlined. In conclusion we discuss the short-term goals of the Aegis collaboration that will pave the way for the first gravity measurement in the near future