HACKSTOCK P.

The foreseen production of cold antihydrogen atoms at CERN's Antiproton Decelerator (AD) opened up the possibility to perform direct measurements of Earth's gravitational acceleration on antimatter bodies. This is one of the goals of the AEgIS collaboration: measure the value of g using a pulsed source of cold antihydrogen and a moiré...

We investigate experimentally the possibility of enhancing the production of 2S3 positronium atoms by driving the 1S3-3P3 and 3P3-2S3 transitions, overcoming the natural branching ratio limitation of spontaneous decay from 3P3 to 2S3. The decay of 3P3 positronium atoms toward the 2S3 level has been efficiently stimulated by a 1312.2 nm...

Positronium in the 2S3 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, 2S3 positronium is produced, in the absence of an electric field, via spontaneous radiative decay from the...

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±5) μm on the position of the ionized positronium –in the plane...

The 33P state of positronium is an intermediate level suitable for producing long-lived positronium states. On one hand, it can be used in a two-step laser excitation scheme from the ground state to Rydberg levels. On the other hand, excitation of positronium to 33P level is a simple pathway for producing metastable 23S positronium atoms by...

We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4K and are read out by...

Studies of antimatter are important for understanding our universe at a fundamental level. There are still unsolved problems, such as the matter-antimatter asymmetry in the universe. The AEgIS experiment at CERN aims at measuring the gravitational fall of antihydrogen in order to determine the gravitational force on antimatter. The proposed...

Producing positronium (Ps) in the metastable 23S state is of interest for various applications in fundamental physics. We report here on an experiment in which Ps atoms are produced in this long-lived state by spontaneous radiative decay of Ps excited to the 33P level manifold. The Ps cloud excitation is obtained with a UV laser pulse in an...

AEgis (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is a CERN based experiment aiming to probe the Weak Equivalence Principle of General Relativity with antimatter by studying free fall of antihydrogen in the Earthfs gravitational field. A pulsed cold beam of antihydrogen produced by charge exchange between Rydberg positronium...

Forming a pulsed beam of cold antihydrogen using charge-exchange with Rydberg positronium (Ps) is the goal of the AE?IS collaboration, which aims to a first gravity measurement on neutral antimatter. Recently achieved results in Ps formation and laser spectroscopy in the main AE?IS apparatus are summarized. First, Ps has been produced using...

The AEgIS experiment aims at producing antihydrogen (and eventually measuring the effects of the Earth gravitational field on it) with a method based on the charge exchange reaction between antiproton and Rydberg positronium. To be precise, antiprotons are delivered by the CERN Antiproton Decelerator (AD) and are trapped in a multi-ring Penning...