Advances towards a new measurement of the 1S–2S transition of positroniumThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010

In this paper, a new experiment is presented to measure the 1S–2S transition of positronium, the bound state of an electron and a positron. The goal is to improve the current accuracy by a factor of 5 to reach a precision of the order of 0.6 ppb, to check recent QED calculations. This accuracy is challenging, but it seems well within reach in view of the technological advances that have occurred during the last two decades. We will present the details of the experimental set-up, the advances in the production of positronium, the developments of the laser system, and as well our new experimental technique for the detection of Ps in the 2S state.