Antihydrogen formation in low-energy antiproton collisions with excited-state positronium atoms

© 2018, Springer Nature Switzerland AG. The convergent close-coupling method is used to obtain cross sections for antihydrogen formation in low-energy antiproton collisions with positronium (Ps) atoms in specified initial excited states with principal quantum numbers ni= 5. The threshold behaviour as a function of the Ps kinetic energy, E, is consistent with the 1/E law expected from threshold theory for all initial states. We find that the increase in the cross sections is muted above ni= 3 and that here their scaling is roughly consistent with ni2, rather than the classically expected increase as ni4

Status Report for Experiment AD-4/ACE

Annual report on AD-4 Experiments performed during 201

Using Monolithic Active Pixel Sensors for Fast Monitoring of Therapeutic Hadron Beams

It has been shown that Monolithic Active Pixel Sensors (MAPS) are very promising tools for direct online beam monitoring, for current heavy ion therapy facilities as well as for future innovative cancer treat- ments with antiprotons. More specific, the dead-time free Mimotera sensor has been proven to be capable of dealing with extremely short pulses of antiprotons of only 500 ns duration, as well as with continuous beams of carbon ions in the complete intensity- and energy range used in today\u2019s heavy ion \ufffc\ufffcfacilities. It shows a linear behavior up to 7.5 ions/cm2/s

Towards the production of an ultra cold antihydrogen beam with the AEGIS apparatus

The AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment is an international collaboration, based at CERN, with the experimental goal of performing the first direct measurement of the Earth's gravitational acceleration on antihydrogen. In the first phase of the experiment, a gravity measurement with 1% precision will be performed by passing a beam of ultra cold antihydrogen atoms through a classical Moiré deflectometer coupled to a position sensitive detector. The key requirements for this measurement are the production of ultra cold (T∼100mK) Rydberg state antihydrogen and the subsequent Stark acceleration of these atoms. The aim is to produce Rydberg state antihydrogen by means of the charge exchange reaction between ultra cold antiprotons (T∼100mK) and Rydberg state positronium. This paper will present details of the developments necessary for the successful production of the ultra cold antihydrogen beam, with emphasis on the detector that is required for the development of these techniques. Issues covered will include the detection of antihydrogen production and temperature, as well as detection of the effects of Stark acceleratio