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Members of the ALPHA collaboration during shift work in the control room

AEgIS – Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy

Measuring g with a beam of antihydrogen

The primary scientific goal of the AEgIS experiment - a collaboration of physicists from all over Europe - is the direct measurement of the Earth's gravitational acceleration, g on antihydrogen.

In the first phase of the experiment, the AEgIS team will pass an antihydrogen beam through a classical Moire deflectometer coupled to a position- sensitive detector to measure the strength of the gravitational interaction between matter and antimatter to a precision of 1%.

A system of gratings in the deflectometer splits the antihydrogen beam into parallel rays, forming a periodic pattern. From this pattern, physicists can measure how much the antihydrogen beam drops during its horizontal flight. Combining this shift with the time each atom flew and fell, the AEgIS team can then determine the strength of the gravitational force between the Earth and the antihydrogen atoms.

The AEgIS experiment will represent the first direct measurement of a gravitational effect on an antimatter system.