Speaker
Jan Hendrik Derking
(CERN)
Description
The AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment at CERN has as main goal to perform the first direct measurement of the Earth’s gravitational acceleration on antihydrogen atoms within 1% precision. To reach this precision, the antihydrogen should be cooled down to about 100 mK to reduce its random vertical velocity. This is obtained by mounting a Penning trap consisting of 10 high-voltage electrodes on the mixing chamber of a dilution refrigerator with cooling capacity of 100 µW at 50 mK.
We have investigated the design of the electrodes taking into account that the electrodes should have a temperature lower than 100 mK, must be made of radiation hard materials, and should be in compliance with the ultra-high beam vacuum and a 1T magnetic field of high homogeneity. Some of the electrodes must be electrically split into four sectors. The electrodes need to conduct thermally well while being able to withstand a high-voltage of 1 kV between neighbouring electrodes and the sectors within an electrode.
Currently, the electrodes are made of sapphire with gold deposited high-voltage sectors. To increase the thermal contact, a thin indium sheet is mounted between the electrodes and the mixing chamber to which the electrodes are screwed. We have experimentally tested the thermal performance of the electrode design at operation conditions. In this paper, after recalling the design of the electrodes, we will discuss the thermal link to the mixing chamber and the measured performance of the electrodes.
Author
Jan Hendrik Derking
(CERN)
Co-authors
Gerhard Burghart
Joanna Liberadzka
(W)
Johan Bremer
(CERN)
Thomas Eisel
(CERN)
Torsten Koettig
(CERN)
