Speaker
Mr
Viktor Ratza
(Helmholtz-Institut für Strahlen- und Kernphysik, Germany)
Description
In the context of the upgrade of the LHC during the second long shutdown the interaction rate of the ALICE experiment will be increased up to
50 kHz for Pb-Pb collisions. As a consequence, a continuous operation and read-out of the Time Projection Chamber (TPC) will be required.
To handle the expected increase of space-charge distortions without a gating grid, the ion backflow of the charge amplification system has to be significantly reduced, maintaining at the same time an excellent detector performance and stability. Although a solution with four Gaseous Electron Multipliers (GEMs) has been adopted for the upgraded chambers,
an alternative approach using one Micromegas (MM) and two GEMs has also been investigated. Due to the geometric and electrostatic structure of the MM the ion backflow suppression capability is superior to a single GEM. The two GEM stages in front of the MM are installed to further reduce the ion backflow and to keep the discharge probability of the device at a reasonable level. The recent results of this study will be presented and compared to measurements with four GEM foils.
Supported by BMBF and EU.
Primary author
Mr
Viktor Ratza
(Helmholtz-Institut für Strahlen- und Kernphysik, Germany)
Co-authors
Prof.
Bernhard Ketzer
(Helmholtz-Institut für Strahlen- und Kernphysik, Germany)
Dr
Markus Ball
(Helmholtz-Institut für Strahlen- und Kernphysik, Germany)
