24-28 February 2020
Budker Institute of Nuclear Physics
Asia/Novosibirsk timezone

Commissioning of the New ALICE Inner Tracking System

25 Feb 2020, 10:10
Contributed Oral Tracking and vertex detectors Tracking and vertex detectors


Mr James Iddon (CERN)


The upgrade of the Inner Tracking System (ITS) of the ALICE detector will extend measurements of heavy-flavour hadrons and low-mass dileptons to a lower $p_T$ and increase the read-out capabilities to incorporate the full interaction. Furthermore, the tracking efficiency will be improved at low $p_T$. Some of the new measurements of heavy-flavour probes possible after the ITS upgrade and with an integrated luminosity of $10nb^{-1}$ include the nuclear modification factor and anisotropic flow down to $p_T$ of 2 GeV/c and 3 GeV/c respectively for the $\Lambda_c$ baryon. To achieve this, the new ITS is comprised of 7 layers of a custom monolithic active pixel sensor design known as ALPIDE. The use of the ALPIDE-based detector design will reduce the material budget to 0.35%$X_0$ per layer for the inner most three layers, and to 1.0%$X_0$ per layer for the outer most four layers, compared to 1.14%$X_0$ per layer in the previous ITS. The readout rate will be improved to 100 kHz for Pb-Pb interactions, which is the double of the upgrade requirement. In addition, the radius of the first layer of the ITS will be reduced from 39mm to 23mm and the pixel size reduced to $O(30\mu m)$ x $O(30\mu m)$. The effort in over 10 construction sites has resulted in a fully assembled and connected detector, which is currently under going on surface commissioning before it will be installed in the ALICE cavern in July 2020. This contribution will discuss the current status of the commissioning of the new ITS, including the methods used to characterise the detector and the results obtained so far.

Primary authors

Presentation Materials