Speaker
Katja Klein
(Rheinisch-Westfaelische Tech. Hoch. (DE))
Description
The performance of the Tracker of the CMS experiment, comprising of a pixel and a strip detector, has so far been excellent, as reflected in the wealth of beautiful physics results from CMS. However, the foreseen increases of both the instantaneous as well as the integrated luminosity by the LHC during the next ten years will necessitate a stepwise upgrade of the CMS tracking detector.
In the extended end-of-year shutdown 2016/17 the pixel detector will be exchanged. The new device is designed for an instantaneous luminosity of 2 x 10^34 cm^-2 s^-1 and an integrated luminosity of 500fb-1. The number of layers will be increased from three to four in the barrel part and from two to three in the end caps, thus providing 4-hit coverage over the full pseudorapidity range. A smaller beampipe allows to decrease the radius of the innermost layer, which improves the tracking performance. Further improvements include a new readout chip, which will decrease dead time and thus increase hit efficiencies; reduction of material; and the installation of more efficient cooling (two-phase CO2) and powering (DC-DC conversion) systems.
Around 2022, in Long shutdown 3, the whole tracker will need to be replaced, in order to be able to cope with an instantaneous luminosity of 5 x 10^34 cm^-2 s^-1 and an integrated luminosity of 3000 fb-1, as expected for the High Luminosity LHC (HL-LHC). A new challenge is the requirement that tracker information should be usable in the Level 1 trigger decision. This has lead to a dedicated module design with two closely spaced sensor layers whose hits are correlated in the module electronics. In this way an estimate on the transverse momentum can be made and stiff tracks can be selected, significantly reducing the data volume to be processed.
This talk will motivate the design choices for the CMS pixel and outer tracker upgrades. The status and plans of these projects will be summarized and highlights of the R&D will be described
Primary author
Katja Klein
(Rheinisch-Westfaelische Tech. Hoch. (DE))
