Upgrade of the CMS Tracker with tracking trigger

Abstract

The planned upgrades of the LHC and its injector chain are expected to allow operation at luminosities around or above 5×10 34 cm −2 s −1 sometimes after 2020, to eventually reach an integrated luminosity of 3000 fb −1 at the end of that decade. In order to fully exploit such operating conditions and the delivered luminosity, CMS needs to upgrade its tracking detectors and substantially improve its trigger capabilities. To achieve such goals, R&D activities are ongoing to explore options and develop solutions that would allow including tracking information at Level-1. Some of the options considered are reviewed, discussing their potential advantages and disadvantages.

CMS HPK sensor characterisation

“…Now we are beginning to study implications of the measured sensor properties on a binary readout and on the discrimination concept as described in [4]. This should allow us, together with the additional measurements, to conclude on the baseline sensor material for the CMS Tracker Upgrade by spring 2013.…”

“…For the Upgrade we investigate thinner sensors (50 µm to 320 µm) because of the smaller expected full depletion voltage and leakage current and the reduced material budget. For a currently discussed module type (2S-module [4]) consisting of two strip sensors the difference between 300 µm and 200 µm thick silicon makes up about 30% of the total radiation length of the module and therefore also a large fraction of the radiation length of the tracker. The radiation length of the tracking region needs to be kept to a Figure 1: Radial dependence of the particle fluence as simulated by FLUKA for the current CMS tracker layout assuming an integrated luminosity of 3000 fb −1 (data from [2]).…”

“…This can be used to spare the commonly used additional glass pitch-adapter by implementing the pitch-adapter on the sensor itself. Another application is the connection of sensitive regions in the centre of the sensor to the outer edge for a more convenient connection to the read-out chips as needed for the 2S-module concept [4]. All these aspects are addressed by one big irradiation and measurement campaign within the CMS Tracker Upgrade group.…”

“…IV 4 and CV 5 measurements, Transient Current Technique (TCT) [7] and edge-TCT measurements to extract the charge collection efficiency (CCE), trapping and electric fields. Thermally Stimulated Current and Deep Level Transient Spectroscopy to investigate defect characteristics.…”

A simulation framework for the CMS Track Trigger electronics

“…The current trigger system of CMS is unable to cope with the anticipated collision rate. Hence, tracks of charged particles in the silicon tracker must be considered by the first level trigger to take reliable trigger decisions [2]. Figure 1 shows the CMS Track Trigger within the context of the global CMS trigger system.…”