Sep 25 – 29, 2006
Valencia, Spain
Europe/Zurich timezone

Stacked Tracking for CMS at Super-LHC

Sep 29, 2006, 11:50 AM
Valencia, Spain

Valencia, Spain

IFIC – Instituto de Fisica Corpuscular Edificio Institutos de Investgación Apartado de Correos 22085 E-46071 València SPAIN


John Jones (Imperial College London)


We report on recent work on the design of a pixel detector for CMS at the Super-LHC. This work builds on previous studies on a tracking detector capable of providing track stubs to be used in the Level-1. We now focus on the use of two layers of tracking, each comprising stacks of pixel sensors with 20x50x10μm3 pitch (θxφxr) and separated by a few millimetres. Preliminary work on track reconstruction in Field Programmable Gate Arrays (FPGAs) is also presented.


Currently groups of researchers are actively discussing possible scenarios of
upgrades of the LHC machine. According to the most financially realistic scenario the
LHC will be upgraded to provide proton beams of an order of magnitude larger
intensity (1035 cm-2 sec-1) colliding at twice the frequency (80 MHz) of the present
design but have the same centre of mass energy. This machine design is commonly
referred as the Super-LHC and it is expected to be operational after 2015. A
consequence of this design is that the backgrounds due to minimum bias events will
increase by at least a factor of 5. It is anticipated that CMS will require tracking
information in order for the trigger to be operated efficiently in this environment.

The performance of a single stack has been discussed in LECC 2005. In this paper we
review this approach, using a PYTHIA-based Monte Carlo as a reference. We then expand
the approach to cover the use of multiple stacks (in particular the double-stack
method), showing potential improvements in reconstructed resolution (both momentum
and position) as well as reconstruction purity. It has been found that the
reconstruction method can be implemented in the current generation of FPGAs, on a
comparable scale to the other trigger systems currently in CMS, and within the
current time budget of the Level-1 trigger.

Primary author

John Jones (Imperial College London)


Mr Andrew Rose (Imperial College London) Mr Benjamin Constance (Imperial College London) Dr Costas Foudas (Imperial College London) Prof. Geoffrey Hall (Imperial College London) Mr Keija Zhu (Imperial College London) Dr Mark Raymond (Imperial College London)

Presentation materials