Orateur
Dr
auguste besson
(Institut Pluridisciplinaire Hubert Curien)
Description
CMOS Pixel Sensors (CPS) are foreseen to equip vertex detectors
where priority is given to granularity, material budget and power
consumption, potentially at the expense of read-out speed and
radiation tolerance. Being initially developed for an experiment
at the ILC, the sensors came out to be well suited to Heavy Ion
Collision experiments (STAR at RHIC, CBM at FAIR, ...) and their
intrinsic potential offers attractive perspectives for the vertex
detector to be operated at the SuperB factory. Another trend
motivating their continuous development concerns trackers, where
granularity is less an issue but material budget, power consumption
and fabrication costs may be significantly reduced when using CMOS
pixel sensors intead of usual semi-conducting devices.
For many years, CPS were manufactured with commercial wafers
featuring exclusively low resistivity (i.e. typically 10 ohm.cm)
epitaxial layers. The interest of industry for high resistivity
epitaxial layers is a rather recent event, with a considerable
impact on the potential of the CPS (e.g. a typical signal-to-noise
ratio of about 35-40). Several sensors were fabricated since early
2010 with a 400 ohm.cm resistivity epitaxial layer, available in
a 0.35 mum process, and tested on particle beams. Their detection
performances were assessed extensively, mainly in perspective of
their implementation in the two internal layers of the STAR-HFT.
Featuring a total material budget per layer of 0.37 % of radiation
length, the HFT is foreseen to start data taking in 2013/2014.
The talk will summarise the test results of the STAR-HFT sensor
and provide insight of the next steps of the R&D, which are based
on an emerging CMOS technology using a 0.18 mum feature size and
offering a >= 1 kohm.cm epitaxy. Moreover, the development of a
very light ladder equipped on both faces with 50 mum thin sensors,
as well as supportless pixelated systems featuring < 0.15 % of
radiation length, will be described. Finally, the evolution of
the R&D, exploiting specific features of the 0.18 mum technology,
will be overviewed, including a large area beam telescope for the
EU-FP7 project AIDA.
Auteur principal
Auguste Besson
(IReS)
