Speaker
Description
The ALICE collaboration is pursuing the development of a novel and
considerably improved vertexing detector called ITS3, to replace the
three innermost layers of the Inner Tracker System during the LHC Long
Shutdown 3.
The primary goals are to reduce the material budget to the
unprecedented value of 0.05% X_{0} per layer, and to place the first layer
at a radial distance of 18 mm from the interaction point. These
features will boost the impact parameter resolution by a factor two
over all momenta and drastically enhance the tracking efficiency at
low transverse momentum.
The new detector will consist of true cylindrical layers. Each
half-cylinder is based on curved wafer-scale monolithic pixel
sensors. The bending radii are 18, 24 and 30 mm, and the length of the
sensors in the beam direction is 27 mm.
The sensors will be produced using a commercial 65 nm CMOS Imaging
technology and a recent technique called stitching. This allows to
manufacture chips reaching the dimensions of 27 cm x 9 cm on silicon
wafers of 300 mm diameter. The chips will be thinned down to 50 um or
below.
The ITS3 concept foresees cooling by air flow, ultra-light carbon foam
support elements and no flexible printed circuits in the active area.
This demands a power density limit of 20 mW/cm^{2} for the sensor,
and the need to distribute supply and transfer data over the entire
sensors towards circuits located at the short edges of the chip.
This contribution will summarise the status of the microelectronic
developments and present selected results from the characterisation of
the first prototype chips.
Furthermore, it will describe the ongoing efforts on the design of a
first wafer-scale stitched sensor prototype, the MOSS (Monolithic
Stitched Sensor) chip.
| Collaboration | ALICE Collaboration |
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