Speaker
Description
Silicon strip sensors have long set the standard for precision tracking, but
next-generation heavy-ion experiments demand detectors that combine ultra
low mass with extreme rate capability. The Silicon Tracking System (STS) of
the Compressed Baryonic Matter (CBM) experiment addresses these unique
challenges: fixed-target operation, very high track multiplicities, and continu-
ous, self-triggered readout, while targeting a 2–7% X 0 material budget across 4
m 2 of active area and hit rates of 10 MHz/cm 2 .
To meet these demands, we employ double-sided, double-metal (DSDM) sil-
icon microstrip sensors (320±15 µm thick) with 2 × 1024 channels at 58 µm
pitch, providing excellent spatial granularity. Sensors are connected via ultra-
light aluminum–polyimide microcables to minimize material while preserving
signal integrity. Readout is provided by the SMX2.2 ASIC, a self-triggering
front end with fast shaping, discrimination, a 5-bit flash-ADC amplitude mea-
surement, and 14-bit time stamping. This architecture delivers timing precision
of ∆t ≈ 5 ns and maintains low noise of about 1000 e. Dense detector in-
tegration, together with optimized grounding and powering, yields a per layer
material budget below 1% X 0 and stable performance under high-radiation, high
occupancy CBM conditions.
We present the current status of STS construction, with nearly three-quarters
of the detector modules produced and tested. Module and ladder level integra-
tion results, including pulse-scan studies under various SMX2.2 configurations,
demonstrate the STS’s readiness for large-scale deployment in the CBM heavy-
ion program.