Speaker
Description
The Compressed Baryonic Matter (CBM) experiment is currently under development at Facility for Antiproton Ion Research (FAIR) in Darmstadt, Germany. It is a fixed-target heavy-ion experiment designed to explore the Quantum Chromodynamics (QCD) phase diagram at high net baryon densities and moderate temperatures in a triggerless, free-streaming data-acquisition mode. Its Micro-Vertex Detector (MVD), placed inside vacuum and located 5$-$20 cm downstream of the target, provides precise tracking and vertex reconstruction in the high track-density and radiation environment close to the interaction point, requiring a low material budget with each layer contributing only 0.3$-$0.5$\%$ X$_{0}$.
CMOS Monolithic Active Pixel Sensors (MAPS), specifically the MIMOSIS derived from ALPIDE (TJ-180 nm), will be employed for all MVD stations. It features a 1024 $\times$ 504 pixel matrix (26.88 $\times$ 30.24 $\mu$m$^{2}$ pitch) with a nominal 5 $\mu$s frame time and about 5-6 $\mu$m single-hit spatial resolution. Additionally, MIMOSIS prototype includes standard and modified pixel variants, two epitaxial options (25/50 µm) and AC/DC-coupled front-ends, which provide a comprehensive design phase space. The sensors are required to withstand a Total Ionizing Dose (TID) of about 5 Mrad and Non-Ionizing Energy Loss (NIEL) fluences up to 7 $\times$ $10^{13}\ \mathrm{n_{eq}}\,\mathrm{cm}^{-2}$ per year of CBM operation. Several prototype generations have been developed through a joint R$\&$D effort by IPHC Strasbourg, Goethe University Frankfurt and GSI Darmstadt. Performance benchmarks and validation of design specifications were established by testing these prototypes both in the laboratory and with minimum-ionizing particles during beam tests. Furthermore, comprehensive tests of radiation tolerance, robustness against heavy-ion impacts and response to inclined tracks have been performed. Beam tests show $>$ 99$\%$ detection efficiency and 5$-$6 $\mu$m spatial resolution after a mixed radiation (TID+NIEL) of 5 Mrad and 1 $\times$ $10^{14}\ \mathrm{n_{eq}}\,\mathrm{cm}^{-2}$.
Baseline integration mounts sensors, wire-bonded to thin flex cables, on Thermal Pyrolytic Graphite (TPG; 380$\mu$m) carriers, which provides stiff, low-X$_{0}$ support and high in-plane thermal conduction ($\sim$1500 W/m.K) within the acceptance. These carriers are clamped to Aluminum (Al) heat sinks for active cooling outside the acceptance. Sensors are integrated on both sides of carrier to achieve 100$\%$ fill factor.
In this contribution, we present recent results from MIMOSIS sensors and outline the plan for pre-production as we progress toward station assembly and Day-1 readiness for first beam.
| Position | Postdoc |
|---|---|
| Affiliation | Goethe University Frankfurt |
| Country | Germany |
