Speaker
Description
The ePIC silicon vertex tracker (SVT) will feature five-barrel layers and five disks at each end. The outer barrel (OB) consists of two layers at radii of 270 mm (L3) and 420 mm (L4). All parts of the SVT must satisfy extremely low material targets, of 0.25% X0 for L3 and 0.55% X0 for L4. The SVT will utilise a reduced-size version of the MOSAIX MAPS sensor, originally developed for the ALICE ITS3 detector. These large area sensors (LAS) are thinned to 40 μm, with dimensions of 20 mm in width and either 110 mm or 130 mm in length.
Mechanically, the OB layers are segmented into staves, each two sensors wide and supporting a total of 8 sensors (L3) or 16 sensors (L4). The power consumption per stave is approximately 25 W (L3) or 50 W (L4). To minimize service material, we aim to use serial powering and air cooling. Serial powering requires an ancillary chip that generates significant heat, necessitating careful thermal management. Air cooling will primarily rely on forced airflow through the stave core.
Since the last forum, several quarter-length stave prototypes have been constructed to validate forced internal airflow cooling performance. Thermomechanical dummy modules simulate heat load from the LAS and ancillary ASIC. Experimental assessments of thermal performance, pressure loss and airflow induced vibrations were carried out to verify the accuracy of computational fluid dynamics (CFD), and Finite Element simulations. These assessments have guided the design of a full-length L4 stave, currently in production. This talk will present the updated stave design, along with results from experimental testing, mechanical and thermal finite element analysis (FEA) and CFD of the airflow in the stave core.
