ALICE ITS3 - A bent wafer-scale monolithic pixel detector

About

ALICE is upgrading its inner three silicon tracker layers with a bent wafer-scale monolithic pixel detector (ITS3). Each layer comprises two sensors, 27 cm long, 50 µm thick and bent to concentric half-layers around the beam pipe (radii: 19, 25, 32 mm) supported by carbon foam stiffeners. The sensors with 40 mW/cm² consumption and a material budget of 0.07% X0 per layer are air-cooled. Fabrication of 27 cm long sensors, requires stitching at foundry level connecting identical reticle-sized sensor elements, bypassing the need for flexible printed circuits. Pixel test structures on a 300 mm, 65 nm TPSCo technology were validated with a resolution of 5 µm, an efficiency of > 99%, a fake hit rate of < 10-2/pixel/s and a radiation load of 4*1014 1 MeV neq cm-2. These findings were further corroborated with 26 cm long Monolithic Stitched Sensor prototypes, confirming the stitching and integration process in laboratory and beam tests. Prototype silicon sensors thinned to ≤ 50 µm were successfully bent to the ITS3's required radii while retaining full functionality. Mechanical engineering models with 50 µm thick dummy sensors demonstrated a mechanical stability of ± 0.5 μm under an 8 m/s airflow, consistent with the sensor's power consumption and the interconnection scheme. The design of the final full-function sensor prototype (MOSAIX) with a pixel size of 22.8 x 20.8 µm2 is underway. The seminar will report on the R&D phase, the final sensor design and detector integration.

Coffee will be served at 10:30 .

0:00:00 Slide 1

0:02:29 Slide 2

0:04:20 Slide 3

0:05:40 Slide 4

0:17:02 Slide 5

0:18:14 Slide 6

0:20:26 Slide 7

0:21:29 Slide 8

0:23:05 Slide 9

0:24:34 Slide 10