ATLAS Pixels

Sebastián Grinstein

The Pixel group develops new silicon detector technologies for high energy physics experiments and other applications. After making key contributions to the ATLAS IBL and AFP sub-systems the group is qualifying for the production of 3D sensor modules for the ITk pixel detector while playing a leading role in HGTD. In parallel the group is developing smart silicon sensors for neuromonitoring and exploring new materials for radiation detection.

3D Pixel Sensors for the HL-LHC

After IFAE demonstrated the radiation hardness capabilities of 3D sensors (which surpass any other sensing technology), ATLAS selected these sensors for the innermost layer of the pixel tracker for the high-luminosity era. IFAE is now qualifying it’s assembly line to produce 3D modules for the first barrel layer of the ITk pixel detector. The first step will be the fabrication of RD53A mock modules to be used in demonstrator tests. Three publications were produced in 2020 around the 3D sensor activities.
Figure 1: Assembly process of ITk pixel dummy modules.
Figure 2: ITk pixel dummy modules fabricated at IFAE.


The ATLAS High Granularity Timing Detector (HGTD) upgrade project was approved by ATLAS and CERN in July 2020. IFAE continued to play a leading role in the HGTD activities, leading the sensor, module assembly and test-beam groups. IFAE is also leading the digital design of the final HGTD readout chip (the ALTIROC2) which will be submitted in the first quarter of 2021.


The CMOS effort during 2020 concentrated on the tests of the TaichuPix1 ASIC, an early prototype for the CEPC vertex detector. The TaichuPix1 was partially designed by IFAE and has been characterized in our laboratory. Furthermore, the group continues to explore the usage of HV-CMOS sensors beyond high energy physics, developing CMOS SPADs in the context of a BIST funded project with ICFO. Finally, together with ICN2, IFAE is exploring the usage of 2D materials for MIP detection, also in the framework of a BIST Ignite project.