Sep 12 – 17, 2021
University of Birmingham
Europe/London timezone

Testbeam performance results of bent ALPIDE MAPS in view of the ALICE Inner Tracking System 3

Sep 17, 2021, 8:02 AM
Teaching and Learning Building (University of Birmingham)

Teaching and Learning Building

University of Birmingham

Edgbaston Campus University of Birmingham B15 2TT UK
poster Advances in Pixel Detectors and Integration Technologies Poster Sesion 6 (Advances in Pixel Detectors and Integration Technologies)


Mr Bogdan Mihail Blidaru (ALICE Collaboration)


The ALICE Inner Tracking System (ITS) has been recently upgraded to a full silicon detector consisting entirely of Monolithic Active Pixel Sensors (MAPS), arranged in seven concentric layers around the beam pipe. Further ahead, during the LHC Long Shutdown 3, ALICE intends to replace the three innermost layers of this new ITS with a novel vertex detector. To accomplish this, the proposed design features wafer-scale, ultra-thin, truly cylindrical MAPS. The new sensors will be thinned down to 20-40 $\mu$m, featuring unprecedented low material budget of below 0.05% X0 per layer and will be arranged concentrically around the beam pipe, as close as 18 mm from the interaction point.

Anticipating the first prototypes in the new 65 nm technology node, an active R&D programme is underway to test the response to bending of existing 50 $\mu$m-thick ALPIDE sensors. A number of such chips were successfully bent, even below the targeted innermost radius, without signs of mechanical damage, while retaining their full electrical functionality in laboratory tests. The curved detectors were subsequently tested during particle beam campaigns, where their particle detection performance was assessed.

In this contribution, testbeam highlights from the data analysis of bent ALPIDE sensors, will be presented. It was proved that the current ALPIDE 180 nm technology retains its properties after bending. The results show an inefficiency that is generally below $10^{-4}$, independent of the inclination and position of the impinging beam with respect to the sensor surface. This encouraging outcome proves that the use of curved MAPS is an exciting possibility for future silicon detector designs, as the sensor can not only survive the bending exercise, but its performance as a vertex detector is comparable to that in the flat state.

Institute Ruprecht Karls Universitaet Heidelberg (DE)
Your name Bogdan Blidaru
Title Mr

Primary author

Mr Bogdan Mihail Blidaru (ALICE Collaboration)

Presentation materials