Activities of the Korea ALICE group for the development and production of the next-generation silicon tracker

TL;DR

ALICE3 aims to upgrade the LHC's heavy-ion program with a MAPS-based silicon tracking system offering high spatial resolution and low material budget for robust low-$p_T$ tracking in high-multiplicity events. The Korea ALICE group contributes by industrializing the module assembly for the Outer Tracker, leveraging ITS2 experience and partnering with MEMSPACK to build a scalable production workflow. Their work includes automated sensor-to-PCB placement using general-purpose die-bonders, validation of $150~\mu\mathrm{m}$ inter-sensor spacing, and evaluation of room-temperature-curable glues to improve productivity without compromising stability. A proton-irradiation campaign at KOMAC tests glue radiation hardness up to $2.5~\mathrm{Mrad}$ TID and $1.5\times 10^{13}$ neq/cm$^{2}$, informing production choices. The results support a scalable, industry-backed production workflow capable of delivering thousands of MAPS-based OT modules, enabling ALICE3's expanded physics program.

Abstract

ALICE 3 is the proposed next-generation heavy-ion experiment at the CERN Large Hadron Collider (LHC), envisioned for operation during Run 5. The tracking system of ALICE 3 will consist of a high-precision vertex detector integrated into a retractable structure inside the beam pipe, complemented by a large-area outer tracker covering a broad pseudorapidity range. Both systems will be based on the Monolithic Active Pixel Sensor (MAPS) technology, building upon the developments realized for the recently upgraded ALICE Inner Tracking System (ITS2) and the future ITS3 upgrade. The total silicon area of the ALICE 3 tracking system is expected to be approximately five times larger than that of ITS2, presenting significant challenges in terms of large-scale sensor testing and module production. To address these challenges, research and development activities have been initiated in Korea, including the adaptation of an automated die-attach machine, commonly used in the semiconductor packaging industry, for efficient sensor-to-substrate assembly. This contribution presents the ongoing efforts of the Korea ALICE group toward the development and production of the ALICE 3 silicon tracker. The scope includes sensor evaluation, automated assembly techniques, and prototype module construction, with the aim of establishing scalable procedures for future mass production.

Figures (7)

• Figure 1: The schematic view of the ALICE 3 detector.
• Figure 2: Dummy modules assembled with the ITS2 Outer Barrel (OB) mechanical design.
• Figure 3: Dummy modules assembled with the ALICE 3 OT module mechanical design.
• Figure 4: Dummy modules assembled with two different glues.
• Figure 5: Conceptual diagram of the automated setup for continuous production of detector modules.