# Material Budget Calculation of the new Inner Tracking System, ALICE

**Authors:** Wanchaloem Poonsawat, Chinorat Kobdaj, Mario Sitta, Yupeng Yan  
**arXiv:** [1706.02110](https://arxiv.org/abs/1706.02110)  
**Date:** 2017-06-07  
**Summary page:** https://www.summarizepaper.com/en/paper/1706.02110v2/

## Key points

- The ALICE Collaboration is dedicated to studying the physics of strongly interacting matter through a heavy-ion detector.
- The Inner Tracking System (ITS) is crucial and located at the core of the ALICE Detector around the interaction point.
- An upgrade plan for the ITS aims to enhance detection of rare probes at low transverse momentum.
- The new ITS design includes seven layers of silicon pixel sensors on a supporting structure to reduce material budget per layer.
- Detailed calculations using ALIROOT software show feasibility in achieving targeted material budget reduction for inner and outer barrel components.
- Manufacturing prototypes based on these designs and calculations is underway, with focus on refining material budget distribution within the ITS system.
- Continued efforts will optimize performance for rare probes by leveraging simulation tools and meticulous planning.

## Summary

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The ALICE Collaboration is dedicated to studying the physics of strongly interacting matter through the construction of a heavy-ion detector. The Inner Tracking System (ITS) plays a crucial role in this endeavor, situated at the core of the ALICE Detector around the interaction point. In line with their commitment to advancing research, ALICE has embarked on a plan to enhance the inner tracking system specifically for rare probes at low transverse momentum. This upgrade involves implementing a new ITS design comprising seven layers of silicon pixel sensors on a supporting structure. A key objective of this new design is to reduce the material budget ($X/X_0$) per layer, aiming for 0.3% for inner layers and 0.8% for middle and outer layers. To achieve this goal, detailed calculations based on geometry descriptions of different supporting structures for both inner and outer barrel components were conducted using ALIROOT software. The results demonstrate that it is indeed feasible to achieve the targeted reduction in material budget for both sections of the barrel as envisioned. Furthermore, efforts have been made towards manufacturing prototypes based on these calculations and designs. A comprehensive analysis encompassing various stave models has been carried out, with each model undergoing material budget distribution calculations. Insights and feedback from these calculations have been shared with prototype production teams involved in the ALICE ITS upgrade project. Moving forward, continued focus will be placed on refining the material budget (X/X0) within the ITS system to optimize its performance for rare probes at low transverse momentum. By leveraging advanced simulation tools and meticulous planning, ALICE aims to push boundaries in understanding strongly interacting matter while ensuring efficient detector operation and data collection capabilities are maintained throughout the upgrade process.