Purpose: This paper presents a novel method to reconstruct the incident angle of electromagnetic showers in isotropic calorimeters, aiming to improve angular resolution. Methods: To address events with arbitrary incident angles, a virtual layer method is employed to virtually segment the calorimeter into multiple layers perpendicular to the shower axis. The energy distribution within these layers is calculated based on the deposited energy and volume proportions. Subsequently, the Adjacent-Cells Energy Ratio (ACER) method is applied to reconstruct the shower axis with high precision. Results: At 1 TeV, the angular resolution achieves 0.91<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation> with the proposed method. In contrast, Principal Component Analysis (PCA) and Convolutional Neural Networks (CNNs) yield resolutions of 1.52<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation> and 0.97<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>. For beam test data at 200 GeV, this method attains a resolution of 0.72<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>, showing significantly better performance than the CNN method which obtain 0.99<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$^{\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation> resolution. Conclusion: The ACER method provides a robust and high-precision solution for the angular reconstruction of electromagnetic showers in isotropic calorimeters.

Angle reconstruction using adjacent-cells energy ratio method in 3D isotropic calorimeter

期刊论文
发表日期：

2026年5月14日

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Hao Chen,
Cheng Zhang,
Peidong Chen,
Shanglin Li,
Hengyi Cai,
Zhicheng Tang,
Senquan Lu,
Zetong Sun,
Fengze Zhang,
Haotian Yang,
Yuhang You,
Zixuan Yan,
Ye Tian,
Hongqing Wu,
Zuhao Li

摘要

Purpose: This paper presents a novel method to reconstruct the incident angle of electromagnetic showers in isotropic calorimeters, aiming to improve angular resolution. Methods: To address events with arbitrary incident angles, a virtual layer method is employed to virtually segment the calorimeter into multiple layers perpendicular to the shower axis. The energy distribution within these layers is calculated based on the deposited energy and volume proportions. Subsequently, the Adjacent-Cells Energy Ratio (ACER) method is applied to reconstruct the shower axis with high precision. Results: At 1 TeV, the angular resolution achieves 0.91 $^{\circ }$ $^{\circ}$ with the proposed method. In contrast, Principal Component Analysis (PCA) and Convolutional Neural Networks (CNNs) yield resolutions of 1.52 $^{\circ }$ $^{\circ}$ and 0.97 $^{\circ }$ $^{\circ}$ . For beam test data at 200 GeV, this method attains a resolution of 0.72 $^{\circ }$ $^{\circ}$ , showing significantly better performance than the CNN method which obtain 0.99 $^{\circ }$ $^{\circ}$ resolution. Conclusion: The ACER method provides a robust and high-precision solution for the angular reconstruction of electromagnetic showers in isotropic calorimeters.