# Scalable Deep Convolutional Neural Networks for Sparse, Locally Dense Liquid Argon Time Projection Chamber Data

## TL;DR

This paper demonstrates that Submanifold Sparse Convolutional Networks significantly improve the efficiency and scalability of deep learning for sparse 3D LArTPC data, enabling accurate particle reconstruction in large detectors.

## Contribution

It introduces the application of SSCNs to LArTPC data, achieving substantial reductions in computation and memory costs while maintaining high accuracy in particle identification and reconstruction.

## Key findings

- Inference cost reduced by factors of 364 (3D) and 93 (2D)
- Achieved 93.9% Michel electron identification efficiency
- Reconstructed Michel electrons with over 95% clustering efficiency and purity

## Abstract

Deep convolutional neural networks (CNNs) show strong promise for analyzing scientific data in many domains including particle imaging detectors such as a liquid argon time projection chamber (LArTPC). Yet the high sparsity of LArTPC data challenges traditional CNNs which were designed for dense data such as photographs. A naive application of CNNs on LArTPC data results in inefficient computations and a poor scalability to large LArTPC detectors such as the Short Baseline Neutrino Program and Deep Underground Neutrino Experiment. Recently Submanifold Sparse Convolutional Networks (SSCNs) have been proposed to address this challenge. We report their performance on a 3D semantic segmentation task on simulated LArTPC samples. In comparison with standard CNNs, we observe that the computation memory and wall-time cost for inference are reduced by factor of 364 and 33 respectively without loss of accuracy. The same factors for 2D samples are found to be 93 and 3.1 respectively. Using SSCN, we present the first machine learning-based approach to the reconstruction of Michel electrons using public 3D LArTPC samples. We find a Michel electron identification efficiency of 93.9% with 96.7% of true positive rate. Reconstructed Michel electron clusters yield 95.4% in average pixel clustering efficiency and 95.5% in purity. The results are compelling to show strong promise of scalable data reconstruction technique using deep neural networks for large scale LArTPC detectors.