Advanced particle acceleration methods have produced high-peak-current ion beams with broad energy spread and complex spatial distribution. There is an urgent need to develop online spatial-resolved energy spectrometers for high-energy pulsed ions. This paper introduces a novel spectrometer based on a scintillation-fiber cube for online diagnosis of proton beams with broadband energy spread and complex spatial distribution. We present its working principles, experimental setup, and comprehensive calibration using monoenergetic and spatially uniform proton beams generated by a synchrotron accelerator. Calibration results confirm an energy measurement range of 6-93 MeV, a relative energy uncertainty of 0.6% at 80 MeV, and a pixel size of 0.5 mm for beam profile reconstruction. By exploiting a custom-designed energy degrader, we generated a complex proton beam and measured it with the scintillation-fiber cube spectrometer (SFICS). The results demonstrate the spectrometer's potential for online measurement of the energy spectrum and spatial distribution of complex proton beams.
@article{arxiv.2604.20163,
title = {A Spatial-Resolved Proton Energy Spectrometer Based on a Scintillation-Fiber Cube},
author = {Tan Song and Ying Gao and Di Wang and Yujia Zhang and Jiarui Zhao and Qingfan Wu and Zhuo Pan and Shirui Xu and Ziyang Peng and Yulan Liang and Tianqi Xu and Zihao Zhang and Haoran Chen and Qihang Han and Xuan Liu and Ye Yang and Maocheng Wang and Siguang Wang and Yihua Yan and Zhongming Wang and Wenjun Ma},
journal= {arXiv preprint arXiv:2604.20163},
year = {2026}
}