Title: Determination of the absolute energy scale of the DAMPE calorimeter with the geomagnetic rigidity cutoff method Show Chinese title

Title: DAMPE 量能器绝对能量刻度的确定采用地磁刚度截止法

Abstract: The Dark Matter Particle Explorer (DAMPE) is a satellite-borne detector designed to detect high-energy cosmic ray particles with its core component being a BGO calorimeter capable of measuring energies from $\sim$GeV to $O(100)$ TeV. The 32 radiation lengths thickness of the calorimeter is designed to ensure full containment of showers produced by cosmic ray electrons and positrons (CREs) and $\gamma$-rays at energies below tens of TeV, providing high resolution in energy measurements. The absolute energy scale therefore becomes a crucial parameter for precise measurements of the CRE energy spectrum. The geomagnetic field induces a rapid drop in the low energy spectrum of electrons and positrons, a phenomenon that provides a method to determine the calorimeter's absolute energy scale. By comparing the cutoff energies of the measured spectra of CREs with those expected from the International Geomagnetic Reference Field model across 4 McIlwain $L$ bins - which cover most regions of the DAMPE orbit - we find that the calorimeter's absolute energy scale exceeds the calibration based on Geant4 simulation by $1.013\pm0.012_{\rm stat}\pm0.026_{\rm sys}$ for energies between 7 GeV and 16 GeV. The absolute energy scale should be taken into account when comparing the absolute CREs fluxes among different detectors. Show Chinese abstract

Abstract: 暗物质粒子探测器（DAMPE）是一个搭载在卫星上的探测器，其核心组件是一个BGO量能器，能够测量从$\sim$GeV到$O(100)$TeV的能量。 量能器的32个辐射长度厚度设计用于确保在低于几十TeV的能量下，对宇宙射线电子和正电子（CREs）以及$\gamma$-rays产生的簇射进行完全包容，从而提供高能量测量分辨率。 因此，绝对能量标度成为精确测量CRE能量谱的关键参数。 地磁场会导致电子和正电子的低能谱迅速下降，这一现象提供了一种确定量能器绝对能量标度的方法。 通过将测得的CREs谱的截止能量与国际地磁参考场模型在4个McIlwain$L$区间的预期值进行比较——这些区间覆盖了DAMPE轨道的大部分区域——我们发现，在7 GeV至16 GeV的能量范围内，量能器的绝对能量标度比基于Geant4模拟的校准高出$1.013\pm0.012_{\rm stat}\pm0.026_{\rm sys}$。 在比较不同探测器的绝对CREs通量时，应考虑绝对能量标度。