[P-CG23] [EE] 宇宙・惑星探査の将来計画と関連する機器開発の展望

[PCG23-01] Contamination in electron observations from Cluster/RAPID/IES instrument in the Earth's radiation belts and ring current

★招待講演

*Elena Kronberg^1,2、Mikhail Rashev¹、Patrick W. Daly¹、Yuri Shprits³、Drew Turner⁴、Alexander Drozdov¹⁰、Mikhail Dobynde⁵、Adam Kellerman¹⁰、Ted Fritz⁶、Vivien Pierrard⁷、Kris Borremans⁷、Berndt Klecker⁸、Reiner Friedel⁹ (1.Max Planck Institute for Solar System Research, Göttingen, Germany、2.Ludwig Maximilians University, Munich, Germany、3.Helmholtz Centre Potsdam GFZ German Research Centre For Geosciences and University of Potsdam, Potsdam, Germany、4.The Aerospace Corporation, El Segundo, California USA、5.Skolkovo Institute of Science and Technology, Skolkovo, Russia、6.Center for Space Physics, Boston University, Boston, MA, USA、7.Belgian Institute for Space Aeronomy (BISA), Brussels, Belgium、8.Max Planck Institute for extraterrestrial Physics, Garching, Germany、9.Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico USA、10.Department of Earth Planetary and Space Sciences, University of California, Los Angeles, CA, USA)

キーワード：particle detector, contamination, radiation belts

For over 16 years, the Cluster mission passes through Earth’s radiation belts at least once every two days for several hours, measuring the energetic electron intensity at energies from 30 to 400 keV. This vast amount of data has previously been considered as rather useless due to contamination by penetrating energetic particles (protons at >100 keV and electrons at >400 keV). In this study, we assess the efficiency with which aluminium shielding of RAPID/IES detector filters out contaminating high-energy electrons and protons. We base our estimation on the analysis of experimental data and a radiation transport code (Geant4). In our simulations, we use the incident particle energy distribution of the AE9/AP9 radiation belt models. We identify the Roederer L-values and energy channels that should be used with caution and show examples of misinterpreting the data. Comparison of the data with electron and proton observations from RBSP/MagEis indicates that the subtraction from the IES electron data of proton intensities at energies ~230–630 keV cleans well the data from the proton contamination. We show that the data from this detector measured in the radiation belts is still useful for many scientific applications. This is very valuable as it provides one of the longest available radiation belt data sets.