The Lunar Lander Neutron and Dosimetry (LND) Experiment on Chang'E 4

Abstract

Chang'E 4 is the first mission to the far side of the Moon and consists of a lander, a rover, and a relay spacecraft. Lander and rover were launched at 18:23 UTC on December 7, 2018 and landed in the von Kármán crater at 02:26 UTC on January 3, 2019. Here we describe the Lunar Lander Neutron & Dosimetry experiment (LND) which is part of the Chang'E 4 Lander scientific payload. Its chief scientific goal is to obtain first active dosimetric measurements on the surface of the Moon. LND also provides observations of fast neutrons which are a result of the interaction of high-energy particle radiation with the lunar regolith and of their thermalized counterpart, thermal neutrons, which are a sensitive indicator of subsurface water content.

The Electron Proton Helium INstrument as an Example for a Space Weather Radiation Instrument

“…The E6 Instruments on the Helios spacecrafts have shown that adding a Cherenkov detector behind the detector stack can be utilized in order to distinguish between both directions (Marquardt and Heber, 2019) while the COSPIN/KET instrument on Ulysses (Simpson et al, 1992) has proven the possibility to distinguish between relativistic protons up to 2.1 GeV and electrons utilizing an Aerogel Cherenkov detector. An energy-loss histogram of one of the inner detectors in anti-coincidence to all other detectors would have provided more capabilities in the analysis of γ-rays following the approach of the Lunar Lander Neutron and Dosimetry experiment (LND) on Chang'e4 (Wimmer-Schweingruber et al, 2020) and PSP/IS IS/EPI-Hi (McComas et al, 2016). By utilizing the increased on-board processing capabilities of these state of the art instruments compared to the 25 year old EPHIN electronics, the proposed improvements could be included without the need of significant higher telemetry rate.…”

First Solar energetic particles measured on the Lunar far-side

“…The Chang'E-4 mission, which consists of a lander, a rover and a relay satellite, is humanity's first mission landing on the lunar far-side, located at von Kármán Crater. The Lunar Lander Neutron and Dosimetry experiment (LND) (Wimmer-Schweingruber et al 2020) on board the lander of Chang'E-4 is designed to take active dosimetry measurements on the surface of the Moon as its chief scientific goal. Apart from the primary objective of LND which is to measure the radiation level on the lunar far-side preparing for astronaut missions (Zhang et al Science advance, accepted), the charged particle telescope could also provide high quality data of energetic particles and contribute to heliophysics.…”