Removing the dose background from radioactive sources from active dose rate measurements in the Lunar Lander Neutron & Dosimetry (LND) experiment on Chang'E 4

Abstract

Removing the dose background from radioactive sources from active dose rate measurements in the Lunar Lander Neutron & Dosimetry (LND) experiment on Chang'E 4 D. Hou,

First measurements of the radiation dose on the lunar surface

“…Ignoring the data acquired while Yutu-2 was still piggybacked on the lunar lander module and while the TCS was active [11 January 2019 (14:41) to 3 February 2019 (07:53)], we measured an average total dose rate in silicon of 13.2 ± 1 and 3.1 ± 0.5 Gy/hour in silicon for neutral particles. The background due to the RTG and RHUs was measured in August 2018 (20), and the values reported above have been corrected accordingly; the corresponding errors are reported separately in Table 1. Thus, we find that neutral particles contributed a nonnegligible fraction of 23 ± 8% to the total dose (22).…”

“…Summary of measurements of the radiation dose rate measured in Gy/hour on the lunar surface. The errors of the background dose rate from the RTG/RHUs (20) are considered systematic errors and have been added quadratically when reporting the final values in the rightmost column.…”

“…To survive this extreme thermal environment, the Chang'E 4 lander contains a radioisotope thermoelectric generator (RTG) and three radioisotope heater units (RHUs); in addition, the Yutu-2 rover is also equipped with an RTG. We have measured the contributions of the lander RTG and RHUs in August 2018 before the launch of the spacecraft and have thus determined their contribution to be 5.2 ± 0.6 Gy/hour to the total dose rate and 1.7 ± 0.4 Gy/hour to the neutral dose rate (20). These values have been subtracted from the measurements shown in Fig.…”

First measurements of low-energy cosmic rays on the surface of the lunar farside from Chang’E-4 mission

“…The differential flux of a specific type of charged particles in a certain kinetic energy range can be obtained on the basis of the information of their count rate, geometric factor, and kinetic energy range interval. More details about the LND instrument can be found in the literature ( 36 , 64 ).…”

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

“…The background from the RTG and RHUs was measured at the 18-th Research Institute, China Electronics Technology Group Corporation in Tianjin, China. The results are reported in [51].…”