Effects of Ultraviolet Irradiation and Atomic Oxygen Erosion on Total Electron Emission Yield of Polyimide

Jian-gang, WU; Miyahara, Akira; Khan, Arshad M.; Iwata, Makoto; Toyoda, Kazuhiro; Cho, Mengu; Zheng, Xiao Quan

doi:10.1109/tps.2013.2288699

Cited by 21 publications

(12 citation statements)

References 14 publications

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“…Thus, the un-bonded electron in the free radical is considered to enhance the generation of the secondary electron and photoelectron. Our previous research on the ultraviolet irradiation on total electron emission yield proved to be the same tendency 17) . However, the PEY of electron irradiation polyimide film decreased with the rising of electron irradiation dose, which infers, there exists other degradation effects besides of the generation of free radicals.…”

Section: Discussion and Analysismentioning

confidence: 63%

Effects of Energetic Electron and Proton Irradiation on Electron Emission Yield of Polyimide Induced by Electron and Photon

Miyahara

Khan

et al. 2014

AEROSPACE TECHNOLOGY JAPAN

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As the electron emission yield induced by electron and photon plays a key role in surface potential of spacecraft materials, the ground based degradations including 500 keV electron and 50 keV proton irradiation with 4 different fluences were conducted for the polyimide film separately. Based on the developed measuring systems, the comparative measurements of total electron emission yield and photoelectron emission yield were carried out for the virgin and degraded polyimide samples respectively. The total electron emission yield and photoelectron emission yield tended to have different variation tendency after high energy electron and proton irradiation. The Monte-Carlo analysis software Casino and SRIM were used to analysis the distribution and stopping power of electron and proton respectively. According to the measurement results and analysis, the free radicals caused by irradiation was considered to be the main effect for polyimide films, which can primarily reveal the degradation mechanism of energetic electron and proton on the emission yield of polyimide.

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Section: Discussion and Analysismentioning

confidence: 63%

Effects of Energetic Electron and Proton Irradiation on Electron Emission Yield of Polyimide Induced by Electron and Photon

Miyahara

Khan

et al. 2014

AEROSPACE TECHNOLOGY JAPAN

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“…Exposure of PI to UV irradiation results in the formation of a high concentration of radicals as confirmed by EPR studies [112][113][114][115]. These radicals originate from a broken C-N bond in the imide group and the C-O bond of the ether of PI [116]. Results of spectroscopic ellipsometry of UV-exposed PI films suggested that the UV generated radicals are situated near the surface of the film, with~500 nm depth of damaged layer [117].…”

Section: Changes In Chemical Propertiesmentioning

confidence: 78%

Review of Radiation-Induced Effects in Polyimide

Plis¹,

Engelhart²,

Cooper

et al. 2019

Applied Sciences

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Polyimide (PI, Kapton-H®) films are widely utilized in the spacecraft industry for their insulating properties, mechanical durability, light weight, and chemical resistance to radiation. Still PI materials remain exposed to a combination of high-energy electrons, protons, and ultraviolet (UV) photons, particles primarily responsible for radiation-induced damage in geosynchronous Earth orbit (GEO), which drastically change PI’s properties. This work reviews the effect of electron, proton, and UV photon irradiation on the material properties (morphology, absorption, mechanical properties, and charge transport) of PI. The different damaging mechanisms and chemical consequences that drive changes in the material properties of PI caused by each individual kind of irradiation will be discussed in detail.

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“…This theory is supported by a study on the effects of ultraviolet irradiation on LEO spacecraft surfaces. It was found that UV photons, the radiation responsible for the photoemission of electrons from the sensor surfaces, normally travel up to a depth of 0.1 μm in material (Wu et al., 2014). This implies that surface irregularities within the top 0.1 μm of the DAG‐213 coating may play the largest role in the photoemission properties of the EFW sensors.…”

Section: Discussionmentioning

confidence: 99%

Calculation of the Atomic Oxygen Fluence on the Van Allen Probes

et al. 2020

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The Van Allen Probes Mission consists of two identical spacecraft flying in highly elliptical orbits, with perigee altitudes originally near 600 km. During the low‐altitude periods of the orbits, the spacecrafts are immersed in a region of high‐density atomic oxygen. Atomic oxygen is known to change and degrade the properties of spacecraft surfaces (Banks et al., 2004), such as those of the Van Allen Probes Electric Field and Waves (EFW) instrument. The consistency of the sensor surfaces in EFW is important because the mechanisms used to ensure the collection of high‐quality electric field measurements requires that the photoemission properties of each sensor are uniform and stable. Oxidation or erosion of the sensor surfaces could limit the instrument's ability to balance the currents produced by both the plasma electrons and the controlled bias current applied to the sensors and thus to properly operate the device. We have modeled the atomic oxygen exposure to the spacecraft to help understand the potential impact it has had on the sensors. We have calculated the fluence (time‐integrated flux) of atomic oxygen particles that have collided with the spacecrafts over the entire course of the mission. We have also looked at the distribution of atomic oxygen flux over time to further analyze malfunctions in the sensor readings at different points along the course of the mission. Additionally, we have investigated how different surfaces of the spacecraft are affected differently due to their orientation with respect to the spacecraft's motion.

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Effects of Ultraviolet Irradiation and Atomic Oxygen Erosion on Total Electron Emission Yield of Polyimide

Cited by 21 publications

References 14 publications

Effects of Energetic Electron and Proton Irradiation on Electron Emission Yield of Polyimide Induced by Electron and Photon

Effects of Energetic Electron and Proton Irradiation on Electron Emission Yield of Polyimide Induced by Electron and Photon

Review of Radiation-Induced Effects in Polyimide

Calculation of the Atomic Oxygen Fluence on the Van Allen Probes

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