Absorbed dose measurements on LDEF and comparisons with predictions

Area of Science:

• Space physics and radiation dosimetry.
• Investigating the space radiation environment and its effects.

Background:

• The Long Duration Exposure Facility (LDEF) provided a platform for studying the space radiation environment.
• Understanding radiation exposure is crucial for astronaut safety and spacecraft design.

Purpose of the Study:

• To monitor the radiation environment on LDEF using cumulative absorbed dose measurements.
• To analyze the impact of location, shielding, and trapped proton anisotropy on radiation doses.

Main Methods:

• Utilized thermoluminescent dosimeters (TLDs) at various locations and shielding depths on LDEF.
• Measured absorbed doses across different experiments including Biostack, Seeds in Space, and Fiber Optics Data Link.
• Investigated shielding depths ranging from 0.48 to 15.4 g/cm² Al equivalent.

Main Results:

• Absorbed doses varied significantly based on location (east, west, Earth sides) and shielding.
• West side doses were notably higher (up to 6.48 Gy) compared to the east side (up to 2.58 Gy), indicating trapped proton anisotropy.
• Doses on the Earth side were intermediate, suggesting directional effects of space radiation.

Conclusions:

• Shielding thickness and directional dependence of trapped protons significantly influenced absorbed doses on LDEF.
• The findings provide valuable data for modeling space radiation environments and assessing risks.
• Results contribute to understanding radiation effects in low Earth orbit and for deep space missions.