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Updated: Aug 4, 2026
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Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
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Dose rate, dose-equivalent rate, and quality factor in SLS-1
G D Badhwar1, L A Braby, F A Cucinotta
1NASA Johnson Space Center, Houston, TX 77058.
International Journal of Radiation Applications and Instrumentation. Part D, Nuclear Tracks and Radiation Measurements
|July 1, 1992
Summary
A tissue-equivalent proportional counter measured space radiation on STS-40. Galactic cosmic radiation dose exceeded trapped radiation, and models underestimated actual dose rates.
Area of Science:
- Space physics and radiation dosimetry.
- Astronaut radiation exposure assessment.
Background:
- Space missions expose astronauts to significant radiation.
- Accurate measurement and modeling of space radiation are crucial for crew safety.
Purpose of the Study:
- To measure the radiation environment during the STS-40 mission using a tissue-equivalent proportional counter (TEPC).
- To compare in-flight measurements with predictions from radiation models like AP8MAX and CREME.
- To better map South Atlantic Anomaly (SAA) protons with improved low-energy resolution.
Main Methods:
- Utilized a modified TEPC with a lineal energy range of 0.26-300 keV/µm.
- Collected data during the STS-40 Spacelab mission for 7470 minutes.
- Separated radiation contributions into trapped and galactic cosmic radiation (GCR) components.
Main Results:
- The dose rate from GCR (5.34 mrad/day) was higher than from SAA protons (4.21 mrad/day) due to the mission's high inclination and low altitude.
- The overall quality factor for the flight was 2.38.
- The AP8MAX and CREME models underestimated the measured dose rates by factors of 1.8 and 2, respectively.
Conclusions:
- The TEPC provided valuable in-flight radiation measurements.
- Existing models show significant discrepancies in predicting space radiation doses.
- Further refinement of radiation transport codes and models is necessary for accurate mission planning and crew protection.
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