Spatial resolution requirements for active radiation detectors used beyond low earth orbit

Area of Science:

• Space Science
• Radiation Detection
• Particle Physics

Background:

• Accurate measurement of heavy ionizing (HZE) particle fluence is crucial for astronaut radiation risk assessment.
• Thin detectors misclassify fragmented heavy ions as single particles due to coincident events.
• Spacecraft shielding exacerbates particle fragmentation, complicating accurate detection.

Purpose of the Study:

• To investigate methods for reducing coincident events in radiation detectors.
• To determine optimal detector segmentation to avoid over-design and complexity.
• To improve the accuracy of identifying individual particles in fragmentation spectra.

Main Methods:

• Monte Carlo simulations using Geant4 were employed.
• Simulations included helium, carbon, silicon, and iron ions at various energies.
• Aluminum shielding of different areal densities was modeled.

Main Results:

• A novel proximity distribution analysis was used to examine downstream particles.
• Pixel dimensions of approximately 1 mm were found to be sufficient.
• This segmentation effectively reduces errors caused by coincident events.

Conclusions:

• Detector segmentation is key to accurately identifying individual particles after fragmentation.
• 1 mm pixel dimensions offer a practical solution for reducing coincident event errors.
• This research enhances the reliability of active space radiation detectors for astronaut safety.