Photon Counting Imaging with Low Noise and a Wide Dynamic Range for Aurora Observations

Area of Science:

• Aerospace applications
• Astrophysics
• Photon counting imaging

Background:

• Auroral radiation intensity in the far-ultraviolet (FUV) band varies significantly, necessitating wide dynamic range imaging for aerospace applications.
• High spatial resolution imaging and high event rates are challenging to combine in photon counting systems.

Purpose of the Study:

• To develop and characterize a photon counting imaging system for FUV aurora observation.
• To investigate counting errors in high counting rate applications using anode readout and time response models.

Main Methods:

• Developed a FUV photon counting imaging system utilizing a microchannel plate (MCP) stack with a wedge strip anode (WSA) and high-speed electronics (CSA, pulse shaper).
• Constructed anode readout and time response models to analyze counting errors.

Main Results:

• The system achieves 111 µm spatial resolution at 400 kilo counts per second (kcps) with low dark counts (0.610 s⁻¹ cm⁻²).
• Photon count loss was observed at high incident intensities, approaching the system's capacity.
• A correlation between counting rate and imaging resolution was established.

Conclusions:

• The developed FUV photon counting imager meets specific performance criteria for aurora observation.
• Improving response time is crucial for preserving image quality at high photon rates, potentially at the cost of noise performance.
• The findings provide guidance for designing future space observation instruments with optimized counting rates and imaging resolution.