Multihit two-dimensional charged-particle imaging system with real-time image processing at 1000 frames/s

Area of Science:

• Particle Physics
• Spectroscopy
• Advanced Imaging Techniques

Background:

• Accurate detection and counting of charged particles are crucial for various scientific disciplines.
• Existing imaging systems often face limitations in speed, sensitivity, and spatial resolution for dynamic particle events.
• Time-resolved photoelectron imaging (TR-PEI) requires high temporal and spatial accuracy for detailed analysis of molecular dynamics.

Purpose of the Study:

• To develop and present a high-speed imaging system for accurate two-dimensional charged particle counting.
• To enhance the capabilities of time-resolved photoelectron imaging (TR-PEI) through improved particle detection.
• To achieve real-time processing and high-accuracy measurements of particle distributions.

Main Methods:

• Utilized microchannel plates coupled with a short-lifetime phosphor screen for visualizing particle impacts.
• Employed a 1 kHz complementary metal-oxide-semiconductor (CMOS) image sensor (512x512 pixels) for image capture.
• Integrated a multistage image intensifier to boost the low sensitivity of the CMOS sensor.
• Implemented a field-programmable gate array (FPGA) circuit for real-time calculation of centers of gravity (COG) of light spots.
• Validated the system using time-resolved photoelectron imaging (TR-PEI) of NO via (1+1(')) resonance-enhanced multiphoton ionization with a femtosecond laser.

Main Results:

• The developed system successfully enabled COG detection of over ten particles per frame at a 1 kHz acquisition rate.
• Demonstrated extremely high accuracy in measuring photoelectron angular distributions during TR-PEI experiments.
• The combination of microchannel plates, fast phosphor, intensified CMOS, and FPGA processing achieved the desired high-speed performance.

Conclusions:

• The new high-speed imaging system provides a significant advancement for real-time, high-accuracy two-dimensional charged particle counting.
• This system enhances the precision of TR-PEI, enabling more detailed studies of molecular photoionization dynamics.
• The successful implementation paves the way for improved diagnostics and research in fields requiring fast particle detection.