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US-12625288-B2 - Ultrafast 3D imaging technique employing event-driven cameras

US12625288B2US 12625288 B2US12625288 B2US 12625288B2US-12625288-B2

Abstract

A source emits a pulse to an object to generate a particle, and an imaging detector produces a light flash at an X/Y hit position of the particle. The detector outputs a waveform arising from the particle. An event-driven camera provides a signal from the detector that includes intensity and time-over-threshold signals related to the light flash, time-of-arrival information of the event, and the X and Y hit position of the particle. A photodiode determines a time origin of the pulse from the source. A timing circuit is coupled to the detector and to the photodiode, and determines time-of-flight (TOF) of the particle based on the waveform, and based on the time origin of the pulse. The 3D coordinates are generated based on the X/Y hit position synchronized with the TOF of the particle.

Inventors

  • Wen Li
  • Suk Kyoung Lee
  • Gabriel Stewart
  • Duke Debrah

Assignees

  • WAYNE STATE UNIVERSITY

Dates

Publication Date
20260512
Application Date
20220208

Claims (20)

  1. 1 . A system, comprising: an imaging detector positioned to receive a particle generated by a pulse of emissions from a source to produce a light flash as an event that is indicative of an X and Y hit position of the particle in the imaging detector, and the imaging detector configured to output a waveform arising from the particle; an event-driven camera directed toward the imaging detector and capable of providing an imaging detector signal based on the event, wherein the imaging detector signal includes: 1) Intensity and time-over-threshold (TOT) signals related to the light flash; 2) Time-of-arrival (TOA) information of the event; and 3) The X and Y hit position of the particle based on a location of the light flash; a photodiode positioned to detect unimpeded emission signals from unimpeded emissions from the source, wherein the unimpeded emission signals are indicative of a time origin of the pulse from the source, and wherein the emissions include the unimpeded emissions, and wherein the unimpeded emissions did not pass through materials; a timing circuit coupled to the imaging detector to receive the waveform and coupled to the photodiode to receive the unimpeded emission signals, the timing circuit configured to determine a time-of-flight (TOF) of the particle based on the waveform from the imaging detector and the time origin of the pulse from the photodiode; and a hardware processor and a memory having a program communicatively connected to the hardware processor, the hardware processor being communicatively connected to the timing circuit and to the event-driven camera, the hardware processor provides operations including: generation of 3D coordinates of the particle, wherein the 3D coordinates include the X and Y hit position of the particle synchronized with the TOF of the particle.
  2. 2 . The system of claim 1 , wherein the imaging detector is one of a micro-channel plate (MCP)/phosphor imaging detector and an image intensifier.
  3. 3 . The system according to claim 1 , wherein the synchronization the determined TOF of the particle with the X and Y hit position of the particle includes synchronization of 1) a first global time stamp that corresponds with the detected unimpeded signal from the photodiode with 2) a second global time stamp that corresponds with the TOA from the event-driven camera.
  4. 4 . The system according to claim 1 , wherein the timing circuit includes a digitizer coupled to the hardware processor, the digitizer configured to digitize the unimpeded emission signals from the photodiode, and to digitize the TOT signals from the event-driven camera, and the hardware processor determines the TOF based on the digitized unimpeded emission signals from the photodiode and based on the digitized TOT signals.
  5. 5 . The system according to claim 1 , wherein the TOF is based on a time difference between the time origin of the pulse from the photodiode and a time of a peak of counts based on the waveform from the imaging detector signal.
  6. 6 . The system of claim 1 , wherein the source is a laser.
  7. 7 . The system of claim 1 , wherein the particle is one of an ion, an electron, and a photon.
  8. 8 . The system of claim 1 , wherein the timing circuit is triggered by the imaging detector signal.
  9. 9 . The system of claim 1 , further comprising one or more electrodes having openings through which the particle is accelerated from an object to the imaging detector.
  10. 10 . A method, comprising: emitting a pulse of emissions to an object to generate a particle; positioning an imaging detector to receive the particle, the imaging detector configured to produce a light flash as an event that is indicative of an X and Y hit position of the particle in the imaging detector, and to output a waveform arising from the particle; directing an event-driven camera toward the imaging detector and capable of providing an imaging detector signal that includes, when the event occurs: 1) Intensity and time-over-threshold (TOT) signals related to the light flash; 2) Time-of-arrival (TOA) information of the event; and 3) The X and Y hit position of the particle based on a location of the light flash; positioning a photodiode to detect unimpeded emission signals from unimpeded emissions from a source, wherein the unimpeded emission signals are indicative of a time origin of the pulse from the source, and wherein the pulse of emissions include the unimpeded emissions, and wherein the unimpeded emissions did not pass through materials; coupling a timing circuit to the imaging detector and to the photodiode, the timing circuit configured to determine a time-of-flight (TOF) of the particle based on the waveform from the imaging detector and the time origin of the pulse from the photodiode; and communicatively connecting a hardware processor and a memory having a program to the hardware processor, and communicatively connecting the hardware processor to the timing circuit and to the event-driven camera, and providing the hardware processor operations including: generating 3D coordinates of the particle; wherein the 3D coordinates include the X and Y hit position of the particle synchronized with the TOF of the particle.
  11. 11 . The method according to claim 10 , wherein the imaging detector is one of a micro-channel plate (MCP)/phosphor imaging detector and an image intensifier.
  12. 12 . The method according to claim 10 , wherein synchronization of the determined TOF of the particle with the X and Y hit position of the particle comprises synchronization of 1) a first global time stamp that corresponds with the detected unimpeded signal from the photodiode with 2) a second global time stamp that corresponds with the TOA from the event-driven camera.
  13. 13 . The method according to claim 10 , wherein coupling the timing circuit includes coupling a digitizer to the hardware processor, and configuring the digitizer to digitize the unimpeded emission signals from the photodiode and the waveform from the imaging detector.
  14. 14 . The method according to claim 10 , wherein the TOF is based on a time difference between the time origin of the pulse from the photodiode and a time of a peak of counts based on the waveform from the imaging detector signal.
  15. 15 . The method of claim 10 , wherein the source includes a laser to emit the pulse.
  16. 16 . The method of claim 10 , wherein the particle includes one of an ion, an electron, and a photon.
  17. 17 . The method of claim 10 , further comprising triggering the timing circuit by the imaging detector signal.
  18. 18 . The method of claim 10 , further comprising positioning one or more electrodes having openings through which the particle is accelerated from the object to the imaging detector.
  19. 19 . A method, comprising: determining, via an event-driven camera, an X and Y hit position of a particle received on an imaging detector, the particle generated by emissions from a pulse; determining a time of flight (TOF) of the particle based on 1) a waveform from the imaging detector, and 2) based on a time origin of the particle, wherein the time origin of the particle is based on a photodiode signal from a photodiode that receives unimpeded emissions of the pulse that generated the particle, and wherein the unimpeded emission is a pulse do not pass through materials; and generating 3D coordinates for the particle based on the X and Y hit position of the particle synchronized with the TOF of the particle.
  20. 20 . The method of claim 19 , wherein the imaging detector is one of a micro-channel plate (MCP)/phosphor imaging detector and an image intensifier.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63/147,269, filed Feb. 9, 2021, the contents of which are incorporated herein in their entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with government support under DE-SC0012628 awarded by DEPARTMENT OF ENERGY. The government has certain rights in the invention. FIELD OF TECHNOLOGY Exemplary fields of technology for the present disclosure may relate to, for example, electron/ion imaging and an event-driven camera-based three-dimensional (3D) imaging system related to same. BACKGROUND Determination of the complete kinematic information of ions and electrons in an ionization/dissociation event typically makes use of knowledge of the full 3D momentum distribution information of the coincident fragments. Therefore, momentum imaging is one of the most powerful tools used in atomic, molecular, optical (AMO) and chemical physics. In recent years tremendous efforts and resources including a myriad of photoelectron-photoion coincidence spectrometers have been committed to understanding molecular fragmentation and ionization processes. Two common momentum imaging spectrometers used in understanding reaction dynamics are velocity map imaging (VMI) and reaction microscopy (REMI) or cold-target recoil-ion momentum spectroscopy (COLTRIMS). Two common types of detectors employed, typically, are the 2D MCP/phosphor imaging detector and the delay-line detector for VMI and COLTRIMS, respectively. The 2D MCP/phosphor detector has outstanding multi-hit capability and high event rates but lacks the time resolution thus the 3D momentum can only be reconstructed with mathematical transformations, e. g. inverse Abel transform. On the other hand, delay-line detectors had achieved a very good time resolution but due to its longer dead time (˜5 ns), has a limited multi-hit capability, especially for detecting electrons with small kinetic energy. A few variations of delay-line detectors have been developed to circumvent this issue, among which are the multi-quadrant delay line anode with independent four sets of processing electronics and a delay-line anode incorporated with a phosphor screen to provide positional information. Recently, a hybrid camera-based 3D imaging system has been developed that achieves great multi-hit capability and time-of-flight (TOF) resolution. This system uses a CMOS camera to measure the 2D positions of electron/ion hits while using a synchronized digitizer to obtain the TOF through full waveform digitization and peak detection. The achieved TOF resolution is 32 ps and a dead time less than 0.7 nanoseconds. Even though the camera employed in the 3D imaging setup is fast (1 Kframes/s) compared to conventional charge-coupled device (CCD) cameras, with current technology it is not fast enough to operate at an event rate approaching 1 Mhits/s, with the highest event rate achieved so far as 2 Khits/s with a laser running at 10 kHz. Ultrafast cameras do exist and can achieve 1 Mframes/s. However, these cameras are prohibitively expensive, and the durations of acquisition are usually very short due to the requirement of enormous amount of data storage. Recently, a new type of camera (event-driven) has been developed for both scientific and commercial usage. Instead of capturing frames that contains a fixed number of pixels in a conventional camera, in an event-driven camera, each pixel works independently and can timestamp each over-threshold event with high timing accuracy. Because the output is a stream of over-threshold events (true events) instead of a frame that could be full of zero-value pixels, the data rate may be greatly reduced. For example, the Tpx3Cam camera was designed to achieve more than 10 Mpixels/s with a standard 1 Gbs Ethernet connection. It should be noted that even though the Tpx3Cam and other event-driven cameras have achieved a few nanoseconds timing resolution, this resolution is not enough for electron or photon TOF measurements. Accordingly, there is a need for systems and methods that improve ultrafast 3D cameras. BRIEF DESCRIPTION According to the disclosure, a system includes a source configured to emit a pulse of emissions to an object, to generate a particle in the object, and an imaging detector positioned to receive the particle, and configured to produce a light flash as an event that is indicative of an X and Y hit position of the particle in the imaging detector, and configured to output a waveform arising from the particle. An event-driven camera is directed toward the imaging detector and capable of providing an imaging detector signal that includes, when the event occurs: intensity and time-over-threshold (TOT) signals related to the light flash, time-of-arrival (TOA) information of the event, and the X and Y hit position of the particle based on a location of the light flash. A photodiode is positioned to det