Single photon detection and localization accuracy with an ebCMOS camera

Photon Counting Imaging with an Electron-Bombarded Pixel Image Sensor

“…The photon event brightness in EB pixel image sensors is strongly dependent on the acceleration voltage, and as the photon events typically cover an area of a few pixels, resolution lost in the detection process can be recovered by photon event centroiding—both one-iteration centre-of-mass [ 20 ] and iterative fitting [ 58 ] algorithms have been shown to produce excellent results. The local count rate is given by the frame rate of the camera; EBCMOS cameras with 500 frames per second have been described [ 46 ], and 1000 Hz planned. The global count rate depends on the number of pixels in the sensor, and as both CMOS and CCD sensors can be manufactured in large, megapixel arrays, the detection of hundreds or thousands of photons per frame is possible.…”

“…However, despite the many applications and advantages of the ideal EBCCD, and being commercially available for over 15 years, there have been drawbacks, such as low frame rates of a few Hz and artefacts in the images, and it seems the development of these sensors has stopped before their full potential has been realised. EBCMOS cameras, on the other hand, are a recent development and not yet widely available, but show great potential, especially regarding the increased frame rate (500 Hz has been demonstrated [ 46 ]). A distinctive advantage of EB-sensors is the low dark count due to thermionic emission from the photocathode, in common with other photocathode and MCP-based devices, for which 0.02 events/s/cm 2 have been quoted [ 63 ], This would be useful for situations where a good signal to noise ratio is required, e.g., for very weak bioluminescence, or decay measurements of probes with microsecond decay times, for example oxygen sensing, or time-resolved fluorescence anisotropy measurements of large molecular weight proteins for which nanosecond decay times are too short.…”

“…Brighter, larger ion events are also detected. Single photon events detected with EBCMOS cameras are reported to be very similar to EBCCD photon events (see, for example, Figure 3 in [ 46 ]).…”

“…For scientific research, the development of EBCMOS cameras originated from applications in particle physics, and Mimosa 5 was demonstrated in 2007, with 1024 × 1024 pixels, 40 Hz frame rate and operating voltage of 6–10 kV [ 43 ]. A number of other sensors have been developed [ 44 , 45 ], with the latest development offering a 500 Hz frame rate [ 46 ].…”

Wide-field TCSPC-based fluorescence lifetime imaging (FLIM) microscopy

“…Single photon detection is also possible with electron-bombarded (EB) sensors, where the photoelectrons from the photocathode are accelerated directly into a CCD or CMOS sensor. [44][45][46][47] Unlike MCPs where the statistical electron multiplication process creates a broad pulse height distribution, in EB sensors the photon event brightness depends on the gain voltage. Thus, by sweeping the gain voltage during the exposure time, it could be possible to obtain photon arrival time information from the photon event brightness.…”