High-throughput single photon counting

PhotonPix is the solution for ultra-fast single photon counting. The heart of the detector is a microchannel plate based photomultiplier tube combined with electronics with a dead time below 1.6ns, so the counting chain follows bursts up to 500 MHz without pile-up. For detector lifetime the recommended continuous count rate is 5MHz. The overexposure protection switches the photocathode off at 120MHz. The combination of high throughput detection with a timing resolution below 35ps makes PhotonPix an ideal photon detector for your application. Its large ⌀8 mm sensitive area can accommodate one of four highly sensitive photocathodes, matching the spectral range you are interested in.

Software

The included control software gives you full access to every PhotonPix connected to your PC, with no limit on the number of devices. A single window shows live count rates, discriminator threshold and high-voltage settings for each detector, so multi-channel experiments can be configured and monitored side by side. Settings are stored per device and reloaded on startup, and all parameters exposed in the interface are also available through the API for integration into your own acquisition scripts.

Ultra-low deadtime

An oscilloscope diagram of dead-time measurement

The oscilloscope trace shows two consecutive photon events as seen at the anode (upper beam) and at the logical NIM output (lower beam). The second pulse is resolved cleanly 1.6ns after the first, with no pile-up and no amplitude loss on either channel — the measured dead time of the detector. Because the integrated constant-fraction discriminator retimes every event, the NIM pulses retain uniform width and amplitude at the shortest spacing, which is what allows burst rates approaching 500MHz without paralysis of the counting chain.

Specification Table

Performance

Max. recommended count rate, MHz

5 (detector lifetime)

Maximum burst counts in 10µs

5000 (500MHz)

Overexposure shutdown (protection), MHz

120

Discrimination

Integrated constant-fraction discriminator

Dark count rate after cooling, Hz

< 30 (Blue, Aqua)
< 50 (Green)
< 200 (Red)

Timing jitter, ps (FWHM)

< 35 (1MHz)
< 45 (10MHz)
< 75ps (100MHz)

Active area, mm

⌀8

Dead time, ns

<1.6ns

Signal Output

Output connectors

2× SMA Female

Logical output signal

NIM, 50 Ω

Anode output signal

Negative 0-100mV, @50Ω

General

Power supply

5…12V, 2A min

Optical connector

C-Mount (1-32 UN 2A)

Dimensions, (w × d × h), mm

145 ×78 ×50

Unit weight, g

700

Computer interface

USB2.0

Cooling

Integrated Peltier cooling

Secondary cooling

External liquid cooling (sold separately)

HiQE Photocathodes spectra

The photocathode defines the detector's spectral sensitivity, and PhotonPix can be ordered with one of four PHOTONIS HiQE cathodes so the response can be matched to your excitation and emission wavelengths. The plot shows the available sensitivity curves: Blue and Aqua for the UV to blue-green region, Green for the central visible band, and Red for extended sensitivity towards the near-infrared. Each variant covers the full ⌀8 mm active area, so the choice of cathode affects only the spectral response — dead time, timing resolution and count-rate capability are unchanged. Dark count rate does scale with the red sensitivity of the cathode, from below 30 Hz for Blue and Aqua to below 200 Hz for Red, so the narrowest cathode that covers your wavelength range gives the best signal-to-background ratio. If your application falls between two curves, we can advise on the best compromise before you order.

Publications

S. Karl, V. Leopold, S. Richter, Y. Prokazov, E. Turbin, G. Sintotskiy, D. Orlov, J. von Zanthier. High-throughput single photon detection for effective stellar intensity interferometry. Proc. SPIE 13448, Advanced Photon Counting Techniques XIX (2025). doi:10.1117/12.3056039
D. A. Orlov, Y. Prokazov, E. Turbin, E. Kernen. PhotonPix: single-photon detector with 10 ps timing precision and high dynamic range. J. Instrum. 21, C05006 (2026). doi:10.1088/1748-0221/21/05/C05006, arXiv:2603.21848

Photonis/Photonscore.PhotonPix