Silicon photomultipliers (SiPMs) have numerous applications in high precision single-photon timing measurements, including LIDAR, biophotonics, and Positron-Emission-Tomography. Their ability to detect the photon number of scintillation events is a key feature to achieve high fidelity signals with very low noise levels. The extraction of the photon number from the detector output pulse is traditionally achieved with a fast ADC or with multiple level analog discriminators (time-over-threshold approach). Swabian Instruments together with KETEK GmbH demonstrated an alternative method using only a single input threshold and relying on signal pulse duration. By detecting both the rising and falling edge, we obtain an apparent pulse width, that directly encodes the photon number. This measurement capability is provided by Swabian Instruments Time Tagger Ultra. Its high timing precision enables exquisite characterization of the detector’s timing jitter.
Our pulse width filtering method is capable of resolving the photon number and simultaneously provides precise timing information of the detected photon. The simultaneous access to the photon number and timing information, taking advantage of the streaming architecture of the Time Tagger, shows the versatility of the Time Tagger and its software engine. The Time Tagger proves to be a useful tool for multi-photon detector characterization and in the development of various applications like positron-emission tomography (PET).
For technical details please take a look at our application note.