The four channel router PHR 800 is an accessory for the PicoHarp 300 Time-Correlated Single Photon Counting (TCSPC) System (from hardware revision 2.0). Using the PHR 800, users can connect up to 4 (even different) single photon detectors to perform simultaneous multi-channel time-resolved measurements. These can provide another valuable dimension of information, e.g. colour and/or polarization as well as improved collection efficiency. This permits sophisticated and fast multi-dimensional fluorescence detection methods in the life sciences or in general sensitive analytics.

The 4-channel router supports both histogramming and Time-tagged Time-resolved (TTTR) mode. The latter allows the recording of each individual photon with its picosecond timing and the detector channel it came from. This permits ultimate flexibility in data analysis e.g. for burst detection or Fluorescence Correlation Spectroscopy (FCS) combined with fluorescence lifetime information. Using two or more detectors and TTTR mode it is possible to perform cross correlations in FCS. Up to four external synchronization signals can also be connected to the frontpanel of the PHR 800. They appear as marker signals in TTTR data files and allow e.g. to synchronize the data acquisition with the movement of a scanner for Fluorescence Lifetime Imaging (FLIM).

The settings of the PHR 800 can be adjusted through the software interface of the PicoHarp 300, the PicoHarp 300 Programming Library or the SymPhoTime software. This allows selection of the input polarity and the trigger threshold, so that almost any detector signal can be used. Standards supported are TTL and NIM from commonly used SPAD detectors (e.g. the PDM-Series). Dependent on the chosen configuration, the PHR 800 can optionally contain Constant Fraction Discriminators (CFD), separate for all four inputs and also adjustable by the software. This supports detectors with fluctuating pulse heights such as Photo Multiplier Tubes (PMT) and Multi Channel Plate Photo Multiplier Tubes (MCP-PMT).