We are reporting on the application of the solid state photon counting system for time resolved spectroscopy

The photomultiplier tube (PMT) is usually used as a detector for picosecond time resolved spectroscopy. The dynode type is sufficient for sub-nanosecond time resolution and the multi-channel plate (MCP) type allows to work in order of ten picoseconds. We are reporting another way using the all-solid state single photon detector as its compact replacement.

The application of Single Photon Avalanche Detector (SPAD) in spectroscopy has been reported in [1]. Main features of its are simplicity, compact design, wide operational temperature range, low voltage and power requirements, quantum efficiency higher than 1% in range 350 – 1000nm and the photon counting linearity in wide range. For practical use in spectroscopic system one of inherent property of active quenched detectors is interesting: detector cannot been destroyed by accidental e.g. daylight exposure. Now we are developed a new control circuit and the time resolution 60ps with 100microns chips was achieved.

Comparison tests are presented. The time resolution is comparable with MCP. Relatively small active detection area was compensated by higher quantum efficiency (than used S1 photocathode) and using focussing optics. The dark noise of 20 microns chip on room temperature is 30Hz. SPAD is operated in active quenched mode.

In present the compact interface unit between SPAD and Edinburgh Analytic Instruments spectrograph system dislocated on Dept. of Physical Electronics of FNSPE CTU is developing. It will allowed used our detector as either as a reference photon counter for excitation intensity measurement or as a detector in second channel for picosecond time resolved spectroscopy.

References

This research has been conducted within the framework of CTU research project \ J04/98:210000022V.2

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