Ultra-compact 32-channel system for time-correlated single-photon counting measurements

Abstract

Modern Time-Correlated Single-Photon Counting applications require to detect spectral and temporal fluorescence data simultaneously and from different areas of the analyzed sample. These rising quests have led the development of multichannel systems able to perform high count rate and high performance analysis. In this work we describe a new 32-channel TCSPC system designed to be used in modern setups. The presented module consists of four independent 8-channel TCSPC boards, each of them including two 4-channel Time-Amplitude Converter arrays. These TAC arrays are built-in 0.35 μm Si-Ge BiCMOS technology and are characterized by low crosstalk, high resolution, high conversion rate and variable full-scale range. The 8-channel TCSPC board implements an 8-channel ADC to sample the TAC outputs, an FPGA to record and organize the measurement results and a USB 2.0 interface to enable real-time data transmission to and from an external PC. Experimental results demonstrate that the acquisition system ensures high performance TCSPC measurements, in particular: high conversion rate (5 MHz), good time resolution (down to 30 psFWHM with the full scale range set to 11 ns) and low differential non-linearity (rms value lower than 0.15% of the time bin width). We design the module to be very compact and, thanks to the reduced dimensions of the 8-channel TCSPC board (95×40 mm), the whole system can be enclosed in a small aluminum case (160×125×30 mm)

Fluorescence lifetime imaging (FLIM): Basic concepts and some recent developments

“…Recent work by Antonioli et al (2013) has resulted in a 32-channel TCSPC system employing the hybrid integration of a custom 32 SPAD array with 32-channel active quench and time to analogue converter array. The timing resolution and detector characteristics are separately optimized providing the ultimate performance for physics and biomedical research.…”

Fast Timing Techniques in FLIM Applications

“…For this reason TDCs have found widespread use in SPAD arrays, and the development of this technology is expected to continue. Recently a 32-channel TCSPC system has been developed employing the hybrid integration of a custom 32 SPAD array with 32-channel active quench and time to analog converter array [87, 133,134]. Although the fill-factor and SPAD performance are compromised by having such a large number of detectors and timing electronics on a single substrate, this detector has a TDC in each pixel with 55 ps resolution, allowing independent TCSPC in each pixel of a 32×32 pixel array simultaneously.…”

Wide-field TCSPC: methods and applications

“…Recently a 32-channel TCSPC system has been developed employing the hybrid integration of a custom 32 SPAD array with 32-channel active quench and time to analogue converter array [144]. The design of detectors and timing electronics on a single substrate provides compactness and large numbers of channels but compromises fill-factor and SPAD performance (jitter, photon detection efficiency, afterpulsing and dark count).…”