Cornelius DPC 230 Specifications download pdf (Page 7)

Introduction

The DPC-230 photon correlator card records absolute photon times in up to 16 parallel detec-

tion channels. Depending on how the photons are correlated, fluorescence correlation (FCS),

fluorescence cross correlation (FCCS), photon counting histograms, or waveforms of the light

signals are obtained. In combination with optical scanning time-resolved images can be re-

corded. The maximum time resolution of the recording is 165 ps per time channel.

The DPC-230 is available as a single PCI card for installation in a standard PC, or as a com-

pact ‘Simple-Tau DPC’ system based on a laptop computer with an extension box, see Fig. 1.

Fig. 1: DPC-230 card (left) and Simple-Tau DPC system (right)

The DPC-230 especially targets on a new type of fluorescence correlation spectroscopy that

records correlation over a time interval of 10 orders of magnitude [12]. Thus, singlet decay

rates, rotational relaxation rates, rate constants of conformational changes, triplet transition

and decay rates, and diffusion times of free fluorophores and fluorophores bound to proteins,

lipids or nanoparticles can be obtained within a single measurement.

Moreover, the DPC-230 can be used for recording luminescence decay curves or lumines-

cence lifetime images from the sub-nanosecond to the millisecond range, for LIDAR experi-

ments, FCS, time-of flight mass spectroscopy, or any other experiments based on acquiring

the temporal distribution of detection events in a large number of detector channels.

The DPC-230 is operated by the same software as the bh SPC modules [2]. Although the sys-

tem parameters and operation modes of the DPC differ from those of the SPC modules the

general software philosophy is the same. Moreover, the DPC can be used with the same detec-

tors, detector assemblies, detector controllers, excitation sources, and optical systems as the

SPC modules. This handbook should therefore considered an addendum to the ‘bh TCSPC

Handbook’ available on www.becker-hickl.com [2].

Principle of Data Acquisition

Time-to-Digital Conversion

The recording process in the DPC-230 is based on a digital TDC (‘Time to Digital Converter’)

principle. A TDC uses the delay of fast CMOS gates as a timing reference. A reference pulse

is cycling within a ring structure consisting of a number of similar CMOS gates, see Fig. 2.

When a photon (or any other input event) is detected the position of the reference pulse in the

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Cornelius DPC 230 Specifications Page 7