Imaging using pulses: a simple and fast (>100 kHz) solution

Imaging is an important component of spectroscopy. A good imaging system is expected to work with a high-pixel resolution using signals of high count-rates with as little dead time as possible to deliver an image quickly and reliably. It is not uncommon for such a system to be highly specialized, expensive and to consist of many dedicated electronic components. In this work, we present a simple imaging algorithm that can be used with a pulse (TTL) data signal, such as that produced by some photomultipliers and electron detectors. This algorithm works with only a simple general purpose data acquisition computer card (NI PXI/PCI-6259) from National Instruments residing in a computer. The system has been tested with signal rates in excess of 100 kHz to produce images at a pixel resolution of 512 x 512. The system's ability to handle such high count-rates hinges on utilizing the buffered data collection feature on the said card, in a hitherto unreported configuration. This system now offers a simple and cost-effective manner of incorporating high count-rate imaging features, such as in a scanning electron microscope, into a purely spectroscopic system. Further, since the use of the NI DAQ cards are supported under other computer platforms, the current imaging formalism is readily transferrable to computer platforms such as Linux or Mac OS.