A customer has developed a breakthrough technique for the application of laser-induced fluorescence (LIF) detection to high performance liquid chromatography, capillary e lectrophoresis, sequencing and microbial analysis. The technique involves using fluorescence decay curves at multiple wavelengths simultaneously, leading to true 3-D fluorescence spectroscopy (i.e., fluorescence intensity as a function of wavelength and delay time relative to pulsed excitation).
They have a requirement to increase the laser pulse repetition frequency (PRF) from 20-50 pulses per second to 500-1000 pulses per second. Basically, they want to collect and time resolve the fluorescence signal for approximately 250 ns following the laser pulse, which is ~1 ns in duration. A digitization rate of at least 2 GS/s is desired. At a PRF of 1 kHz, the time between laser shots is 1000 microseconds, so a dead time between triggers of less than 1000 microseconds is required (in order to not miss any shots). At 2 GS/s and with a 250 ns time range, the record length per single shot is 500 points. They would like to average the waveforms over 250-1000 shots (data acquisition time of 0.25-1 second at 1 KHz). 8-bit digitization is required. After an averaged waveform has been collected, the customer wants to keep the time before the next averaging sequence is initiated to a minimum.
The customer selected the GaGe CompuScope 82G since it can sample at the required 2GS/s. The CS82G provides a fast PCI data transfer rate between on-board acquisition memory and PC RAM. This high-speed interface allowed the customer to transfer his 500 data points off of the CS82G between acquisitions and keep up with the required 1 KHz trigger rate.
The customer was easily able to implement his own signal averaging routine by slightly modifying an existing sample program included with the CompuScope Software Development Kit for C/C++ for Windows. This involved merely performing 1000 sequential acquisitions inside a loop and summing the results into a single averaging buffer. The average data from this buffer was then maintained in PC RAM and the application was rapidly prepared for a subsequent acquisition and averaging of 1000 records.
We encourage you to contact us and discuss your medical application in more detail with our engineering team. GaGe can provide tailored custom data acquisition hardware and software solutions to meet specific application requirements: