Editorials

Laser Induced Fluorescence (LIF) Customer Case 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 [...]

Optical Spectroscopy Customer Case A customer who is completing his doctorate in Chemistry at the California Institute of Technology has identified the need to measure fast optical signals using fast photo-detectors. The signal pulse width is as short as 2ns. Signals will be acquired at a 1KHz repetition rate, with a record length of 1,000 to 10,000 data points. GaGe Case Solution The CompuScope 82G, an 8-bit, 2GS/s A/D and Scope card for PCI Bus, is the best solution for this customer. With relatively small record sets, the customer is able to keep up with the 1KHz Pulse Repeat [...]

Kinetics of Preotein Dynamics Customer Case The customer is measuring kinetics of protein dynamics with a time scale of between a few nanoseconds and about a hundred milliseconds. The customer's two response signals occur after a few-nanosecond-pulse excitation that repeats at a rate of 1-10Hz. This requires a bandwidth from DC to a few hundred MHz, sampling speed of about 1-2GS/s, and processing time for one acquisition that is less than 1-0.1secs. An analog signal of about 10-30mV comes from a Photo-Multiplier Tube (PMT) or a photo-diode with a trans-impedance pre-amplifier. The customer is currently using a couple of [...]

Radioactive Nuclear-Decay Detection Customer Case The customer has a requirement for PC-based waveform digitizer cards to digitize shaped pulses derived from nuclear-decay detectors. These pulses vary in their rate (frequency of occurrence) and amplitude. Their shape is approximately Gaussian with a full-width at half the maximum amplitude (FWHM) of 3-5 microseconds. The characterization of each pulse is critical for the accurate and precise determination of the activity of radioactive materials. These materials have very low count-rates (0.02 pulses per minute) to relatively high count-rates (>1000 pulses per minute). Important to the measurement process are the speed and reliability of [...]

Neutrino Detection System Customer Case Neutrinos are tiny (possibly massless) neutral elementary particles which interact with matter via the weak nuclear force. The weakness of the weak force gives neutrinos the property that matter is almost transparent to them. The sun, and all other stars, produce neutrinos copiously due to nuclear fusion and decay processes within the core. Since they rarely interact, these neutrinos pass through the sun and the earth (and you) unhindered. Other sources of neutrinos include exploding stars (supernovae), relic neutrinos (from the birth of the universe) and nuclear power plants (in fact a lot of [...]

Nuclear Particle Location Customer Case The customer studies nuclear particles traveling in an electrically charged medium. The particles emit two types of short 53 MHz signal bursts. The first type lasts for 1.6 ms, the second type lasts for 6 ms. The customer had to capture these bursts in at least two locations and analyze their amplitudes in order to determine the position and some of the characteristics of the nuclear particles. The application requires two channels of capture at speeds of at least 500 MS/s. The depth of capture at 1 GS/s is 6,000 samples for the 6 [...]

Ozone Profiling Lidar System Customer Case The customer is designing an ozone-profiling lidar system for measuring the concentration of ozone from ground level up to about 4 kilometer (km) altitude. The system operates in the ultraviolet range and uses multiple receiver telescopes to cover the range. The dynamic range of the signal is enormous, so small aperture telescopes are used to collect backscattered light from low altitudes and large ones are used to collect backscattered light from high altitudes. The customer is operating simultaneously at three laser wavelengths, and the current design requires a total of nine photodetectors (three [...]