Spectroscopy acquisition system SpectraDAS

The SpectraDAS has two independent analogue measuring channels with 16 bit ADC in each channel and one digital measuring channel for counting of pulses going from registration modules in photon-counting mode.

The SpectraDAS has been developed for the integrated operation with the powerful software SpectraSP for data acquisition and analysis. Software SpectraSP includes full range of control modes which are required for creation of complete spectroscopy systems based on the wide variety of spectral instruments and accessories manufactured by SOL instruments.

Each SpectraDAS analog channel measures voltage from any single-channel detectors including solid state detectors and PMT, equipped with preamplifiers. Input voltage range is from 0 to 2 V positive or negative polarity (software selectable) in the frequency range from 0 to 10 kHz. Each channel uses a 16-bit ADC with acquire data at up to 100,000 measurements per second.

There are overvoltage protection functions, programmed input offset correction (in the range from 0 to ± 0.2 V), software switchable amplifiers (1/10 scale), and also the operational PMT output current monitoring (to switch off the PMT supply voltage to avert the PMT photocathode from excessive light) in both analogue input channels.

The SpectraDAS digital channel measures an amount of output pulses from a detector (PMT or avalanche photodiode) operating in the photon counting mode. The photon counting channel is used to ensure high sensitivity and high accuracy of spectral measurements. A Photon counting approach is one of the most effective and widely demanded method of PMT measuring a very low-level optical signal. The detectors used must include an internal amplifier/discriminator and provide an output pulse amplitude of 2.2 ÷ 3.3 V with loads of 50 Ohm. The digital channel provides the temporal resolution of pairs of pulses up to 20 ns or a continuous frequency input up to 200 MHz. In addition, the digital measuring channel has a PMT overexposure protection function. The SpectraDAS switches off the PMT supply voltage to avert the PMT from excessive light. The SpectraDAS has a buffer for storing results of up to 5000 measurements.

The SpectraDAS has two independent 12-bit D/A converters to control the PMT power supply voltage in any SOL instruments detectors such as РТА-928, РТА-5108 or РТМ-14768. When using these sensors, it is possible a programmed control the detector sensitivity in a wide range by changing the PMT power supply voltage.

In addition, the SpectraDAS has two low-voltage power supplies to use them with PMT detectors or with the SDA-010 photodiode detector manufactured by SOL Instruments.