FAST ComTec: 7074

Quad Analog-to-Digital Converter Model 7074

The Model 7074 will be discontinued.

The 7074 is replaced by the Dual ADC Model 7072, ADC / SVA

FEATURES

Four independent Wilkinson-type ADC's with 100 MHz clock rate in a single width NIM-module
16k Conversion Range
256 to 16k Conversion Gain independently selectable for each ADC
Instantaneous Dead-Time bar graph display for each ADC
Lower Level and Upper Level Discriminator
Pulse Height Analysis with automatic peak detection
Simultaneous Single-Channel Output on rear panel connector
Designed for easy interfacing to Multichannel Analyzers and Computers
Economically priced
the 7074 is the solution for most applications requiring analog mixers and routers

DESCRIPTION
The model 7074 contains four independent 16k Wilkinson-type Analog-to-Digital Converters with 100 MHz clock rate. The 7074 is ideally suited for applications in multiparameter spectrometry. In Alpha Spectroscopy the 7074 replaces analog mixers and routers. The upper- and lower-level discriminator of each ADC has an output on the rear panel connector. The economically priced 7074 is an ideal replacement for analog mixers and routers which typically degrade the resolution of the connected detectors and significantly limit the count rate capabilities of such a system. Available Multichannel Analyzers with four ADC ports: SPA-3, and the MPA-3 Multiparameter System. For technical data contact FAST ComTec.

SPECIFICATIONS for each ADC channel

INPUTS (front panel) Signal Input: BNC-Connector accepts +25mV to +8V (standard / +10V optional) linear pulses, Zin = 1k Ohm, risetime: > 100ns to 100µs, fall time: 200ns to 100µs, 0.5µs flat top width, dc coupled. Gate: BNC-Connector accepts positive TTL signal OUTPUTS Data: 14 bit binary data lines, data transfer commands, Deadtime, SCA out on PC-board connector and flat ribbon cable with 25 pin D-sub connector. INDICATORS: DEADTIME: 10 LED-bar graph display indicates activity of the ADC. Range 0 to 100% deadtime Conversion Range: 7 LED display indicates selected range from 256 to 16k channels

PC-BOARD CONTROLS: Jumper selectable type of deadtime signal: a) conversion deadtime only b) conversion deadtime and duration of input pulse Jumper selectable gate mode: a) coincidence b) anticoincidence FRONT PANEL CONTROLS: Conversion Gain: Push button selects conversion gain from 256, 512, 1k, 2k, 4k, 8k and 16k channels for full scale input. LLD: Precision potentiometer sets the lower level discriminator. ULD: Precision potentiometer sets the upper level discriminator. OUTPUT WIDTH: Front panel 22-turn screwdriver adjustable potentiometer to set width of slow positive output pulse, which is equal to the internal dead time of the discriminator - max. setting: 1.5 micro sec. Zero: Precision potentiometer sets the "zero" level from 0 to +/-200mV.

PERFORMANCE

Conversion Time: (1.0 + 0.01*N) µs, where N is the channel address generated by the 7074 ADC

ADC Deadtime: time-to-peak + 1µs + conversion time.

Typical ADC deadtime using a Gamma-spectrum containing I-131, Ru-103, Cs-137 and Cs-134g measured with a Germanium detector:

Conversion
Gain
1024
2048
4096
8192

Average deadtime
/conversion
3.7µs
7.1µs
13.9µs
27.4µs

Integral non-linearity: less than +/-0.05% of full scale over top 99% of selected range.

Differential non-linearity: less than +/-0.75% over top 99% of selected range.

Gain stability: better than 50 ppm/^oC

Baseline stability: 50µV/^oC

Temperature range: 0^oC to +50^oC

Power Requirements

+24V, 450 mA, -24V, 500 mA+ 6V, 550 mA

Physical

Size: single width NIM module (1.35 x 8.71 inches

3.43 x 22.13 cm) as per TID - 20893

Shipping weight: 1.2 kg (net 0.8 kg)

Overview NIM - Modules