AD413A CAMAC Quad 8k ADC

Multiplexed, 4-input, 8064-channel ADC with CAMAC and fast FERAbus TM readout for multi-parameter experiments
6-ľs conversion time per active input, and 100 ns/word FERAbus readout
FERAbus readout can skip ADCs with no information in 3 ns
CAMAC control of: FERAbus/CAMAC readout, zero and overflow suppression, master gate, individual gates, singles/coincidence modes, and each lower-level discriminator
Differential inputs suppress ground-loop noise

The ORTEC Model AD413A CAMAC Quad 8k ADC is a multiplexed, four-input, 13-bit analog-to-digital converter (ADC) with CAMAC and fast FERAbus readout. It is a very productive solution for high-multiplicity multiparameter experiments because it has a conversion time of 6 ľs per active input, and a 100-ns-per-word FERAbus readout with the ability to skip ADCs with zero information in 3 ns. This 8064-channel ADC can be used with Ge detectors, silicon charged-particle detectors, scintillation detectors, proportional counters, and ionization chambers.

Each of the four analog inputs has its own peak amplitude stretcher, and accepts pulses in the linear range from 0 to +10 V. The stretchers are multiplexed on a first-come, first-served basis to a 13-bit, successive-approximation ADC with sliding scale linearization. If two or more inputs receive coincident pulses, the pulse amplitudes are stored in their respective stretchers, so that the ADC can successively convert each input. The dc-coupled analog inputs accept unipolar and bipolar pulses from standard spectroscopy amplifiers with shaping times from 0.25 to 20 ľs. Differential inputs are incorporated to suppress ground-loop noise when connected to systems with multiple power supplies and grounds.

Each analog input has its own gate input (GATE 1, 2, 3, 4) to suppress analysis of unrelated events when the master gate in the FERA (Fast Encoding and Readout ADC) ECL CONTROL bus is used to synchronize coincident events. The master gate is also available as a TTL input on a LEMO connector, for use in the coincidence mode with CAMAC readout. CAMAC commands permit enabling and disabling the module's response to any gate input. This is useful when selecting the coincidence mode or the singles mode for the Model AD413A under CAMAC control. Four LEMO connectors on the rear panel accept the pile-up rejector logic signals from the four spectroscopy amplifiers supplying the associated analog input pulses.

Additional modes selectable by CAMAC command are: CAMAC or FERAbus readout, zero suppression or no zero suppression during readout, overflow suppression, singles or coincidence analysis, and random access versus sequential access during CAMAC readout. Each analog input has its own lower-level discriminator, separately adjustable by CAMAC command over the range from 0 to 512 mV with 2 mV/bit resolution.

The Model AD413A is compatible with the standard LeCroy FERA control and data output busses. This system can provide very fast readout of the ADCs with non-zero events in a CAMAC crate full of ADCs. For both data acquisition and readout, the control bus synchronizes all ADCs with the experiment's master trigger. This permits identification of all the ADC outputs from the same event and their subsequent assimilation into a common block of data. To the standard FERAbus features, ORTEC has added the ability to select the singles or coincidence analysis mode for any Model AD413A. This feature allows checking the functionality of a detector via the singles spectrum at any time during an experiment.

Normally, all the ADCs in the crate are connected to a LeCroy Model 4301 FERA Driver for control and readout (Fig. 1). The FERA Driver, in turn, delivers the data to either a LeCroy Model 4302 Dual Port Fast Memory in CAMAC, or a CES Model HSM8170 High Speed Memory in VMEbus. Both memories operate in the list mode to assemble the block of coincident events for further processing by an event builder.

To facilitate making the interconnection between the FERAbus Modules, the C-ECLBUS Cable Kit is recommended as a separately ordered accessory. This kit contains the cables and connectors needed for a crate full of FERAbus Modules.

ORDERING INFORMATION

Model		Description
AD413A		CAMAC Quad 8k ADC
C-ECLBUS		Cable Kit for the ECLBUS


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