Trade.Information

Product Name: ICB Programmable Digital Signal Processor - Model 9660

Product Description

The Model 9660 Digital Signal Processor represents the state of the art in high rate/high resolution pulse processing subsystems for gamma spectroscopy. Using high speed DSP circuits and sophisticated filtering algorithms, the 9660 replaces the traditional shaping Amplifier/ADC combination in traditional analog based spectroscopy systems.

With traditional analog signal processing, the detector signal is amplified, shaped, filtered and baseline restored by the shaping amplifier. The signal is then digitized by the ADC at the end of the processing chain. The 9660 performs pre-conditioning and amplification of the signal presented by the preamplifier, then digitizes the signal directly at a very high sampling rate. The filtering, baseline restoration and optimization processes are then applied to the digitized data using real time digital processing algorithms. This reduces noise effects while making possible the use of more efficient and sophisticated filtering algorithms than can be achieved in the analog domain. The net result is a reduced processing time for better throughput with improved resolution and enhanced stability.

The weighting function applied in the 9660 filter algorithm produces a symmetrical and near ideal Triangular/Trapezoidal filter function. Trapezoidal shaping requires less processing time for equivalent resolution obtained with semi-Gaussian shaping. The result is less dead time, less pileup, more events processed and higher throughput. Conversely, superior resolution results when the trapezoidal processing time is increased to match a particular semi-Gaussian processing time. The duration of the trapezoidal flat top can be automatically or manually adjusted to eliminate detector ballistic deficit and charge collection effects. Triangular shaping is optimal for small detectors which don’t exhibit ballistic deficit or charge collection irregularities and is obtained by reducing the trapezoidal flat top to zero.

With the 9660, users can achieve count throughput rates in excess of 100 000 counts per second. In general the trade off between resolution and throughput is unsurpassed when compared to traditional analog electronics. For example, a trial run comparing the fastest available analog system, the CANBERRA 2024 Amplifier and 8715 ADC to the 9660 produced a peak resolution of 2.4 FWHM at 70 000 cps for the 9660, compared to 2.6 FWHM for the 2024/8715.

Traditionally, the spectroscopist had to make tradeoffs between resolution and throughput – the higher the throughput, the poorer the resolution and vice versa. While this tradeoff still occurs, the 9660 user will observe higher overall throughput or better resolution at a lower throughput than with analog electronics.

The 9660 accepts programming information over an 8-bit wide CANBERRA bus standard called the Instrument Control Bus (ICB). ICB NIMs connect to this bus via a host module such as the Model 556 Acquisition Interface Module (AIM) as part of a hierarchy of networked acquisition and control managed by a Genie family computing platform.

Adjustments are made through the Graphical User Interface of the Genie software environments. Equivalent batch procedure commands are also available in the environments. All ICB NIM parameters are stored in the single data file structure of the Genie family, allowing verification of correct set up from one experiment to the next. All ICB NIMs feature a characteristic READY LED to indicate operational status. Software commands initiate automatic measurement of and correction for ballistic deficit effects. The pole/zero is adjusted manually from the software.

The 9660 includes a two-point digital stabilizer that provides both gain and zero stabilization. The stabilizer is programmable and allows adjustment interactively. Adjustment menus in the software allow the stabilizer to be turned on and off, or placed in a “hold” state which freezes the adjustments for subsequent counts.

Features
Triangular and trapezoidal digital filter functions 
Processing times from 0.8 to 76 µs 
Digital baseline restorer and pileup rejector 
Reduced processing time for improved resolution/throughput 
Throughput in excess of 100 kcps 
Improved stability, repeatable performance 
Automatic measurement of and correction for ballistic deficit 
16K channel resolution 
Compatible with Loss Free Counting Systems* 
Wide gain range x2 to x1536 
Gain and zero digital stabilizers 
Secure computer operation without conflicting front panel controls 
Interfaces to network based Model 556 Acquisition Interface Module (AIM)

Company Details

For over 35 years, the name Canberra has been known for world class nuclear measurement equipment and services. Now... meet the new Canberra.