Pulse Height Analyzer Digital Integration High Count Rates

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Solution Overview

Problem

Classic pulse height analyzers in nuclear well logging have limited throughput and are inadequate for processing high count rates due to their discontinuous operation and reliance on analog-to-digital conversion time, which limits their ability to distinguish between adjacent energy levels and process multiple pulses efficiently.

Innovation Solution

A method and apparatus that utilize an integrator to capture the total charge from a nuclear detector, digitize the output using a high-resolution ADC, and employ synchronous reset with the ADC acquisition clock to enable continuous data acquisition without dead-time, allowing for high throughput and minimal spectral distortion while maintaining high energy and time resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a classic pulse height analyzer with shaping amplifier and sample-and-hold circuit is used, then good energy resolution is achieved, but throughput is limited due to ADC conversion time

Engineering Contradiction:

Improveenergy resolutionVSAvoidthroughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the analog pulse height analysis system with a digital integration system. Instead of using shaping amplifiers and sample-and-hold circuits, the invention uses an integrator to accumulate charge from detector pulses and a digital processor to analyze the integrated signal. This substitution of analog components with digital processing enables continuous operation at high throughput while maintaining energy resolution through digital signal processing techniques.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous data acquisition by using an integrator that continuously accumulates charge from detector pulses without dead time. The integrator operates continuously, and the digital processor handles the integrated signal, allowing the system to process high count rates without the discontinuous operation inherent in classic analyzers that must wait for ADC conversion to complete before accepting the next pulse.

Inventive Principle:

Principle #20Continuity of useful action

2Measurement precision

If the analyzer operates in discontinuous fashion with ADC conversion, then energy resolution is maintained, but time resolution and ability to process high count rates deteriorates

Engineering Contradiction:

Improveenergy resolutionVSAvoiddead time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the discontinuous analog-to-digital conversion process with continuous digital integration and processing. The integrator continuously accumulates charge, and the digital processor continuously analyzes the integrated signal, eliminating the dead time associated with ADC conversion in classic systems. This enables the system to maintain energy resolution while processing high count rates without time loss.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a shaping amplifier with pseudo Gaussian impulse response is used, then signal rise time is increased for better peak sampling, but signal return to baseline is slowed down

Engineering Contradiction:

Improvepeak sampling accuracyVSAvoidsignal return to baseline speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the analog shaping amplifier with a digital integration and processing system. The integrator accumulates charge from detector pulses, and the digital processor performs the analysis, eliminating the need for pseudo Gaussian impulse response filtering. This substitution allows the signal to return to baseline quickly while maintaining measurement precision through digital processing of the integrated signal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides uninterrupted data flow and improved spectral resolution, enabling the processing of high count rates with minimal spectral distortion and pile-up rejection, effectively addressing the limitations of traditional systems by using digital signal processing and minimizing the need for pulse shape compensation.

Implementation Method 1

integrating the electronic input pulse at an integrating device to produce an integrated output signal

Methodology Applied

Scientific EffectIntegration:

Implementation Method 2

digitally sampling the integrated output signal of the integrating device at intervals to produce a stream of digital samples

Methodology Applied

Scientific EffectAnalog-to-Digital Conversion:

Data Source

PatentUS9703004B2High throughput pulse height analyzer

Publication Date: 2017.07.11 SCHLUMBERGER TECH CORP

AI summary

A method and system for acquiring spectral information from an energy sensitive nuclear detector is disclosed. The method includes detecting nuclear radiation at a detection device and generating an electronic input pulse indicative of energy deposited in the detection device. The method further includes integrating the electronic input pulse at an integrating device to produce an integrated output signal and digitally sampling the integrated output signal of the integrating device at intervals to produce a stream of digital samples. The method further includes resetting the integrator synchronously with a sampling clock when a limit condition is reached.