Electron Multiplier Gain Control for Leak Detection

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Solution Overview

Problem

Existing devices for measuring and processing high dynamic input signals, such as those used in leak detection, face challenges with discontinuous gain control of electron multipliers, leading to long response times and instabilities, particularly when signals approach amplification range limits.

Innovation Solution

A device and method that determine the exponent of the electron multiplier's gain prior to calculating control circuit parameters, allowing for precise adjustment without iterative measurements, using a logarithmic compressor amplifier and varying supply voltage to measure and calculate gain and offset parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional iterative adjustment method is used to set gain and offset parameters, then the output signal range can be adjusted, but the adjustment process becomes time-consuming due to interdependence of parameters requiring multiple iterations

Engineering Contradiction:
Improveoutput signal range accuracyVSAvoidadjustment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by calculating theoretical gain and offset parameters using a predetermined exponent value before actual measurement. This pre-calculation approach eliminates the need for iterative adjustments during operation, significantly reducing adjustment time while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a predetermined exponent value as a simplified model that replaces complex iterative parameter tuning. This predetermined value acts as a 'cheap' approximation that provides sufficient accuracy without requiring time-consuming iterative measurements, effectively trading minor precision for significant time savings.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Adaptability or versatility

If the gain parameter of the control circuit is adjusted, then the output signal range changes, but both offset and gain of the output signal range change due to parameter interdependence

Engineering Contradiction:
Improveoutput signal rangeVSAvoidcontrol circuit parameter interdependence
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the parameter adjustment process by calculating gain and offset parameters separately through theoretical computation. By using a predetermined exponent to independently determine each parameter, the method eliminates the interdependence complexity that would otherwise require coordinated adjustment of multiple parameters simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the approach from iterative parameter tuning to direct theoretical calculation. By transforming the adjustment process into a mathematical computation based on a predetermined exponent, the system achieves adaptability without the complexity of interdependent parameter interactions.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If offset parameter is adjusted to change output signal range, then the range is modified, but both offset and gain change requiring fine tuning and multiple iterations

Engineering Contradiction:
Improveoutput signal stabilizationVSAvoidadjustment speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary calculation of both gain and offset parameters using a predetermined exponent before actual operation. This pre-computation ensures manufacturing precision through accurate parameter determination while eliminating the need for time-consuming iterative fine-tuning, thereby improving productivity.

Inventive Principle:
Principle #10Preliminary action

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

This approach enables continuous signal measurement over a wide dynamic range, reducing the need for iterative adjustments and stabilizing output signals more efficiently, thus improving processing accuracy and speed.

Implementation Method 1

Electron multipliers are components that have an amplifying function. Their generally very high gain can go up to 10^5

Methodology Applied
Scientific EffectSecondary electron emission:

Implementation Method 2

a logarithmic compressor amplifier delivering an output signal and also acting on the control circuit

Methodology Applied
Scientific EffectLogarithmic compression:

Data Source

PatentEP2376943B1Device for measuring and processing a high dynamic input signal, and corresponding leak detector and measuring and processing method
Publication Date: 2017.11.22 PFEIFFER VACUUM SAS
  • EP2376943B1 patent drawingFigure 1
  • EP2376943B1 patent drawingFigure 2~3
  • EP2376943B1 patent drawingFigure 4

AI summary

The invention relates to a device for measuring and processing an input signal (To) of at least two decades, comprising: an electron multiplier (4) that has an exponential gain on the basis of the power supply voltage (Vm) thereof and which receives said input signal (To); a power supply (5) that provides the power supply voltage (Vm) of said multiplier (4); a control circuit (6) of the power supply (5), the gain (10) and shift (11) parameters of which are adjustable and define an output signal range while varying the exponential gain of said multiplier (4); a logarithmic compression amplifier (T), the output of which is received as an input of the control circuit (6) so as to vary the exponential gain of the electron multiplier (4), in a continuous manner over the dynamic range of a measurement, on the basis of the output signal (IoG) of the electron multiplier (4), and forming the output signal (Vout) of said device; a measuring and calculating means for predetermining the value of the exponent (b) for the exponential gain of the electron multiplier (4) and for calculating the gain (10) and shift (11) parameter values of said control circuit (6) on the basis of the value of said predetermined exponent (b). The invention also relates to a corresponding leak detector and measuring and processing method.