Dynode Detector Dynamic Gain Control

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Solution Overview

Problem

Existing particle detector electron multipliers face operational lifetime challenges due to high secondary electron fluxes leading to carbon deposition on dynodes, especially in poor vacuum conditions, which reduces secondary yield and necessitates costly maintenance.

Innovation Solution

A novel intermediate dynode structure with a partitioned surface area and coupled control circuit that regulates voltage gain in real-time to prevent high current pulses from hitting downstream dynodes, dynamically adjusting the gain to prevent unnecessary current amplification and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high gain values are used to improve signal-to-noise ratio for low-level signal detection, then detection sensitivity is improved, but carbon deposition on dynodes increases rapidly leading to reduced operational lifetime

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidoperational lifetime
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The patent applies dynamic gain control by monitoring the real-time signal from an intermediate dynode and dynamically adjusting the gain of downstream dynodes. This allows the system to operate at high gain for low-level signals when needed while preventing excessive gain that would cause carbon deposition, thereby extending operational lifetime while maintaining detection sensitivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control by monitoring the signal generated by an intermediate dynode in real-time and using this information to regulate the gain of downstream dynodes. This feedback mechanism prevents the system from operating at excessively high gain levels that would cause rapid carbon deposition, while still allowing high gain operation when signal levels are low.

Inventive Principle:
Principle #23Feedback

2Power

If the voltage applied to the electron multiplier is increased to increase gain, then signal amplification is improved, but intense electron currents hit the final stages causing carbon buildup

Engineering Contradiction:
Improvesignal amplificationVSAvoidcarbon buildup
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by monitoring the signal at an intermediate dynode stage before the intense electron currents reach the final dynodes. This early detection allows the system to preemptively adjust the gain of downstream dynodes to prevent excessive electron currents and carbon deposition before they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediate dynode as a mediator to monitor the electron multiplication process. By detecting the signal at this intermediate stage, the system can regulate the gain of downstream dynodes without directly exposing them to excessive electron currents, thus preventing carbon buildup while maintaining signal amplification.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If discrete dynode architecture is used to enable better control of individual dynodes, then dynamic control capability is improved, but strong electron currents still accumulate in final stages

Engineering Contradiction:
Improvecontrol capabilityVSAvoidelectron current
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by differentiating the control of individual dynode stages. Instead of uniform gain control, the system monitors the intermediate dynode signal and selectively adjusts the gain of downstream dynodes based on local conditions, preventing electron current accumulation in specific high-risk stages while maintaining overall signal amplification.

Inventive Principle:
Principle #3Local quality

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 solution effectively extends the operational lifetime of particle detectors by preventing high current pulses and reducing carbon deposition, thereby improving the stability and longevity of the detector components.

Implementation Method 1

a plurality of cascaded dynodes configured to provide a sensed current at an anode that is related to the number of received incident particles; an interposed partitioned dynode arranged as part of the plurality of cascaded dynodes to provide a detection current indicative of the magnitude of the one or more input signals

Methodology Applied
Scientific EffectElectron emission and current detection: Photoelectric Effect

Implementation Method 2

a control circuit coupled to one or more downstream dynodes within the plurality of cascade dynodes and configured to receive the detection current so as to regulate the voltage gain to the one or more downstream dynodes

Methodology Applied
Scientific EffectElectrical potential regulation and gain control: Electrical Resistance

Implementation Method 3

The potential difference between a pair of dynodes is often designed so that an electron striking a dynode can produce more than one secondary electron. The average number of secondary electrons per primary electron produced at a particular dynode is the gain of that stage of the electron multiplier

Methodology Applied
Scientific EffectSecondary electron emission: Photoelectric Effect

Data Source

PatentEP3528278B1Method of operating a discrete dynode detector with dynamic gain control
Publication Date: 2022.08.17 THERMO FINNIGAN LLC
  • EP3528278B1 patent drawingFigure 1A~1B
  • EP3528278B1 patent drawingFigure 2
  • EP3528278B1 patent drawing

AI summary

A method of operating a particle detector is introduced, the method comprising the steps of receiving incident particles that represent at least one input signal in the particle detector, emitting electrons from a first dynode in response to receiving the incident particles, directing the emitted electrons to a plurality of additional dynodes arranged in a cascading relationship, measuring a detection current generated at an intermediate dynode, and regulating a gain to at elast one dynode positioned downstream of the intermediate dynode based on the measured detection current.