SiPM Reflective Pulse Compression for Recovery Tail Cancellation

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Solution Overview

Problem

Silicon photomultiplier (SiPM) devices face challenges due to their recovery time after detecting a photon, leading to overlapping tail recovery periods and amplifier saturation in high photon flux scenarios, which complicates individual photon response discrimination and limits detection bandwidth and dynamic range.

Innovation Solution

The implementation of a Reflective Pulse Compression (RPC) method using a transmission line stub with a complex impedance termination, which absorbs and reflects specific components of the SiPM pulse, allowing for cancellation of the recovery tail and improved temporal resolution by amplifying a combination of the detected and time-delayed reflected signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low pass filter is added to reduce bandwidth below recovery time, then overlapping tail recovery is mitigated, but detection bandwidth is limited

Engineering Contradiction:
Improvephoton response discriminationVSAvoiddetection bandwidth
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The harmful recovery tail is extracted and separated from the useful signal using a T-network filter. The filter extracts only the tail portion (slow component) while allowing the fast signal component to pass through, thereby mitigating overlap without limiting overall detection bandwidth

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Different frequency components of the signal are treated differently by the T-network filter. The fast signal component (useful information) passes through with minimal attenuation, while the slow tail component (harmful overlap) is selectively attenuated. This local quality differentiation resolves the contradiction between maintaining bandwidth and reducing overlap

Inventive Principle:
Principle #3Local quality

2Reliability

If active/amplified circuit tail compensation is used, then tail response is compensated, but system linearity is lost due to amplifier saturation

Engineering Contradiction:
Improvetail compensationVSAvoidsystem linearity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention replaces expensive, complex active amplification circuits with a simple passive T-network filter composed of basic RLC components. This passive approach provides effective tail compensation without requiring amplification, thereby maintaining system linearity and avoiding saturation issues

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

Solution Approach 2:

The active electronic amplification system is replaced with a passive filter network. The T-network uses passive components (resistors, capacitors, inductors) to achieve tail compensation through impedance matching and frequency-selective attenuation rather than active amplification, preserving system linearity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If PZC circuit is used after TIA stage, then tail length is reduced, but nonlinearities from amplifier saturation occur

Engineering Contradiction:
Improverecovery tail lengthVSAvoidsignal linearity
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The T-network filter is positioned before the amplifier stage to perform preliminary tail compensation on the signal. By attenuating the tail component before amplification, the filter prevents subsequent amplifier saturation and maintains signal linearity throughout the amplification process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The T-network filter acts as an intermediary between the SiPM detector and the amplifier. It conditions the signal by selectively attenuating the tail component while preserving the fast signal component, thereby preparing the signal for clean amplification without saturation

Inventive Principle:
Principle #24Intermediary (Mediator)

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 results in a narrower signal profile with enhanced temporal resolution and full dynamic range utilization, effectively addressing the issues of recovery time and amplifier saturation, enabling better discrimination of individual photon responses and maintaining system linearity.

Implementation Method 1

a transmission line stub between the SiPM and amplifier input configured to receive the SiPM signal and generate a time-delayed reflected signal back into the amplifier input

Methodology Applied
Scientific EffectSignal reflection: Reflection

Implementation Method 2

The end of the transmission line stub is terminated with a complex impedance that can simultaneously absorb some components of the SiPM pulse response, and reflect others

Methodology Applied
Scientific EffectImpedance matching: Electrical Impedance Tomography

Implementation Method 3

the amplifier is configured to amplify a combination of the detected signal and the time-delayed reflected signal

Methodology Applied
Scientific EffectSignal amplification: Magnetic Amplifier

Implementation Method 4

An arriving photon causes avalanche current to flow in the SiPM APD cell

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Implementation Method 5

A silicon photomultiplier (SiPM) device or multipixel photon counter (MPPC) is an array of small avalanche photodiodes (APDs) capable of detecting single photons

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3998464B1Silicon photomultipliers reflective pulse compression
Publication Date: 2024.12.11 THORLABS INC
  • EP3998464B1 patent drawingFigure 1
  • EP3998464B1 patent drawingFigure 2
  • EP3998464B1 patent drawingFigure 3

AI summary

A photon detection device including: a silicon photomultiplier (SiPM) configured to generate a detected signal when the SiPM absorbs a photon; an amplifier; and a transmission line stub between the SiPM and amplifier input. The SiPM connection is configured to transmit the detected signal to the amplifier and a transmission line stub is also configured to receive the SiPM signal and generate a time-delayed reflected signal back into the amplifier input; wherein the amplifier is configured to amplify a combination of the detected signal and the time-delayed reflected signal. The end of the transmission line stub is terminated with a complex impedance that can simultaneously absorb some components of the SiPM pulse response, and reflect others.