Solid-State Photomultiplier with Current Dividers for Spatial Resolution
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Solution Overview
Problem
Existing photomultiplier devices face challenges in achieving high spatial resolution with low sensitivity to misalignment and minimal operational complexity, particularly in detecting low light intensities and single photons, due to the need for a large number of output channels which increases complexity and power consumption.
Innovation Solution
A position-sensitive photomultiplier device with a reduced number of output channels is designed, utilizing current dividers with resistive and capacitive partitions to determine photon impact position along one or two dimensions, minimizing distortions and maintaining high temporal resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of output channels is increased to achieve high spatial resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple microcell groups that share common readout electrodes, merging their signals through current dividers. This allows multiple photodetector elements to be read out through a reduced number of channels while preserving spatial information through signal processing
Solution Approach 2:
The patent introduces current dividers as intermediary components between the microcell groups and readout channels. These dividers proportionally distribute currents from multiple microcells to shared readout electrodes, enabling position encoding with fewer channels
2Measurement precision
If the pitch of photomultiplier elements is decreased to improve spatial resolution, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple microcell groups onto a single semiconductor substrate with shared readout circuitry, reducing the number of discrete components and interconnections required, thereby simplifying manufacturing while achieving fine spatial resolution through dense microcell arrangement
3Measurement precision
If the number of output channels is increased to achieve high spatial resolution, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent combines multiple microcell readout circuits into shared readout channels, reducing the total number of active electronic components and their associated power consumption while maintaining spatial resolution through proportional current division and signal processing
4Device complexity
If position-sensitive photomultiplier devices are used to reduce output channels, then device complexity is reduced, but measurement precision deteriorates due to signal distortions
Solution Approach 1:
The patent modifies the electrical parameters of the readout circuitry, specifically designing current dividers with proportionally varying resistances and capacitances that compensate for signal distortions. This parameter optimization maintains measurement precision while using fewer output channels
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 enables accurate determination of photon impact position with reduced signal distortions and operational complexity, achieving high spatial and temporal resolution while being less sensitive to misalignments and suitable for low light intensity detection.
Implementation Method 1
Each one of said light sensitive microcells comprises a reversely polarized avalanche photodiode that responds independently of the others, emitting an elementary charge packet in the moment when a photon is detected
Implementation Method 2
Each light sensitive microcell furthermore comprises a quenching circuit that is connected to the photodiode in series and is suited to quench said avalanche effect that was established in the same photodiode following the impact of a photon on its sensitive surface
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A solid-state photomultiplier device comprising a surface (2) sensitive to photons (F) provided on a semiconductor substrate (3) and provided with a plurality of light sensitive microcells (4) divided into a plurality of sub-groups arranged one after the other according to a pre-established trajectory. The device comprises a plurality of current dividers (7), each of which is electrically connected to at least one of the sub-groups, and where each of the current dividers (7) comprises a first resistor (71) and a second resistor (72) to implement a current partition of the resistive type. The first resistors (71) and the second resistors (72) respectively have a gradually descending and gradually increasing conductance value in proportion to the position along the pre-established trajectory of the sub-group to which each of the current dividers (7) is electrically connected. The device also comprises a first output channel (10) electrically connected to one end of the first resistors (71) and a second output channel (11) electrically connected to one end of the second resistors (72).