PMT Light Detector with Thermally Conductive Shield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light detectors with photomultiplier tubes (PMTs) face challenges in compactness and condensation prevention, particularly in optical-based analytical instruments where space is limited and condensation can contaminate samples or optics, limiting their performance in fluorescence and luminescence measurements.
Innovation Solution
A compact light detector design incorporating a PMT with a thermoelectric cooling device, a heat sink, and a thermally conductive shield that transfers heat to prevent condensation, ensuring the PMT remains at a temperature that prevents moisture buildup while maintaining optical path integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PMT is cooled to reduce dark counts, then measurement precision is improved, but condensation develops on the PMT and surrounding components
Solution Approach 1:
A thermally conductive shield is introduced as an intermediary component between the heat sink and the PMT housing. This shield acts as a thermal mediator that conducts heat to the housing and surrounding components, preventing condensation while the PMT itself remains cooled for reduced dark counts.
Solution Approach 2:
Different thermal conditions are applied to different parts of the system: the PMT is locally cooled to reduce dark counts, while the housing and surrounding components are locally heated by the thermally conductive shield to prevent condensation. This spatial differentiation of thermal properties resolves the contradiction.
2Productivity
If a cooled PMT is integrated into a compact instrument, then productivity is improved, but the instrument size increases due to cooling components
Solution Approach 1:
Multiple functions are merged into a single integrated assembly: the PMT cooling device, heat sink, and thermally conductive shield are combined into one compact unit that simultaneously achieves dark count reduction and condensation prevention, eliminating the need for separate cooling systems and reducing overall instrument footprint.
Solution Approach 2:
The components are nested within each other to minimize space: the PMT is positioned within the housing, the thermally conductive shield is positioned between the heat sink and housing, and all components share common thermal and structural pathways, creating a space-efficient nested configuration.
3Reliability
If thermally conductive material is added to prevent condensation, then reliability is improved, but heat transfer to the PMT increases causing condensation
Solution Approach 1:
The thermally conductive shield provides localized heating to the housing and surrounding components to prevent condensation, while the PMT itself remains thermally isolated and cooled. The different thermal properties are locally applied to different components, allowing simultaneous condensation prevention and PMT cooling.
Solution Approach 2:
The thermally conductive shield acts as a thermal intermediary that directs heat flow preferentially to the housing and surrounding components rather than the PMT. This mediator component enables differential thermal management, providing warmth where needed for condensation prevention while maintaining cold temperatures at the PMT for reduced dark counts.
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 effectively cools the PMT, reducing dark counts and preventing condensation, thus enhancing measurement accuracy and instrument compactness, allowing for single PMT use in multiple applications without compromising performance.
Implementation Method 1
A compact light detector design incorporating a PMT with a thermoelectric cooling device
Implementation Method 2
a heat sink in thermal contact with the hot side
Implementation Method 3
a thermally conductive shield substantially enclosing the PMT device, the shield comprising an opening through which the optical path passes, wherein the shield is in thermal contact with the heat sink such that the heat sink transfers heat to the shield
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light detector includes a cooling device between a photomultiplier tube (PMT) device and a heat sink. A thermally conductive shield encloses the PMT device and the cooling device and is in thermal contact with the heat sink such that the heat sink transfers heat to the shield. The light detector may be included in sample analyzing apparatus configured for making optical measurements of a sample.