Multi-Material Foil Target Window for Isotope Production
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Solution Overview
Problem
Conventional target windows in isotope production systems, such as those used in Positron Emission Tomography (PET) cyclotrons, face challenges with high-pressure and high-temperature conditions, leading to activation of Havar foils and transfer of long-lived radioactive isotopes to target media, which can be harmful when injected into patients.
Innovation Solution
A multi-member target window is introduced, comprising foil members with different materials and properties stacked in a specific arrangement, where one foil member provides strength to resist high pressure and temperature, and another reduces the production of long-lived isotopes by being chemically inert, such as using a Cobalt-based alloy (Havar) for strength and Niobium for inertness, optionally with an aluminum member for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Havar foil is used to form the target window, then the window can withstand high pressure and high temperature conditions, but long-lived radioactive isotopes are activated and transferred to the target media
Solution Approach 1:
The target window is divided into multiple separate foil members stacked together. The first foil member (Havar or similar) provides structural strength, while the second foil member (Niobium or other low-activation material) prevents radioactive isotope transfer to the target media. This segmentation allows each layer to perform its specific function independently.
Solution Approach 2:
The target window uses a composite structure of different foil materials. The Havar foil provides mechanical strength to withstand pressure and temperature, while the Niobium foil provides chemical inertness and low radioactive activation. The combination creates a multi-functional window that addresses both structural and radiological requirements.
2Device complexity
If a single foil material is used for the target window, then the structure is simple, but it cannot simultaneously provide both strength and chemical inertness under extreme conditions
Solution Approach 1:
Instead of using a single foil, the window is segmented into multiple foils with different material properties. This allows the system to achieve both strength and chemical inertness without compromising reliability under extreme pressure and temperature conditions.
Solution Approach 2:
Different regions of the target window have different material properties optimized for their specific functions. The Havar foil region provides strength where mechanical loads are highest, while the Niobium foil region provides chemical inertness where contact with target media occurs. Each local region is optimized for its specific requirement.
Data Source
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AI summary
Target windows for isotope production systems are provided. One target window includes a plurality of foil members in a stacked arrangement. The foil members have sides, and wherein the side of a least one of the foil members engages the side of at least one of the other foil members. Additionally, at least two of the foil members are formed from different materials.