CT Security Scanner Dynamic X-ray Shielding Curtains
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Solution Overview
Problem
Computed tomography (CT) security inspection systems face inadequate X-ray shielding due to high throughput rates, resulting in insufficient attenuation of scattered X-rays in ingoing and outgoing tunnels, as existing solutions like adding more lead-containing curtains or extending tunnels are impractical or costly.
Innovation Solution
Implementing separate conveyor belts for ingoing, X-ray scanning, and outgoing tunnels, with the ingoing and outgoing belts operating at higher speeds than the X-ray scanning belt to allow lead-containing curtains sufficient time to return to their fully down position between trays, ensuring adequate X-ray shielding while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the throughput rate is increased to improve productivity, then more trays can be scanned per hour, but scattered X-rays are not adequately attenuated in the ingoing and outgoing tunnels
Solution Approach 1:
The system uses dynamically adjustable lead-containing curtains that can quickly move between raised and lowered positions. The curtains are synchronized with tray movement to provide shielding only when needed, allowing high throughput while maintaining radiation safety. The curtains transition from a static shielding approach to a dynamic, time-based shielding solution.
Solution Approach 2:
The lead-containing curtains are raised in advance before trays enter the ingoing and outgoing tunnels, and lowered in advance before trays reach the X-ray scanning region. This preliminary positioning ensures that shielding is already in place when trays arrive, eliminating the need for long tunnel lengths while maintaining safety at high throughput rates.
2Object-affected harmful factors
If more lead-containing curtains are added to improve X-ray shielding, then scattered X-rays are better attenuated, but the system complexity and cost increase
Solution Approach 1:
The lead-containing curtains operate in periodic cycles, being raised before tray entry and lowered before tray arrival at the scanning region. This periodic operation allows a small number of curtains to provide continuous shielding coverage over time, replacing the need for multiple static curtains and reducing system complexity.
Solution Approach 2:
The curtains are automatically controlled by sensors that detect tray position and trigger curtain movement. The system self-regulates the shielding without requiring manual intervention or complex centralized control, reducing operational complexity while maintaining effective radiation protection.
3Object-affected harmful factors
If the tunnel length is extended to improve X-ray shielding, then scattered X-rays are better attenuated, but the system size and installation space requirements increase
Solution Approach 1:
The patent replaces the mechanical solution of long tunnel lengths with a time-based shielding approach using rapidly movable curtains. Instead of relying on physical distance for attenuation, the system uses temporal separation - raising curtains before trays arrive and lowering them before trays reach the scanning region - achieving the same safety goal in a compact space.
4Measurement precision
If the conveyor belt speed is reduced in the X-ray scanning region to improve image quality, then image resolution increases, but the overall throughput rate decreases
Solution Approach 1:
The conveyor system is divided into separate zones with different speed requirements: the ingoing and outgoing tunnels operate at high speeds for efficient tray transport, while the X-ray scanning region operates at a slower speed for high-quality imaging. The dynamically positioned curtains enable this speed segmentation by providing shielding during the high-speed transition zones, allowing the scanning region to optimize for image quality without compromising overall throughput.
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 effectively reduces scattered X-rays by ensuring lead-containing curtains can fully attenuate X-rays between trays, enhancing safety and efficiency without increasing power or system complexity, within the constraints of airport and security-sensitive locations.
Implementation Method 1
lead-containing curtains (e.g., 3 to 6 curtains) have hitherto been placed in each of the tunnels... adequately attenuate the moderate amount of scattered X-rays
Data Source
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AI summary
A method for scanning an object in an X-ray security inspection system, wherein the X-ray security inspection system comprises an ingoing tunnel equipped with radiation-shielding curtains, an X-ray section and an outgoing tunnel equipped with radiation-shielding curtains, the method comprising: passing the object through the ingoing tunnel at a first rate of speed and with a first extent of separation between successive objects; passing the object through the X- ray section at a second rate of speed and with a second extent of separation between successive objects; and passing the object through the outgoing tunnel at a third rate of speed and with a third extent of separation between successive objects; wherein the second rate of speed is less than the first rate of speed and the third rate of speed, and wherein the second extent of separation between successive objects is less than the first extent of separation between successive objects and the third extent of separation between successive objects.