Dynamic Quadrupole Lens Control for Compact Particle Beam Transport

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Solution Overview

Problem

Existing charged particle beam transport systems face challenges in maintaining a small beam spot size and compact dimensions while scanning over large angles, due to beam energy spread and dispersion, leading to unsatisfactory focal properties at the target.

Innovation Solution

An apparatus comprising a dipole magnet upstream and at least three dynamically adjustable quadrupole lenses between the dipole magnet and the scanning means, with the ability to adjust field strength based on scanning angles, ensuring achromatism and minimizing beam spot size, and an additional quadrupole lens for maintaining beam direction consistency across angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the beam is scanned over large angles, then the coverage area on the target is improved, but the beam spot size increases due to dispersion and energy spread

Engineering Contradiction:
Improvecoverage area on targetVSAvoidbeam spot size
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs dynamic adjustment of quadrupole lens field strengths in response to scanning angle changes. The quadrupole lenses are controlled to modify their focal properties in real-time as the beam scans across different angles, maintaining consistent beam spot size throughout the coverage area.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the optical parameters (focal lengths) of the quadrupole lenses dynamically based on the scanning angle. By adjusting these parameters, the system compensates for dispersion effects and energy spread, keeping the beam spot size small across the entire target coverage area.

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If the beam transport line is made more compact, then the device dimensions are reduced, but the beam profile characteristics deteriorate

Engineering Contradiction:
Improvebeam line lengthVSAvoidbeam profile characteristics
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The compact beam transport line incorporates dynamically adjustable quadrupole lenses that can change their focal properties on-the-fly. This dynamic capability allows the system to maintain proper beam profiling even in a compressed spatial configuration, overcoming the limitations of fixed optics in compact designs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The quadrupole lenses serve multiple functions: they provide fixed focusing, dynamic focal adjustment for different scanning angles, and compensation for dispersion effects. This multi-functionality allows a compact design to achieve beam profile characteristics previously requiring longer, more complex transport lines.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the focal properties are adjusted for one scanning angle, then the beam spot size is minimized at that angle, but the beam spot size increases at other angles

Engineering Contradiction:
Improvebeam spot size at specific angleVSAvoidbeam spot size across all angles
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system uses dynamic control of quadrupole lens field strengths that are specifically tuned to compensate for scanning angle effects. As the beam scans to different angles, the quadrupole lenses adjust their focusing power accordingly, ensuring consistent beam spot size across the entire angular range rather than being optimized for a single angle.

Inventive Principle:
Principle #15Dynamics

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 achieves a stable and compact beam transport system with a small beam spot size, capable of scanning over large angles without deteriorating beam profile characteristics, maintaining high beam quality and allowing for efficient non-destructive screening and sterilization applications.

Implementation Method 1

dipole magnets for bending the beam path

Methodology Applied
Scientific EffectElectromagnetic deflection: Lorentz Force

Implementation Method 2

at least three quadrupole lenses arranged between the dipole magnet and the means for scanning and means for adjusting the field strength of said at least three quadrupole lenses

Methodology Applied
Scientific EffectElectromagnetic field interaction: Lorentz Force

Implementation Method 3

a scanner for scanning the charged particle beam over a target. The scanner imparts an angular deflection to the charged particle beam

Methodology Applied
Scientific EffectElectromagnetic scanning: Lorentz Force

Data Source

PatentEP2193525B1Particle beam transport apparatus and method of transporting a particle beam with small beam spot size
Publication Date: 2012.02.01 ION BEAM APPL
  • EP2193525B1 patent drawingFigure 1~2

AI summary

The present invention is related to an apparatus (10) for transporting a charged particle beam. The apparatus comprises: means (12) for scanning the charged particle beam on a target (3), a dipole magnet (15) arranged upstream of the means for scanning, at least three quadrupole lenses (17) arranged between the dipole magnet and the means for scanning and means for adjusting the field strength of said at least three quadrupole lenses in function of the scanning angle of the charged particle beam. The apparatus can be made at least single achromatic.