Selective Ionization of Palladium Isotopes via Multi-Stage Laser Excitation

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Solution Overview

Problem

Current methods for selectively ionizing palladium isotopes with odd mass numbers from spent nuclear fuel or natural substances are inefficient, as they do not effectively consider the ion core state during excitation, leading to suboptimal ionization efficiency.

Innovation Solution

A selective ionization method and device that utilize multiple laser beams with specific wavelengths to excite palladium isotopes from a ground level to an autoionization level, maintaining the ion core state throughout the excitation process, thereby enhancing the ionization efficiency of palladium isotopes with odd mass numbers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional laser excitation methods are used to ionize palladium isotopes, then the ionization process can be performed, but the ionization efficiency is low and does not achieve selective separation

Engineering Contradiction:
Improveionization efficiencyVSAvoidselectivity of isotope separation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling laser wavelengths to match specific transition energies of odd-mass palladium isotopes. By tuning the laser wavelengths to excite only odd-mass isotopes through specific quantum transitions, the method achieves both high ionization efficiency and selective separation, resolving the contradiction between productivity and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by targeting specific quantum states and energy levels of odd-mass palladium isotopes. The laser excitation is localized to specific transitions (e.g., from ground state to excited states with particular quantum numbers), enabling selective ionization of odd-mass isotopes while leaving even-mass isotopes unaffected, thus achieving both high efficiency and selectivity.

Inventive Principle:
Principle #3Local quality

2Productivity

If multi-stage laser excitation is implemented to maintain ion core state, then ionization efficiency increases significantly, but the device complexity and operational requirements increase

Engineering Contradiction:
Improveionization efficiencyVSAvoidcomplexity of laser excitation system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the ionization process into multiple discrete excitation stages, each with a specific wavelength and energy transition. This segmentation allows precise control over which isotopes are excited and ionized, maintaining high efficiency while making the complex process manageable through systematic breakdown into controllable steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by first exciting odd-mass palladium isotopes to specific intermediate excited states before final ionization. This preliminary excitation to controlled intermediate states ensures that only the desired isotopes proceed to ionization, maintaining high efficiency while the systematic approach helps manage operational complexity.

Inventive Principle:
Principle #10Preliminary action

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 method achieves significantly higher ionization efficiency for palladium isotopes with odd mass numbers, allowing for their selective and efficient separation from a mixture of palladium isotopes, as demonstrated by experimental results showing ionization intensities 100 times or more compared to previous methods.

Implementation Method 1

a first laser beam having a first wavelength and a second laser beam having a second wavelength selectively excite the palladium isotopes having an odd mass number from the plurality of types of palladium isotopes to a second excited level through a first excited level

Methodology Applied
Scientific EffectPhotoionisation: Photoionisation

Implementation Method 2

the second excited level is the autoionization level. Otherwise, a third laser beam having a third wavelength excites the palladium isotopes at the second excited level to the autoionization level

Methodology Applied
Scientific EffectAutoionization: Photoionisation

Data Source

PatentEP3391956B1Device and method for selective ionization of palladium isotopes
Publication Date: 2023.07.26 RIKEN CO LTD
  • EP3391956B1 patent drawingFigure 1
  • EP3391956B1 patent drawingFigure 2A~2B
  • EP3391956B1 patent drawingFigure 3

AI summary

A first laser beam having a first wavelength excites palladium isotopes at a ground level to a first excited level. A second laser beam having a second wavelength excites the palladium isotopes at the first excited level to a second excited level. At first and second excitation steps, palladium isotopes having an odd mass number are selectively excited to the second excited level, with the identity of the ion core state of each of the palladium isotopes retained between the first excited level and the second excited level. The first wavelength and the second wavelength are selected to allow the second excited level to be an autoionization level or, in a case where the second excited level is not the autoionization level, the first wavelength, the second wavelength, and a third wavelength are selected to excite the palladium isotopes at the second excited level to the autoionization level with a third laser beam having the third wavelength at a third excitation step.