Multi-Beam Klystron Magnetic Field Segmentation

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Solution Overview

Problem

In multi-beam klystron apparatuses, the complexity of the electron gun unit and the divergence of electron beams due to radial magnetic fields make it challenging to achieve efficient radio-frequency power amplification without increasing the complexity of the magnetic field distribution and causing thermal issues.

Innovation Solution

A converging magnetic field device with a main magnetic field generating unit and an electron-gun-unit-side magnetic field generating unit, including bucking magnets and matching magnets, is used to create parallel magnetic fields near the electron beam axis, allowing for simpler cathode arrangement and reduced magnetic field leakage effects, thereby maintaining efficient beam convergence and power amplification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If holes for passing electron beams are formed at locations apart from the center axis of the pole piece, then multiple electron beams can be generated, but lines of magnetic force diverge as distance increases causing electron beam divergence

Engineering Contradiction:
Improvenumber of electron beamsVSAvoidelectron beam convergence
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The magnetic field generating system is segmented into multiple independent units: main magnetic field generating units for overall field generation, and electron-gun-unit-side magnetic field generating units for localized field control near each electron beam passage. This segmentation allows independent optimization of magnetic fields for each beam location, preventing divergence while maintaining multiple beams.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Magnetic shielding plates are introduced as intermediary elements between the pole piece holes and the electron beam paths. These plates prevent magnetic field leakage from one beam location from affecting other beams, thereby maintaining parallel magnetic field lines and preventing beam divergence while allowing multiple beams to pass through holes at locations apart from the center axis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If a shared pole piece is disposed near the cathode of the electron gun unit to generate magnetic field for convergence, then multiple electron beams can be converged, but the electron gun unit becomes complex and thermal issues arise

Engineering Contradiction:
Improvenumber of electron beamsVSAvoidelectron gun unit structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The magnetic field generating function is segmented and distributed to multiple independent magnetic field generating units positioned around the electron gun unit, rather than using a single shared pole piece. This segmentation simplifies the electron gun unit structure by eliminating the need for a complex shared pole piece while still providing magnetic field convergence for multiple beams.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic field generating function is extracted from the electron gun unit structure and placed in separate magnetic field generating units. This extraction removes the complexity and thermal issues associated with integrating a shared pole piece near the cathode, while maintaining the ability to converge multiple electron beams.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If very large holes are provided in the pole piece for magnetic field immersion type convergence, then electron beams can pass through, but magnetic fields from other holes affect the electron beam

Engineering Contradiction:
Improveelectron beam passageVSAvoidmagnetic field interference from other beams
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Magnetic shielding plates are positioned between the pole piece holes and the electron beam paths to block magnetic field leakage from one beam location from reaching other beams. This intermediary structure allows the use of smaller holes in the pole piece while preventing harmful magnetic field interference between multiple electron beams.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic field distribution is optimized locally at each electron beam passage location using independent electron-gun-unit-side magnetic field generating units. This local optimization allows smaller holes to be used in the pole piece while maintaining proper magnetic field conditions for each beam, preventing interference from other beams.

Inventive Principle:
Principle #3Local quality

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 configuration allows for efficient radio-frequency power amplification with reduced beam deflection and thermal issues, enabling the use of smaller pole piece holes and simpler electron gun unit design, while maintaining high output conversion efficiency.

Implementation Method 1

a converging magnetic field device with a main magnetic field generating unit and an electron-gun-unit-side magnetic field generating unit, including bucking magnets and matching magnets, is used to create parallel magnetic fields near the electron beam axis

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

an electron gun unit which generates a plurality of electron beams

Methodology Applied
Scientific EffectThermionic emission: Thermionic Emission

Data Source

PatentEP1964146B1Multi-beam klystron apparatus
Publication Date: 2013.01.16 KK TOSHIBA
  • EP1964146B1 patent drawingFigure 1
  • EP1964146B1 patent drawingFigure 2
  • EP1964146B1 patent drawingFigure 3

AI summary

The present invention provides a multi-beam klystron apparatus (11). In the above-described multi-beam klystron apparatus, the magnetic field generating element (52) of the electron-gun-unit-side magnetic field generating unit (41) is disposed around the electron gun unit (18), and a plurality of magnetic gaps (54, 55) are provided in the inner peripheral surface of the magnetic pole (53), which covers the magnetic field generating element, in the direction of travel of the electron beams. Therefore, lines of magnetic force, which are parallel to the center axis of the radio-frequency interaction unit (19), can be generated. Thus, even the electron beam, which is generated from the location apart from the center axis of the electron gun unit, can be guided to the radio-frequency interaction unit in the same manner as in the location at the canter axis of the electron gun unit.