The dispersion relation for a cylindrical Cherenkov free electron maser

Christos Petichakis; R. A. Stuart; C. C. Wright; A. I. Al-Shamma'a; J. Lucas

doi:10.1016/s0168-9002(03)00879-9

The dispersion relation for a cylindrical Cherenkov free electron maser

Christos Petichakis, R. A. Stuart, C. C. Wright, A. I. Al-Shamma'a, J. Lucas

University of Liverpool

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

2 Citations (Scopus)

Abstract

We have constructed a Cherenkov maser oscillator designed to operate at 16.9 GHz with a solid electron beam accelerated to 70 kV, using an alumina tube, fitted into a copper pipe. Although we achieved nearly 100% transmission of a 100 mA electron beam, no microwave output was observed despite the theoretical small signal gain being > 300%. To resolve this problem, we have measured the dispersion curves of various dielectrically loaded structures and have observed a marked discrepancy between the theoretical and experimentally measured data in the case of alumina. This was sufficiently large to explain the non-operation of the FEM. After considering possible causes, we concluded that the small gap between the alumina liner and the copper waveguide (only 1% of the diameter of the guide), was responsible for the difference.

Original language	English
Title of host publication	Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Pages	256-260
Number of pages	5
Volume	507
Edition	1-2
DOIs	https://doi.org/10.1016/s0168-9002(03)00879-9
Publication status	Published - 11 Jul 2003
Externally published	Yes

Keywords

Cherenkov maser
Dielectric loaded waveguide
FEM
Waveguide dispersion curve

Access to Document

10.1016/s0168-9002(03)00879-9

Cite this

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title = "The dispersion relation for a cylindrical Cherenkov free electron maser",

abstract = "We have constructed a Cherenkov maser oscillator designed to operate at 16.9 GHz with a solid electron beam accelerated to 70 kV, using an alumina tube, fitted into a copper pipe. Although we achieved nearly 100\% transmission of a 100 mA electron beam, no microwave output was observed despite the theoretical small signal gain being > 300\%. To resolve this problem, we have measured the dispersion curves of various dielectrically loaded structures and have observed a marked discrepancy between the theoretical and experimentally measured data in the case of alumina. This was sufficiently large to explain the non-operation of the FEM. After considering possible causes, we concluded that the small gap between the alumina liner and the copper waveguide (only 1\% of the diameter of the guide), was responsible for the difference.",

keywords = "Cherenkov maser, Dielectric loaded waveguide, FEM, Waveguide dispersion curve",

author = "Christos Petichakis and Stuart, \{R. A.\} and Wright, \{C. C.\} and Al-Shamma'a, \{A. I.\} and J. Lucas",

year = "2003",

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doi = "10.1016/s0168-9002(03)00879-9",

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pages = "256--260",

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The dispersion relation for a cylindrical Cherenkov free electron maser. / Petichakis, Christos; Stuart, R. A.; Wright, C. C. et al.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Vol. 507 1-2. ed. 2003. p. 256-260.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - The dispersion relation for a cylindrical Cherenkov free electron maser

AU - Petichakis, Christos

AU - Stuart, R. A.

AU - Wright, C. C.

AU - Al-Shamma'a, A. I.

AU - Lucas, J.

PY - 2003/7/11

Y1 - 2003/7/11

N2 - We have constructed a Cherenkov maser oscillator designed to operate at 16.9 GHz with a solid electron beam accelerated to 70 kV, using an alumina tube, fitted into a copper pipe. Although we achieved nearly 100% transmission of a 100 mA electron beam, no microwave output was observed despite the theoretical small signal gain being > 300%. To resolve this problem, we have measured the dispersion curves of various dielectrically loaded structures and have observed a marked discrepancy between the theoretical and experimentally measured data in the case of alumina. This was sufficiently large to explain the non-operation of the FEM. After considering possible causes, we concluded that the small gap between the alumina liner and the copper waveguide (only 1% of the diameter of the guide), was responsible for the difference.

AB - We have constructed a Cherenkov maser oscillator designed to operate at 16.9 GHz with a solid electron beam accelerated to 70 kV, using an alumina tube, fitted into a copper pipe. Although we achieved nearly 100% transmission of a 100 mA electron beam, no microwave output was observed despite the theoretical small signal gain being > 300%. To resolve this problem, we have measured the dispersion curves of various dielectrically loaded structures and have observed a marked discrepancy between the theoretical and experimentally measured data in the case of alumina. This was sufficiently large to explain the non-operation of the FEM. After considering possible causes, we concluded that the small gap between the alumina liner and the copper waveguide (only 1% of the diameter of the guide), was responsible for the difference.

KW - Cherenkov maser

KW - Dielectric loaded waveguide

KW - FEM

KW - Waveguide dispersion curve

U2 - 10.1016/s0168-9002(03)00879-9

DO - 10.1016/s0168-9002(03)00879-9

M3 - Conference contribution

VL - 507

SP - 256

EP - 260

BT - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

ER -

The dispersion relation for a cylindrical Cherenkov free electron maser

Abstract

Keywords

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