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Novel Materials for Particle Acceleration and EM Wave ProductionR. Seviour

Novel Materials for Particle Acceleration and EM Wave Production

Prof. Rebecca Seviour

Royal Holloway


𝒗𝒃𝒆𝒂𝒎 ≲ 𝒗𝒈Energy Transfer from Wave to Beam

𝒗𝒃𝒆𝒂𝒎 ≳ 𝒗𝒈Energy Transfer from Beam to Wave


Phase constant


Effective Media

Metamaterial - Pendry/Smith 1990- Veselago 1968


Effective Media

Kock 1940’s


Aleksey Tolstoy (1914)


<< λ


μ

ε


Wave propagation


RFin RFout

Electron Beam

20

dm c γ e vdt

� E

20 1 0

dm c γ e vdt

� E

22 1

1 dγ γ2 dγ

' '

in

20

21

in

out

PeIcmΔγ

dγd

21

PΔP

�

1st order perturbation >> Spontaneous emission

2nd order perturbation >> Stimulated emission

Madey’s Theory

Lorentz's Force

Tan & Seviour, Europhys.Lett.87:34005,2009


Phase constantTan & Seviour, Europhys.Lett.87:34005,2009


20

dm c γ e vdt

� E

20 1 0

dm c γ e vdt

� E

22 1

1 dγ γ2 dγ

' '

in

20

21

in

out

PeIcmΔγ

dγd

21

PΔP

�

1st order perturbation >> Spontaneous emission

2nd order perturbation >> Stimulated emission

Madey’s Theory

Lorentz's Force

Frequency [GHz]

X determined by wave/beam velocity,

X > 0 𝑣𝑏𝑒𝑎𝑚 < 𝑣𝑔

Tan & Seviour, Europhys.Lett.87:34005,2009


E field 9.6 GHz π - Mode


50 KeV upgrade to our existing electron system


Yiming Xu and Rebecca Seviour 2012 New J. Phys. 14 013014 doi:10.1088/1367-2630/14/1/013014

http://dx.doi.org/10.1088/1367-2630/14/1/013014


1 pC, 10 ps short electron bunches,initial energy 16MeV, repetition frequency 3.429GHz

E B

Peak E field 46.8MV/m Peak B field 120.2 kA/m

acceleration gradient of 32MV/m

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