TY - GEN

T1 - Spectral limits and frequency sum-rule of current and radiation noise measurement

AU - Ianconescu, R.

AU - Gover, A.

AU - Nause, A.

PY - 2014

Y1 - 2014

N2 - The current noise spectrum of an electron beam is generally considered white and expressed by the shot-noise formula (eI0). It is possible to control the spectral energy of a random electron beam current by longitudinal space charge micro-dynamics and dispersive transport. Both noise suppression (relative to eI0) and noise enhancement have been demonstrated, exhibiting sub/super-Poissonian particle distribution statistics, respectively. We present a general theory for the current noise of an e-beam and its radiation emission in the entire spectrum. The measurable current noise spectrum is not white. It is cut-off at high frequencies, limited by the measurement length and the beam axial momentum spread (fundamentally limited by quantum uncertainty). We show that under certain conditions the current noise spectrum satisfies a frequency sum-rule: exhibiting noise enhancement in one part of the spectrum when suppressed at another part and vice versa. The spontaneous emission (radiation noise) into a single radiation mode or single direction in any scheme (OTR, Undulator etc.) is sub-radiant when the beam current is sub-Poissonian and vice versa, but the sum-rule does not apply.

AB - The current noise spectrum of an electron beam is generally considered white and expressed by the shot-noise formula (eI0). It is possible to control the spectral energy of a random electron beam current by longitudinal space charge micro-dynamics and dispersive transport. Both noise suppression (relative to eI0) and noise enhancement have been demonstrated, exhibiting sub/super-Poissonian particle distribution statistics, respectively. We present a general theory for the current noise of an e-beam and its radiation emission in the entire spectrum. The measurable current noise spectrum is not white. It is cut-off at high frequencies, limited by the measurement length and the beam axial momentum spread (fundamentally limited by quantum uncertainty). We show that under certain conditions the current noise spectrum satisfies a frequency sum-rule: exhibiting noise enhancement in one part of the spectrum when suppressed at another part and vice versa. The spontaneous emission (radiation noise) into a single radiation mode or single direction in any scheme (OTR, Undulator etc.) is sub-radiant when the beam current is sub-Poissonian and vice versa, but the sum-rule does not apply.

UR - http://www.scopus.com/inward/record.url?scp=84999885134&partnerID=8YFLogxK

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AN - SCOPUS:84999885134

T3 - Proceedings of the 36th International Free Electron Laser Conference, FEL 2014

SP - 362

EP - 367

BT - Proceedings of the 36th International Free Electron Laser Conference, FEL 2014

T2 - 36th International Free Electron Laser Conference, FEL 2014

Y2 - 25 August 2014 through 29 August 2014

ER -