A Two-Stage RF Linear Collider Using a Superconducting Drive Linac

  • W. Schnell
Part of the Ettore Majorana International Science Series book series (EMISS, volume 29)


The classical RF-driven, room-temperature, travelling-wave linac is capable of generating accelerating gradients approaching or exceeding 100 MV/m. If such a structure is to be used in a linear collider of the order of 2 × 1 TeV an economic source of peak power has to be found and the average power efficiency from mains input to beam power must be made acceptable. Clearly, to drive a structure with shunt impedance per unit length E 0 2 /R′ to an average accelerating gradient E0 the peak power \({\hat p_L}\) per section length L must exceed \(E_o^2/R'\). As this power is enormous the electron linac is always pulsed with a very small duty cycle. On the other hand, as the quality factor Q is much too small to conserve an appreciable fraction of stored energy over a realistic repetition period it is often assumed that the average RF input to one linac is roughly given by
$$\frac{{ < {P_b} >}}{\eta }$$
where <Pb> is the average beam power and η the fraction of stored energy extracted by a beam pulse. This fraction cannot be very large, certainly not above 10% if the beam’s energy spread — about η/2 — should remain acceptable or at least correctible.


Beam Power Energy Spread Drive Cycle Transfer Structure Wake Field 
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Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • W. Schnell
    • 1
  1. 1.CERNGenevaSwitzerland

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