MEIC/ELIC design

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This page summarizes the technical aspect and assumptions of the MEIC/ELIC design.

MEIC / ELIC accelerator design

20 GeV electron beam

The highest electron energy of 20 GeV can be obtained by boosting electron energy from 11 GeV (feeded from CEBAF) to 20 GeV in the ring with RF cavity, just like the proton beam. Of course there are accelerator issues that need to be addressed. For the allowable maximum beam current the principal issue is synchrotron radiation (and in the technical side, the maximum heat load to the beam pipe). The synchrotron radiation power goes as fourth power of energy, so a factor of 2 energy increase causes a factor of 16 radiation power increase, much much fast, unfortunately. Normally we need to set an engineering limit to the total radiation power per meter, then we will see a factor of 16 beam current reduction immediately. Other factors may also come in to limit the current. The luminosity loosely depends linearly on the beam current, if it has not reached other limits (such as beam-beam) yet. Then you will see immediately a factor of 16 reduction of luminosity due to synchrotron radiation. However, a high gamma of particle should also reduce the beam-beam tune-shift so one can theoretically increase proton beam current and therefore increase luminosity. Without detailed calculation, the luminosity reduction factor is somewhere between 16 to 8. Just to be safe, a factor of 10 seems fair.