3.9 GHz Cryomodule Shipment to DESY E.Harms on behalf of the Third Harmonic Effort Team (AD & TD, with help from PPD, FESS, BS). What is the 3.9 GHz Effort?.
Parameter List for ACC39
The Third harmonic system (3.9GHz) is proposed to compensate the nonlinear distortion of the longitudinal phase space due to cosine-like voltage curvature of 1.3 GHz cavities. It will linearize the energy distribution upstream of the bunch compressor thus allowing allowing the achievement of extremely small normalized emittance ~1.10-6 m*rad (few time less than without).
V3=V1 / 9
Example: bunch phase space before and after bunch compressor without (left) and with (right) the 3rd harmonic cavity, calculated for TTF-2 photoinjector.