Revisiting the Cold ILC Parameters

Discussions are currently underway to re-examine the parameters of the cold ILC. Using the TESLA parameters MathCad program developed in 1991 [1], I examined several variations to explore consequences to the capital and operating costs of the linac (cryomodules, RF & refrigeratorn only). The cost coefficients were chosen to match the distribution of the above items in the TESLA TDR at a gradient of 25 MV/m. One parameter to vary is the gradient from 25 to 50 MV/m coupled with a realistic Q (which falls with gradient) as well as with an optimistic Q (held constant at 10¹⁰). Other parameters to vary are: number of bunches, bunch spacing, and repetition rate to decrease costs and separately to decrease the damping ring size.