As part of the RF studies of the resonant cavities of the
“IPHI” accelerator project (“Injector of Proton High
Intensity”), a fully computer controlled bench for the field
distribution measurement has been developed. Based on
the perturbation method, the acquisition of the s21
transmission coefficient phase shift is synchronized with
the displacement of a bead. A systematic study of the
noise and uncertainties has led to a clearly enhanced
signal over noise. The measured raw data are then
converted to a quantity proportional to the
electromagnetic field magnitude. Specifically for the RFQ
tuning study, different transverse section positions where
to guide the bead have been tested on our RFQ cold
model.
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