To reduce the cavity transverse section at low
frequencies, people use to increase the inductance using
the longitudinal direction (coaxial RFQ). In the four rods
cavity, the electrical current goes longitudinally in rods
supports. The disadvantage of this technique is the
increased power deposition in these supports. The
proposed geometry is derived from the four vanes
technology. The vanes are identical near the beam but
asymmetrically cut near the bottom of the cavity to force
the longitudinal electrical current. The benefit is a
massive copper structure easy to cool and using
technology and knowledge developed for the RFQ of the
IPHI project. We give for an example the RF power
depositions calculated with SOPRANO and mechanical
deformations calculated with IDEAS of the design
performed in favour of the SPIRAL II project (LINAG).
asymmetrical between vertical and horizontal planes. |
