Design of medium energy beam transport line between the RFQ and the Linac in the radioactive ion beam facility at VECC, Kolkata

Abstract

The design of a medium energy beam transport (MEBT) line comprising of a re-buncher and four quadrupoles, two upstream and the other two downstream of the re-buncher, has been presented. The design was done to ensure almost 100% transport of heavy-ion beams of about 99 keV/u energy from RFQ having a q/A not less than 1/14 through the re-buncher and then through IH Linac of about 0.6 m length in which beam would be accelerated to about 185 keV/u. The re-buncher has been designed to operate at 37.8 MHz, the resonating frequency of both the RFQ and the IH Linac. The entire beam line has been installed and recently O 5+ beam from RFQ has been transported through the re-buncher and subsequently accelerated in the IH Linac successfully.

Development and testing of 37.8 MHz, 3.0 kW RF amplifier system for Radioactive Ion Beam facility at VECC Kolkata

“…The RFQ accelerates 𝐴/𝑞 = 14 ions from 1.75 keV/u to 100 keV/u while the energy at the end of the third Linac module is 400 keV/u. In order to accommodate an experimental setup in the beam line between RFQ and Linac, considerable drift length has been kept and to compensate for the resultant longitudinal de-bunching a re-buncher has been installed [5]. The operating frequency of these accelerator cavities is set at 37.8 MHz, matching with that of the RFQ linac.…”