Design and development of a radio frequency quadrupole linac postaccelerator for the Variable Energy Cyclotron Center rare ion beam project

Abstract

A four-rod type heavy-ion radio frequency quadrupole (RFQ) linac has been designed, constructed, and tested for the rare ion beam (RIB) facility project at VECC. Designed for cw operation, this RFQ is the first postaccelerator in the RIB beam line. It will accelerate A/q < or = 14 heavy ions coming from the ion source to the energy of around 100 keV/u for subsequent acceleration in a number of Interdigital H-Linac. Operating at a resonance frequency of 37.83 MHz, maximum intervane voltage of around 54 kV will be needed to achieve the final energy over a vane length of 3.12 m for a power loss of 35 kW. In the first beam tests, transmission efficiency of about 90% was measured at the QQ focus after the RFQ for O(5+) beam. In this article the design of the RFQ including the effect of vane modulation on the rf characteristics and results of beam tests will be presented.

Physics design of rod type proton Radio Frequency Quadrupole linac

“…operating at 33.7 and 37.8 MHz [2,3]. Main advantage of this type of RFQ is -robust mechanical structure with embedded cooling channels, no brazed joints and ease of frequency tuning.…”

Longitudinal bunch length measurement of RFQ beam using in-house developed detector system

“…Figure 3(a) depicts the longitudinal phase space distribution of beam simulated by PARMTEQ [21] at the RFQ exit. RFQ gradually bunches the input DC beam in the form of adiabatic bunching thus develops a core with spiraling particles around the core [2]. This effect is reduced for high current beam owing to coupling between the transverse and longitudinal dimensions.…”

“…The Radio Frequency Quadruple (RFQ) Linear accelerator is the first post-accelerator of VEC-RIB facility [1,2]. It operates at resonance frequency of 37.8 MHz, and designed to accelerate heavy ion beam of q/A ≥ 1/14 from 1.5 keV/u to 98 keV/u.…”

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

“…The post-accelerators in the Radioactive Ion Beam facility (RIB) at Variable Energy Cyclotron Centre (VECC) comprise Radio Frequency Quadruple (RFQ) Linear accelerator [1,2] followed by three IH-Linac modules [3,4]. 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.…”