This paper presents an overview of RFQ working principles, highlights the relevant parameters and summarises the different design approaches for the high, medium and low intensity cases. Attention is then focussed on the beam dynamics design in decelerating RFQs and, in particular, on how to cope with the intrinsic problems of deceleration (e.g. physical emittance increase and reduction of the longitudinal stable area). Fields of application for decelerating RFQs and their advantages with respect to conventional decelerating techniques will also be highlighted. The beam dynamics of the RFQD, the post decelerator for the CERN Antiproton Decelerator (AD) ring, will be presented in detail. This RFQ is intended to decelerate the 5.3 MeV antiproton beam coming from the AD down to an energy of virtually zero. Several decelerating schemes have been studied to fit the experimenters' need for a high quality beam with the final energy varying in the range 0 to 100 keV. Various potential solutions will be presented and discussed, with particular attention given to the intended approach.
[1]
N. Ireland.
ATOMIC SPECTROSCOPY AND COLLISIONS USING SLOW ANTIPROTONS
,
2000
.
[2]
L. Guiraud.
The Antiproton Decelerator
,
1998
.
[3]
W. R. Thompson,et al.
Atomic spectroscopy and collisions using slow antiprotons
,
1997
.
[4]
J. Tuyn,et al.
The Antiproton Decelerator: AD
,
1997,
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167).
[5]
G. Bezzon,et al.
Construction and Commissioning of the RFQ for the CERN Lead-Ion Facility
,
1994
.
[6]
M. Weiss.
Radio-frequency quadrupole
,
1987
.
[7]
T. Wangler.
Space-charge limits in linear accelerators
,
1980
.
[8]
W. D. Kilpatrick,et al.
Criterion for Vacuum Sparking Designed to Include Both rf and dc
,
1957
.