Dr Suzie Sheehy

Abstract:

The Intense Beam Experiment (IBEX) is a linear Paul trap designed to replicate the dynamics of intense particle beams in accelerators. Similar to the S-POD apparatus at Hiroshima University, IBEX is a small scale experiment which has been constructed and recently commissioned at the STFC Rutherford Appleton Laboratory in the UK. The aim of the experiment is to support theoretical studies of next-generation high intensity proton and ion accelerators, complementing existing computer simulation approaches. Here we report on the status of commissioning and first results obtained.

Abstract:

These notes provide an overview of Fixed-Field Alternating-Gradient (FFAG) accelerators for medical applications. We begin with a review of the basic principles of this type of accelerator, including the scaling and non-scaling types, highlighting beam dynamics issues that are of relevance to hadron accelerators. The potential of FFAG accelerators in the field of hadron therapy is discussed in detail, including an overview of existing medical FFAG designs. The options for FFAG treatment gantries are also considered.

Abstract:

In this paper we describe the methods and tools used to characterize a 150 MeV proton scaling Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University Research Reactor Institute. Many of the techniques used are unique to this class of machine and are thus of relevance to any future FFAG accelerator. For the first time we detail systematic studies under- taken to improve the beam quality of the FFAG. The control of beam quality in this manner is crucial to demonstrating high power operation of FFAG accelerators in future.

Abstract:

We report on the status and design of the Intense Beam Experiment (IBEX) at RAL. This small experiment consists of a linear Paul trap apparatus similar to the S-POD system at Hiroshima University, confining non-neutral Argon plasma in an rf quadrupole field. The physical equivalence between this device and a beam in a linear focusing channel makes it suitable for accelerator physics studies including resonances and high intensity effects. We give an overview of the design and construction of IBEX and outline plans for commissioning and the future experimental programme.

Abstract:

Although modern high power proton machines can now routinely deliver MW level operating powers, the next generation accelerators will be required to reach powers orders of magnitude higher [1,2]. Significant developments will be needed both in technology and in understanding the limits of high intensity operation. The present study investigates the beam dynamics in three experimental linac designs when the beam intensity is increased above current levels such that for CW regimes, beam powers of up to 400 MW can be attained. In the first, a 1 A proton beam is accelerated to 400 MeV using normal conducting structures. In the second, a comparison is made when two front ends accelerate 0.5 A beams to ∼20 MeV where they are funnelled to 1 A and accelerated to 400 MeV. Similarly, in the third, two 0.25 A beams are funnelled to 0.5 A and then accelerated in superconducting structures to 800 MeV. In addition, alternative unconventional methods of generating high current beams are also discussed. The further studies that are needed to be undertaken in the future are outlined, but it is considered that the three linac configurations found are sufficiently promising for detailed technical designs to follow.