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IBA-JINR 400 MEV/U SUPERCONDUCTING CYCLOTRON FOR HADRON THERAPY
No full textThe compact superconducting isochronous cyclotron
C400 [[1, 2, 3, 4] has been designed by the IBA-JINR
collaboration. It will be the first cyclotron in the world
capable of delivering protons, carbon and α ions for
cancer treatment. The cyclotron construction will start
probably this year within the framework of the
ARCHADE project [5] (Caen, France). 12C6+ and 4He2+
ions will be accelerated to 400 MeV/u and extracted by
the electrostatic deflector. H2
+ ions will be accelerated to
the energy of 265MeV/u and extracted by stripping.
The magnet yoke has a diameter of 6.6 m; the total weight
of the magnet is about 700 t. The designed magnetic
fields are 4.5 T and 2.45 T respectively in the hills and
in the valleys. Superconducting coils will be enclosed in a
cryostat. All other parts and subsystems of the cyclotron
will be warm. Three external ion sources will be mounted
on the switching magnet on the axial injection line located
below the cyclotron.
The main parameters of the cyclotron, its design, the
current status of the development work on the cyclotron
systems are presented.IMP;Chinese Academy of Science
STABLE OPERATION OF RF SYSTEMS FOR RIBF
No full textAt RIKEN RI-Beam Factory (RIBF), very heavy ion
beams like uranium are accelerated up to 345 MeV/u by
the RIKEN heavy ion linac (RILAC) and four ring cyclotrons,
the RIKEN Ring Cyclotron (RRC), the fixedfrequency
ring cyclotron (fRC), the intermediate-stage
ring cyclotron (IRC), and the superconducting ring cyclotron
(SRC) [1]. In order to provide high intensity beams
up to 1 pμA, all the RF systems must be stable enough for
a long term (a few weeks) within ± 0.1% in voltages and
±0.1 degrees in phases. For a stable operation of RIBF, we
have started to investigate a degree of stability of the RF
systems using a newly developed monitoring system [2].
The efforts to improve the stability will be described.IMP;Chinese Academy of Science
DESIGN OF IBA CYCLONE® 30XP CYCLOTRON MAGNET
No full textIBA is currently developing an evolution of its famous
Cyclone® 30 cyclotron. The Cyclone® 30XP cyclotron will
be a multi-particle, multiport cyclotron capable of
accelerating alpha particles up to 30 MeV (electrostatic
extraction), deuteron (D-) beams between 7.5 and 15 MeV
and proton (H-) beams between 15 and 30 MeV (stripping
extraction). The magnet system has been updated with
improved versions of IBA Cyclone 18/9 and Cyclone 70
features.
At first, coil dimensions have been updated in order to
raise the free space in the median plane to allow mounting a
retractable electrostatic deflector system for the extraction
of the alpha particle beam. Gradient corrector pole
extensions, have been added to ease the alpha beam
extraction. Finally, compensation for relativistic effects
between H- (q/m=1/1) and D-/alpha (q/m=1/2) beams is
made by the use of movable iron inserts located in two
valleys, as is done in IBA Cyclone® 18/9 cyclotrons.
These modifications could have an adverse effect on the
flutter. In addition, the second harmonic induced by the
movable iron inserts drives the machine in the 2.νr=2
resonance close to the extraction. As a consequence,
modifications on the pole sectors and chamfers have been
made in order to improve the flutter and eliminate harmful
resonance up to extracted energies.
After the presentation of the magnet features, some
results on beam extraction are also discussed.IMP;Chinese Academy of Science
BEAM LOSS MONITORING AND CONTROL FOR HIGH INTENSITY BEAMS AT THE AGOR-FACILITY
No full textThe experiments at the AGOR facility require intense
heavy ion beams. Typical examples are 1013 pps of 20Ne6+
at 23.3 MeV/A and ≥1012 pps 206Pb27+ at 8.5 MeV/A. To
prevent damage to components by the beam (power
density up to 1 kW/mm3 in unfavourable cases) a modular
beam loss monitoring and control system has been
developed for the cyclotron and high energy beam lines.
The architecture of the system is described and the
considerations for the major design choices discussed.
The system uses the CAN-bus for communication and
verification of system integrity. The injected beam is
chopped at 1 kHz with a variable duty factor between 5
and 90 %. The beam intensity at injection and a number
of locations in the high energy beam line is measured by
inductive pick-ups. Furthermore, localized beam losses on
slits and diaphragms are directly measured. When beam
loss in any section exceeds the predefined maximum
value, the duty factor of the beam is automatically
reduced.IMP;Chinese Academy of Science
THE SIMULATION ON BEAM INTERACTION WITH BACKGROUND PARTICLES
No full textA particle simulation with Monte Carlo was developed
to study beam interaction with background particles in
neutral beam injector (NBI). The collision processes
associated with charge state change and reaction
cross-section were analyzed for neutralization and
re-ionization. Take the neutralization processes as a
reference, for positive arc discharge ion source, there are
three different original ion species in the energetic ion
beam. In evolution, a fast particle will suffer kinds of
collisions decided by the collision cross-section or no
impact within the target gas. Classify those collisions and
their cross-sections according the change of charge state
and momentum. The neutralizer is divided into many
extremely short segments averagely. So the gas density
quantity at middle point can be regarded as that of each
segment. According to the collision cross-section, select a
random number to determine the evolution of particle
states in each segment. With that particle simulation, the
neutralization efficiency is estimated.IMP;Chinese Academy of Science
BEAM DIAGNOSTIC COMPONENTS FOR SUPERCONDUCTING CYCLOTRON AT KOLKATA
No full textVEC Centre Kolkata has constructed a K500
superconducting cyclotron (SCC). Several beam
diagnostic components have been designed, fabricated
and installed in SCC. In the low energy beam line,
uncooled slits, faraday cup, beam viewers, and
collimators are used. The inflector is also operated in a
faraday cup mode to measure the beam inside SCC. The
radial probe and viewer probe are respectively used to
measure beam current and to observe the beam size and
shape inside SCC. The magnetic channels, electro-static
deflectors and M9 slit are also used to measure beam
current at the extraction radius. Water cooled faraday cup
and beam viewers are used in the external beam line. The
radius of curvature of the radial probe track was reduced
to align the internal and external track during its assembly.
It was observed that the probe did not functioning
properly during beam trials. Different modifications were
incorporated. But, problem with the probe persisted. The
paper describes the beam diagnostic components used in
the cyclotron, discusses the problems faced in operating
the radial probe, modifications tried and outlines the
future steps planned to operate the beam diagnostic
components.IMP;Chinese Academy of Science
THE VARIAN 250 MeV SUPERCONDUCTING COMPACT PROTON CYCLOTRON: MEDICAL OPERATION OF THE 2nd MACHINE,PRODUCTION AND COMMISSIONING STATUS OF MACHINES
No full textVarian Medical Systems Particle Therapy has
successfully commissioned its 2nd superconducting
compact proton cyclotron for use in proton therapy in
2008. The 250 MeV machine serves as proton source for
treatments at the first clinical proton therapy center in
Germany which opened in early 2009. Furthermore,
Varian is currently commissioning and factory testing its
3rd machine.
We report on the operation and performance of the 2nd
machine as well as on the successful cool-down, quench
testing, and magnetic shimming of the 3rd machine.
In addition we present RF commissioning plans using a
newly developed solid state amplifier, and plans for the
upcoming factory beam commissioning in the new Varian
cyclotron scanning nozzle test cell, scheduled for October
2010. Finally we provide a brief status and outlook on
machines no. 4 to 7.IMP;Chinese Academy of Science
NEW TOOLS FOR THE IMPROVEMENT OF BEAM BRIGHTNESS IN ECR ION SOURCES
No full textAccording to the model that has driven the
development of ECRIS in the last years, a large variation
of the pumping microwave frequency (order of GHz)
along with the proportional increase of the magnetic field
boosts the extracted current for each charge state because
of a larger plasma density. Recent experiments have
demonstrated that even slight frequency’s changes (of the
order of MHz) considerably influence the output current,
and what’s more important, even the extracted beam
properties (beam shape, brightness and emittance) are
affected. A number of tests have been carried out in the
last few years and they will be reviewed along with the
results of numerical simulations which are able to explain
the observed phenomena. The frequency has been
systematically changed and the beam output has been
recorded either in terms of charge state distributions and
beam emittance. The detected bremsstrahlung X-rays are
additionally analysed: they give insights about the
electron energy distribution function (EEDF). An
overview about the possible future improvements of ECR
ion source will be given.IMP;Chinese Academy of Science
OPERATING EXPERI ENCE WITH THE RF SYSTEM FOR THE SUPERCONDUCTING RING CYCLOTRON OF RIKEN RIBF
No full textAt RIKEN RIB-factory (RIBF) an accelerator complex
as an energy booster which consists of superconducting
ring cyclotron (SRC), intermediate-stage ring cyclotron
(IRC) and fixed-frequency ring cyclotron (FRC) provides
very heavy ion beams like uranium with an energy of 345
MeV/u [1]. In December 2006, the SRC has become operational
and it was succeeded to extract the first beam from
SRC[2]. Since then, we have experienced various problems
with the rf system for SRC and improvements have been
made to achieve designed performance solving the problems
one by one. This paper will discuss on our efforts to
understand the source of troubles and improvements and
modifications of the rf system.IMP;Chinese Academy of Science
BEAM DIAGNOSTICS FOR CYCLOTRONS
No full textAn overview of beam diagnostic systems for cyclotron
operation and development is presented. The focus is on
devices installed within the cyclotron with its special
"environmental" conditions and limitations. Emphasis is
placed on the requirements of high current beams, as
produced by the PSI Injector 2 and Ring cyclotrons [1].IMP;Chinese Academy of Science