RIKEN Nishina Center, Wako
The RIKEN RI Beam Factory (RIBF) is pushing the limits of energy for heavy ion cyclotrons. The first experiment of the RIBF has successfully finished with the discovery of new isotopes 125Pd and 126Pd* in June 2007 with a 345-MeV/nucleon uranium beam. However, the total transmission efficiency was limited to be less than 1%. In addition, a carry-over of oil was found in the refrigerator of the Superconducting Ring Cyclotron (SRC), which was the main accelerator of the RIBF. To solve these problems, we have improved beam monitors, upgraded the oil remover system of the compressor of the liquid helium cryogenic plant at SRC and made a series of acceleration tests. As a result, 0.3 pnA of a 345-MeV/nucleon uranium beam was stably delivered to RIBF users in November 2008 and a 345-MeV/nucleon 48Ca beam with the intensity of 170 pnA was obtained in December 2008. In the PAC09 presentation, we will summarize our operating experience with the SRC and developments of RIBF accelerators in addition to most up-to-date performance of the RIBF accelerator complex.
*T. Ohnishi et al., J. Phys. Soc. Jpn. 77 (2008) 083201
CIAE, Beijing
CYCIAE-100 is a 100 MeV, 200 muA H- cyclotron being constructed at CIAE. The tolerance of the magnetic field is as tight as 1.2 Gauss for isochronous field and 2 Gauss for first harmonics. Due to the absence of coil adjusting in this machine, a measure that helps to achieve a more compact structure (435 ton for the main magnet), the imperfection hence becomes a much more critical factor in our consideration. The effects by the various kinds of imperfection are investigated numerically and the imperfection fields are predicted for beam dynamics simulation, serving as a basic guidance in the magnet construction for CYCIAE-100. Some of the important results will be reported in this paper, including
- the deformation of the main magnet by the gravity itself, 480 ton EM force and 120 ton vacuum pressure,
- segregation, inclusion and contraction cavity induced by the casting procedure,
- fabrication and assembling tolerance, and
- thermal deformation.
CIAE, Beijing
TUB, Beijing
To limit the cost for the main magnet of a compact cyclotron CYCIAE-100, the cast steel is used for the top/bottom yoke and return yoke. The imperfection may not be ignored and the harmonic coils on the return yokes will make the fields reaching the requirements easier during the shimming. The centering coils will not only compensate the 1st harmonic fields at the center region, which is usually remain big, but also correct the off-center injection of the beam. The thermal deformation and the vacuum pressure may change the fields distribution during the machine operation and therefore It is necessary to use trim coils to adjust the fields. We arrange the trim coils inside the two opposite valleys of the main magnet. The second harmonics from the trim coils are not big eough to affect the beam dynamics significantly from the beam dynamics study. In this paper, the effects of correction coils of three types are presented. The detail configuration of the correction coils is introduced in the paper as well. One concern is the potential interference of some water cooled coils could have with vacuum. Some experience for the coils inside the high vacuum tank is tested and the results are given.
HUST, Wuhan
Funding: National Natural Science Foundation of China (No. 10435030)
A 10MeV H- compact cyclotron (CYCHU-10) is under construction in Huazhong University of Science and Technology (HUST). This paper presents a magnetic field measurement system for measuring the cyclotron magnet. A Hall probe and a granite x-y stage are adopted in the project. The Cartesian mapping will replace traditional polar system. The motion control and data acquisition system for the magnetic field measurement consists of a Teslameter and Hall probe, servomotors, a motion control card, optical linear encoder systems and an industrial PC. The magnetic field will be automatically scanned by this apparatus, and a flying mode will be the main running mode to reduce measure time.
HUST, Wuhan
Funding: Work supported by National Nature Science Foundation of China (10435030) and National Science Foundation for Post-doctoral Scientists of China (20080430973)
Low energy compact cyclotrons for short-life isotopes production delivered to the Positron Emission Tomography (PET) facilities have foreseeable prospects with growing demands in medical applications. The Huazhong University of Science and Technology (HUST) proposed to develop a 10MeV PET cyclotron CYCHU-10. The design study of the main magnet and the central region was introduced. A matrix shaping method with the radial fringe field effect and artificial control was adopted to obtain field isochronisms precisely. The central region was optimized to attain 35° RF phase acceptance and low vertical beam loss rate.
Sigmaphi, Vannes
Vector Fields Ltd., Oxford
Oxford Instruments, Accelerator Technology Group, Oxford, Oxon
A tender for the study and construction of a large superconducting split solenoid for the C400 carbon therapy cyclotron was issued by IBA in March 2008 and awarded to Sigamphi. Although the current density is moderate, the large radius and average field imply quite a high level of hoop stress. Simple formulas range between 140 and 180 MPa and, with such large values and uncertainties, it was felt necessary to perform a finite element analysis of the structure. Average fields in a cyclotron are very well modeled using an axially symmetrical structure and the stress was therefore studied using the stress module of the Vector Fields Opera2d suite. Different models were tried with different levels of details. A comparison is made between them as well as with the analytical results.
TRIUMF, Vancouver
The replacement of the 30-year-old Philips cryogenerator with a modern LINDE-1630 helium refrigerator is an important component of TRIUMF’s ongoing 500 MeV cyclotron refurbishing program. Two 10.7 m long cryopanels are cooled with liquid helium rather than with 17 K helium gas, as was the case with the cryogenerator. This has increased the pumping speed and, respectively, improved the vacuum in the approximately 100 m3 cyclotron tank. Additionally, the thermal shield, previously cooled with helium gas, is now cooled with liquid nitrogen. These changes have resulted in increased reliability of the cyclotron vacuum system and, consequently, longer operation periods without maintenance. The new refrigeration unit was commissioned in September 2007. The results from over one year of operational experience are discussed. Also, data on hydrogen cryopumping is presented.
CIAE, Beijing
TRIUMF, Vancouver
The design and cryo-test system of a plug-in cryopump used in CYCIAE-100 is introduced. The plug-in cryopump consists of two cryopanels, a baffle, a half-opened shield, and two GM refrigerators (CGR411, CVI) which power is 83W/80K at the first stage and 7.5W/20K at the second stage, its designed pumping speed is 15000L/s. Cryo-test system of plug-in cryopump employs the flux method to test pumping speed, cool-down time, ultimate pressure, temperature distribution on cryopanel and capacity at the pressure of 10-6Pa to 1Pa. The heat load calculation of cryopanel and shield including baffle is conducted in succession. In the end a comparison between design parameters and test results is drawn.
Imperial College of Science and Technology, Department of Physics, London
JAI, Oxford
OXFORDphysics, Oxford, Oxon
For PAMELA project, the injection lay out for both protons as well as carbon 6+ ions is discussed. Injection system would consist of a 30 MeV cyclotron for protons and a chain of elements for carbon ions such as ECR ion source, bending magnets and focusing solenoids; RFQ, IH/CH structures and a striping foils. The charge particle simulation for different protons as well as carbon ions passing through the elements has been carried out with General Particle Tracer (GPT), software.
TUB, Beijing
PSI, Villigen
CIAE, Beijing
In high intensity cyclotrons with small turn separation, both the space charge effects of single bunch and the interaction of radially neighbouring bunches play important roles. A PIC-based three-dimensional parallel code, OPAL-CYCL, is newly developed under OPAL framework which self-consistently covers these two collective effects. In this paper we also present the simulation results from the compact cyclotron CYCIAE-100 in the context of the ongoing upgrade program of BRIF at CIAE, with the goal of 100 MeV, 200 μA CW proton beam on target.
HUST, Wuhan
Funding: Nation Nature Science Foundation of China,10435030
At Huazhong University of Science and Technology (HUST), the design study of a 10 MeV compact cyclotron CYCHU-10 for the application of Positron Emission Tomography (PET) has been developed since 2007. This paper describes the recent status of RF cavities including numerical calculation results of basic parameters, the capacitive trimmer to overcome frequency shift when in operation and the construction and cold test of the 1:1 scale prototype. The inductive coupling loop design and matching simulation with the RF power generator are also presented
HUST, Wuhan
Funding: Work supported by National Nature Science Foundation of China, 10435030
In order to reduce the cost of the signal generator comprising a high performance direct digital synthesizer (DDS), the method of picking up a desired aliased signal of DDS output is adopted in the study. The chip AD9850 is used to synthesize RF signal in the system, and the amplitude modulation of the system is achieved by altering the external connection resistance of the chip. The output frequency is tunable from 99.5 to 101MHz. The principle and the test results of the signal synthesizer will be presented. The amplifier based on tetrode technology can deliver the 10kW RF power in a continuous wave (CW) mode of operation. The driver amplifier consists of two solid-state modules, and it can provide the tetrode with up to 300W input power. The tetrode operates in the grounded cathode configuration. The conceptual design of the final stage amplifier will also be demonstrated in this paper.
CRE, Wuppertal
The modular architecture of high power solid state rf amplifiers for the frequency range of 72 to 3000MHz is described. The characteristic features of the modular components are presented, focusing on the multi transistor amplifier modules delivering a power in the 0.5 to 1.5 kW range, the transmission line combiner system combining up to 150 amplifier modules, the monitoring of the rf power flow in the system and other relevant performance parameters, as well as the heat exchanger concept and the digital amplifier control system.
LBNL, Berkeley, California
UCB, Berkeley, California
Funding: This work was supported by the Director, Office of Science, Office of High Energy and Nuclear Physics, Division of Nuclear Physics of the US Department of Energy under Contract No. DE-AC02-05CH11231.
A RF system of 500W - 10.75 to 12.75 GHz was designed and integrated into the Advanced Electron Cyclotron Resonance (AECR) ion source of the 88-inch Cyclotron at Lawrence Berkeley National Laboratory. The AECR produces ion beams for the Cyclotron giving large flexibility of ion species and charge states. The broadband frequency of a Traveling Wave Tube (TWT) allows modifying the shape of the annular ellipsoidal-shaped volume that couples and heats the plasma. Details of the RF source and Automatic Gain Control Unit designs for the TWT and integration with the AECR source are provided.
INFN/LNS, Catania
The study of the Superconducting Cyclotron named SCENT300 [1] was carried out by the accelerator R&D team of LNS-INFN of Catania in collaboration with the University of Catania and supported by IBA (Belgium). The new design features concerning the magnetic properties of the machine and the last results about the beam dynamic are presented.
KAERI, Daejon
Kyungpook National University, Daegu
KIRAMS, Seoul
Funding: This work was perfomed as a part of the Proton Engineering Frontier Project and supported by the ministry of Education, Science and Technology of Korea.
A prototype LEPT(Low Energy Proton Therapy) system was developed and established at the MC-50 cyclotron in 2007. Some of the users of the PEFP (Proton Engineering Frontier Project) has been requiring a irradiation system for in-vivo experiments for the beam utilization in the fieds of medical and biological sciences. We are studying on the possibility of in-vivo experiments the prototype LEPT system. The LEPT system consists of collimators, range shifter, modulator for SOBP, dose meaurement system, etc. The energy and current from the cyclotron was 45 MeV and a few nA. For the in-vivo experiments accurate control of dose rate and penetration depth range is essential. The other important issue is how we can control the irradiation area and depth with high uniform dose distribution. We investigated the dose rate and uniformity of dose distribution inside the sample using PMMA and water phantom. The dose was measured by using ionization chamber and GAF films. The dose rate was 0.2~1Gy/sec and the penetration depth was 10~15 mm. The further studies using small animals using this LEPT system will be done by the users.
Manchester University, Manchester
UMAN, Manchester
It has been proposed to use a proton Fixed Field Alternating Gradient (FFAG) accelerator to drive an Accelerator Driven Subcritical Reactor (ADSR) as they have the potential to provide high current beams to energies needed, 500 MeV to 1 GeV. This paper describes the results of 6D simulations of acceleration in possible lattice designs to explore longitudinal acceptance. This is needed to evaluate accelerator duty cycle and options for acceleration such as harmonic number jumping.
NCC, Korea, Kyonggi
SNU, Seoul
An accelerator mass spectrometer (AMS) based on a compact cyclotron has been studied for biomedical uses. The system will have the mass resolving power of over 4000 to analyze a few different kinds of isotopes for tracing or chronometric dating. High transmission efficiency is a major design goal to compete with a Tandem AMS. A compact magnet with high stability, a saw tooth harmonic buncher, and flat-topping rf system are the components needed to achieve the goal. The results of design study for the AMS cyclotron and its injection line will be presented as well as the results of model tests for the cavity and the buncher.
University of Huddersfield, Huddersfield
UMAN, Manchester
PSI, Villigen
CEA, Grenoble
STFC/RAL, Chilton, Didcot, Oxon
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
The current paper discusses possible designs for a high intensity stand alone muon source for muSR studies of condensed matter. In particular we shall focus upon the potential implementation of a new generation of high power but relatively compact and cost effective proton drivers based on non-scaling fixed field alternating gradient (ns-FFAG) accelerator technology. The technical issues which must be addressed are also considered.
HUST, Wuhan
Funding: Nation Nature Science Foundation of China,10435030
The design study of Cyclotron CYCHU 10MeV has been developed at Huazhong University of Science and Technology (HUST). Because of the low center frequency (100MHz) of it’s RF system, we should choose suitable directional couplers for the RF system which is supposed to be high-directivity and tight-structure. This paper analyses and synthesizes kinds of directional couplers, espacially microstrip structure, for it’s tinier volume at the low center frequency compared with stripline and branch structures. The achievement of the high-directivity with microstrip configuration is carried out by the distributed capacitor to decrease the even and odd mode phase difference. Capacitive compensation is performed by the interdigital capacitors. The proposed structure is easy to fabricate and incorporate another microwave device due to planner microstrip.
NSCL, East Lansing, Michigan
Funding: Michigan State University
The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is implementing a system called the ReA3 to reaccelerate rare isotope beams from projectile fragmentation to energies of about 3 MeV/u. The 80.5 MHz triple-harmonic buncher before the ReA3 Radio Frequency Quadrupole (RFQ) linac has recently been implemented and measurements made. Tests using beams from the Electron Cyclotron Resonance (ECR) ion source test stand are being performed. The beam properties after the buncher are fully characterized using various diagnostic tools (e.g. fast Faraday cup, energy analyzer, emittance scanner). As a result, the tuning procedures for the buncher operations are developed. We will present the detailed results of the beam based buncher studies and compare them with simulations.
CERN, Geneva
The modification of microwave signals passing through an electron cloud can be used as a diagnostic tool for detecting its presence and as a measure for its effective density. This observation method was demonstrated in pioneering measurements at the CERN SPS in 2003 with protons and at PEP-II in 2006 with positron beams in the particle accelerator field. Results and applications of this technique are discussed as well as limitations and possible difficulties. A strong enhancement of the electron related signals due to cyclotron resonance is theoretically predicted and has been observed in different machines. The application of this method can also be extended for space applications and plasma physics where microwave diagnostics is known and used since many years. The question whether suitably chosen microwaves might also be employed for electron-cloud suppression will be addressed. An electron cloud may also emit microwaves itself and the intensity of this emission depends on external parameters such as the electrical bias field and resonator frequencies related to trapped mode resonances in a beam-pipe.
LBNL, Berkeley, California
LLNL, Livermore, California
SLAC, Menlo Park, California
Funding: This work was supported by the Office of Science, U. S. Department of Energy, under Contract No. DE-AC02-05CH11231.
A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lb << 2*π/ωc, (lb = bunch duration, ωc = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor of approximately 3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined density "stripes" of multipactoring found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations, the reason for the bunch-length dependence, and details of the dynamics will be discussed.
C.M. Celata is presently also a visitor in Physics, Mathematics, and Astronomy at California Institute of Technology.
Fermilab, Batavia
MSU, East Lansing, Michigan
St. Petersburg State University, St. Petersburg
Innovations in computer techniques in combination with increased sophistication in modeling are required to accurately understand, design and predict high-energy, and, in particular, the new generation of frontier accelerators for HEP and other applications. A recently identified problem lies in the simulation and optimization of FFAGs and related devices, for which currently available tools provide only approximate and inefficient simulation. For this purpose new tools are being developed within the advanced accelerator code COSY INFINITY to address complex, specific electromagnetic fields, including high-order fringe fields, out of plane fields, edge effects, and general field profiles; tools linked to modern global optimization techniques that can further accommodate the ultra-large emittances of proposed beams to allow efficient probing of very high dimensional parameter space. This new set of tools based on modern techniques and simulation approaches will be furnished with modern GUI-based user interfaces.
TRIUMF, Vancouver
In the TRIUMF cyclotron when a spark occurs it is necessary to shut off the RF drive and to initiate a RF restart procedure. It is also desirable to restore the full operational dee voltage as soon as possible in order to prevent thermal detuning of the resonant cavity. However, when the RF drive is shut off, the disappearance of Lorentz force on the resonator hot-arms causes the hot-arms to vibrate at their mechanical resonant frequency. When the RF field is being restored, the electromagnetic resonance is coupled to the mechanical resonance through the Lorentz force, and the amplitudes of both the mechanical vibration and the RF field depend on the timing when RF drive is re-applied. Computer simulations and experimental results will be presented to demonstrate that an optimum exists as to when to initiate the RF restart. With this optimal timing, the Lorentz force is used to damp the mechanical vibrations of the hot-arms. The reduction in hot-arm vibrations increases the probability of successful restarts as well as reduces the stress on the RF components.
CIAE, Beijing
In the commissioning phase of CRM cyclotron, the RF cavity resonance frequency changes rapidly due to cavity thermal instability and electronics interference inside tuning loop. To solve the later issue, a set of cavity tuning control electronics has been re-designed, fabricated and tested in 2008. The new tuning control electronics and related experimental results will be described in this paper. A wide dynamic range phase detector with double balanced mixer were selected to detect the cavity detuning angle by comparing the phase difference between the cavity pickup signal and cavity driven signal. One analogue P.I. controller was utilized for loop regulation, taking advantage of shorter developing time. A current amplifier is also included to magnify the driven ability of the P.I. regulator for cavity fine tuning motors. A careful layout has been performed to avoid interference between RF part, DC small signal part and the current amplifier part. The desk experiment yields good phase detection sensitivity and acceptable stability after the mixer reaches natural thermal balance.
Bruce Technologies Inc., North Billerica, MA
D-Pace, Nelson, British Columbia
Many of today’s PET cyclotrons are delivered from the factory for fully-automated “black box” operation in a hospital-based clinical program. Simplicity and ease of operation by non-specialists is desired, and this is achieved in-part through relatively low current targets bolted directly to the PET cyclotron’s main vacuum tank. However, commercial-scale production of short-lived radiopharmaceuticals is becoming increasingly prevalent where substantially higher-current target operation* requiring greater optimization of beam parameters through compact external beamlines**,*** is necessary to meet ever-more demanding production schedules and delivery commitments. This paper describes a system which incorporates the highest current and highest power PET water targets and a short well-instrumented beamline for beam centring/focusing and maximum productivity.
*M. Stokely et al, WTTC11, Cambridge, 2006, p.{10}2.
**M.P. Dehnel et al, NIM B 261, 2007, p. 809.
***J.E. Theroux et al, CYC2007, Giardini Naxos, Italy, 2007, p. 361.
Yale University, Beam Physics Laboratory, New Haven, Connecticut
Yale University, Physics Department, New Haven, CT
Omega-P, Inc., New Haven, Connecticut
Fermilab, Batavia
Funding: Supported by US Department of Energy, Office of High Energy Physics
A detailed analysis is presented of a new concept for a high current, high gradient proton beam accelerator in a normal conducting (i.e. room temperature) structure. The structure consists of a cascade of RF cavities in a nearly uniform magnetic axial field. The proton energy gain mechanism relies upon cyclotron resonance acceleration in each cavity. In order to check the concept and determine its limits, an engineering design is presented of a four cavity electron counterpart test accelerator under construction that will mimic parameters of the multi-cavity proton accelerator.
CIAE, Beijing
The beam phase monitor was designed to address phase slide issue, which can lead to significant beam loss inside 100MeV cyclotron. The measured phase information can be used to direct cyclotron magnetic field fine tuning. The system describes in this paper consists of the following part: 10 sets of beam phase pickup, a phase detector, a set of RF multiplexer and a phase shifter to compensate different phase offset generated by cables, connectors etc. The last one is a computer interface consisting of two 16 bits AD converters, one ARM 7 processor was included in this module to support RS232 connection and perform necessary signal process. All parts except the probe were located in one 3U VME standard crate, 8 slots were occupied and one user defined backplane was developed to carry necessary power supply lines and inter-connections. Preliminary tests for the electronic system has been performed, and a good result was obtained in the procedure. Yet the leakage from RF cavity in the 100MeV cyclotron is still an undermined limitation for this application.
JAEA/TARRI, Gunma-ken
CNS, Saitama
It is possible to fold the tails of the transverse beam profile into the inside, or even to uniformize the beam distribution in the properly-designed nonlinear beam transport system. A two-dimensionally uniform beam profile was formed using sextupole and octupole magnets at the azimuthally-varying-field cyclotron facility of Japan Atomic Energy Agency. Such a uniform beam exhibits a unique feature in the viewpoint of a uniform irradiation system; as compared to the raster scanning system, it enables us to perform uniform irradiation over the whole area of a large sample at a constant particle fluence rate. For the application of materials sciences, uniformization of heavy-ion beams as well as protons has been performed. In order to reduce undesirable beam halos at the target, tail-folding of the spot beam is also planed using the nonlinear focusing method.
TRIUMF, Vancouver
Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada.
The TRIUMF cyclotron is 6-fold symmetric, but has a 3rd harmonic magnetic field gradient error. As well, there is a 3rd harmonic component generated from the beating of the primary harmonics with the 9th harmonic. Both can contribute and drive the nur=3/2 resonance. As a consequence, the radial phase space ellipses become stretched and mismatched; this introduces a radial modulation of beam density and thereby causes a sensitivity of the extracted current to, for example, small changes in rf voltage. The cyclotron has "harmonic" correction coils, but these were designed to generate a first harmonic, not a third harmonic. Their 6-fold symmetric layout can only generate a 3rd harmonic at one particular phase and so can only partially compensate for this resonance. For a complete compensation, the 6 pairs of this harmonic coil would have to shift in azimuth by ~30degr. This paper describes the simulations performed with COMA to study the effect of this resonance. Initial measurement results are also presented.
TRIUMF, Vancouver
Injection from an external ion source into a cyclotron results in unavoidable emittance growth when the cyclotron's pole gap is not small compared with the first turn radius. In such a congested geometry, the injected beam first has the two transverse directions coupled on entering the axial magnetic field of the cyclotron, then transverse and longitudinal phase spaces are coupled by the inflector. Generally, to avoid loss, the beam is focused tightly through the inflector. It thus arrives at the first turn strongly mismatched because the vertical focusing in such a cyclotron is rather weak (vertical tune < 0.3). Space charge exacerbates the mismatch because it depresses the vertical tune further. Emittance growth from all these effects can be calculated using the full Sacherer 6D envelope formalism. We develop the technique to include cyclotrons and in particular the transverse optics of the rf gaps, and apply it in particular to the re-design of the TRIUMF 300 keV vertical injection line.
Commanding Communications Academy, Wuhan
CIAE, Beijing
Under the influence of applications using virtual reality in accelerator R&D, this paper discusses the complete process of developing Communication Equipment Operation Simulation (CEOS) based on Creator/Vega Visual Scenery Simulation Technology, operation rules modeling and solutions to its key problem. The virtual scene model for communication equipment is designed with 3D modeling software MultiGen Creator, especially its DOF technology and Switch node. The basic graphs such as wires are drawn through OpenGL call-back functions. By the virtual scene drive Vega, the application of CEOS comes true. Its simulation example shows greatest traits on building similar simulation system e.g. cyclotron virtual prototyping system as well as virtual cyclotron control system.
Istituto Nazionale di Fisica Nucleare, Milano
Universita' degli Studi di Milano & INFN, Segrate
Naples University Federico II and INFN, Napoli
CERN, Geneva
Bari University, Science Faculty, Bari
e2v, Chelmsford, Essex
INFN-Bari, Bari
ACLIP is a proton 3 GHz SCL linac designed as a booster for a 30 MeV commercial cyclotron . The final energy is 60 MeV well suitable for the therapy of ocular tumours or for further acceleration (up to 230 MeV) by a second linac in order to treat deep seated tumours. ACLIP has a 5 modules structure coupled together. The first one (able to accelerate proton from 30 to 35 MeV) has been completely assembled. High power tests are in progress at e2v in Chelmsford, UK, where the possibility of using magnetrons as the source of RF power is under investigation. Acceleration tests are foreseen for Spring 2009. In this paper we will review the main features of the linac and discuss the results of RF measurements, high power RF tests and possibly acceleration tests.
CIAE, Beijing
TRIUMF, Vancouver
As a high intensity compact cyclotron, CYCIAE-100 is designed to provide proton beams in two directions simultaneously. At the extraction region, the fringe field of the main and the field of the combination magnet will influence the beam optics. The fringe field may become critical by comparison with the separated sector machine because of the compact structure. The dispersion during the beam extraction should not be ignored, which may make the beam envelop become evidently bigger. Then the beam loss and residual radiation increase. To study the beam optics at the extraction region of CYCIAE-100, the orbit tracking and transfer matrix calculation and symplectic by function extension of the code GOBLIN and modification of STRIPUBC have been implemented. The characteristics of the extracted beam have been investigated based on the main field from a FEM code and overlapping with the field generated from the combination magnet at each extraction port. The results are also compared with those from the CIAE’s code CYCTRS to confirm this precise prediction. The transfer matrix from this simulation is analyzed and used for the down stream beam line design.
CIAE, Beijing
FZJ, Jülich
The 10 mA, 40keV H- pulsed injection line for the CIAE 10 MeV CRM cyclotron has two main operation modes for bunched beams: delivering 5 mA CW beam or chopped pulse with more than 100uA. Chopped pulse is achieved by placing behind the 70.5 MHz bunching cavity a sinusoidal transverse deflecting cavity with frequency of 2.2 MHz, 1/32 of the bunching frequency. Particles outside the wanted ±3° phase width @ 2.2 MHz, corresponding to ±90° @ 70.5 MHz, are either absorbed in a 50cm drift after chopper or at round slit1, 1cm aperture. Time dependence of sinusoidal chopping field causes RMS emittance increase by a factor 3 and changes twiss parameter alpha by a factor 2 before the round slit1. Solenoid couples motion in transversal planes, but equalizes both RMS emittances. Particle tracking results are presented for the chopped pulse, showing longitudinal-transverse coupling in the deflector and equalization of RMS emittances in the solenoid. Optimised focusing strength leads to about 1 % transmission efficiency for the chopped pulse. The CRM inflector receives 2.4 ns long pulse at about 4.4 MHz repetition rate, 1/16 of the RF frequency.
ENEA C.R. Frascati, Frascati (Roma)
SPARKLE S.r.l., Casarano (Lecce)
SPARKLE company is setting up in the south of Italy (Casarano) a new cyclotron facility based on a 18 MeV, 150 uA IBA Cyclone 18/9. The aim is to create a multidisciplinary research site for the medical applications of accelerators. The main activity will be the production of standard and new radionuclides, by internal targets and one external beam line. Another opposite beam line has been reserved for low current proton irradiations for radiotherapy studies, and a linac booster between 18 and 24 MeV was designed and built to this end. The beam line, which focuses and matches the beam to the linac, includes a chopping system to synchronize the beam to the pulsed linac and to collect 99% of the beam not synchronous to the linac. The linac uses a 3 GHz SCDTL structure powered by a magnetron modulator system. In the paper we report an overview of the beam line, component design, and tests.
JINR, Dubna, Moscow Region
The current status of the JINR FLNR cyclotrons and plans of their modernization are reported. At present time, four isochronous cyclotrons: U400, U400M, U200 and IC100 are under operation at the JINR FLNR. The U400 and the U400M are the basic cyclotrons that are under operation about 6000 and 3000 hours per year correspondingly. Both the accelerators are used in DRIBS experiments to produce and accelerate exotic very neutron-rich isotopes of light elements such as 6He and 8He. The U400 (pole diameter of D=4 m) is designed to accelerate ion beams of atomic masses from 4 to 209 to maximum energy of 26 MeV/u for synthesis of the new super heavy elements and other physical experiments. The U400M cyclotron (D=4 m) is used to accelerate ions of elements from Li to Ar up to 50 MeV/u and heavier ions such as 48Ca, Kr,Xe, up to 6 MeV/u after recent modernization. The U200 cyclotron (D=2 m) is used to produce isotopes by using He ions with energies about 9 MeV/u, modernization of the cyclotron injection is planned. Modernized IC100 accelerator (D=1m) is used to produce track membranes and carrying out experiments in solid-state physics by using Ar, Kr and Xe ions at energies of 1.2 MeV/u.
JINR, Dubna, Moscow Region
In axial injection channels of FLNR JINR cyclotrons the axial symmetric ion beam is formed just after the analyzing bending magnet. This gives an opportunity to use for beam focusing at vertical part of the channel solenoidal magnetic lenses only. During the motion of intense axial symmetric beam in the longitudinal magnetic field of solenoids and cyclotron the transverse tunes Qx, Qy coincide. In this case the small disturbance of beam axial symmetry leads to excitation of coupling resonance Qx-Qy=0 due to beam self-fields. The influence of the resonance results in significant asymmetry of the transverse beam emittances. The magnitude of this asymmetry is evaluated within the framework of moments method and is in a good agreement with one obtained in the macro-particles simulation. The correction of resonance by means of the normal quadrupole lens is proposed.
JINR, Dubna, Moscow Region
IBA, Louvain-la-Neuve
C400 is compact superconducting cyclotron for hadron therapy. The permissible level of the transverse magnetic field at the horizontal part of axial injection beam line of a cyclotron is about 10 Gauss. At the same time the C400 magnetic field is about 500 Gauss in magnitude at the places of the ion sources, vertical bending magnet and quadrupole lens location. Thereby the screening of these beam-line elements is needed. The 3D OPERA model of the cyclotron and channel elements is used for this purpose.
JINR, Dubna, Moscow Region
IBA, Louvain-la-Neuve
C400 is compact superconducting isochronous cyclotron for carbon beam therapy designed by IBA, Louvain-La-Neuve (Belgium) in collaboration with JINR, Dubna (Russia). The cyclotron can accelerate all ions with charge to mass ratio 0.5. Protons are accelerated as single charge 2H+ molecules and extracted by stripping at 270 MeV. All other ions are extracted by an electrostatic deflector at 400 MeV/u. The final layout of the axial injection beam line of C400 cyclotron is given. Two ion sources for production of 12C6+ ions and Alphas beams are located at the horizontal part of the channel before both side of the combination vertical magnet. The third ion source for the production of 2H+ is placed in straight line on the vertical axis. The rotational symmetry of the beam is reestablished with the help of one quadrupole lens placed just after analyzing magnet. The beam focusing at the vertical part of the channel is provided by three solenoidal lenses instead of four quadrupoles used in the previous version of beam line. The results of simulation of ion beams transport in the axial injection channel are presented.
CIAE, Beijing
TRIUMF, Vancouver
Department of Physics, Central China Normal University, Wuhan
There is increasing interest in high current compact H- cyclotrons for RIB, isotope production or as injectors for sub-critical reactor testing facilities. For compact cyclotrons, a practical limit on the output energy, to prevent significant Lorentz stripping and resulting activation, is ~100 MeV. Vacuum dissociation is another critical problem, because a compact structure and small parts inside the tank make high vacuum challenging. This paper describes how Lorentz stripping and vacuum dissociation were calculated for our “CYCIAE-100” under construction. In order to take into account non uniform magnetic fields and vacuum, losses were calculated by numerically integrating loss equations along tracked orbits, as these were being calculated by the beam dynamics code. To verify the code, losses derived with field and vacuum data from the TRIUMF 500 MeV cyclotron were compared with measurements. For the CYCIAE-100 cyclotron we predict that electromagnetic losses will account for less then 0.3% of total beam, vacuum losses for less than 0.58%, with peak magnetic fields up to 1.35T and average vacuum up to 5·10-8 Torr.
UBC & TRIUMF, Vancouver, British Columbia
It is sometimes asserted that Thomas's proposal to provide additional axial focusing in cyclotrons (to enable them to operate isochronously at relativistic energies) by introducing an azimuthal variation in the magnetic field was an early example of alternating-gradient focusing. While Thomas cyclotrons certainly exhibit alternating field gradients, it is shown that the alternating focusing produced is very much weaker than the edge focusing (everywhere positive) arising from orbit scalloping.
UBC & TRIUMF, Vancouver, British Columbia
TRIUMF, Vancouver
This paper describes tracking studies of FFAGs and radial-sector cyclotrons with reverse bends using the cyclotron equilibrium orbit code CYCLOPS. The results for FFAGs confirm those obtained with lumped-element codes, and suggest that cyclotron codes will prove to be important tools for evaluating the measured fields of FFAG magnets. The results for radial-sector cyclotrons show that the use of negative valley fields would allow axial focusing to be maintained, and hence allow intense cw beams to be accelerated, to energies of the order of 10 GeV.
NSCL, East Lansing, Michigan
Cyclotron gas stopper is a newly proposed device to stop energetic ions in a high pressure helium gas and to transport them in a singly charged state with a gas jet to a vacuum region. Radioactive ions are slowed down by gas collisions inside the field of a weakly focusing cyclotron-type magnet and extracted via interaction with the Radio Frequency field of sequence of concentric electrodes (RF carpet). The present study focuses on a detailed understanding of space charge effects in the central ion extraction region. Such space charge effects originate from the ionization of the helium gas during the stopping of the ions and are the cause for beam rate limitations. Particle-in-cell simulation of two-component (electron-helium) plasma interacting via Coulomb forces were performed in a field created by ionized ions. Simulation results indicate beam rate capabilities and efficiencies far beyond those achieved with linear gas cells presently used to stop projectile fragments.
ORNL, Oak Ridge, Tennessee
Funding: *Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
HRIBF produces high-quality beams of short-lived radioactive isotopes for nuclear science research, and is currently unique worldwide in the ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier. HRIBF is undergoing a multi-phase upgrade. Phase I (completed 2005) was construction of the High Power Target Laboratory to provide the on-going Isotope Separator On-Line development program with a venue for testing new targets, ion sources, and radioactive ion beam (RIB) production techniques with high-power ORIC beams. Presently under way is Phase II, the Injector for Radioactive Ion Species 2, a second RIB production station that will improve facility reliability and accommodate new ion sources, RIB production, and RIB purification techniques, including laser applications. The Phase III goal is to substantially improve facility performance by replacing or supplementing the Oak Ridge Isochronous Cyclotron production accelerator with either a high-power 25-50 MeV electron accelerator or a high-current multi-beam commercial cyclotron. Either upgrade is applicable to R&D on isotope production for medical or other applications.