| Paper | Title | Page |
|---|---|---|
| TUPLS001 | Enhanced Optical Cooling of Ion Beams for LHC | 1483 |
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| Enhanced optical cooling (EOC) of fully stripped lead ions in LHC is investigated. The method of EOC is based on the usage of pickup and kicker undulators and optical amplifier. External selectivity is arranged by a moving screen located on the image plane of the optical system, projecting the emitted undulator radiation there (see physics/0509196). Nonlinear features of cooling and requirements to the ring lattice, optical and laser systems are discussed. Comparison with classical optical stochastic cooling (OSC) is represented as well. | ||
| TUPLS002 | Dust Macroparticles in HERA and DORIS | 1486 |
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| Charged dust macroparticles are considered as sources of sudden beam lifetime breakdowns detected in many electron storage rings. This phenomenon is still observed in HERA, although the distributed ion pumps, which were previously identified as dust particle sources, have been removed. We report on the observations of trapped dust during the last period of electron operation and present a detailed model of dust macroparticle dynamics in the HERA e-ring and in DORIS with particular emphasis on stability and possible trapping processes. | ||
| TUPLS003 | A Perfect Electrode to Suppress Secondary Electrons inside the Magnets | 1489 |
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| Electron cloud due to multipacting in the positron ring of B-factories is one of the limitations on the machine performance. Electron cloud in the drift region can be suppressed by solenoid. However, solenoid doesn't work inside a magnet. Numerical studies show that there is strong multipacting in the dipole magnet of the B-factory positron ring. Electrons also can be trapped inside quadrupole and sextupole magnets. The electron cloud from the dipole magnet and wiggler in the positron damping ring of the ILC is a critical limitation on the choice of damping ring circumference, which directly results in a choice of two 6km rings as the baseline for the positron damping ring. Various electrodes have been studied using the program CLOUDLAND. Our studies show that a wire type of electrode with a few hundred voltages works perfectly to kill the secondary electrons inside various magnets. | ||
| TUPLS004 | How Einsteinian Tide Force Affects Beam in a Storage Ring | 1492 |
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| In this paper, we will introduce Einsteinian tide force into a storage ring, and discuss the beam characteristic in a storage ring, we can see that it is quite different from Newtonian tide force act on beam in a storage ring which we know very well. We also discuss the method to measure the beam instability in storage ring caused by these two different tide forces. | ||
| TUPLS005 | Preliminary Study of Using "Pipetron"-type Magnets for a Pre-accelerator for the LHC Collider | 1493 |
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| One of the luminosity limitations of the LHC is the rather low injection energy (0.45 TeV) with respect to the collision energy (7 TeV). The magnetic multipoles in the main dipoles at low field and their dynamic behaviour are considered to limit the achievable bunch intensity and emittance. We report on a preliminary study to increase the injection energy to 1.5 TeV using a two beam pre-accelerator (LHCI) in the LHC tunnel. The LHCI is based on "Pipetron" magnets as originally proposed for the VLHC. The aim of the study is to assess the feasibility and to identify the critical processes or systems that need to be investigated and developed to render such a machine possible. | ||
| TUPLS006 | Optics of a 1.5 TeV Injector for the LHC | 1496 |
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| A concept is being developed to install a second ring above the LHC to accelerate protons from 450 GeV to 1.5 TeV prior to injection into the LHC. The arc and dispersion suppressor optics of the LHC would be replicated in the injector using combined function 'transmission line' magnets orginally proposed for the VLHC. To avoid costly civil construction, in the straight sections housing detectors at least, the injector and LHC must share beampipes and some magnets through the detector portion of the straights. Creating the appropriate optics for these injector-LHC transition regions is very challenging: In addition to matching to the nominal LHC lattice functions at these locations, the changes in altitude of 1.1 m between the injector and LHC must be accomplished achromatically to avoid emittance blowup when the beams are transferred to the LHC. | ||
| TUPLS008 | A new HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring | 1499 |
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| At high currents and small bunch lengths beam line components in the PEP-II B-factory experience RF induced heating from higher order RF modes (HOMs) produced by scattered intense beam fields. A design for a passive HOM water cooled absorber for the PEP-II low energy ring is presented. This device is to be situated near HOM producing beamline components such as collimators and provide HOM damping for dipole and quadrupole modes while minimizing impedance to the beam. We present a method of optimizing the impedance characteristics of such devices through the evaluation of loss factors and absorber effectiveness for specific modes using scattering parameter and wakefield analysis. | ||
| TUPLS009 | Design and Tests of New Fast Kickers for the DAFNE Collider and the ILC Damping Rings | 1502 |
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| In this paper we illustrate the design of new, fast stripline kickers to inject or extract bunches in electron/positron rings. The kickers have been designed for the injection upgrade of the Phi-factory DAFNE and as injection/extraction devices for the International Linear Collider (ILC) damping rings. The design is based on tapering the striplines in order to simultaneously obtain low impedance and an excellent uniformity of the deflecting field. The design has been done using 2D and 3D electromagnetic codes such as Superfish and HFSS. High voltage test results on prototypes are also shown. | ||
| TUPLS010 | New Beam Transport Line from LINAC to Photon Factory in KEK | 1505 |
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| The e+/e- injector LINAC in KEK usually injects into four rings which are Low Energy Ring (LER) of KEKB (3.5GeV/e+), High Energy Ring (HER) of KEKB(8.0GeV/e-), Photon Factory (PF)(2.5GeV/e-) and Advanced Ring for pulse x-rays (PF-AR)(3.0GeV/e-). While LINAC continuously injects into LER and HER alternately about every five minutes, both of the KEKB rings usually store almost full operating currents. Time for PF or PF-AR, which includes switching time, took about 20 minutes several times a day. During this, the storage currents in KEKB rings decreased, and the optimum points of luminosity tuning had been lost. It had taken more than two hours to recover the luminosity. It is so useful for KEKB to shorten the time for switch LINAC KEKB to/from PF or PF-AR. In summer of 2005, the transport line from LINAC to PF were renewed, in which a DC bending magnet only for PF line apportions electron beam from the end of LINAC to the new line. We succeeded to reduce the occupancy time for PF injection to about five minutes. In this paper design of the new PF beam transport line and the practical performance achieved according to the design are described. | ||
| TUPLS011 | The Beam Screen for the LHC Injection Kicker Magnets | 1508 |
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| The two LHC injection kicker magnet systems must each produce a kick of 1.2 T.m with a flattop duration variable up to 7.86 μs, and rise and fall times of less than 0.9 μs and 3 μs, respectively. Each system is composed of four 5 Ω transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFN). The LHC beam has a high intensity, hence a beam screen is required in the aperture of the magnets This screen consists of a ceramic tube with conducting "stripes" on the inner wall. The stripes provide a path for the image current of the beam and screen the magnet ferrites against Wake fields. The stripes initially used gave adequately low beam impedance however stripe discharges occured during pulsing of the magnet: hence further development of the beam screen was undertaken. This paper presents options considered to meet the often conflicting needs for low beam impedance, shielding of the ferrite, fast field rise time and good electrical and vacuum behaviour. | ||
| TUPLS012 | Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading | 1511 |
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| In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed. | ||
| TUPLS013 | Protection of the LHC against Unsynchronised Beam Aborts | 1514 |
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| An unsynchronised beam abort in the LHC could cause major damage to other downstream accelerator components, in particular the extraction septum magnets, the experimental low-beta triplet magnet apertures and the tertiary collimators. Although the LHC beam dumping system includes design features to minimise their frequency, such unsynchronised aborts can arise from several sources and cannot be excluded. A system of protection devices comprising fixed and moveable passive diluters and collimators will be built to safely protect the downstream LHC aperture from the mis-directed bunches in case of such a failure. The sources of unsynchronised abort events are described, together with the requirements and design of the protection devices and their expected performance. The accompanying operational requirements and envisaged solutions are discussed, in particular the problem of ensuring the local orbit at the protection devices. | ||
| TUPLS014 | Optics Flexibility and Dispersion Matching at Injection into the LHC | 1517 |
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| The LHC requires very precise matching of transfer line and LHC optics to minimise emittance blow-up and tail repopulation at injection. The recent addition of a comprehensive transfer line collimation system to improve the protection against beam loss has created additional matching constraints and consumed a significant part of the flexibility contained in the initial optics design of the transfer lines. Optical errors, different injection configurations and possible future optics changes require however to preserve a certain tuning range. Here we present methods of tuning optics parameters at the injection point by using orbit correctors in the main ring, with the emphasis on dispersion matching. The benefit of alternative measures to enhance the flexibility is briefly discussed. | ||
| TUPLS015 | Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets | 1520 |
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| The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. They have been produced, tested and calibrated by measuring the integrated magnetic field and the magnet current at different beam energies. The calibration data have been analysed, and the critical parameters are compared with the specifications. Implications for the configuration, control and operation of the beam dumping system are discussed. | ||
| TUPLS016 | Characterization of Crystals for Steering of Protons through Channelling in Hadronic Accelerators | 1523 |
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| Channeling of relativistic particles through a crystal may be useful for many applications in accelerators, and particularly for collimation in hadronic colliders. Efficiency proved to be dependent on the state of the crystal surface and hence on the method used for preparation. We investigated the morphology and structure of the surface of the samples that have been used in accelerators with high efficiency. We found that crystal fabrication by only mechanical methods (dicing, lapping, and others) leads to a superficial damaged layer, which is correlated to performance limitation in accelerators. A planar chemical etching was studied and applied in order to remove the superficial damaged layer. RBS analysis with low-energy protons highlighted better crystal perfection at surface, as a result of the etching. Finally, measurement with 70-GeV protons at IHEP demonstrated a superior performance of the chemically cleaned crystals with respect to conventional samples. A protocol for preparation and characterization of crystal for channelling has been developed, which may be of interest for reliable operation with crystals in accelerators. | ||
| TUPLS017 | Optics Study for a Possible Crystal-based Collimation System for the LHC | 1526 |
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| The use of bent crystals as primary collimators has been long proposed as an option to improve the cleaning efficiency of the LHC betatron and momentum collimation systems. These systems are presently based on two-stage collimation with amorphous scatterers and absorbers. Crystals are expected to help by channeling and extracting the halo particles with large angles, resulting in higher cleaning efficiency. Independent of ongoing studies for crystal qualifications (not reported here), it is important to understand the required deflection angles and the possible locations of absorbers for the LHC layout. Optics studies have been performed in order to specify the required angles for various LHC beam energies and possible locations of absorbers for the deflected halo beam. A possible layout for crystal-assisted collimation at the LHC is discussed, aiming for a solution which would not change the LHC layout but would make use of the existing collimator location. | ||
| TUPLS018 | Collimation Efficiency during Commissioning | 1529 |
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| The design of the LHC collimation system naturally focused on understanding and maximizing the ultimate performance with all collimators in place. However, for the commissioning of the LHC it is important to analyze the collimation efficiency with certain subsets of collimators, with increased collimation gaps and relaxed set-up tolerances. Special studies on halo tracking and energy deposition have been performed in order to address this question. The expected cleaning performance and intensity limits are discussed for various collimation scenarios as they might be used during commissioning and initial operation of the LHC. | ||
| TUPLS019 | Critical Halo Loss Locations in the LHC | 1532 |
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| The requirements on cleaning efficiency in the LHC are two to three orders of magnitude beyond the needs at existing super-conducting colliders. The LHC will therefore operate in unknown territory, which can only be assessed by powerful simulation tools. Such tools have been developed at CERN over the last years, making it possible to perform detailed simulations of the LHC cleaning processes and multi-turn loss patterns around the LHC ring. The simulation includes all collimators, diluters and absorbers in the LHC. Proton loss maps are generated with a 10 cm resolution, which allows performing advanced studies for quenches of super-conducting magnets along with the analysis of the deposited energy in the machine elements. The critical locations of beam halo losses are discussed, both for the ideal machine and for various scenarios of closed-orbit distortion and beta-beating. From these results it can be shown that it is sufficient to use a limited number of BLM's for the setup and optimization of the LHC collimation system. | ||
| TUPLS021 | First Observation of Proton Reflection from Bent Crystals | 1535 |
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We recently suggested using short bent crystals as primary collimators in a two-stage cleaning system for hadron colliders, with the aim of providing larger impact parameters in the secondary bulk absorber, through coherent beam-halo deflection*. Tests with crystals a few mm long, performed with 70 GeV proton beams at IEHP in Protvino, showed a channeling efficiency exceeding 85%. We also observed disturbing phenomena such as dechanneling at large impact angle, insufficient bending induced by volume capture inside the crystal, multiple scattering of non-channeled protons and, for the first time, a proton flux reflected by the crystalline planes. Indeed, protons with a tangent path to the curved planes somewhere inside the crystal itself are deflected in the opposite direction with respect to the channeled particles, with an angle almost twice as large as the critical angle. This effect, up to now only predicted by computer simulations**, produces a flux of particles in the wrong direction with respect to the absorber, which may hamper the collimation efficiency if neglected.
*A. Afonin et al. PhysRevLett.87.094802(2001).**A. M. Taratin and S.A.Vorobiev, Phys.Lett. A119(1987)425. |
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| TUPLS022 | Experimental Study of Crystal Channeling at CERN-SPS for Beam-halo Cleaning | 1538 |
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| An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Russia (St. Petersburg) and Italy (Ferrara) have developed crystal production methods, which considerably improve the crystal quality. In view of the crystal-collimation experiments at the Tevatron and of the potential improvement compared with the phas·10-1 LHC collimation system, considering the recent progress in crystal technology, we proposed experiments for crystal characterization in the SPS beam lines. Major objectives will be: 1) qualification of the new crystals to be used in the Tevatron; 2) measuring the channeling efficiency of long crystals with 1 mrad and/or 8 mrad bending angle; and 3) comparison of loss patterns around the ring for a crystal with one for amorphous material. In this paper we will report the progress towards the SPS experiment. | ||
| TUPLS024 | FFAGs as Muon Accelerators for a Neutrino Factory | 1541 |
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| The FFAG accelerator is a solution for rapid acceleration of muons because of its large aperture and no need of magnet ramping. Its particle dynamics is, however, peculiar due to high energy gain per turn and large transverse amplitude, which has not been seen in other types of circular accelerators. One variation of FFAG, called non-scaling FFAG, employs quite new scheme, namely, out of bucket acceleration. We studied emittance distortion, coupled motions among 3-D planes, effects of resonance lines, etc., based on a newly developed tracking code. In this paper, we will emphasize new regime of particle dynamics as well as a modeling technique of FFAG. | ||
| TUPLS025 | Racetrack Non-scaling FFAG for Muon Acceleration | 1544 |
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| The non-scaling Fixed-Field Alternating Gradient (FFAG) machines have very strong focusing, large momentum acceptance, and small dispersion and betatron functions. This report is a study of using a compact non-scaling FFAG in combination with the superconducting linac to accelerate the muons. The drift space between two kinds of combined function magnets in the previous non-scaling FFAG is removed. The time of flight in the non-scaling FFAG has a parabolic dependence on momentum. The large energy acceptance of the machine requires matching between the linac and the non-scaling FFAG arcs for both the betatron and dispersion functions over the entire energy range. | ||
| TUPLS027 | A Non-scaling FFAG for Radioactive Beams Acceleration (RIA) | 1547 |
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| One of the most expensive components of proposals to accelerate heavy radioactive beams is the superconducting linac. This is an attempt to design a non-scaling Fixed-Field Alternating-Gradient (FFAG) lattice to allow acceleration of heavy radioactive beams in a short time period with an acceptance in momentum of ±50%. As it had been previously reported the non-scaling FFAG has very small orbit offsets, very strong focusing, and large momentum acceptance. The lattice with small combined function magnets would provide substantial savings in the cost of the RF. | ||
| TUPLS028 | An Irradiation System for Carbon Stripper Foils with 750 keV H- Beams | 1550 |
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| Carbon stripper foils of around 300 ug/cm2 will be used as a stripping of H-ion beam of the 3 GeV Rapid Cycling Synchrotron in the J-PARC. The foil should have a long lifetime with mechanically strong against high temperature of 1800K due to high-energy deposition by high intensity H-ion and circulating bunched proton beam irradiations. For this purpose, we have installed a new irradiation system using high intensity pulsed and dc H-beams of the KEK 750keV Cocksfoot-Walton accelerator. By adjusting the peak intensity and the pulse length of the hydrogen beams appropriately, the energy deposition becomes equivalent to that exerted by the incoming H- and the circulating beams at the injection process of the RCS. The new irradiation system and some preliminary results of the carbon stripper foil will be reported. | ||
| TUPLS029 | Optical Scheme of an Electrostatic Storage Ring | 1553 |
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We consider the optical scheme of an electrostatic storage ring for low energy heavy ions/molecules* with special requirements to type of optical functions. Results of calculation are presented.
*C. P. Welsch et al. Proc. of PAC’03, 12-16 May 2003, Portland, Oregon, USA, p.1622. |
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| TUPLS031 | Commissioning of the ISAC-II Heavy Ion Superconducting Linac at TRIUMF | 1556 |
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| A new heavy ion superconducting linac at TRIUMF is being installed to boost the final energy of radioactive beams from ISAC from 1.5MeV/u to above the Coulomb barrier. A first stage of 20MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being commissioned in early 2006. The cavities (Beta0=0.057, 0.071) operate cw at 106MHz with design peak fields of Ep=30MV/m, Bp=60mT while delivering an accelerating voltage of 1.08MV at ~4W power consumption. The report will summarize the commissioning results and early operating experience. | ||
| TUPLS032 | Superconducting Driver Linac for the New Spiral 2 Radioactive Ion Beam Facility GANIL | 1559 |
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| The new Spiral 2 facility will deliver high intensity rare isotope beams for fundamental research in nuclear physics, and high neutron flux for multidisciplinary applications. Based into the ISOL and in-flight isotope production methods this facility will cover broad areas of the nuclide chart. The driver accelerator must deliver CW beams of deuterons (40 MeV, 5 mA) and heavy ions (q/A=1/3, 15 MeV/A, 1 mA). The injector is composed of two ion sources (deuterons and heavy ions) and a common RFQ cavity (88 MHz). The Superconducting Linac is composed of two sections of Quarter Wave Resonators (beta 0.07 and 0.12, frequency 88 MHz) with room temperature focusing devices. After two years of preliminary study, and following the recent decision to launch the construction phase, a complete design of the Driver Accelerator is presently completed. Important results have been obtained during the initial R&D phase, in particular on ion sources, RFQ and superconducting resonators prototypes. Status report on both the design and the prototype performances will be given in this contribution. | ||
| TUPLS033 | First Stage of a 40 MeV Proton Deuteron Accelerator Commissioning Results | 1562 |
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| In 2006 the first stage of a 40MeV superconducting linear accelerator for protons and deuterons will be commissioned at SOREQ. This paper will present commissioning of the ECR source after final assembly. First results of the 1.5MeV/u cw RFQ are expected, further test results of the beta=0.09 half wave superconducting resonators are presented, and resonator geometry improvements with respect to electron multipacting behaviour will be discussed. An outlook on the project with respect to achieve the final energy of 40MeV will be given. | ||
| TUPLS034 | UNILAC Upgrade Programme for the Heavy Element Research at GSI-SHIP | 1565 |
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| In the field of heavy-element research using the velocity separator SHIP significant achievements were made at GSI during the last 30 years. The experiences obtained of experiments clearly show that superheavy-element research was always based on efforts to extend the limits of technical possibilities - of these the increase of beam intensity is one of the major contributions. This paper provides for technical information on the already planned upgrades of the present facility, which results in a significant overall increase of the experimental sensitivity. It is foreseen to investigate and to build a sc 28 GHz-ECR ion source, which should increase the primary beam intensities. The beam coming from the new ECR source will be delivered to the GSI-High Charge State Injector by a second LEBT-system. An upgrade program for the rf-amplifiers and the rf-structures is intended to increase the duty factor from 30 % to 50 %. Besides the ECR-source a new RFQ accelerator and the IH structure may alternatively serve as an injector for an new advanced stand alone accelerator providing for 100 % duty factor. Two different linac-layouts will be discussed. | ||
| TUPLS035 | The HITRAP Decelerator Project at GSI | 1568 |
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| The heavy ion trap (HITRAP) at GSI is a funded project since 2004. Highly charged ions up to U92+ provided by the GSI accelerator facility will be decelerated and subsequently injected into a Penning trap for further cooling almost to rest. A combination of an IH- and an RFQ-structure decelerates the ions from 4 MeV/u down to 6 keV/u. In front of the decelerator a double-drift-buncher-system provides for phase focusing and a final debuncher integrated in the RFQ-tank reduces the energy spread in order to improve the efficiency for beam capture in the cooler trap. The report gives an overview of the final beam dynamic design of the entire decelerator. Besides the construction status of the cavities, particular beam diagnostic features due to the short pulses of 1 μs and 108 MHz bunch frequency, and the measures for technical and controls integration into the existing GSI accelerator complex are presented. Finally the recent time schedule and considerations for commissioning are shown. | ||
| TUPLS036 | Status of the Linac-commissioning for the Heavy Ion Cancer Therapy Facility HIT | 1571 |
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| A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector and a 6.5 Tm synchrotron to accelerate the ions to final energies of 50-430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz. In this contribution the current status of the linear accelerator is reported. After first tests with 1H+ beam of the RFQ at GSI, the commissioning of the accelerator in Heidelberg has already started. The commissioning with beam is performed in three steps for the LEBT, the RFQ and the IH-DTL. For this purpose a versatile beam diagnostic test bench has been designed. It consists of a slit-grid emittance measurement device, transverse pick-ups providing for time of flight energy measurements, SEM-profile grids and different devices for beam current measurements. This paper will provide for a status report of the linac-commissioning. | ||
| TUPLS037 | The Frankfurt Funneling Experiment | 1574 |
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| The goal of the Frankfurt Funneling Experiment is to multiply beam currents of RFQ accelerators at low energies to avoid problems with space charge. The two beams from the ion sources are injected into two RFQ channels. The last part of the RFQ electrodes have been replaced to achieve a 3d focus at the crossing point of the two beam axis where the funneling deflector as a central peace of the experiment is located. The newly designed multi-cell deflector is adapted to the optimised funneling section. It is mechanically solid, easy to tune in and ready for operation. First measurements will be presented. | ||
| TUPLS038 | The MAFF IH-RFQ Test Stand at the IAP Frankfurt | 1577 |
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| The IH-type RFQ for the MAFF project at the LMU in Munich is presently under construction and will be integrated into a beam test stand at the IAP in Frankfurt. It is the second RFQ following the IH resonator concept and the first one that can be directly compared to a very similar 4-rod type machine, namely the REX-ISOLDE RFQ at CERN. The MAFF RFQ has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. First RF-measurements have already been executed and can be compared to appropriate simulation results. Parts of the test stand are currently under construction, such as the volume ion source for He+ at an extraction voltage of 12 keV and an electrostatic quadruplet for injection with an integrated steering system. These tests and accompanying theoretical investigations will be done with special respect to the applicability of such normal conducting RFQ accelerators to the EURISOL post accelerator. | ||
| TUPLS039 | Proposal of a Normal Conducting CW-RFQ for the EURISOL Post-accelerator and a Dedicated Beta-beam Linac Concept | 1580 |
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| A combination of three superconducting RFQs has been proposed for the EURISOL post accelerator layout. At least the first RFQ of this triplet could be replaced by a normal conducting continuous wave (c.w.) device. Efficient cooling systems have already been designed and applied to existing machines at the IAP in Frankfurt. Preliminary electrode and cavity designs can be presented. Since a parallel use for beta-beam applications was intended, we have optimized the design not only for heavy ion applications with negligible beam currents at c.w. but also for lighter ions with currents up to 7.5 mA at pulsed operation. More recent investigations on beta-beams came up with currents around 50 mA, which then would make a separate linac solution for beta-beams necessary. We worked out some preliminary design suggestions for such a dedicated 100 MeV/u machine. | ||
| TUPLS040 | Tuning of a 4-rod CW-mode RFQ Accelerator | 1583 |
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| A four-rod RFQ accelerator has been built which operates in CW mode with a power consumption of 250 kW. The assembly of a high power RFQ structure requires a precise mechanical alignment and field tuning of the electrode field. The field distribution must be very flat to enable a proper operation with few losses. Adjusting of the field distribution is critical in long structures. Simulations and the status of the tuned structure will be discussed. | ||
| TUPLS041 | The HITRAP RFQ Decelerator at GSI | 1586 |
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| The HITRAP linac at GSI will decelerate ions from 5 MeV/u to 6 keV/u for experiments with the large GSI Penning trap. The ions, provided by the GSI accelerator facility, will be decelerated at first in the existing experimental storage ring (ESR) down to an energy of 5 MeV/u, and injected into a new IH decelerator and decelerated to 5oo keV/u. The following 4- Rod type RFQ will decelerate the ion beam from 5oo keV to 6 keV/u. The RFQ has been designed and will be built at the Institute for Applied Physics in Frankfurt. The properties of the RFQ decelerator and the status of the project will be discussed. | ||
| TUPLS042 | First Cryogenic Tests of the Superconducting CH-structure | 1588 |
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| The CH-structure is a new multi-cell drift tube structure operated in the TE21-mode and is well suited for the acceleration of low and medium beta ion and proton beams. Due to the mechanical stiffness room temperature as well as superconducting CH-cavities can be realised. A 19-cell, beta=0.1 superconducting CH-prototype cavity has been developed and built. First cryogenic tests have been performed at 4.5 K in Frankfurt successfully. An effective accelerating voltage of 3.6 MV has been achieved so far. This corresponds to an electric peak field of 23 MV/m. Actual measurements aim on a localisation of possible field emission centers, afterwards further surface preparation will take place. | ||
| TUPLS043 | Simulations for the Frankfurt Funneling Experiment | 1591 |
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| Beam simulations for the Frankfurt Funneling Experiment are done with RFQSim and FUSIONS. RFQSim is responsible for the beam transport through an RFQ accelerator. Behind the accelerator the particle dynamic program FUSIONS calculates the macro bunches of both beam lines through an r.f. funneling deflector. A new space charge routine has now been included. The status of the development of FUSIONS and the results of the simulations will be presented. | ||
| TUPLS044 | The 3D Beam Dynamics with the Space Charge in the Low and Middle Energy Super-conducting Option of HIPPI | 1594 |
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| For the low and middle energy of the High Intensity Proton Pulse Injector (HIPPI), a superconducting option is considered.The 3D beam dynamics simulation results in the slot and the finger-slot sections covering the energy range from 3 to 160 MeV are presented. The optimization aim is the increase of beam current together with the reduction of emittance growth, beam losses and costs. The slot structure is compared with the conventional spoke structure. | ||
| TUPLS045 | Completion of the Commissioning of the Superconducting Heavy Ion Injector PIAVE at INFN-LNL | 1597 |
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| At INFN-LNL the commissioning of the injector PIAVE, based on superconducting RFQs, has been completed. All the superconducting cavities (two RFQs and 8 quarter wave resonators - QWR) have shown very satisfactory stability with respect to changes of the liquid helium pressure and microphonics. Beam parameters are very close to the nominal values. The commissioning was completed by accelerating the pilot beam 16O3+ with the PIAVE injector and the booster linac ALPI (summer 2005). Since December 2005, a number of test beams were accelerated (mainly noble gas species) with PIAVE and ALPI and delivered to user experimental stations. Regular operation will be scheduled from Fall 2006 onwards. | ||
| TUPLS047 | An Analysis of Lumped Circuit Equation for Side Coupled Linac (SCL) | 1600 |
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| The behaviour of a SCL module is generally described by resorting to an equation system borrowed from lumped circuit theories. This description holds for a narrow frequency band (mono-modal cavity behaviour). A milestone in this field is represented by the classical analysis made by Knapp & alii where the equations allow for the resonant frequencies of the cavities and the first and second order coupling constants. Eigenvalues and eigenvectors (resonant frequencies of the system and relevant current amplitudes) are also given. We show that the system is not correct in the second and last but one equations for the case of half cell termination and non zero second order coupling constants. Due to the relevance of this formulation and of the case treated, we pay a particular attention to find the missing terms in the above mentioned equation. We suggest a correction term, having in addition a deep meaning from electromagnetic point of view. By means of this term we may justify the analytical solution given by the authors. Some numerical examples are also given showing that a discrepancy appears comparing the new equations with the results of the non-correct formulation. | ||
| TUPLS048 | Optimization Design of a Side Coupled Linac (SCL) for Protontherapy: a New Feeding Solution | 1603 |
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| It is proposed to use an SCL, starting at 30MeV, up to 230MeV. The linac consists of 25 modules (two tanks each). Twelve, 3GHz power generators, feed two modules in parallel, with the last power generator feeding the last module. The SCL is designed, assuming a mean accelerating field in the cavities of 16,5MV/m. The longitudinal and transverse beam dynamics has been studied, assuming that the input parameters (emittance, energy spread and mean current) are those of commercial 30MeV cyclotrons. The characteristics of the ejected beam were analysed: the transmittance value is largely sufficient to deliver a correct dose for therapy; the beam line activation is kept largely below allowed levels; the output energy spread is sufficiently small. The first prototype module is under construction and a second one is under design. Contacts with e2v have been established for defining an agreement, which proposes to use magnetrons as feeders for the acceleration tests. Attention was therefore paid to phase locking constraints between feeders. Theoretical studies suggest that transmittance stays constant if de-phasing is kept into values that seem attainable with magnetrons. | ||
| TUPLS049 | A Rationale to Design Side Coupled Linac (SCL): a Faster and More Reliable Tool | 1606 |
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| A module of an SCL is formed by a cascade of two or more tanks, connected by a Bridge Couplers (BC) with an RF feeder, which realizes a well defined accelerating field configuration in all the coupled cavities. Even resorting to geometrical scaling for the design of the adjacent tanks in the module it is not possible to reproduce the same e-m parameters. In addition to this the BC's for each tanks have a different geometrical design because of phasing constraints. The standard procedure may leads a very slow convergence of the design to the optimum and it is not in general clear if the optimum is reached. In this paper a rationale for designing a module of an SCL will be described and it will be presented its application to PALME first module (30-3???MeV). From a lumped circuit model one may get useful relations between e-m global response of the system and single cell parameters. Therefore it provides a certain number of tools which are used for the designing steps in connection with the standard electromagnetic CAD's, the results of which were used as "measurements". | ||
| TUPLS051 | Development of PEFP 20 MeV Proton Accelerator | 1609 |
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| A 20 MeV proton accelerator has been developed as a low energy part of PEFP (Proton Engineering Frontier Project) 100 MeV accelerator. The 20 MeV accelerator consists of ion source, LEBT (Low Energy Beam Transport), 3 MeV RFQ (Radiofrequency Quadrupole) and 20 MeV DTL (Drift Tube Linac). After the field tuning and high power RF conditioning of the accelerating cavities, the first beam test of the 20 MeV accelerator is underway. During the test, the pulsed proton beam was extracted from the ion source by pulsing the high voltage power supply. Two 1.1 MW, 350MHz RF systems were used to drive the 20 MeV accelerator. The current transformers between DTL tanks and Faraday cup at the end of 20 MeV DTL were used to measure the beam current. In this paper, the development of 20MeV accelerator are summarized and the first beam test results are discussed. | ||
| TUPLS052 | Beam Dynamics of the PEFP Linac | 1612 |
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| The PEFP Linac consists of a 50 keV ion source, LEBT, 3 MeV RFQ, 20 MeV DTL called DTL1, MEBT, and 100 MeV DTL called DTL2. The MEBT includes two small DTL tanks, which match the 20 MeV proton beams into the DTL2, and a bending magnet, which extracts the 20 MeV proton beams to the experimental hall. We will present the full beam dynamics study from the entrance of the DTL1 to the end of DTL2 with the initial beam parameters obtained from a simulation study of the RFQ. Our study focuses on the longitudinal beam matching in order to compensate the missing RF effect between every neighboring DTL tanks as well as the full beam matching between DTL1 and DTL2. | ||
| TUPLS053 | Beam Dynamics of a High Current IH-DTL Structure for the TWAC Injector | 1615 |
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| A powerful ion injector based on a laser ion source is needed for an efficient operation of the Tera Watt Accumulator (TWAC) complex including a heavy ion synchrotron and a storage ring, which is under progress now at ITEP, Moscow. The Interdigital H-type drift tube linac (IH-DTL) structure operating at 162 MHz is proposed for the second stage of the injector linac behind of a 81 MHz RFQ. Consisting of independently driven sections with inter-tank quadrupole triplet focusing, this structure will accelerate highly stripped ions with charge-to-mass ratios above 1/3 in the energy range from 1.57 MeV/u at the RFQ exit to 7 MeV/u. Beam currents up to 100 mA are expected for medium ions like Carbon or Aluminum. Since the rf frequency is duplicated at the entrance of the IH-DTL in order to reduce size as well as power consumption, space charge effects are dominant at full current. Beam dynamics and structure parameters are discussed in detail. | ||
| TUPLS054 | The Isochronous Mode of the Collector Ring | 1618 |
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The isochronous mode of a storage ring is a special ion-optical setting in which the revolution time of circulating ions of one species does not depend on their velocity spread. In this mode the ring can be used for mass measurement of exotic nuclei. The Collector Ring (CR) [1] of the FAIR project [2] will operate in such mode as time-of-flight spectrometer for short-lived exotic nuclei (T1/2 > 20 μs) produced and selected in flight with the Super-FRS fragment separator [3]. This technique has been developed at the ESR [4]. The dependence of the revolution time in the isochronous ring from its transverse acceptance, the closed orbit distortion, and nonlinear imperfection of the magnet field was investigated analytically and with a Monte-Carlo simulation. The corresponding results will be presented.
References: [1] A. Dolinskii et. al., GSI Annual Report, 2004 [2] W. Henning, Nucl. Phys. A721 (2003)211c [3] H. Geissel, et. al., Nucl. Instr. Meth. B204 (2003)71 [4] M. Hausmann et. al., Nucl. Instr. Meth. A 446 (2000)569 |
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| TUPLS055 | First Section of a 352 MHz Prototype Alvarez DTL Tank for the CERN SPL | 1621 |
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| In the Linac4/SPL projects at CERN, 352 MHz 30 mA DTL Alvarez accelerating structure will be used to accelerate protons between 3 and 40 MeV. The R&D for the development of a prototype structure for the energy range from 3 to 10 MeV is taking place jointly at ITEP and VNIIEF. The design of this 2.7 m Alvarez tank containing 27 drift tubes is described in this document. Results of calculations of the section parameters are presented. One of the main features of the design is the use of permanent magnets made of SmCo5 alloy as quadrupole focusing lenses (PMQ) inside the drift tubes. Details of the experimental PMQ-equipped drift tube are described. | ||
| TUPLS057 | Linac4, a New Injector for the CERN PS Booster | 1624 |
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| The first bottle-neck towards higher beam brightness in the LHC injector chain is due to space charge induced tune spread at injection in the CERN PS Booster (PSB). A new injector called Linac4 is proposed to remove this limitation. Using RF cavities at 352 and 704 MHz, it will replace the present 50 MeV proton Linac2, and deliver a 160 MeV, 40 mA H beam. The higher injection energy will reduce space charge effects by a factor of 2, and charge exchange will drastically reduce the beam losses at injection. Operation will be simplified and the beam brightness required for the LHC ultimate luminosity should be obtained at PS ejection. Moreover, for the needs of non-LHC physics experiments like ISOLDE, the number of protons per pulse from the PSB will increase by a significant factor. This new linac constitutes an essential component of any of the envisaged LHC upgrade scenarios, which can also become the low energy part of a future 3.5 GeV, multi-megawatt superconducting linac (SPL). The present design has benefited from the support of the French CEA and IN2P3, of the European Union and of the ISTC (Moscow). The proposed machine and its layout on the CERN site are described. | ||
| TUPLS058 | New Prestripping Section of the MILAC Linear Accelerator Designed for Accelerating a High Current Beam of Light Ions | 1627 |
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| In the Kharkov Institute of Physics and Technology, the works on construction of a new prestripping section of the multicharge ion linear accelerator (MILAC) is performed. The task is set to provide acceleration of high current beams of light ions for research works on radiation material engineering and applied investigations. The new prestripping section is designed for accelerating ions with A/q=4 up to the energy of 1 MeV/u; after stripping they will be accelerated in the main section up to the energy of 8.5 MeV/u. Special operational mode will allow to increase noticeably the repetition rate with the same power consumption. The calculation results on beam dynamics in the structure with alternating phase focusing in the version with the stepped change of the synchronous phase, and calculations of electrodynamic characteristics of the accelerating structure of the interdigital type. The peculiarities of the construction of the accelerating structure are described. | ||
| TUPLS061 | Design of a Low Energy Electron Cooler for the Heidelberg CSR | 1630 |
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| The electrostatic Cryogenic Storage Ring (CSR) is currently being designed at MPI-K in Heidelberg. This ring will utilize electrostatic deflectors and focusing elements, and will store ions with kinetic energies in the range 20~300 keV (E/Q) to be mainly utilized in atomic and molecular physics experiments. The CSR will be equipped with a compact magnetic electron cooler, which will serve the double purpose of phase space compression of the stored ion beam as well as an electron target for recombination experiments. The cryogenic photocathode source, developed for the Heidelberg TSR, will be used to provide extremely cold magnetically guided electron beams. The maximum cooling electron energy is 165 eV and the usual operation energy for 20 keV protons will be about 10 eV. The cooler will fit in the 2.8 m straight section of the ring. The device will be installed inside the outer vacuum chamber of the CSR, and the magnetic confinement of the electrons will be provided with high temperature superconducting coils. The design of the magnets of the CSR electron cooler will be presented in this paper. | ||
| TUPLS062 | Cooling Rates at Ultra-low Energy Storage Rings | 1633 |
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| Electrostatic low-energy storage rings have proven to be a highly flexible tool, able to cover experiments from a variety of different fields ranging from atomic, nuclear and molecular physics to biology and chemistry. Future machines will decisively rely on efficient electron cooling down to electron energies as low as some eV, posing new challenges to the cooler layout and operation. The BETACOOL code has already been successfully applied for the layout and optimization of a number of different electron coolers around the world. In this contribution, the results from calculations of the cooling rates at future low-energy machines equipped with an internal target like the Ultra-low energy Storage Ring (USR) at the Facility for Low-energy Antiproton and Ion Research (FLAIR) are presented. | ||
| TUPLS063 | Layout of the USR at FLAIR | 1636 |
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| The Facility for Low-energy Antiproton and Ion Research (FLAIR) and a large part of the wide physics program decisively rely on new experimental techniques to cool and slow down antiprotons to 20 keV, namely on the development of an ultra-low energy electrostatic storage ring (USR). The whole research program connected with anti-matter/matter interactions is only feasible if such a machine will be realized For the USR to fulfil its key role in the FLAIR project, the development of novel and challenging methods and technologies is necessary: the combination of the electrostatic storage mode with a deceleration of the stored ions from 300 keV to 20 keV, electron cooling at all energies in both longitudinal and transverse phase-space, bunching of the stored beam to ultra-short pulses in the nanosecond regime and the development of an in-ring reaction microscope for antiproton-matter rearrangement experiments. In this contribution, the layout and the expected beam parameters of the USR are presented and its role within FLAIR described. The machine lattice and the cooler parameters are summarized. | ||
| TUPLS064 | Design and Commissioning of a Compact Electron Cooler for the S-LSR | 1639 |
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| The ion cooler ring S-LSR has been constructed and commissioned in October 2005. The ring successfully stored a 7 MeV proton beam. The S-LSR is equipped with a compact-electron cooler which has a cooling solenoid length of 0.8 m, a toroid bending radius of 0.25 m and maximum magnetic field in the cooling section of 0.5 kG. The commissioning of the electron cooler was carried out with successful observation of both longitudinal and horizontal cooling of the proton beam. By varying the electric potential on the Pierce electrode in the gun, we have investigated the possibility of generating a hollow shaped electron beam, and studied its effect on the electron cooling process. Also the effect of the electrostatic deflector, installed in the toroid section in order to compensate the drift motion of the secondary electrons, was investigated. The design and results of the commissioning of the compact electron cooler are presented. | ||
| TUPLS065 | Beam Commissioning of Ion Cooler Ring, S-LSR | 1642 |
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| S-LSR is a new ion cooler ring constructed in Kyoto University. The circumference is 22.557 m and the maximum magnetic rigidity is 1 Tm. The constructiion and the vacuum baking had been finished in September, 2005. The beam commissioning was started since October, 2005. The injected beam is 7 MeV proton from the existing linac. The beam circulation test and the electron beam cooling were carried out successfully and the beam information and the characteristics of the ring were measured. One of the subjects of S-LSR is a realization of the crystalline beams using the electron and laser cooling. The lattice of S-LSR was designed to suppress the beam heating as much as possible and we also present such measurement results in this paper. | ||
| TUPLS066 | Peculiarities of Electron Cooler Operation and Construction at Ultra Low Energy in an Electrostatic Ring | 1645 |
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| Few projects of electrostatic rings with electron cooler are discussed now. Electron cooling at low electron energy of 10 eV was realized at the KEK electrostatic ring. The electron cooling permits to suppress the ion multi scattering on residual gas atoms and allows increasing the ion lifetime. Peculiarities of an electron cooler operation and construction at ultra low energy in an electrostatic ring are considered. The cooler gun operation regime is cardinally changed at a reduction of the electron energy to a value comparable with a cathode work function. A virtual cathode and ohmic resistance of cathode emitter give an input in beam formation at ultra low energy. Effective electron cooling of heavy atomic and bimolecular ions at mass of 100-1000 is reached at a small photocathode diameter of 1 mm and a high magnetic expansion factor of 10-1000. The electron cooler construction has traditional design in KEK electrostatic ring. The cooler construction can be simplified at a small circumference of electrostatic ring. Straight cooler schemes without toroidal magnets permit to reduce ring space required for electron cooler. | ||
| TUPLS067 | Status of the HESR Electron Cooler Design Work | 1648 |
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| The electron energy of the HESR electron cooler shall be variable from 450 keV to 4.5 MeV. Furthermore, the design shall not exclude a further upgrade to 8 MeV. Operation of the HESR in a collider mode, which requires electron cooling of both protons and antiprotons traveling in opposite directions, is an interesting option. The status of the technical design of the HESR electron cooling system will be presented. | ||
| TUPLS068 | LEIR Electron Cooler Status | 1651 |
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| The electron cooler for LEIR is the first of a new generation of coolers being commissioned for fast phase space cooling of ion beams in storage rings. It is a state-of-the-art cooler incorporating all the recent developments in electron cooling technology (adiabatic expansion, electrostatic bend, variable density electron beam…) and is designed to deliver up to 600 mA of electron current for the cooling and stacking of Pb54+ ions in the frame of the ions for LHC project. In this paper we present our experience with the commissioning of the new device as well as the first results of ion beam cooling with a high-intensity variable-density electron beam. | ||
| TUPLS069 | Performance of Fermilab's 4.3 MeV Electron Cooler | 1654 |
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| A 4.3 MeV DC electron beam is used to cool longitudinally an antiproton beam in the Fermilab's Recycler ring. The cooling rate is regulated either by variation of the electron beam current up to 0.5 A or by a vertical separation of beams in the cooling section. The paper will describe steps that provided a stable operation and present the status of the cooler. | ||
| TUPLS070 | Chromaticity Control in Linear-field Nonscaling FFAGs by Sextapoles | 1657 |
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| Because of their high repetition rate and large apertures, FFAGs are proposed for high-current medical accelerators suitable for cancer therapy. The linear-field nonscaling FFAG is made from repeating cells containing D and F combined function magnets. The betatron tune profiles decrease with momentum; this leads to the crossing of resonances. We examine how sextapole magnets may be used to flatten the tune profile; in particular (i) whether it is better to place them at the D or F; (ii) what strength is required; and (iii) what is their effect on the closed orbits and path length? The orbit geometry is derived from a thin-element model and the tunes from power series in the quadrupole strength. Chromaticity is corrected by coupling focusing strength to dispersion, which is far stronger in the F element. The zeros of the orbit dispersion become the poles of the "sextapole strength to flatten the tune at some particular momentum". We demonstrate that a weak F sextapole can produce a substantial horizontal tune flattening, and has little impact on other optical properties. Contrarily, placing the sextapole at the D element may destroy the dynamic aperture and or vertical focusing. | ||
| TUPLS071 | Minimum Cost Lattices for Nonscaling FFAGs | 1660 |
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| Previously, linear-field FFAG lattices for muon acceleration have been optimized under the condition of minimum path length variation. For non-relativistic particles, as are employed in the hadron therapy of cancer, that constraint is removed allowing a wider range of design choices. We adopt the thin-element kick model for a degenerate F0D0 cell composed of D and F combined function magnets. The dipole field components are parametrised in terms of the bending at the reference momentum and the reverse bend angle. The split between positive and negative bending sets the shape of the closed orbits. The cost function, based on stored magnetic energy, is explored in terms of the split. Two cost minima are found, one corresponding to minimum peak magnet field in the F element, and another to minimum radial aperture in the D element. Analytic formulae are given for the minimization conditions. The minimum field lattice is similar to existing designs based on minimizing the path length variation, but the minimum aperture lattice presents a new direction for future detailed design studies. | ||
| TUPLS072 | Nonscaling FFAG with Equal Longitudinal and Transverse Reference Momenta | 1663 |
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| An unusual feature of linear-field nonscaling FFAG designs is that the radio-frequency is not necessarily synchronous with the reference orbit and momentum chosen for the lattice design. This arises because optics design prefers the reference geometry to be composed of straight lines and arcs of circles - either at the mean momentum, or at high momentum to centre the orbit in the F element. The asynchronous acceleration proposed for rapid acceleration has strong requirements to set the longitudinal reference at 1/4 and 3/4 of the momentum range to minimize phase slip. The usual particle-tracking programs, such as MAD, though sophisticated in the transverse plane, are far cruder in their longitudinal working and do not allow for a longitudinal reference momentum and RF phase independent of the transverse values. In the context of a thin-element lattice model, we show how to make the transverse reference momentum and optic design coincident with the longitudinal reference by adjusting the ratio of positive and negative bending in the D and F elements, respectively, and retaining a lines and arcs composition for the reference orbit. This prepares the way for MAD tracking. | ||
| TUPLS073 | Formulae for Linear-field Non-scaling FFAG Accelerator Orbits | 1666 |
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| Non-scaling FFAG accelerators using constant-gradient F and D magnets with their fields decreasing outwards can compact ion orbits for a wide range of momentum (e.g., 1:2) into a narrow radial range. Designs to accelerate protons, ions and muons are currently being studied for proton drivers, cancer therapy facilities and neutrino factories. In this paper, analytic formulae are reported for some basic orbit properties, helping to make clear their dependence on the various design parameters and momentum. For the designs tested so far the numerical results are in excellent agreement with those obtained using lattice codes. | ||
| TUPLS075 | Design of the Flat-top Acceleration Cavity for the LNS Superconducting Cyclotron | 1669 |
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| A 3rd harmonic Flat-top acceleration system for the K800 Superconducting Cyclotron of the Laboratori Nazionali del Sud (LNS) was designed to reduce the energy spread of the accelerated particles and to improve the beam quality and the extraction efficiency. The Flat-top effect is realized by the superposition of the 3rd harmonic to the fundamental acceleration frequency. The 3rd harmonic frequency is produced by an additional resonator, capacitively coupled to the K 800 cavities. The Flat-top cavity was designed with the 3D electromagnetic codes Ansoft HFSS and CST MicroWaveStudio. | ||
| TUPLS076 | Beam Extraction of 150 MeV FFAG | 1672 |
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| A beam extraction from FFAG accelerator was performed for the first time at KEK 150MeV proton FFAG synchrotron. The purpose of 150MeV FFAG project is to establish a working prototype for various applications. The beam extraction is thus one of important goals. The extraction is based on fast extraction methode using kicker and pulse septum working at 100Hz. A rapid cycling is also our focus to take advantages of FFAG accelerator. Beam extraction experiment was successful under 100Hz operating. The details of experiment will be presented in this paper. | ||
| TUPLS077 | Development of FFAG-ERIT Ring | 1675 |
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| An intense neutron source with the emittance recovery internal target (ERIT) using the FFAG accelerator is under development. The design of the FFAG storage ring for this purpose will be presented. | ||
| TUPLS078 | Design Studies of the Compact Superconducting Cyclotron for Hadron Therapy | 1678 |
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| An overview of the current status of the design of the compact superconducting isochronous cyclotron C400 able to deliver ion beams with a charge to mass ratio of 0.5 is given. This cyclotron is based on the design of the current PT (proton therapy) C230 cyclotron and will be used for radiotherapy with proton, helium or carbon ions. 12C6+ and 4He2+ ions will be accelerated to 400 MeV/u energy and extracted by electrostatic deflector, H2+ ions will be accelerated to the energy 260MeV and extracted by stripping. Computer modeling results on the axial injection system, magnetic system, inflector and center design are given. Results of simulations of the ion beam injection, acceleration and extraction are presented. | ||
| TUPLS079 | Hadron Cancer Therapy Complex Employing Non-scaling FFAG Accelerator and Fixed Field Gantry Design | 1681 |
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| Non-scaling FFAG rings for cancer hadron therapy offer reduced physical aperture and large dynamic aperture as compared with scaling FFAGs. The variation of tune with energy implies the crossing of resonances during acceleration. Our design avoids intrinsic resonances, although imperfection resonances must still be crossed. We consider a system of three non-scaling FFAG rings for cancer therapy with 250 MeV protons and 400 MeV/u carbon ions. Hadrons are accelerated in a common RFQ and linear accelerator, and injected into the FFAG rings at v/c=0.1128. The H+/C6+ ions are accelerated in the two smaller/larger rings to 31 and 250 MeV/52.5 and 400 MeV/u kinetic energy, respectively. The lattices consist of symmetrical triplet cells with a straight section for RF cavities. The gantry with similar triplet cells accepts the whole required momentum range at fixed field. This unique design uses either High Temperature super-conductors or super-conducting magnets reducing gantry size and weight. Elements with a variable field at the beginning and at the end set the extracted beam at the correct position for the specific energy and adapt the beam to specific requirements during treatment. | ||
| TUPLS080 | The Proposed 2 MeV Electron Cooler for COSY-Juelich | 1684 |
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| The design, construction and installation of a 2 MeV electron cooling system for COSY-Juelich is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the design of the 2 MeV electron cooler for COSY is intended to test some new features of the high energy electron cooler for HESR at FAIR/GSI. The design of the 2 MeV electron cooler will be accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. Starting with the boundary conditions of the existing electron cooler at COSY the requirements and a first general scheme of the 2 MeV electron cooler are described. | ||
| TUPLS081 | Flat Beams and Application to the Mass Separation of Radioactive Beams | 1687 |
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| The notion of flat beam is now well established and has been proven theoretically and experimentally with applications for linear colliders. In this paper, we propose a new and simple demonstration of the "flat beam theorem", and a possible application in the frame of radioactive ion beams (RIB) production. It consists in using a magnetized multi-specie heavy ion beam extracted from a high frequency ECR source, decoupling the transverse phase planes in such a way to obtain a very small emittance in the horizontal one, and using a dipole to separate the isotopes. A design of such a transport and separation line will be proposed and commented. | ||
| TUPLS082 | The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) | 1690 |
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|
About 40ns long proton pulses with an energy of 120keV and currents of up to 200mA will be produced at the 150kV high current injector with a rep.rate of up to 250kHz. The main acceleration will be done by a 175MHz-RFQ. After this section the proton bunches will have an energy of about 1.7MeV. A 4-gap cavity will allow for an energy increase up to 2.2MeV.In order to get 1ns short pulses at the Li-7-Target we propose a buncher-system of the Mobley-Type*, whereby periodic deflection at one focus of a dipole-magnet guides the bunche train from the linac on different paths to the other focus, where the n-production traget is located in the time focus.By 7Li(p,n)B·107 reactions low-energy neutron bunches will be produced with an averaged integrated flux-density of 4*107/(cm2 s) at a distance of 0.4m. The upper limit for the neutron spectra will be 500keV. The main challange with respect to this buncher is the strong space charge action, which has to be treated by careful particle simulations. FRANZ is among other duties well suited for (n,gamma)-cross-sectional measurements with astrophysical relevance**/***. It is characterised by high n-intensities and by its pulse-structure.
*Phys. Rev. 88(2), 360-361 (1951). **Phys. Rev. C 71, 025803 (2005).***Phys. Rev. Lett. 94, 092504 (2005). |
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| TUPLS083 | A Low Energy Accumulation Stage for a Beta-beam Facility | 1693 |
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| The EU supported EURISOL Design Study encompasses a beta-beam facility for neutrino physics. Intense electron (anti-)neutrino beams are in such a machine generated through the decay of radioactive ions in a high energy storage ring. The two main candidate isotopes for the generation of a neutrino and an anti-neutrino beam are 6He2+ and 18Ne10+. The intensities required are hard to reach, in particular for the neon case. A possible solution to increase the intensity is to use an accumulator ring with an electron cooler. Critical parameters such as cooling times and current limitations due to space charge and tune shifts are presently being optimized. We will in this presentation give an overview of the low energy accumulation stage and review recent work on this option. | ||
| TUPLS084 | Estimation of Decay Losses and Dynamic Vacuum for the Beta-beam Accelerator Chain | 1696 |
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| The beta-beam is based on the acceleration and storage of radioactive ions. Due to the large number of ions required and their relatively short lifetime, beam losses are a major concern. This paper estimates the decay losses for the part of the accelerator chain comprising the CERN PS and SPS machines. For illustration purposes, the power deposition in these accelerators is compared to that expected for nominal CNGS proton operation. The beam losses induced vacuum dynamics is simulated and the consequences for machine operation are discussed. | ||
| TUPLS085 | Stacking Simulations in the Beta-beam Decay Ring | 1699 |
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| The so-called beta-beam concept for accelerator-driven neutrino experiments envisages the production of a pure beam of electron neutrinos (or their antiparticles) through the beta-decay of radioactive ions circulating in a high-energy storage ring. An unprecedented number of ions must be collected in the decay ring and maintained in a few short bunches. Stacking is unavoidable to match the available source rates with this demand. A new stacking method makes use of off-momentum injection into the decay ring to approach the circulating beam without requiring ultra-fast injection elements, rotation in the longitudinal plane to bring the fresh bunches onto the central orbit and asymmetric merging to transport these ions into the centre of the large stack. Simulation results are presented for the complete repetitive stacking process for two candidate ion species of significantly different charge-to-mass ratio. | ||
| TUPLS086 | Charge Breeding Exploration with the MAXEBIS | 1702 |
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| The demand of exotic ions prior to their injection into an accelerator has driven the development of the charge breeding method. Existing facilities like REX-ISOLDE or ISAC at TRIUMF are already using a charge state booster for the post acceleration of radioactive ions. Planned facilities like EURISOL for instance have identified the need of a breeding system. In order to be comparable to the efficiency to a brut force acceleration employing stripper, the efficiency of a charge breeder has to be maximized and the breeding time has to be shortened comparing the existing breeder systems. Therefore the exploration and optimization of the charge state breeding is mandatory and supported by the EU. The Frankfurt MAXEBIS has been modified within the past years towards high current electron beam and external injection of alkaline ions by a surface ionisation source. The electron gun, the inner electrode structure and the collector of the MAXEBIS have been modified. The system has been shipped to GSI and re-assembled. The goals of the following experiments will be systematic studies of the breeding efficiency. The new setup and first experimental results will be presented. | ||
| TUPLS087 | Recent Gains in Polarized Beam Intensities for the Cooler Synchrotron COSY at Jülich | 1705 |
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| Since January 1996, the cyclotron JULIC operates as the injector of H(-) or D(-) beams for the cooler synchrotron COSY at the IKP of the Forschungszentrum Juelich. Routinely about 8 microA of unpolarized or 1 microA of polarized H(-) ions are delivered for charge-exchange injection into COSY. A polarization in excess of 90 % was measured for protons inside the synchrotron COSY. Additionally, polarized and unpolarized D(-) ions have been delivered to experiments. A sequence of up to eight different polarization states for deuterons has been provided for experiments. By advancing the components of the polarized ion the number of polarized particles for injection into the cyclotron has been increased by a factor of three to 5,5x1012 protons, delivered in a 20 ms pulse with a repetition rate of 2 seconds. This report sums up the characteristics of the ion sources and the cyclotron in their present mode of operation and describes the achievements towards higher beam intensities as well as for providing unpolarized and polarized H(-) and D(-) beams with high reliability. | ||
| TUPLS088 | Energy Distribution of H- Ions from the ISIS Ion Source | 1708 |
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| We have used a specially designed retarding field energy analyzer with a resolution (Δ E /E) of approximately 2 x 10 -4 in order to measure the energy distribution, under different operating conditions, of the H- beam of the ISIS ion source. The poster presents the details of the analyzer and the first results obtained on the Ion Source Test Facility at RAL. | ||
| TUPLS089 | Pseudospark-sourced Beams of Electrons and Ions | 1711 |
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| A pseudospark discharge has undergone intensive studies with regard to its unusual and interesting discharge properties during last fifteen years. The pseudospark attracts significant attention from diverse fields such as pulsed-power switching, electron beam generation, free electron masers, ion beam generation, extreme-ultraviolet radiation sources, microthrusters and pseudospark-triggered wakefield acceleration. This paper will present experiments and measurements of pseudospark-sourced electron and ion beams for accelerators. Pulsed electron beams with current intensity over 108 Am-2, high brightness up to 1012A m-2 rad-2 and emittance of tens of mm mrad were produced from a multi-gap pseudospark discharge. The transportation of the pseudospark electron beams is also investigated in order to produce high peak current, high quality, short (~100 picosecond) or long duration (2~100ns) high-brightness electron beam pulses. Recent results from a high current density pseudospark-produced ion beam experimentally investigated with hydrogen gas will be presented. | ||
| TUPLS090 | LEBT Simulations and Ion Source Beam Measurements for the Front End Test Stand (FETS) | 1714 |
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| The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration (0-3MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. Optimisation of the beam focussing within the Low Energy Beam Transport (LEBT) is necessary to minimise beam losses upon acceleration within the FETS RadioFrequency Quadrupole (RFQ). Simulations of the LEBT are currently under way using the General Particle Tracer package (GPT). Previous envelope calculations suggest weak and strong focussing solutions for the LEBT solenoids. Definitive beam dynamics simulations in GPT require further measurements of the transverse emittances and beam profile of the ion source beam, due to the sensitivity of the simulations on the initial beam profile and level of space charge compensation. A pepperpot emittance/profile measurement system has been designed for use on the ISIS ion source development rig. Results from this pepperpot system are used to constrain the initial conditions for the GPT simulations. | ||
| TUPLS092 | Implementations on the RF Charge Breeder Device BRIC with Test Measurements | 1717 |
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The Radioactive Ion Beam (RIB) production with ISOL technique should require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept RIB with charge state +1 and increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds and it has been assembled at the LNL (Italy) laboratory. BRIC could be considered as a solution for the charge state breeder of the SPES project under study also at the LNL. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) - Quadrupole aiming to filtering the unwanted masses and then making a more efficient containment of the wanted ions. The RF test measurements seem confirm, as foreseen by simulation results* that a selective containment can be obtained. Most accurate measurements, however, are needed and for that implementations of the system have been carried out.
*V. Variale and M. Claudione. "BRICTEST: a code for charge breeding simulations in RF quadrupolar field", NIM in Phys. res. A 543 (2005) 403-414. |
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| TUPLS093 | AG Acceleration using DPIS | 1720 |
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| We are investigating high current and high repetition rate ion production methods for various heavy ions which can be utilized for an injector of an FFAG accelerator. Direct Plasma Injection Scheme (DPIS) is one of the candidates of the ion production methods and to confirm the capability of the DPIS, we are now preparing for accelerating high intensity Ag15+ ions. The DPIS uses a combination of Laser Ion Source (LIS) and RFQ linac. The plasma goes into the linac directly without transportation line and the ions are extracted at RFQ entrance. To determine the specifications of new RFQ electrodes, the plasma properties were measured. With the Nd-glass laser (3 J / 30 ns), we could not obtain high charge state ions. A new Nd-YAG laser (2.3 J / 6 ns) enabled us to observe many high charged ions and the most produced ions were Ag15+. We completed the plasma distribution measurements. Based on these results, we designed the new RFQ, which will accommodate Q / M = 1 / 8 particles, supposing Ag+15. | ||
| TUPLS094 | Development of a Permanent Magnet Microwave Ion Source for Medical Accelerators | 1723 |
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| A permanent magnet microwave ion source was developed to improve availability of proton accelerator application systems based on industrial microwave ion source technologies. The ion source needs no filament in the discharge chamber, which leads to reliability improvement and less maintenance time. Because the ion source uses a permanent magnet, the ion source needs no coils, no coil power and no coil coolant. The hydrogen beam of over 60 mA has been extracted from a single 5mm diameter aperture with a proton fraction of 85% at a microwave power of 1.3kW. Rise times of the microwave power and beam current to 90 % of the final value were about 30 and 100μseconds respectively at a pulse operation mode with 400μseconds pulse width and 20 Hz repetition rate. These performance parameters are equal to the solenoid coil ion source parameters, making the ion source desirable for accelerator applications like proton therapy systems. | ||
| TUPLS095 | Recent Progress about DPIS | 0 |
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| We have focused on high brightness of induced plasma in Laser Ion Source (LIS) to provide intense highly charged ions efficiently. To take the advantage of the intrinsic density of the laser plasma, Direct Plasma Injection Scheme (DPIS) has been developed. The induced laser plasma has initial expanding velocity and can be delivered directly to the RFQ. Extraction electrodes and focusing devices in LEBT are not needed. Since 2004, a newly designed RFQ has been used to verify the capability of the new ion production scheme. We succeeded to accelerate 60 m A of Carbon beam and 60 mA of Aluminium beam. We have also tried to understand plasma properties of various species by measuring charge states distributions and time structures, and are now ready to accelerate heavier species. Currently Silver 15+ beam is planned to be accelerated. In the conference, design strategies and detailed techniques for the DPIS will be described based on the measured plasma properties of various elements and new findings obtained from recent acceleration experiments. The durability and the reproducibility will be also explained. | ||
| TUPLS096 | Strongly Focused He+ Beam Source for Alpha Particle Measurement at ITER | 1726 |
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| A He+ beam source for He0 beam probe for measurement of fusion produced alphas due to D-T nuclear reaction in a thermonuclear fusion plasma has been designed and constructed. The ion source consists of a 300 mm diameter and 280 mm length plasma chamber and a beam extraction system which has three concaved electrodes. Helium plasma is confined by line cusp magnetic fields produced by Sm-Co permanent magnets. The magnetic field strength near the extraction region is designed to be less than 20 gauss. Through the 100 mm diameter extraction area of the concaved electrodes 300 beamlets are formed with apertures of 4 mm. The focal length of the concaved electrodes is designed to be 750 mm. The beam quality of the extracted He+ beam will be measured by several beam diagnostic apparatuses. The total beam current, the beam profile and the beam emittance will be measured to design a proper alkali metal vapor cell for a He- beam production by a double charge exchange process and a beam transport line to the post accelerator up to MeV region. In the article, the details of the ion source and the beam diagnostic system will be described. | ||
| TUPLS097 | Application of DPIS to IH Linac | 1729 |
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| We are now designing a Laser Ion Source (LIS), which will be operated with an Inter-digital H (IH) structure linac using the Direct Plasma Injection Scheme (DPIS). The DPIS has been applied to RFQ linacs and has successfully achieved very high current with simple structure. The IH structure linac was designed to accept 40 keV proton beam which could be produced by the DPIS. The combination of the DPIS and IH structure linac will realize quite compact accelerator complex with intense proton beam. The detailed design study of a plasma production chamber with a cryogenic cooler is investigated. | ||
| TUPLS099 | The New 14 GHz Ion Source for the U-400 Heavy Ion Cyclotron | 1732 |
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| The new 14 GHz ion source DECRIS-4, to be used as a second injector of heavy multiply charged ions for the U-400 cyclotron and, in the future, also as a "charge breeder" (the "1+ -> n+" method) for the second phase of the DRIBs project, has been designed and constructed at the FLNR. The main feature of the ion source design is the creation of the extended resonance zone in a comparatively compact ECRIS. For this purpose the axial magnetic field is formed with a flat minimum by mounting only one additional solenoid coil to the classical CAPRICE magnetic structure. In this case the superposition of the axial magnetic field and the radial field of the permanent magnet hexapole, made from NdFeB, allows one to create a larger resonance volume. First results of the ion source tests show that in this resonance volume electrons are heated very efficiently which allows to produce intense beams of medium charge state ions with comparatively low level of input microwave power. The basic design features, construction issues and the first results of ion source tests are presented. | ||
| TUPLS100 | Generation of Highly Charged Ions Using ND-glass Laser | 1735 |
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The parameters of ions (charge state distributions, currents and pulse durations) were measured in laser plasma generated by 3 J/30 ns Nd-glass laser for wide range of elements from 12C to 181Ta and for different laser power densities at the target surface. It is shown that such a laser can effectively generate highly charged ions for elements from 12C to 56Fe. Registered ion charge states significantly drops for heavier elements because of recombination losses of highly charged ions during laser produced plasma expansion into vacuum. Absolute currents and numbers of ions with different charge states were obtained by normalization of charge state distributions summary on total ion currents measured by Faraday cup for 1011 W/cm2 and 1012 W/cm2 laser power densities at the target surface. The results obtained are very useful for Laser Ion Source (LIS) development, in particular, for Direct Plasma Injection Scheme (DPIS) study*.
*M. Okamura et al. Laser and Particle Beams, 20, 2002, pp. 451 - 454. |
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| TUPLS103 | Further Development of a Low Inductance Metal Vapor Vacuum Arc (LIZ-MeVVA) Ion Source | 1738 |
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A Low Impedance Z-Discharge Metal Vapor Vacuum Arc (LIZ-MeV) ion source* is being explored as an alternate pre-injector for the Brookhaven Relativistic Heavy Ion Collider (RHIC). With the vacuum arc operating at tens of kiloamperes and an aluminum electrode, LIZ-MeV has been run in two regimes: an LC dominated "ringing" arc of period 4.1 microseconds, which decays after about 6 cycles, and a 1-3 microsecond wide "pulsed" arc, where a small series resistance has been added to critically damp ringing. Metal ions are extracted from the plasma using a two-grid system with a triggered, variable-delay voltage of up to 10 kV. Time-of-Flight (TOF) measurements are taken using a Faraday cup located at the end of a 15-76 cm drift tube. TOF measurements from both arc regimes have been obtained suggesting generation of about a billion ions per pulse of charge states +1 and +2, and occasionally +3 states. TOF results are compared with simple theoretical models.
*B. M. Johnson, et al. Two approaches to electron beam enhancement of the metal vapor vacuum arc ion source. Laser and Particle Beams 21, 103 (2003). |
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| TUPLS104 | Matching of High Intensity Ion Beams to an RFQ: Comparison of PARMTEQ and IGUN Simulations | 1741 |
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| The classical way of matching an ion source to the low energy accelerator RFQ generally is performed by adjusting the matching optics of the LEBT to provide the rms ellipse twiss parameter requirements of the RFQ shaper section. By matching to the rms parameters (the equivalent rms beam method) the actual shape of the distribution plays a smaller role according to F. Sacherer. In many cases, however, the matching optics are creating not only aberrations to the ion beam but also a very non-elliptical shape of the emittance figure, and a more exact match may be required. As a way out, an ion extraction program (IGUN) has been modified to also take into account the rf-focusing of non-modulated RFQ vanes in the shaper section. This makes it feasible to use this program for the simulation from the ion source plasma until the beginning of modulation inside the RFQ, and it can also handle dc fields in the injection region of the RFQ. In order to demonstrate the differences of both approaches we apply them to well defined experimentally proved designs of RFQ shaper sections. | ||
| TUPLS105 | Sputter Probes and Vapor Sources for ECR Ion Sources | 1744 |
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| Sputter probes are a promising method for injecting controlled quantities of metallic elements inside ECRIS ion source, provided that sputter rate can be controlled, so that high charge states and low sample consumption rate will be attained. Moreover pressure at the probe and inside source should be different. With a simple differential pumping scheme and a sputter probe at 25 mm from ECRIS plasma, a 200 nA current of 120Sn18+ was easily obtained. Typical results (for Sn and Ti) of an inductively heated rf oven are discussed for comparison. Improvements of sputter probe concept and geometry are also described. | ||
| TUPLS106 | Pulsed Bending Magnet of the J-PARC MR | 1747 |
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| Japan Proton Accelerator Research Complex (J-PARC) is under construction with a collaboration between Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The J-PARC consists of a 180 MeV linac, a 3 GeV rapid-cycle synchrotron (RCS) and a 50 GeV synchrotron (MR). The bunch trains, which extracted from the RCS, is delivered both to the “Materials and Life Science Facility” and to the MR, two beam transport lines, 3-NBT and 3-50BT, are constructed. The switching of bunch trains is performed by a pulsed bending magnet. The field strength of 1.21 Tesla with rise and fall time of less than 40 msec is required. It was found that an effect induced by eddy current, which flows at thick end-plates, disturbs the flatness of the magnetic field. A simple compensation circuit has been adopted for a cure. A result from a field measurement, which shows a sufficient flatness, is presented. | ||
| TUPLS107 | Operation of the Opposite-Field Septum Magnet for the J-PARC Main-Ring Injection | 1750 |
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| The opposite field septum magnet system has been applied to the injection system of the J-PARC 50-GeV proton synchrotron. The features of the system are a force-free structure, easy pulse excitation and the possibility of a large-aperture, thin-septum structure. The septum magnet has the structure of an inside-vacuum to eliminate the thickness of the vacuum-chamber walls and electric-insulation layer to make the septum thickness as thin as possible. However the magnet cores and return coils are outside of the vacuum to reduce the out-gassing rate of the vacuum system. Finally, the larger beam aperture than the full acceptance of the ring and larger separation angle can be obtained at the septum magnet for low-loss injection. In this paper we will introduce the methods to eliminate the error fields caused by fabrication errors and eddy current with pulse excitation and stability of high current power supply of 50 kA. | ||
| TUPLS108 | Realization of Thick Hybrid Type Carbon Stripper Foils with High Durability at 1800K for RCS of J-PARC | 1753 |
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| The J-PARC requires thick carbon stripper foils (250-500 ug/cm2) to strip electrons from the H-beam supplied by the linac before injection into a 3 GeV Rapid Cycling Synchrotron. The 200 MeV H- beam from the linac has a pulse length of 0.5 ms with a repetition rate of 25 Hz and an average beam current of 335 uA. By much energy deposition of these high-intensity H- and circulating bunched beams, commercially available best stripper foils (CM) will break in a very short time and even a diamond foil will rupture at around 1800K by MW class accelerators. We have realized for first time the hybrid boron doped carbon stripper foils with long life time for J-PARC. The foils of 250-500 ug/cm2 were made by a controlled DC arc-discharge method. The lifetime was tested by using 3.2 MeV Ne+ DC beam of 2.5 uA and 750 keV H- DC beam of 500 uA, in which a significant amount of energy was deposited in the foils. The maximum lifetime was extremely long, 120- and 480-times than those of diamond and CM foils. The foils were also free from any shrinkage, and showed low thickness reduction rate even at high temperature of 1800K during long time irradiation of 90h. | ||
| TUPLS109 | Present Status of the L3BT for J-PARC | 1756 |
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| L3BT is a beam transport line from J-PARC (Japan Proton Accelerator Research Complex) linac to the succeeding 3-GeV RCS (Rapid Cycling Synchrotron). The construction of the L3BT has been almost finished. The beam commissioning of the L3BT will be started soon. On the other hand we have performed 3D particle simulations with PARMILA and IMPACT to evaluate the performance of the halo scraping, momentum compaction and beam diagnostics. In this paper, results of the beam simulation of the L3BT are presented. The construction status of the L3BT is also presented in brief. | ||
| TUPLS110 | Measurement of the Extraction Kicker System in J-PARC RCS | 1759 |
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Kicker magnet system in the J-PARC RCS is now under construction at JAEA (Japan Atomic Energy Agency). Their role in RCS is to kick the accelerated 3 GeV proton beam to the following extraction line at a repetition rate of 25 Hz. There are three kinds of kicker magnets (S, M, L), distinguished by the difference in the size of their apertures. The specification of 2 % is required on the magnetic field in terms of homogeneity in time and space from the beam optical point of view. The required flatness of the temporal uniformity was accomplished by superposing the waveforms of the two kicker magnet*. The required specification to the special uniformity is also very severe to achieve because our kicker magnet is designed with a large aperture in order to accept a maximum beam power of 1 MW. We established the search coil as a detector and 3-axes stage to perform magnetic field mapping. In order to reduce the signal noises and detect the stable output signals, matching register and integrated circuit were carefully selected. The 3-axes stage was precisely aligned. The distribution of the magnetic field (By) and integrated BL were systematically measured for the three types of kickers.
*J. Kamiya et al. “Magnetic field measurement of the extraction kicker magnet in J-PARC RCS,” submitted for publication to the proceedings of the 19th International Conference on Magnet Technology. |
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| TUPLS111 | Experimental Results of the Shift Bump Magnet in the J-PARC 3-GeV RCS | 1762 |
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| The shift bump magnet produces a fixed main bump orbit to merge the injection beam into the circulating beam. In order to control the injection beam for the short injection time (500 microseconds) with sufficient accuracy, the shift bump magnet needs a wide uniform magnetic field and the high speed exciting pattern of the high current. The magnetic field design and the structural analysis of the shift bump magnets have been performed using three-dimensional electromagnetic analysis code and mechanical analysis code, respectively. The magnetic field distributions were measured with a long search coil, thus giving a BL product over a magnet gap area. The temperature distributions at the various points of the magnet were measured by thermocouples over 24 hours till they saturated. General trend of these measurements agrees well with calculations. | ||
| TUPLS112 | Present Status of Injection and Extraction System of 3 GeV RCS at J-PARC | 1765 |
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| The injection and extraction system for 3GeV RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex) have many challenging issues, in order to realize MW beam in the RCS ring. The system is consisted in 3 parts, such as the injection line, the dump line, and the extraction line. And they are constructed from many kinds of components, such as DC and pulse magnets, a charge exchange system, beam monitors, titanium and ceramic vacuum chamber, a beam dump, and so on. Up to now, final designs are accomplished and developments and experiments of some components are carried out. In this presentation, summary of the injection and extraction system, recent status of developments, and beam commissioning scheme for beam injection and extraction are introduced. | ||
| TUPLS113 | Designs of Septum Magnet at 3 GeV RCS in J-PARC | 1768 |
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| 3 GeV RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex) consists in many kinds of septum magnets. There are two septum magnets to inject the beam into the ring, three septum magnets to extract the beam for the users, and two septum magnets to dump the beam which can not be exchanged its charge at the first foil. In order to reduce the magnetic leakage field from the septum magnets at the beam orbit in the ring, the silicon steel sheets are set at the outside of the septum magnets for the magnetic shields. However sufficient spaces to set the thick magnetic shields are not securable at the divergent duct areas. Therefore the vacuum chambers are made by the magnetic stainless steel and the leakage fields in the chambers can be reduced. As results of the 3D field calculations by TOSCA, the magnetic leakage field can be suppressed to a few Gauss or less. | ||
| TUPLS114 | An Improvement of Matching Circuit of RF Kicker Electrodes | 1771 |
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| Beam extraction system at accelerator of The Wakasa Wan Energy Research Center employs RF knockout technology. Narrow band RF noise is applied to the transverse kicker electrodes to increase betatron amplitude of the beam. Recently some improvements of the beam extraction system are introduced: To improve the shape of the spill, a feedback control of noise amplitude is introduced. The feedback control system works as an attenuator, therefore it is necessary to enhance the noise amplitude of the kicker electrodes to obtain agreeable effect on the spill shape. In order to obtain a higher voltage, we revamp the matching circuit at the electrodes. By introducing the resonating characteristic at the matching circuit, we obtained 3 times more amplitude at the electrodes. General shape of the spill is improved by this work, and extraction efficiency at a real operating condition is also improved. | ||
| TUPLS115 | Transverse Phase Space Painting for the CSNS Injection | 1774 |
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| The CSNS accelerators consist of an 80 MeV proton Linac, and a 1.6 GeV rapid cycling synchrotron (RCS). The ring accumulates 1.88*1013 protons via H－stripping injection in the phase CSNS-I. The injected beam is painted into the large transverse phase space to alleviate space-charge effects. The uniformity of beam emittance is important in reducing the tune shift/spread due to space charge effect. The paper introduces two parameters to evaluate the uniformity of a distribution. To satisfy the low-loss design criteria, extensive comparison of different painting scenarios has been carried out by using the simulation code ORBIT. This paper gives detailed studies on painting schemes and the dependence on the lattice tune, the injection peak current, and also chopping rate. | ||
| TUPLS116 | Extraction System Design for the CSNS/RCS | 1777 |
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| The CSNS extraction system takes use one of the four dispersion-free straight sections. Five vertical kickers and one Lambertson septum magnet are used for the one-turn extraction. The rise time of less 250 ns and the total kicking angle of 20 mrad are required for the kickers that are grouped into two tanks. The design for the kicker magnets and the PFN is also given. To reduce the low beam loss in the extraction channels due to large halo emittance, large apertures are used for both the kickers and septum. Stray magnetic field inside and at the two ends of the circulating path of the Lambertson magnet and its effect to the beam has been studied. | ||
| TUPLS117 | Beam Transport Lines for the CSNS | 1780 |
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| This paper presents the design of two beam transport lines at the CSNS: one is the injection line from the linac to the RCS and the other is the target line from the RCS to the target station. In the injection beam line, space charge effects, transverse halo collimation, momentum tail collimation and debunching are the main concerned topics. A new method of using triplet cells and stripping foils is used to collimate transverse halo. A long straight section is reserved for the future upgrading linac and debuncher. In the target beam line, large halo emittance, beam stability at the target due to kicker failures and beam jitters, shielding of back-scattering neutrons from the target are main concerned topics. Special bi-gap magnets will be used to reduce beam losses in the collimators in front of the target. | ||
| TUPLS118 | Injection System Design for the CSNS/RCS | 1783 |
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| The CSNS injection system is designed to take one uninterrupted long drift in one of the four dispersion-free straight sections to host all the injection devices. Painting bumper magnets are used for both horizontal and vertical phase space painting. Closed-orbit bumper magnets are used for facilitating the installation of the injection septa and decreasing proton traversal in the stripping foil. Even with large beam emittance of about 300 pmm.mrad used, BSNS/RCS still approaches the space charge limit during the injection/trapping phase for the accumulated particles of 1.9*1013 and at the low injection energy of 80 MeV. Uniform-like beam distribution by well-designed painting scheme is then obtained to decrease the tune shift/spread. ORBIT code is used for the 3D simulations. Upgrading to higher injection energy has also been considered. | ||
| TUPLS119 | Design Study of the Axial Injection System of C400 Cyclotron | 1786 |
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| Computer modeling results on the axial injection system design are given. Results of simulations of the Carbon, Hydrogen and Helium ion beam injection are presented. | ||
| TUPLS122 | Implementation of the Proposed Multiturn Extraction at the CERN Proton Synchrotron | 1789 |
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| Following the positive results of the three-year measurement campaign at the CERN Proton Synchrotron concerning beam splitting with stable islands in the transverse phase space, the study of a possible implementation of the proposed multi-turn extraction was undertaken. The novel approach would allow a substantial reduction of beam losses, with respect to the present scheme, when delivering the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project. Major modifications to the ring layout are foreseen, such as a new design of the extraction bumps including also the installation of three additional kickers to create a closed-bump over the five turns used to extract the split beam. The ring aperture was reviewed and improvements are proposed to reduce possible beam losses between beam splitting and extraction. The goal consists of implementing the proposed changes by the end of the 2007/2008 PS shutdown and to commission the novel extraction during the 2008 physics run. | ||
| TUPLS123 | Design of the LHC Beam Dump Entrance Window | 1792 |
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7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper* the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized.
*A. Presland et al. "A large diameter entrance window for the LHC beam dump line". Proc. PAC 2005, 1698-1700. |
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| TUPLS125 | Spin Transport from AGS to RHIC with Two Partial Snakes in AGS | 1795 |
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| The stable spin direction in the RHIC rings is vertical. With one or two strong helical Siberian snakes in the AGS, the stable spin direction at extraction is not vertical. Interleaved vertical and horizontal bends in the transport line between AGS and the RHIC rings also tend to tip the spin away from the vertical. In order to preserve polarization in RHIC, we examine several options to improve the matching of the stable spin direction during beam transfer from the AGS to each of the RHIC rings. While the matching is not perfect, the most economical method appears to be a lowering of the injection energy by one unit of G*gamma to 45.5. | ||
| TUPLS126 | Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators | 1798 |
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The LHC will operate at 7 TeV with a luminosity of 1034 cm-2s-1. Each beam will have 2808 bunches, with nominal intensity per bunch of 1.1x1011 protons. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since their jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code* while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code**. Our calculations suggest that the LHC beam may penetrate up to 10 m in solid carbon, resulting in a substantial damage of collimators and beam absorbers.
*V. E. Fortov et al. Nucl. Sci. Eng. 123 (1996) 169. **A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, La Jolla, California, 2003. |
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| TUPLS127 | Permanent Deformation of the LHC Collimator Jaws Induced by Shock Beam Impact: an Analytical and Numerical Interpretation | 1801 |
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| Inspections carried out on jaws of the LHC collimator prototype, which underwent the 450 GeV robustness test in CERN TT40 extraction line, revealed no visible damage, except a permanent deformation of the jaw metal support of ~300 um. An explanation of this phenomenon is proposed in this paper. The temperature increase on the metal support induced by the thermal shock, though limited to ~70°C, led to a sudden expansion of the copper-based support which was partially prevented by the inertia of the material itself, thus generating compressive stresses exceeding the elastic limit of OFE-copper. An analytical assessment of the process, followed by a finite-element transient elasto-plastic analysis, is presented. Numerical results are in good agreement with measured data. In order to confirm this analysis, a special test on series production jaws, where OFE-copper has been replaced by Dispersion Strengthened Copper (Glidcop®), is scheduled for the second half of 2006. | ||
| TUPLS128 | A New Analytical Method to Evaluate Transient Thermal Stresses in Cylindrical Rods Hit by Proton Beams | 1804 |
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| This paper presents an analytical solution for the thermo-mechanical problem of CNGS target rods rapidly heated by fast extracted high energy proton beams. The method allows the computation of the dynamic transient elastic stresses induced by a proton beam hitting off-axis the target. The studies of such dynamic thermo-mechanical problems are usually made via numerical methods. However, an analytical approach is also needed to quickly provide reference solutions for the numerical results. An exact solution for the temperature field is first obtained, using Fourier-Bessel series expansion. Quasi-static thermal stresses are then computed as a function of the calculated temperature distribution, making use of the thermoelastic displacement potential for the equivalent isothermal two-dimensional stress problem. Finally, the contribution of dynamic stresses due to longitudinal and bending stress waves is determined by means of the modal summation method. This method can be effectively applied to any solid having cylindrical shape, made out of isotropic elastic material. | ||
| TUPLS129 | EURISOL 100 kW Target Stations Operation and Implications for its Proton Driver Beam | 1807 |
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| Targets for the next generation radioactive ion beam (RIB) facilities (RIA, EURISOL) will be subjected to energy deposition levels that call for a specific design of the target and ion source assembly to dissipate the deposited heat and to extract and ionize isotopes of interest efficiently. EURISOL, the next generation European RIB facility, plans to operate four target stations in parallel, three 100 kW direct targets and one 5 MW spallation neutron source with a GeV proton linac driver. The nature of the beam sharing has yet to be defined because in practice it will have a direct impact on target design, operation and lifetime. Splitting the beam in time implies that each target would be subjected to a pulsed beam, whose pulse width and repetition cycle have to be optimized in view of the RIB production. The 100 kW targets are expected to have a goal lifetime of three weeks. Target operation from the moment it is installed on a target station until its exhaustion involves several phases during which the incident proton beam intensity will vary. This paper discusses challenges for high power targetry at EURISOL, with an emphasis on requirements for the proton linac parameters. | ||
| TUPLS130 | Comparison between Measured and Simulated Beam Loss Patterns in the CERN SPS | 1810 |
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| A prototype of an LHC collimator has been tested with proton beams at the CERN SPS. The interaction of the circulating proton beam with the carbon collimator jaws generated showers that were lost in the downstream SPS aperture. The measured beam loss patterns are compared in detail with the results of dedicated loss simulations. The simulation package includes (1) a 6D particle tracking through the SPS lattice; (2) the scattering interaction of protons with the collimator jaw material; (3) the time-dependent displacement of the collimator jaws with respect to the beam orbit; (4) a detailed aperture model of the full SPS ring. It is shown that the simulation tools can reliably predict the measured location of losses. This provides an important assessment of the simulation tools in view of the LHC beam loss studies. | ||
| TUPLS132 | Estimation of the Energy Deposited on the CNGS Magnetic Horn and Reflector | 1813 |
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| In the CNGS installation two magnetic lenses, namely the horn and the reflector, focus the secondary beam generated in the target station. The gap between the horn and reflector is chosen to optimize a wide-band high-energy muon-neutrino beam. These two focusing elements are two coaxial lenses similar in length but different in shape: the outer conductor has a cylindrical shape whereas the inner conductor consists of a sequence of conical shapes to optimize the focusing capacity. The evaluation of the heat load on the support structures is crucial since modifications in the elements around the horn and reflector are under way and the support structures can be adapted to the heat load found. Furthermore, the heat load in the whole horn area has been evaluated to optimize the cooling-ventilation system. The FLUKA geometry input of the horn and reflector electrical connections has been notably improved in order to accommodate the detailed striplines design to the thermal expansion. The energy deposited on the horn and reflector as well as on their adjacent elements has been estimated using the FLUKA Monte Carlo package and results are presented in this document. | ||
| TUPLS133 | Material Irradiation Damage Studies for High Power Accelerators | 1816 |
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| High-performance targets intercepting multi MW proton beams are the key toward intense muon or neutrino beams. To achieve this goal one must push the envelope of the current knowledge on material science and material endurance and survivability to both short and long proton beam exposure. The demand imposed on the targets of high power accelerators and the limitations of most materials in playing such pivotal roles have led to an extensive search and experimentation with new alloys and composites. These new high-performance materials and composites, which at first glance, appear to possess the right combination of properties satisfying target requirements, are explored under accelerator target conditions where both shock and irradiation damage are at play. Results of the on-going, multi-phased experimental effort under way at BNL involving heavy irradiation of candidate materials using 200 MeV protons at the end of the BNL Linac as well as results on post-irradiation analysis assessing irradiation damage are presented. | ||
| TUPLS134 | Managing the Quality Assurance Documentation of Accelerator Components Using an EDMS | 1819 |
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| Quality assurance (QA) documents are often collected locally on a per-component basis by the manufacturing teams, while project engineers require global evaluations of the QA documents e.g. for production control or during installation and commissioning of the machine. DESY is using an Engineering Data Management System (EDMS) for supporting and unifying the QA documentation of different accelerator components. The EDMS provides dedicated user interfaces which are optimized for the needs of the specific engineering teams which are working on the components (including industrial manufacturers), and at the same time integrates the QA documents into a central database for further overall analysis and applications. The poster introduces the general structure of QA procedures, describes the benefits of using an EDMS for QA documentation and describes examples from different applications at XFEL and PETRA III. | ||
| TUPLS135 | Technical Infrastructure Monitoring at CERN | 1822 |
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| The Technical Infrastructure Monitoring system (TIM) is used to survey and control CERN's technical services from the CERN Control Centre (CCC). The system's primary function is to provide CCC operators with reliable real-time information about the state of the laboratory's extensive and widely distributed technical infrastructure. TIM is also used to monitor all general services required for the operation of the accelerator complex and the experiments. A flexible data acquisition mechanism allows TIM to interface with a wide range of technically diverse installations, using industry standard protocols wherever possible and custom designed solutions where needed. The complexity of the data processing logic, including persistence, logging, alarm handling, command execution and the evaluation of data-driven business rules is encapsulated in the system's business layer. Users benefit from a suite of advanced graphical applications adapted to operations (synoptic views, alarm consoles, data analysis tools etc.), system maintenance and support. Complementary tools for configuration data management and historical data analysis will be available before the start-up of the LHC in 2007. | ||
| TUPLS136 | Air Temperature Analysis and Improvement for the Technical Zone at TLS | 1825 |
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| This paper presents the air temperature analysis and control improvement for the technical zone, where many critical instrumentations of power supply, rf, vacuum and control apparatuses are located, at the Taiwan Light Source (TLS). The technical zone with circular shape is located on the core area of the storage ring. The diameter and height of the technical zone are 28.5m and 3m, respectively. Totally 13 temperature sensors are installed in this zone to online record the air temperature history. Because of insufficient cooling capacity and poor air circulation of the air-conditioning (A/C) system, the air temperature may reach to 30 degrees C, and spatial air temperature difference may be more than 7 degrees C. To cope with those problems, a computational fluid dynamics (CFD) code is applied to simulate the spatial temperature distribution. The A/C cooling capacity will be increased, and the air exit and exhaust distribution will be modified according to the simulated results. | ||
| TUPLS137 | Design of the Utility System for the 3 GeV TPS Electron Storage Ring | 1828 |
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| After 13-year operation of the Taiwan Light Source (TLS), National Synchrotron Radiation Research Center (NSRRC), had proposed to construct a new light sourc, Taiwan Photon Source (TPS) in the near future. TPS is preliminarily designed with 3.0 GeV in energy, 518.4m in circumference and 24 Double-Bend Achromat (DBA). This study designed the utility system, including the electrical power system, grounding system, de-ionized cooling water (DIW) system and air conditioning (AC) system for the TPS. Special considerations are focused on the stability of the electrical power and grounding system and temperature control of the DIW and AC systems. The power and cooling loads had been estimated according to each subsystem of the accelerator. Layouts of main utility equipment and piping system had also been preliminarily designed. | ||
| TUPLS140 | An Overview of the SNS Accelerator Mechanical Engineering | 1831 |
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| The Spallation Neutron Source (SNS) is an accelerator-based neutron source currently nearing completion at Oak Ridge National Laboratory. When completed in 2006, the SNS will provide a 1GeV, 1.44MW proton beam to a liquid mercury target for neutron production. SNS is a collaborative effort between six U.S. Department of Energy national laboratories and offered a unique opportunity for the mechanical engineers to work with their peers from across the country. This paper presents an overview of the overall success of the collaboration concentrating on the accelerator ring mechanical engineering along with some discussion regarding the relative merits of such a collaborative approach. Also presented are a status of the mechanical engineering installation and a review of the associated installation costs. | ||
| TUPLS141 | Measured Residual Radioactivity Induced by U Ions of Energy 500 MeV/u in a Cu Target | 1834 |
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| Several laboratories in the world have started or plan to build new powerful ion accelerators. These facilities promise to provide very valuable tools for experiments in fundamental nuclear physics, physics of high energy density in matter and for medical applications as well. One of the most important problems that have to be solved during the design stage is the radiation protection of the accelerator. Due to the complexity, it is hardly possible to obtain reliable radionuclide production data for accelerator structure materials from radiation transport codes. Thus, the experimental data which can be measured at the presently existing facilities are necessary for the evaluation of the induced levels of radioactivity around intense heavy ion accelerators. The Uranium beam losses are the most dangerous ones in the FAIR facility. Results of the measurement of activation induced by U beam with energy of E = 500 MeV/u in the copper target are presented in this paper. |