Paper | Title | Other Keywords | Page |
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MOP013 | Focusing Solenoids for the HINS Linac Front End | solenoid, focusing, linac, alignment | 82 |
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Low energy part of the linac for the HINS project at Fermilab will use superconducting solenoids as beam focusing elements (lenses). While lenses for the conventional, DTL-type accelerating section of the front end require individual cryostats, in the superconducting accelerating sections solenoids will be installed inside rf cryomodules. Some of the lenses in the conventional and in the superconducting sections are equipped with horizontal and vertical dipole correctors. Lenses for the conventional DTL section are in the stage of production with certification activities ongoing at Fermilab. For the superconducting sections of the linac, several prototypes of focusing lenses were built and tested. Solenoid magnetic axis is used for alignment of the lenses in the transport channel of the accelerator. Corresponding technique has been developed at Fermilab and is used during certification of the production lenses for the DTL section. This report will summarize main design features, parameters, and test results of the focusing lenses of the linac. Magnetic axis alignment technique will also be described. |
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MOP034 | Heavy Ion Radio-Frequency Quadrupole LINAC for VEC-RIB Facility | rfq, ion, linac, ECRIS | 142 |
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Radio Frequency Quadrupole (RFQ) would be the first post accelerator for the upcoming Rare Isotope Beam (RIB) facility at Variable Energy Cyclotron Centre (VECC), India. A 33.7 Mhz RFQ capable of accelerating stable as well as RI beams of q/A > 1/16 to about 30 keV/u has already been constructed and operational since September 2005 . This has been installed in a dedicated beam line for doing material science experiments. Another 3.4 m long RFQ resonating at 37.6 Mhz and capable of accelerating heavy ion beams up to 98 keV/u have been fabricated which is to be installed in the beam line for the VEC-RIB facility. The physical parameters,rf test along with the measurements of accelerated beams from RFQ would be presented. |
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MOP038 | Fabrication and Testing of TRASCO RFQ | rfq, vacuum, quadrupole, coupling | 151 |
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The Legnaro National Laboratory (LNL) is building the 30 mA, 5 MeV front end injector for the production of intense neutron fluxes for interdisciplinary application. This injector comprises a proton source, a low energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a beam transport line designed to provide a 150 kW beam to the berillium target used as neutron converter. The RFQ, developed within TRASCO project for ADS application, is designed to operate cw at 352.2 MHz. The structure is made of OFE copper and is fully brazed. The RFQ is built in 6 modules, each approximately 1.2 meter long. This paper covers the mechanical fabrication, the brazing results and acceptance tests for the various modules. |
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MOP046 | Commissioning of the New GSI-Charge State Separator System for High Current Heavy Ion Beams | emittance, ion, space-charge, heavy-ion | 175 |
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A dedicated charge separator system is now installed in the transfer line to the GSI-synchrotron SIS18. In former times charge separation was performed with a single 11 degree dipole magnet after a 25 m beam transport section. This was not adequate to meet the requirements during high current operation for FAIR: it only allows for charge state separation of low intensity and low emittance beams. With the new compact charge separator system emittance blow up and unwanted beam losses for high intensity beam operation will be avoided. Additionally a new beam diagnostics test bench is integrated. With this the beam parameters (ion current, beam profile, beam position, transversal emittance, bunch structure and beam energy) for the injection into the SIS18 can be measured in parallel to the routine operation in the transfer line. Results of the commissioning with high intensity argon beams as well as with an uranium beam will be reported. |
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MOP064 | Bent Solenoid Tuning Simulations for the COMET Beamline | solenoid, simulation, target, electron | 226 |
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The COMET experiment beamline uses bent solenoids for the muon transport and the spectrometer used to analyse the decay electrons from stopped muons. The bent solenoid includes not just a solenoid field but also a vertical dipole field. It is therefore important to have the ability to tune the field distribution. However, since the field distribution is mainly determined by the geometry it is difficult to adjust once the solenoids have been constructed. A cost effective method to provide tuning capability of the field distribution of the bent solenoids is proposed and the results of simulations presented. |
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MOP076 | Integration of Fringe Field Alpha Magnets into the V-Code Beam Dynamics Simulation Tool | simulation, multipole, electron, focusing | 254 |
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Funding: This work was partially funded by DESY Hamburg and DFG (SFB 634). |
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MOP079 | Development of Modulating Permanent Magnet Sextupole Lens for Focusing of Pulsed Cold Neutrons | neutron, sextupole, focusing, permanent-magnet | 263 |
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We are developing a modulating permanent magnet sextupole lens to focus pulsed cold neutrons. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to adjust the strength, the magnet is divided into two nested co-axial rings, where the inner ring is fixed and the outer ring can be rotated. Synchronizing the modulation with neutron beam pulse suppresses the chromatic aberration. These devices largely improve the utilization efficiency of neutrons, which makes even small linac based neutron sources practical. We have fabricated a half-scale model and studied its strength, torque and temperature rise during the operation. The main causes of the temperature rise are eddy-current loss in the poles made of soft magnetic material in inner ring and hysteresis loss. A laminated structure reduced the eddy-current loss. The temperature rise was suppressed to about half of the former model. We now study their B-H curve to optimize the thickness of the sheet. Annealing of the material is supposed to reduce the hysteresis loss, which will be tested soon. The experimental results of very-cold neutrons focusing with the half-scale model are also described. |
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MOP102 | Electron Beam Dynamics in the DARHT-II Linear Induction Accelerator | electron, induction, focusing, impedance | 311 |
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Funding: Work supported by USDOE under contract DE-AC52-06NA25396 *"Long-pulse beam stability experiments on the DARHT-II linear induction accelerator", Carl Ekdahl, et al., IEEE Trans. Plasma. Sci. Vol. 34, 2006, pp. 460-466. |
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TUP004 | Status of the CTF3 Probe Beam Linac CALIFES | linac, alignment, laser, klystron | 389 |
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The CLIC project based on the innovative Two Beams Acceleration concept is currently under study at CTF3 where the acceleration of a probe beam will be demonstrated. This paper will describe in details the status of the probe beam linac called CALIFES. This linac (170 MeV, 1 A) is developed by CEA Saclay, LAL Orsay and CERN. It will be installed in the new experimental area of CTF3 to deliver short bunches (1.8 ps) with a charge of 0.6 nC to the CLIC 12 GHz accelerating structures. The linac consists in an rf gun triggered by a laser beam, three LIL sections for bunching and acceleration, a beam diagnostic system and a single klystron with a pulse compression cavity and a dedicated rf network. We report new results of beam dynamic simulation considering the new CLIC parameters. We will give an estimation of the energy and phase deviation over the bunch train (140 ns long) by transient calculation of beam loading. Details about the fabrication of the rf gun, the cavity BPM, the HV modulator and the power phase shifter will be described. New results from laser system studies are discussed. The construction of CALIFES and the start of commissioning will be also reported. |
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TUP024 | Growth of Density Modulations in an Energy Recovery Linac Light Source due to Coherent Synchrotron Radiation and Longitudinal Space Charge | lattice, linac, simulation, emittance | 444 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
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TUP045 | Generation of Femtosecond Bunch Trains Using a Longitudinal-to-Transverse Phase Space Exchange Technique | emittance, simulation, cavity, electron | 498 |
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Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. DOE and by Northern Illinois University under Contract No. DE-FG02-08ER41532 with the U.S. DOE *P. Emma, Z. Huang, K.-J. Kim, and P. Piot, Phys. Rev. ST Accel. Beams 9, 100702 (2006). |
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TUP054 | Development of the Continuously Adjustable Permanent Magnet Quadrupole for ATF2 | quadrupole, coupling, permanent-magnet, multipole | 524 |
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A final focus quadrupole (FFQ) doublet of ILC should have excellent properties such as strong focusing, compactness and less vibrations. In a baseline design, superconducting magnet is supposed to be used, which may have some vibrations traveling through liquid helium. It may not be suitable for FFQ of ILC unless the vibration effect is proven to be negligible. Since the five-disc-singlet proposed by Gluckstern satisfies these properties including continuous adjustability, we are developing a FFQ aiming at a beam test at ATF2. Although the x-y coupling effect is carefully cancelled in the design, fabrication errors or rotation errors may break the cancellation. We are estimating the effect of these errors on the beam size at the interaction point. Two methods are currently carried out. The first one is transfer matrix calculations, which neglects fringing field and higher multipole components. The second one is beam-tracking calculation in measured or calculated magnetic field. The fabricated magnet is under adjustment measuring the magnetic field. The recent results will be presented. |
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TUP080 | Numerical Study of a New Bunch Length Monitor Utilizing a Detection of Electromagnetic Fields in Millimeter-Wave Region | radiation, vacuum, linac, electron | 582 |
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A new nondestructive bunch-length monitor has been numerically investigated. The monitor detects electromagnetic fields generated through a ceramic gap of a vacuum pipe when a charged particle beam passes through the pipe gap. The frequency spectrum of the electromagnetic fields detected in wave zone spreads over a millimeter-wave length from a microwave length region for a short pulse beam with a bunch length of pico-second region. The frequency spectrum strongly depends on the bunch length of the relativistic charged beam if the geometrical structure of the pipe gap is fixed. The detection principle of the bunch-length monitor and some numerical analysis results applied to a single-bunch electron beam of the KEKB injector linac are described in this report. |
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TUP113 | Emittance Exchange at the Fermilab A0 Photoinjector | cavity, emittance, optics, electron | 667 |
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Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. |
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THP023 | Crab Cavities for Linear Colliders | cavity, collider, beam-loading, linac | 830 |
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Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favours a 3.9 GHz superconducting, multi-cell cavity as the ILC solution, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are special issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders. |
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THP024 | Initial Study on the Shape Optimisation of the CLIC Crab Cavity | cavity, impedance, beam-loading, coupling | 833 |
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The CLIC linear collider will require a crab cavity to align bunches prior to collision. Consideration of the bunch structure leads us to favour the use of X-band copper cavities. Due to the large variation of train to train beam loading, it is necessary to minimise the consequences of beam loading. One solution is to use a travelling wave structure with a large group velocity allowing rapid propagation of amplitude errors from the system. Such a design makes this structure significantly different from previous travelling wave deflecting structures. This paper will look at the implications of this on other cavity parameters and the optimization of the cavity geometry. |
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THP038 | A New SRF Cavity Shape with Minimized Surface Electric and Magnetic Fields for the ILC | cavity, HOM, coupling, wakefield | 867 |
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Funding: Work supported by DOE contract DE-AC02-76SF00515. |
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THP039 | SRF Cavity Imperfection Studies Using Advanced Shape Uncertainty Quantification Tools | cavity, cryomodule, SRF, HOM | 870 |
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Funding: Work supported by DOE contract DE-AC02-76SF00515. |