| Paper | Title | Page |
|---|---|---|
| TUPAN001 | Analytic Models for Quadrupole Fringe-Field Effects | 1386 |
|
||
|
Funding: TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada The linear-field non-scaling FFAG lattices originally proposed for multi-GeV muon acceleration are now being modified for application to order 100 MeV/u proton or carbon medical applications. The momentum range is large and the chromatic tune variation is significant. In the medical case, the time of flight variation is immaterial but the issue of resonance crossing is more acute owing to the much lower rate of energy gain. Magnets with non-normal entry/exit faces are considered as means to reduce the tune variation. Thus one is motivated to study fringe fields and their effects. We make a brief study of dipole and quadrupole magnets with normal and rotated entry/exit faces. For the artificial case of a cosine-squared fall off in the quadrupole field, analytic results are obtained which though approximate are superior to numerical integration. This property is achieved by insisting that the error in the equation of motion is zero and the determinant is unity at the entry, exit and centre of the fringe field. |
||
| TUPAN002 | Large Displacement and Divergence Analytic Transfer Maps Through Quadrupoles | 1389 |
|
Funding: TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada. Linear-field non-scaling FFAGs are proposed for multi-GeV muon acceleration and order hundred MeV/u proton or carbon medical applications. The periodic lattices, which have large momentum acceptance (factor >3), employ cells comprised of combined function magnets. In one implementation, rectangular-shaped quadrupoles are used, with the dipole component generated by off-setting the magnet centre. This feature, coupled with the large radial aperture, gives rise to orbits with large displacement and/or divergence from the quadrupole centre. The angles may be so large that there is a partial interchange of longitudinal and radial momenta. We examine two methods to devise maps (through the body field) that are third order in radial coordinate and higher order in momentum. The WKBJ approximation is concluded to be no better than the usual linear transfer matrix. A Green's function approach is carried through to non-linear mappings for the dynamical variables, which are coupled. The first partial derivative of this map (relates to tune variation) produces a linear transfer matrix which must have unity determinant. For the FFAG application, the map is comparable with numerical integration. |
||
| TUPAN003 | Beam Quality and Operational Experience with the Superconducting LINAC at the ISAC II RIB facility | 1392 |
|
||
| The ISAC II superconducting LINAC is now in the operational phase. The linac was commissioned with stable beams from an off-line source. The commissioning not only proved the integrity of the infrastructure but benchmarked the beam quality and rf cavity performance. Measurements of the transverse and longitudinal emittance are consistent with little or no emittance growth through the acceleration. Transmission near 100% has been achieved though some solenoid steering is evident due to misalignment. The misalignment problem is being evaluated using the beam as diagnostic tool while applying corrections based on the beam measurements. The effectiveness of the corrections will be reported. The machine has been demonstrated to be easy to tune, reliable in restoring beam and flexible enough to accommodate different tuning strategies; software routines have been developed in order to facilitate the tuning process. In this paper the operational routine for tuning and beam delivery will be presented as well as the beam characteristics drawn from the commissioning studies. | ||
| TUPAN004 | Slow Kicker Magnet System with Energy Recover Pulse Power Supply with Extended Flat Top | 1395 |
|
||
| Danfysik has developed a novel Slow Kicker Magnet Power Supply ERMPPS with associated magnet achieving high stability, long flatness top and low energy consumption. Two Slow Kicker Magnet Systems has been built to RAL, one low and one high energy supply. The magnets are laminated window frame type. The RAL synchrotron produces high energy protons at 50 Hz rate. The Slow Kickers operate at 10 Hz, directing a portion of the extracted protons to a second beam line. The flat top width is 600 μs with a flat top and peak-peak stability better than 100 ppm. The rise and fall time is 12 msec. The power supply has been developed with following highlights: High accuracy with adjustable output current, wide range micro-step set able flattop and rise time width, energy recovery, digital flattop and rise time regulation loop in FPGA and variable repetition frequency down to one shoot operation. The flat top- and rise time width settings are bounded by the actual load and internal component values. The paper describes power supply topology, the digital regulation principia and the magnet construction. Performance measurements electrical as well as magnetic measurements are presented. | ||
| TUPAN006 | Design of Slug Tuners for the SPIRAL2 RFQ | 1398 |
|
||
| Tuner parameters: number (or separation distance), diameter, position range, are determined in order to fit two main requirements: (1) compensation of construction errors specified between given bounds, and (2) compatibility with magnetic-field bead-pull measurements. Tuner slopes possibly derived from 2D or 3D simulations are compared. RFQ 4-wire transmission line model is used to calculate tuner position range required to compensate for given capacitance relative errors. The position of the bead guiding-wire is deduced from 3D field maps and magnetic-field-to-voltage calibration accuracy requirement. | ||
| TUPAN007 | 3-D Magnetic Calculation Methods for Spiral Scaling FFAG Magnet Design | 1401 |
|
||
|
Funding: ANR (French Research Agency) 2-D and 3-D magnetic calculation tools and methods have been developed at SIGMAPHI, in collaboration with IN2P3/LPSC, to design spiral FFAG magnets. These tools are currently being used for RACCAM spiral scaling FFAG magnet design. In the particular case of a spiral gap shaped magnet, a careful magnetic design has to be realized in order to keep both vertical and horizontal tunes constant during acceleration process. Promising results, obtained from tracking in 3-D field maps, demonstrate the efficiency of the horizontal and vertical tune adjustment methods presented in this paper. |
||
| TUPAN008 | Spiral FFAG for Protontherapy | 1404 |
|
||
| High rep rate of the FFAG accelerator and compactness of the spiral type of the design makes it a good candidate as medical machine for protontherapy and for biological research. The variable energy extraction with various methods is discussed. The principle of the lattice design together with the injection scheme and the beam dynamics simulations are presented. The spiral magnet design undertaken in the frame of the RACCAM project is briefly described. | ||
| TUPAN009 | Performance of the SARAF Ion Source | 1407 |
|
||
| Since October 2006 an ECR ion source is under operation at SOREQ. The source will be used to generate protons and deuterons in a current range from 0.04 to 5 mA. The paper will present operation results as current, emittance and stability measurements. Further the influence of variables as solenoid fields, RF power and gas flow will be described. A short description of the attached beam transport system and beam diagnostic system will be given as well. | ||
| TUPAN011 | Beam Operation of the SARAF Light Ion Injector | 1410 |
|
||
| In beginning of 2007 the installation of the first stage of SARAF has been finalized. The system consists out of an ECR ion source, a low energy beam transport system, a four rod RFQ, a medium energy transport system and a superconducting module housing 6 half resonators and three superconducting solenoids. This injector will be characterized with a diagnostic plate. The installation allows continuous measurement of beam charge, position and phase. The diagnostic plate in addition provides a beam halo monitor, vertical and horizontal slit and wire systems, a slow and a fast faraday cup, which can only be used in pulsed operation. The paper will describe the status of commissioning, including results of the site acceptance test of major components. | ||
| TUPAN012 | High Intensity Heavy Ion Beam Emittance Measurements at the GSI UNILAC | 1413 |
|
||
|
Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395). The GSI UNILAC, a heavy ion linac originally dedicated for low current beam operation, together with the synchrotron SIS 18 will serve as an high current injector for FAIR (International Facility for Antiproton and Ion Research). The UNILAC post stripper accelerator consists of five Alvarez tanks with a final energy of 11.4 MeV/u. In order to meet the requirements of FAIR (15emA 238U28+, transverse normalised emittances of 0.8mm mrad and 2.5mm mrad) an UNILAC upgrade program is foreseen to increase the primary beam intensity as well as the beam brilliance. A detailed understanding of the beam dynamics during acceleration and transport of space charge dominated beams is necessary. For this purpose the study of the beam brilliance dependency on the phase advances in the Alvarez DTL is suited. Machine investigations were performed with various beam diagnostics devices established in the UNILAC. Measurements done in 2006 using an high intensity heavy ion beam coincide with the beam dynamics work package of the European JRA "High Intensity Pulsed Proton Injector" (HIPPI). Results of these measurements are presented as well as corresponding beam dynamics simulations. |
||
| TUPAN013 | FAIR Synchrotron Operation with Low Charge State Heavy Ions | 1416 |
|
||
|
Funding: Work supported by EU, contract No. 515876 Beam loss caused by charge changing process in connection with dynamic vacuum effects may limit the maximum number of accelerated heavy ions with low charge states in the existing synchrotron SIS18 and the planned SIS100/SIS300 of the FAIR project. With the aim to stabilize the vacuum dynamics and to control ionization beam loss, a substantial upgrade program has been defined for SIS18 and is presently realized. For SIS100, a new lattice design concept has been developed, where each lattice cell acts as a charge seperator and thereby enables the local control of beam loss. Simulation, conducted with the code STRAHLSIM, of the time dependent evolution of beam loss, dynamic residual gas pressure and the effect of the proposed dedicated ion catcher systems will be presented. |
||
| TUPAN014 | Status of the FAIR SIS100/300 Synchrotron Design | 1419 |
|
||
| The project status of the main accelerators, the SIS100 and SIS300 synchrotrons of the FAIR project will be presented. In order to accommodate more preferable technical solutions, the structure of the magnet lattice had to be modified in both machines. After these changes, more appropriate technical solutions for the main magnets and quench protection systems could be adapted. The general machine layout and design, e.g. of the demanding extraction schemes, has been detailed and open design issues were solved. The developments and design of all major technical systems are in progress and prototyping has started or is in preparation. | ||
| TUPAN015 | Ion Optical Layout of the FAIR Synchrotron and Beam Line Systems | 1422 |
|
||
| The ion-optical layout of the two main synchrotrons and the high energy beam transport system of the FAIR project is summarized. SIS100 will be used to generate high intensity beams of all ion species from protons to uranium with a maximum rigidity of 100 Tm. The ion optical layout is optimized for the operation with heavy ions of medium charge states. For this purpose we developed a new ion optical design which provides a separation of the ionized beam particles from the circulating beam in each lattice cell. The chosen lattice structure provides a peaked loss distribution and enables the suppression of beam loss induced pressure bumps. Furthermore a compact layout of the extraction systems for slow and fast extraction at 100 Tm and 300 Tm has been developed. Since both synchrotrons are situated in the same tunnel, the SIS300 ion optical layout has to match the geometrical shape of the SIS100 precisely - although both rings use different lattice structures. The design of the beam transport system allows an effective parallel operation of the two synchrotrons, storage rings and experiments of the FAIR complex. | ||
| TUPAN016 | Rare Isotope Accumulation and Deceleration in the NESR Storage Ring of the FAIR Project | 1425 |
|
||
| The storage ring NESR of the FAIR project can be operated with rare isotope beams which are produced by projectile fragmentation of a fast heavy ion beam. After stochastic pre-cooling at 740 MeV/u in a dedicated collector ring (CR) the rare isotopes will be accumulated in the NESR by a longitudinal accumulation technique in combination with electron cooling. Various schemes for the accumulation have been considered and evaluated. For experiments with stored beams and for transfer to an ion trap the ion beams can be decelerated to a minimum energy of 4 MeV/u. The deceleration mode of the NESR will also be available for deceleration of antiprotons to a minimum energy of 30 MeV. Fast extraction to a trap and slow extraction to fixed target are foreseen. | ||
| TUPAN017 | Development of a Coupled CH Structure for the GSI Proton Injector | 1428 |
|
||
|
Funding: CARE (contract No RIICT-2003-506-395), GSI, BMBF The FAIR facility, under development at GSI, needs a new dedicated proton injector for the production of intense antiprotons secondary beams. This injector will accelerate protons from 3 to 70 MeV at a current of 70 mA, and due to the high voltage gain and shunt impedance will be based on CH cavities powered by a 2.5 MW, 325 MHz klystron. An innovative coupling cell containing one drift tube of length N-beta λ was developed to combine multicell drift tube modules of the CH-type (H210 mode).. In order to study this innovative coupling mechanism a scaled model of the second resonator of GSI Proton injector is under production at IAP. The according full scale prototype, 3 meter long coupled X MV resonator from MeV to MeV is under construction and will be power tested with a 2.5 MW klystron at GSI at the end of 2008. This paper describes in detail the coupled structure together with a general overview of the R&D results achieved on the CH-DTL's cavity. |
||
| TUPAN018 | The Frankfurt Funneling Experiment | 1431 |
|
||
| Funneling is a procedure to multiply beam currents at low energies in several stages. The Frankfurt Funneling Experiment is a prototype of such a stage. Our experiment consists of two ion sources, a Two-Beam RFQ accelerator, a funneling deflector and a beam diagnostic system. The two beams from the ion sources are injected into two RFQ beam lines. These two beams are accelerated in a Two-Beam RFQ and combined to one beam axis with a funneling deflector. The last parts of the RFQ electrodes have been replaced to achieve a 3d focus at the crossing point of the two beam axis. The newly designed multigap deflector is adapted to the optimized funneling section. First results and beam measurements with the new setup will be presented. | ||
| TUPAN019 | The Superconducting Linac Approach for IFMIF | 1434 |
|
||
| The International Fusion Material Irradiation Facility (IFMIF) which is under design will be a high flux source of fast neutrons for the development of new materials needed for future fusion reactors. IFMIF will deliver 250 mA of 40 MeV deuterons. The duty cycle is 100% and the beam power on the lithium target is 10 MW. The beam will be accelerated by two 175 MHz linacs in parallel operation. Beside the room temperature Alvarez solution an alternative design using superconducting CH-structures has been proposed. In this paper we present the superconducting approach for IFMIF with the emphasis on the beam dynamics simulations. The simulations have been performed using the LORASR code. A new space charge routing has been added to the code to increase the number of macro particles to more than 1 million. Additionally a new routine allows the simulation of randomly distributed RF and alignment errors. The optimized linac layout including error and loss studies will be presented. | ||
| TUPAN020 | A RFQ-Decelerator for HITRAP | 1437 |
|
||
| 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 are decelerated at first in the existing experimental storage ring (ESR) down to an energy of 5 MeV/u and will be injected into a new Decelerator-Linac consisting of a IH-structure, which decelerates down to 500keV/u, and a 4-Rod RFQ , decelerating to 5 keV/u. The properties of the RFQ decelerator and the status of the project will be discussed. | ||
| TUPAN021 | RFQ and IH Accelerators for the new EBIS Injector at BNL | 1439 |
|
||
| The new EBIS preinjector at BNL will accelerate ions from the EBIS source with specific mass to charge ratio of up to 6.25, from 17 keV/u to 2000 keV/u to inject into the Booster synchrotron, expanding experimental possibilities for RHIC and NASA experiments. The properties of the RFQ and IH accelerators and the status of the project will be discussed. | ||
| TUPAN024 | HESR at FAIR: Status of Technical Planning | 1442 |
|
||
| The High-Energy Storage Ring (HESR) of the international Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is dedicated to Strong Interaction studies with antiprotons in the momentum range from 1.5 to 15 GeV/c. Powerful phase-space cooling is needed to reach demanding experimental requirements in terms of luminosity and beam quality. Status and details of technical planning including cryogenic concept will be presented. | ||
| TUPAN025 | Selective Containment Measurements on Xe with the RF Charge Breeder Device BRIC | 1445 |
|
||
|
Funding: INFN and UE contract no. 515768 EURISOL_DS (RIDS)
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 breeder" is a device designed to accept RIB with charge state +1 and in order to increase their charge state up to +n. Recently, at the INFN section of Bari first and at LNL (Italy) then, a new charge breeder device, based on an EBIS ion source called BRIC, has been developed. 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 selective more efficient containment of the wanted ions. The RF test measurements for Ar gas confirm, as foreseen by simulation results* that the selective containment can be obtained. More measurements on the selective containment of heavier element ions (more close to the radioactive ion produced with ISOL technique) like Xe are needed to study with more details that effect. In this contribution new measurements on the rf selective containement in BRIC for Xe gas will be presented and discussed.
* 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. |
||
| TUPAN027 | A New Complementary-Scan Technique for Precise Measurements of Resonance Parameters in Antiproton-Proton Annihilations | 1448 |
|
A new technique for precision measurements of resonance widths in antiproton-proton annihilations is presented. It is based on the analysis of excitation curves obtained by scanning the resonance twice, at constant orbit and at constant magnetic bend field, in an antiproton storage ring. The technique relies on precise revolution-frequency and orbit-length measurements, while making the results almost independent of the machine's phase-slip factor. The uncertainty is dominated by event statistics. The technique was recently applied by Fermilab Experiment E835 at the Antiproton Accumulator to obtain the most precise measurements to date of the total and partial widths of the psi(2S) charmonium meson. Future applications may include the PANDA experiment at the FAIR facility in Darmstadt.
On behalf of the Fermilab E835 Collaboration |
||
| TUPAN028 | A Low Beta Section for Polarization Studies of Antiprotons by Spin Filtering | 1451 |
|
||
|
In the framework of the FAIR* project, the PAX collaboration has suggested new experiments using polarized antiprotons**. The central physics issue is now to study the polarization build-up by spin filtering of antiprotons via multiple passages through an internal polarized gas target. The goals for spin-filtering experiments with protons at COSY are to test our understanding of the spin-filtering processes and to commission the setup for the AD experiments with antiprotons at the AD (CERN). Spin-filtering experiments with antiprotons at the AD will allow us to determine the total spin-dependent transversal and longitudinal cross sections. The low-beta section at COSY is composed of two superconducting quadrupole magnets on each side of the target, while at the AD, we will use three quadrupoles on each side. Accelerator technical problems and details for COSY and AD to carry out the planned spin-filtering studies together with the technical problems and details of the superconducting quadrupoles with their respective cryogenics will be discussed in this talk. The status of the construction of the quadrupoles will be reported as well.
* Conceptual Design Report for an International Facility for Antiprotonand Ion Research, www.gsi.de/GSI-future/cdr.** PAX Technical Proposal, www.fz-juelich.de/ikp/pax. |
||
| TUPAN031 | Touschek Background and Beam Lifetime Studies for the DAFNE Upgrade | 1454 |
|
||
| For the low energy collider DAFNE the machine induced backgrounds into the experiments as well as the beam lifetime are dominated by the Touschek effect. Many efforts have been put in its reduction: by adjusting optical parameters, by inserting additional collimators, as well as by simulating and tracking scattered particles in order to find the proper actions that allow reducing these effects. Studies on the distribution and trajectories of the Touschek particles along the ring are discussed here for the Siddarta run configuration with the crabbed waist scheme, together with an evaluation of the beam lifetime. Effectiveness of the scrapers installed in the two rings has been investigated with the new machine configuration and new optimized positions along the beam pipe have been found. | ||
| TUPAN033 | DAΦ NE Setup and Performances During the Second FINUDA Run | 1457 |
|
||
| Beam operations on DAΦNE restarted on October 2006 after a four months shut-down to remove the KLOE experimental detector and to install the FINUDA one. This period has been also used for maintenance and implementation of several upgrades. In the first two months of operation the peak and integrated luminosity already exceeds the values obtained during the first FINUDA run by 20%. The DAΦNE goal is to deliver 1 fb-1 integrated luminosity by the end of May 2007. The collider performances during the run are presented together with the improvements obtained in terms of ring nonlinearities and beam dynamics coming from several collider modifications. | ||
| TUPAN034 | Super-B Factory using Low Emittance Storage Rings and Large Crossing Angle | 1460 |
|
||
|
Funding: Work supported by US DOE contract DE-AC02-76SF00515. Submitted for the High Luminosity Study Group for an Asymmetric Super-B-Factory: Parameters are being studied for a high luminosity e+e- collider operating at the Upsilon 4S that would deliver a luminosity of over 1036/cm2/s. This collider would use a novel combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam at 4 GeV x 7 GeV are stored in low-emittance damping rings similar to those designed for a Linear Collider (LC). A LC style interaction region is included in the ring to produce sub-millimeter vertical beta functions at the collision point. A large crossing angle (±30 mrad) is used at the collision point to allow beam separation and reduce the hourglass effect. Beam currents of about 3 A x 2 A in 1700 bunches can produce a luminosity of 1036/cm2/s. Design parameters and beam dynamics effects are discussed. |
||
| TUPAN035 | Reduction of the Non-Linearities in the DAPHNE Main Rings Wigglers | 1463 |
|
||
| The wigglers of the DAPHNE main rings have been the main source of non-linearities for the beam dynamics in the collider. This paper describes a method to reduce the integrated odd multipoles (the even ones tend to vanish for the periodicity of the magnet) by alternatively displacing the magnetic axis of the poles to compensate the integrated odd multipoles in each half-period of the wiggler. In order to check the effectiveness of this approach, tracking studies have been performed. Tracking results have been used to tune the MAD model of the wiggler. | ||
| TUPAN036 | DAPHNE Upgrade: A New Magnetic and Mechanical Layout | 1466 |
|
||
|
The DAPHNE Phi-Factory upgrade, foreseen for the Siddharta detector run in 2007, will require a new magnetic and mechanical layout to exploit the "large crossing angle" and "crabbed waist" concepts*. New permanent quadrupole magnets and aluminium vacuum chamber with thin window have been designed for the new interaction region, with the aim to reuse at maximum the present magnetic and vacuum chamber components. A vacuum chamber of novel design will allow separating the beams at the second interaction region. Designs and results for the new layout will be presented.
* DAPHNE Upgrade Team, "DAPHNE Upgrade for Siddharta run", DAPHNE Tech. Note G-68, Dec. 2006. |
||
| TUPAN037 | Beam-Beam Simulations for Particle Factories with Crabbed Waist | 1469 |
|
||
| The recently proposed "crabbed waist" scheme for beam-beam collisions can substantially increase luminosity since it combines several potentially advantageous ideas. Large crossing angle together with small horizontal beam size allow having very small beta-functions at the interaction point (IP) and ordinary bunch length without incurring in the "hourglass" effect. The other main feature of such a collision scheme is the "crabbed waist" transformation, which is realized by two sextupoles placed in proper betatron phases around the IP. Such a transformation can strongly suppress the beam-beam betatron resonances induced in collisions with large Piwinski's angle, thus providing significant luminosity increase and opening much more room for choices of the working point. In this paper we present the results of beam-beam simulations performed in order to optimize the parameters of two currently proposed projects with the crabbed waist: the DAFNE upgrade and the Super B-factory project. | ||
| TUPAN039 | Profile Measurement and Transverse Matching in J-PARC Linac | 1472 |
|
||
| Beam commissioning of J-PARC linac has been performed since November 2006. In the beam commissioning, transverse matching has been performed by measurement of beam profiles and emittance with wire scanners. In this presentation, detail of wire scanners and the method of matching are described. | ||
| TUPAN041 | Recent Progress of KEKB | 1475 |
| In this report, we describe the KEKB status focused on recent progress since the summer shutdown in 2005. | ||
| TUPAN042 | Synchroton Radiation Interferometer Calibration Check by Use of a Size Control Bump in KEKB | 1478 |
|
||
| KEKB B-Factory is one of the second generation lepton colliders. The energies of the two beams are 3.5 GeV for positron and 8 GeV for electron. Synchrotron Radiation Monitors(SRMs) are installed in the both rings and usually used for measuring beam sizes on real times. On the other hand, we use useful vertical bumps to control beam sizes of the beams. In this paper a method for calibrating the SRM by using the vertical bumps is described. | ||
| TUPAN043 | RF Amplitude and Phase Tuning of J-PARC DTL | 1481 |
|
||
| The beam commissioning of J-PARC linac has been started in November 2006. In the beam commissioning, the tuning of the RF phase and amplitude for its DTL (Drift Tube Linac) has been performed with a phase-scan method. Detailed results of the RF tuning are presented with a brief discription of the tuning procedure. | ||
| TUPAN044 | Acceleration Scheme in the AIA and its Control System | 1484 |
|
||
|
An All Ion Accelerator (AIA), an injector-free induction synchrotron (IS) is proposed as a modification of the KEK booster*. The Booster is a rapid cycle synchrotron operating at a repetition rate of 20Hz. The AIA based on the booster requires more flexible trigger generation for the acceleration or confinement system than the one used for the IS POP experiment**. Assuming Ar+18 injection from a 200 kV ion source, the revolution period changes from 9.08usec to 333nsec at the end, and the required acceleration voltage changes from few tens of volts to 6.4kV at the middle of acceleration. Since a number of available acceleration cells is finite and their maximum pulse width and output voltage are limited to 500 nsec and 2 kV/cell, respectively, the dynamic allocation of acceleration cells in real time is indispensable, where a trade-off between the voltage amplitude and integrated pulse-length is realized. The acceleration scheme employing fast DSPs and a trigger control system is designed so as to meet the above requirement. Its whole story will be presented, including beam simulation results in the proposed AIA.
* E. Nakamura et al., in PAC07** K. Takayama et al., "Experimental Demonstration of the Induction Synchrotron" appeared in Phys. Rev. Lett. soon and in PAC07 |
||
| TUPAN045 | Beam Operation with Crab Cavities at KEKB | 1487 |
|
||
|
Beam operation with crab cavities is planned in early 2007 at KEKB. The crab crossing scheme is expected to increase the vertical beam-beam tune-shift parameter significantly. One crab cavity will be installed in each ring where conditions for beam optics are matched to compensate the beam crossing angle of 22 mrad. Operation results on collision tuning with the crab cavities will be presented.
For the KEKB Accelerator Group. |
||
| TUPAN046 | A Modification Plan of the KEK 500MeV Booster to an All-ion Accelerators (An Injector-free Synchrotron) | 1490 |
|
||
|
A medium-energy synchrotron capable of accelerating all ion species based on a novel technology of the induction synchrotron* has been proposed as an all-ion accelerator (AIA)**. The AIA without any specific injector employs a strong focusing lattice and induction acceleration, driven by novel switching power supplies. All ions, including cluster ions with any charge state, are accelerated in a single accelerator. A plan to modify the existing KEK 500 MeV Booster to the AIA is under consideration. Its key aspects, such as an ion-source, a low-field injection scheme and induction acceleration***, are described. Deep implant of moderate-energy heavy ions provided from the AIA into various materials may create a new alloy in bulk size. Energy deposition caused by the electro-excitation associated with passing of swift ions through the material is known to largely modify its structure. The similar irradiation on metal in a small physical space of less than a mm in diameter and in a short time period less than 100 nsec is known to create a particularly interesting warm dense-matter state. The AIA capable is a quite interesting device as a driver to explore these new paradigms.
* K. Takayama, et al., "Experimental Demonstration of the Induction Synchrotron", PAC07.** K. Takayama, et al., PCT/JP2006/308502 (2006).*** T. Dixit, et al., PAC07. |
||
| TUPAN047 | Beam-beam Effects in Crab Crossing and Crab Waist Schemes | 1493 |
|
||
| To boost up the luminosity performance in B factories, crab crossing and crab waist schemes are proposed. The crab crossing scheme compensates crossing angle, while the crab waist scheme compensates nonlinear tems induced by crossing angle with sextupole magnets. We discuss which nonlinear terms in the beam-beam map are enhanced by the crossing angle and which terms are compensated by the crab waist sextupole. | ||
| TUPAN048 | Beam-beam Effects With an External Noise in LHC | 1496 |
|
||
| Proton beam do not have any damping mechanism for an incoherent betatron motion. A noise, which kicks beam particles in the transverse plane, gives a coherent betatron amplitude. Nonlinear force due to the beam-beam interactions causes a decoherence for the betatron motion with keeping an amplitude of each beam particle, with the result that an emittance growth arises. We focus fast transverse turn by turn noises caused by a bunch by bunch feedback system and a cavity phase zitter in crab collision. | ||
| TUPAN049 | Low Emittance Lattices and Final Focus Design for the SuperB Project | 1499 |
|
||
|
For the SuperB project* very low emittances (horizontal < 1 nm) and small beta functions at the Interaction Points are required to achieve the design luminosity of 1036/cm2/s. Low emittance lattice have been designed, using the PEP-II magnets, for the two rings of 4 and 7 GeV, which will have the same emittances and damping times. A new Final Focus section has also been designed to get the strong focusing at the Interaction Point, at the same time providing local correction of the high chromaticity and exploiting the large crossing angle and crabbed waist concepts. Lattice features and chromaticity correction schemes will be discussed. Dynamic apertures, with damping wigglers similar to the ILC ones, will also be presented.
* P. Raimondi, "New Developments for SuperB Factories", Invited talk, this Conference |
||
| TUPAN050 | Status of the Induction Acceleration System | 1502 |
|
||
|
Single proton bunch confined by the barrier voltage was accelerated by the induction step-voltage from 500 MeV to 6 GeV at the KEK-PS on March 2006*. We will present the status with the information about troubles and counter-measures for the induction acceleration system.
* K. Takayama, presented in PAC07. |
||
| TUPAN051 | Design of Dynamic Collimator for J-PARC Main Ring | 1505 |
|
||
| The J-PARC main ring has a beam collimator section downstream of the injection area. The allowed beam loss is about 500 W. The beam halo during injection can be scraped by a standard collimator scheme. The beam halo can grow during the acceleration. Such a halo may cause a serious beam loss for extracted beam. A collimation during acceleration (dynamic collimator) is usefull to reduce the uncontrolable beam loss at the extraction. We will report the design and simulation of the dynamic collimation. | ||
| TUPAN052 | New Beam Optics Design of Injection/Fast Extraction/Abort Lines of J-PARC Main Ring | 1508 |
|
||
| J-PARC Main Ring has three straight sections for injection, slow extraction and fast extraction. Injection line has been redesigned so as to give a higher reliability for the thin septa. The magnetic field can be reduced by adding an extra kicker. New optics for the fast extraction with a larger acceptance has been proposed. In this design, the thin septa are replaced by kickers with a large aperture. Beam with an arbitrary energy can be aborted from opposite side from the fast extraction. An external abort line has been designed to deliver the beam aborted with an arbitrary energy to a dump just by using a static quadrupole doublet for the focus. | ||
| TUPAN055 | Present Status of J-PARC Ring RF Ring RF Systems | 1511 |
|
||
|
The RCS high frequency accelerating systems are prepared for beam commissioning in September 2007. Installations of cavities, power supplies and amplifiers have been carried out. The systems have been checked for operation and interoperability. For the MR high frequency accelerating system, the examination of the whole system and its final adjustment are done aiming at installation in October 2007. Here, we report on various issues which had been found and solved during the examination and installation period.
masahito.yoshii@kek.jp |
||
| TUPAN056 | Fabrication Status of ACS Accelerating Modules of J-PARC Linac | 1514 |
|
||
| An ACS (Annular Coupled Structure) cavity has been developed for the J-PARC Linac from 190-MeV to 400-MeV. We fabricated a buncher module with two 5-cell accelerating tanks and one 5-cell bridge tank as the first module. The buncher module is shorter than accelerating module that consists of two 17-cell accelerating tanks and one 9-cell bridge tank. The first buncher module achieved the stable operation of 50 Hz, 600 us, 600 kW in the high-power test, which corresponds to the E0 value of 4.8 MV/m. The second buncher module and three accelerating modules are under fabrication continuously. These results of the frequency tuning and assembling are presented in detail. | ||
| TUPAN058 | High Power Conditioning of the DTL for J-PARC | 1517 |
|
||
| For the J-PARC, DTL (Drift Tube Linac) is used to accelerate an H- ion beam from 3MeV to 50MeV. The DTL consists of 3 tanks and the all tanks were installed in the accelerator tunnel for J-PARC. After the installation, the high power conditioning has been started in Oct. 2006. The required rf power levels for beam acceleration are about 1.08MW, 1.2MW and 1.03MW (the pulse length is 600μsec and the pulse repetition is 25Hz) for the 1st, 2nd and 3rd tanks, respectively. As a result of the conditioning, we have been achieved that the rf power levels are about 1.3MW, 1.45MW and 1.23MW of 1.2 times required power levels (the pulse length is 650μsec and the pulse repetition is 25Hz). In this paper, the results of the high power conditioning of the DTL tanks are described. | ||
| TUPAN059 | The Precise Survey and the Alignment Results of the J-PARC Linac | 1520 |
|
||
| J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. A total length is more than 400 m including the beam transport line to the 3GeV RCS(Rapid Cycling Synchrotron). Precise alignment of the accelerator components is essential for high quality beam acceleration. After the completion of the linac building, floor elevation was surveyed periodically for more than one year to adjust the beam height from the ion source to the RCS. Before the beam commissioning, a metrological survey has been done. The reference points on the tunnel wall were set up to form a survey network to reduce the survey error less than 1mm in the entire linac. Based on the survey results, the linac components were re-aligned finely to satisfy the requirement. In this paper, the results of the floor elevation and the final alignment are described. | ||
| TUPAN060 | The DTL/SDTL Alignment of the J-PARC Linac | 1523 |
|
||
| J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. The length of the linear section is about 300 m which consists of the ion source, the radio frequency quadropole linac(RFQ), the drift tube linac(DTL), separated type DTL(SDTL), and the beam transport line. Precise alignment of the accelerator components is essential for high quality beam acceleration. The required alignment error in the J-PARC linac is 0.1mm in transverse direction. In the DTL/SDTL section, the fine alignment was carried out by using an optical alignment telescope along with the cavity installation. The relay targets were placed at short intervals for smooth connection between neighboring components. After the installation, the DTL/SDTL positions were confirmed by measuring the reference base by using a laser tracker. In this paper, the alignment procedure for the DTL/SDTL section and the results by the laser tracker measurements are described. | ||
| TUPAN061 | Updated Simulation for the Nuclear Scattering Loss Estimation at the RCS Injection Area | 1526 |
|
||
| We have updated the simulation for the realistic beam loss estimation at the RCS (Rapid Cycling Synchrotron) injection area of J-PARC(Japan Proton Accelerator Research Complex). At the injection area, beam loss caused by the nuclear scattering together with the multiple coulomb scattering at the charge-exchange foil is the dominant one and is an important issue for designing mainly the foil thickness and other beam elements like, the falling time of bump magnets after the injection is finished and so on. The simulation tool GEANT for the scattering effect and the real injection process have been employed together in order to estimate the beam loss turn by turn including identification of loss points too. | ||
| TUPAN062 | RF Amplitude and Phase Tuning of J-PARC SDTL | 1529 |
|
||
| In the beam commissioning of J-PARC Linac, RF phase and amplitude of SDTL (Separate-type Drift Tube Linac) cavities have been tuned with a phase-scan method based on the beam-energy measurement. The output beam energy is measured with two FCTs (Fast Current Transformer) using the TOF (Time-Of-Flight) method. The detailed results of RF tuning for SDTL cavity is presented. | ||
| TUPAN063 | High Power Test of MA Cavity for J-PARC RCS | 1532 |
|
||
| We have been testing the RF cavities for the J-PARC RCS, we can operate the cavities without sever problems. Before some MA cores were damaged, then we found such cores have low ribbon resistance. After that we have tested the cavities loaded with improved ribbon resistance. | ||
| TUPAN064 | Use of Solidified Gas Target to Laser Ion Source | 1535 |
|
||
| We examined a laser produced neon plasma as part of a future laser ion source. The ion source is capable of generating highly ionized particles and high intensity beams by irradiating a solid target with a pulsed laser. Rare gases, which are in gas state at room temperature, need to be cooled to solid targets for laser irradiation. We generated solid neon targets by equipping our laser ion source chamber with a cryogenic cooler. This method will generate high current rare gas beams. | ||
| TUPAN065 | Proton Beam Quality Improvement by a Tailored Target Illuminated by an Intense Short-Pulse Laser | 1538 |
|
||
|
Suppression of a transverse proton divergence is focused by using a controlled electron cloud. When an intense short pulse laser illuminates a foil plasma target, first electrons are accelerated and they form a strong electric field at the target surface, then protons can be accelerated by the strong field created. An electron cloud is limited in the transverse direction by plasma at the protuberant part, if the target has a hole at the opposite side of the laser illumination*. The proton beam is accelerated and also controlled by the transverse shaped electron cloud, and consequently the transverse divergence of the beam can be suppressed. In 2.5D particle-in-cell simulations, the transverse shape of the electron cloud is controlled well.
* R. Sonobe, S. Kawata, et. al., Phys. Plasmas 12 (2005) 073104. |
||
| TUPAN066 | Half-mini Beta Optics with a Bunch Rotation for Warm Dense Matter Science Facility in KEK | 1541 |
|
||
|
An all-ion accelerator (AIA) is a quite interesting device as a driver to explore a Warm Dense Matter (WDM) state*. The irradiation onto a target at a small focal spot (< a few mm) with a short pulse duration (< 100 nsec) is required to create an interesting WDM state. The final focus is carried out through a half-mini beta beam line placed after the kickout from the AIA. The half-mini beta beam line should be designed with the space-charge effect due to the high current beam. The design includes effects of a large momentum spread caused by a fast bunch rotation. The beam optics concerned with the effects of space-charge and the large momentum spread during the half-mini beta system is designed for the WDM science in KEK AIA Facility.
* E. Nakamura, et al., "A Modification Plan of the KEK 500MeV Booster to an All-ion Accelerators (An Injector-free Synchrotron)", PAC07. |
||
| TUPAN072 | Analysis of BEPCII Optics Using Orbit Response Matrix | 1544 |
|
Funding: Work supported by Core University Program
Due to the errors in all kinds of components of storage ring, the real ring optics is different from the design one. A computer code LOCO is developed to calibrate the linear optics based on the closed orbit response matrix. This paper discusses mainly on the procedure and results of optics correction at BEPCII BPR. Using LOCO, we have determined the errors of quadrupole strengths, BPM gains and corrector kicks, and found the quadrupole strengths that best restore the design optics with sextupoles on. Optics measurement after correction shows the real optics agrees well with the design optics.
weiyy@mail.ihep.ac.cn |
||
| TUPAN076 | Conceptual Design of the Beam Line for the PEFP User Facility | 1547 |
|
||
|
Funding: The work was supported by the 21C Frontier R&D program in Ministry of Science and Technology of the Korean Government The Proton Engineering Frontier Project (PEFP) will supply 20-MeV and 100-MeV proton beams from a 100 MeV proton linear accelerator for beam applications. The extracted 20 MeV or 100 MeV proton beams will be simultaneously distributed into the five targets through a dipole magnet equipped with a controllable AC power supply. The most important design criterion is the flexibility of the irradiation conditions in order to meet various user requirements in many application fields. For this purpose, we have designed the beamlines to the targets for wide or focused beams, external or in-vacuum beams, and horizontal or vertical beams. This work includes details of the conceptual design of the beamlines. |
||
| TUPAN077 | Error Analysis of the PEFP 100 MeV Linac | 1550 |
|
||
|
Funding: This work was supported by the 21C Frontier R&D program in Mnistry of Science and Technology of the Korean Government. The 100 MeV Linac of the Proton Engineering Frontier Project (PEFP) consists of an ion source, a low energy beam transport (LEBT), a 3 MeV radio frequency quadrupole (RFQ), and an 100 MeV drift tube linac (DTL). The DTL is separated into two parts. The first part includes 4 tanks which accelerate 20 mA proton beams up to 20 MeV. The medium energy beam transport (MEBT) follows the 20 MeV accelerator in order to match proton beams into the next linac as well as to extract and supply 20 MeV proton beams to the user facilities. The second part of the DTL consists of 7 tanks to accelerate proton beams to 100 MeV. This work focuses on the error analysis of the designed 100 MeV linac in order to obtain the tolerance limit in the fabrication and alignment processes of the linac as well as to study the steering magnets which control the beam fluctuations and reduce the potential beam loss. |
||
| TUPAN078 | Design and Fabrication of the PEFP DTL II | 1553 |
|
||
|
Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government The PEFP DTL II which accelerates a proton beam from the energy of 20MeV Beam to 100MeV is now under fabrication. The DTL II which has some similar specifications with the DTL I which accelerates the proton beam to the energy of 20MeV is made of seamless carbon steel with Cu electroplating inside. The DTL tank is divided into 3 sections whose length is about 2.2m. We verified the mechanical and thermal stability using ANSYS code, and we established the fabrication process of the drift tube. The DTL II is now being fabricated. |
||
| TUPAN079 | Scheme for Flattening of Ion Density Distribution on a Target | 1556 |
|
||
| A scheme for flattening of the ion density distribution on a target is considered. The aim is to obtain the ion density distribution with deviation from the medium level not more than 5% on the target having rather big dimensions (up to ~60 cm in width and ~30 cm in height). Such kinds of targets are required for some technological purposes. The Xe ion beam extracted from a cyclotron has the following parameters: mass-to-charge ratio is 4.4, the kinetic energy is 4.2 MeV per nucleon, the beam current is 1 and the beam emittance is equal to 40 mm mrad. The ion beam line consists of quadrupoles doublet and oqtupole lens. After passimg through two quadrupoles the ion beam has big horizontal and small vertical dimensions. After that the oqtupole makes the horizontal ion beam density distribution on the target uniform withing the nessary demands. The geometry of the beam line, the quadrupole and oqtupole lens parameters are found during simulation. The simulated final beam density distribution on the target is also given. | ||
| TUPAN080 | Screening of Cyclotron Magnetic Field in C400 Axial Injection Beam-line | 1559 |
|
||
| The screening of the optical elements placed at the horizontal part of the axial injection beam-line of the C400 cyclotron for hadron therapy is performed. An influence of the injection channel shielding elements on magnetic field distribution in the median plane of the C400 cyclotron was studied. The 3D ANSYS model is used for this purpose. | ||
| TUPAN081 | Axial Injection Beam-Line of C400 Cyclotron for Hadron Therapy | 1562 |
|
||
| The axial injection beam-line of the C400 cyclotron for hadron therapy is presented. The influence of the strong magnetic field from the cyclotron on particles dynamics is taking into account during simulation. The effect of the beam space charge neutralization due to residual gas in the beam-line on parameters of the injected beam is evaluated. | ||
| TUPAN083 | Space-Charge Neutralization in Ion Undulator Linear Accelerator | 1565 |
|
||
|
RF undulator accelerator (UNDULAC-RF) is suggested as an initial part of high intensity ion linac*. Such accelerator can be realized in periodical IH structure where a field has no spatial harmonics in synchronism with the beam. Ion beam is accelerated by the combined field of two non-synchronous harmonics. Accelerating force value is proportional to squared particle charge. Transmission coefficient and accelerating gradient for low velocity ions with the identical sign of charge are the same as in RFQ. The limit beam current can be larger in this type accelerator. Its value was calculated earlier in paper **. But the beam intensity can be substantially increased in UNDULAC by using space charge neutralization of positive and negative charged ions. In UNDULAC positive and negative ions can be accelerated simultaneously within the same bunch. The process of acceleration and focusing of oppositely charged ions with the identical charge-to-mass ratio is discussed in this paper.
* E. S. Masunov, Technical Physics, V. 46, 11, 2001, pp. 1433-1436.**E. S. Masunov, S. M. Polozov, NIM., A 558, 2006, pp. 184-187. |
||
| TUPAN084 | Using Smooth Approximation for Beam Dynamics Investigation in Superconducting Linac | 1568 |
|
||
| The superconducting linac consists of some different classes of the identical cavities. The each cavity based on a superconducting structure with a high accelerating gradient. The distance between the cavities is equal to acceleration structure period L. By specific phasing of the RF cavities one can provide a stable particle motion in the whole accelerator. The ion dynamics in such periodic structure is complicated. The reference particle coordinate and momentum can be represented as a sum of a smooth motion term and a fast oscillation term, a period of which is equal to L. Three dimensional equation of motion for ion beam in the Hamiltonian form is derived in the smooth approximation for superconducting linac. The longitudinal acceptance and maximum energy width in a bunch are found by means of the effective potential function. The general conditions applicability of a smooth approximation to given electrodynamic problem is formulated. The nonlinear ion beam dynamics is investigated in such accelerated structure. | ||
| TUPAN085 | LHC Impedance Reduction by Nonlinear Collimation | 1571 |
|
||
| A nonlinear collimation system can allow larger aperture for the mechanical jaws, and it thereby can help to reduce the collimator impedance, which presently limits the LHC beam intensity. Assuming the nominal LHC beam at 7 TeV, we show how a nonlinear betatronic collimation insertion would reduce considerably the LHC coherent tune shift for the most critical coupled-bunch mode as compared with the conventional baseline linear collimation system of Phase-I. In either case, the tune shifts of the most unstable modes are compared with the stability diagrams for Landau damping. | ||
| TUPAN086 | An Improved Beam Screen for the LHC Injection Kickers | 1574 |
|
||
| The two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. Each system is composed of two resonant charging power supplies and four 5 Ω transmission line kicker magnets with matched terminating resistors and pulse forming networks. A beam screen is placed in the aperture of the magnets: the screen consists of a ceramic tube with conductors on the inner wall. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against Wake fields. The conductors initially used gave adequately low beam impedance however inter-conductor discharges occurred during pulsing of the magnet: an alternative design was discharge free at the nominal operating voltage but the beam impedance was too high for the ultimate LHC beam. This paper presents the results of a new development undertaken to meet the often conflicting requirements for low beam impedance, shielding of the ferrite, fast field rise time and good electrical behaviour. High voltage test results and thermal measurements are also presented. | ||
| TUPAN087 | Scenarios for Beam Commissioning of the LHC Collimation System | 1577 |
|
||
| A complex system of collimators has been designed to protect the superconducting LHC magnets against quench and damage from the high intensity proton beams. The considerable number of collimators and the resulting number of degrees of freedom for their set-up requires a well prepared commissioning strategy. Efficiency studies for various implementations of the LHC collimation system have been performed, taking into account the evolution in optics and beam intensity according to the LHC commissioning schedule. This paper explains the present plans for the set-up sequence of collimators and discusses the relevant tolerances induced from the collimation system for the first years of the LHC operation. | ||
| TUPAN088 | Beam Scraping for LHC Injection | 1580 |
|
||
| Operation of the LHC will require injection of very high intensity beams from the SPS to the LHC. Fast scrapers have been installed and will be used in the SPS to detect and remove any existing halo before beams are extracted, to minimize the probability for quenching of super-conducting magnets at injection in the LHC. We briefly review the functionality of the scraper system and report about measurements that have recently been performed in the SPS on halo scraping and re-population of tails. | ||
| TUPAN089 | The LHC Beampipe Waveguide Mode Reflectometer | 1583 |
|
||
| Several specially developed waveguide-mode reflectometers for obstacle detection in the LHC magnet beampipes have been intensively used for more than 18 months. This "Assembly" version is based on the synthetic pulse method using a modern vector network analyzer. It has mode selective excitation couplers and uses a specially developed waveguide mode dispersion compensation algorithm with external software. In addition there is a similar "in situ" version of the reflectometer which uses permanently installed microwave couplers at the end of each of the nearly 3 km long LHC arcs. A considerable number of unexpected objects have been found in the beampipes and subsequently removed. Operational statistics and lessons learned are presented and the overall performance is discussed. | ||
| TUPAN090 | Parametric Field Modelling for the LHC Main Magnets in Operating Conditions | 1586 |
|
||
| The first injections and ramps in the LHC will require a prediction of the settings of the main ring powering circuits as well as the main correctors. For this reason we are developing a parametric model of the magnetic field generated by the LHC magnets that will provide the field dependence on current, ramp-rate, time, and history. The model of the field is fitted on magnetic field measurements performed during the acceptance tests in operating conditions before their installation in the machine. In this paper we summarise the different steps necessary to select the relevant data and identify the parameters: the data extraction, the cleaning and the validation of the measurements, and the fitting procedure that is used to obtain the parameters from the experimental results. The main result reported is a summary of the value of the parameters obtained with the above procedure, and describing the behaviour of the magnetic field in the LHC main superconducting magnets (i.e. arc, dispersion suppressors and matching sections). | ||
| TUPAN091 | LHC Beam-beam Compensation Using Wires and Electron Lenses | 1589 |
|
||
| We present weak-strong simulation results for a possible application of current-carrying wires and electron lenses to compensate the LHC long-range and head-on beam-beam interaction, respectively, for nominal and Pacman bunches. We show that these measures have the potential to considerably increase the beam-beam limit, allowing for a corresponding increase in peak luminosity | ||
| TUPAN092 | Schedule evolution during the life-time of the LHC project | 1592 |
|
||
| The Large Hadron Collider Project was approved by the CERN Council in December 1994. The CERN management opted from the beginning of the project for a very aggressive installation planning based on a just-in-time sequencing of all activities. This paper aims to draw how different factors (technical development, procurement, logistics and organization) have impacted on the schedule evolution through the lifetime of the project. It describes the cause effect analysis of the major rescheduling that occurred during the installation of the LHC and presents some general conclusions potentially applicable in other similar projects. | ||
| TUPAN093 | Simulation of the CERN PS Booster Performance with 160 MeV H- Injection from Linac4 | 1595 |
|
||
| The ultimate luminosity (2.3 x 1034 cm-2 s-1) in the LHC can only be reached or even exceeded if a major upgrade of the CERN proton injector complex takes place. The first identified bottleneck towards higher brightness beams is the 50 MeV proton injection of Linac2 into the PS booster (PSB). Doubling the intensity in the PSB can be achieved with a new linac (Linac4) which increases the injection energy to 160 MeV. Linac4 will provide H- ions and charge-exchange injection will be used in the PSB instead of using the present multi-turn proton injection scheme. The code ACCSIM is used to study the H- injection process and to determine if the requested intensities can be reached within the specified emittance budgets. The results are then compared with ORBIT simulations. In the longitudinal plane we use ESME to study various capture schemes. | ||
| TUPAN094 | PS2 Injection, Extraction and Beam Transfer Concepts | 1598 |
|
||
| The replacement of CERN's existing 26 GeV Proton Synchrotron (PS) machine with a separated-function synchrotron PS2 has been identified as an important part of the possible future upgrade programme of the CERN accelerator complex. The PS2 will require a number of new beam transfer systems associated with injection, extraction, beam dumping and transfer. The different requirements are briefly presented, together with an overview of the conceptual design of these systems, based on the initial PS2 parameter set. The required equipment sub-system performance is derived and discussed. Possible limitations are analysed and the impact on the overall design and parameter set is discussed. | ||
| TUPAN095 | Design and Performance of the CNGS Secondary Beam Line | 1601 |
|
||
| An intense muon-neutrino beam (1017 nu-mu/day) is generated at CERN and directed towards the Gran Sasso National Laboratory, LNGS, in Italy, 732 km away from CERN. The muon-neutrinos are produced in association with muons in the decay of the pions and kaons created in the target. In the presently approved physics programme, it is foreseen to run the CNGS facility with 4.5 · 1019 protons/year for five years. During a CNGS cycle, i.e. every 6s, two nominal SPS extractions of 2.4 ·1013 protons each at 400GeV/c are sent down the proton beam line to the target. The CNGS secondary beam line, starting with the target, has to cope with this situation, which pushes the beam line equipment and instrumentation to the limits of radiation hardness, mechanical stresses, etc. during the CNGS operation. An overview of the CNGS secondary beam line will be shown. Emphasis will be on the target, the magnetic focusing lenses (horn and reflector) and the muon monitors. The performance of the secondary beam line during beam commissioning and physics operation will be discussed and measurements compared with simulations. | ||
| TUPAN096 | High Intensity Commissioning of the SPS LSS4 Extraction for CNGS | 1604 |
|
||
| The fast extraction in SPS LSS4 serves both the anti-clockwise ring of the LHC and the CERN Gran Sasso Neutrino facility (CNGS). The latter requires 2 fast extractions of 10.5 microsecond long batches per cycle, 50 milliseconds apart. Each batch will consist of 2.4·10+13 protons at 400 GeV, a factor of 10 in energy density above the equipment damage limit in case of beam loss. Active and passive protection systems are in place to guarantee safe operation and to respect the radiation limits close to the extraction region. In summer 2006 CNGS was commissioned including extraction with high intensity. A thorough setting-up of the extraction was performed as part of the CNGS commissioning, including aperture and beam loss measurements, and defining and checking of interlock thresholds for the extraction trajectory, magnet currents, kicker voltage and beam loss monitors. The various systems and the associated risks are discussed, the commissioning results are summarised and a comparison is made with predictions from simulations. | ||
| TUPAN097 | Studies of Beam Losses from Failures of SPS Beam Dump Kickers | 1607 |
|
||
| The SPS beam dump extraction process was studied in detail to investigate the possibility of operation with reduced kicker voltage and to fully understand the trajectory and loss pattern of the mis-kicked beams. This paper briefly describes the SPS beam dump process, and presents the tracking studies carried out for failure cases. The simulation results are compared to the results of measurements made with low intensity beams. | ||
| TUPAN098 | Beam Commissioning of the SPS LSS6 Extraction and TT60 for LHC | 1610 |
|
||
| The new fast extraction system in LSS6 of the SPS and the first 100 m of transfer line TT60 was commissioned with low intensity beam in late 2006. The layout and functionality of the main elements are briefly explained, including the various hardware subsystems and the control system. The systems safety procedures, test objectives and measurements performed during the beam commissioning are described. | ||
| TUPAN100 | Performance Reach of the | 1613 |
|
||
| State-of-the-art tracking tools have been developed for detailed LHC collimation and beam loss studies. This includes full chromatic treatment of both beam lines and error models. This paper reviews the main results on the performance reach of the multi-stage LHC collimation system that is being installed in the LHC. Limitations on the allowed proton loss rates and the stored intensity can be derived from the comparison of local losses with estimated quench limits for the superconducting magnets. The origins of the cleaning-related performance limitations are presented and possible improvements are discussed. | ||
| TUPAN101 | Tracking Studies with Variable Magnetic Field to Characterize Quadrupole Failures in LHC | 1616 |
|
||
| During LHC operation, energies up to 360 MJ will be stored in each proton beam and more than 10 GJ in the superconducting magnets. With these energies, a magnet failure can lead to important equipment damage if the beam is not extracted in time. The machine protection systems should detect such failures and trigger the beam extraction system. In order to characterize the beam response after magnet failures, tracking simulations have been performed with MAD-X. The magnetic field was set to change with time according to realistic current changes in the electrical circuits with the magnets after a powering failure. The effect on the beam of powering failures in the normal conducting quadrupoles has been studied. For fast failures (beam lost in less than 100 ms) the nonlinear effects are negligible. For slower failures, higher order resonances may lead to beam losses of up to ~8% of the beam. | ||
| TUPAN102 | Numerical Study of the Very Forward Background from the Proton-Proton Collisions in the Experimental Insertions of the LHC | 1619 |
|
||
| The results from the numerical DPMJET-FLUKA simulation of the background in the experimental IR's of the LHC are presented. DPMJET3 is used for the generation and analysis of the products from the p-p collision leaving the interaction point in the very forward region. A multi-particle transport code FLUKA is used for the simulation of the resulting secondary cascades in the structure of the LHC long straight sections. The background formation is estimated and analyzed in the LSS's at the locations of the TAN absorber, Roman Pot stations and Beam Loss Monitors, for the purposes of the machine protection and planning of the operation of the detectors. | ||
| TUPAN107 | Beam Loss Response Measurements with an LHC Prototype Collimator in the SPS | 1622 |
|
||
| Beam tests with an LHC prototype collimator were performed at the SPS in autumn 2006. Applying a new collimator control system many new beam measurements were performed. This contribution presents results on collimator-induced beam loss measurements and their applications to beam-based alignment of collimators and measurements of the beam size and position. Interesting features of the recorded beam loss signals are illustrated and possible impacts for LHC operation are discussed. The measured loss distributions around the full SPS ring are analyzed and compared with simulations. | ||
| TUPAN108 | LHC Collimation System Hardware Commissioning | 1625 |
|
||
| The stored energy and intensity of the LHC beam exceed the damage level of the machine and the quench level of the magnets by far. Therefore a robust and reliable collimation system is required which prevents the quenching of the magnets during regular operation and protects the accelerator components from damage in the event of beam loss. To assure that the installed collimators will protect the machine and permit the required performance of the collider, an appropriate hardware commissioning has to be implemented. In this contribution we describe the procedures for the hardware commissioning of the LHC collimation system. These procedures will establish the required precision and reliability of collimator movements and settings before the start of beam operation. | ||
| TUPAN109 | 160 MeV H- Injection into the CERN PSB | 1628 |
|
||
| The H- beam from the proposed LINAC4 will be injected into the four existing rings of the PS Booster at 160 MeV. A substantial upgrade of the injection region is required, including the modification of beam distribution system and the construction of a new H- injection system. This paper discusses beam dynamics and hardware requirements and presents the results of optimisation studies of the injection process for different beam characteristics and scenarios. The resulting conceptual design of the injection region is presented, together with the main hardware modifications and performance specifications. | ||
| TUPAN110 | On Feasibility Study of 8 MeV H- Cyclotron to Charge the Electron Cooling System for HESR | 1631 |
|
||
| A compact cyclotron to accelerate negative Hydrogen ions up to 8 MeV is considered the optimal solution to the problem of charging the high voltage terminal of the Electron Cooling System for High Energy Storage Ring at GSI (HESR Project, Darmstadt). Physical as well as technical parameters of the accelerator are estimated. Different types of commercially available cyclotrons are compared as a possible source of a 1 mA H- beam for HESR. An original design based on the application of well-established technical solutions for commercial accelerators is proposed. | ||
| TUPAN111 | Status Report on the RAL Front End Test Stand | 1634 |
|
||
| High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London and the University of Warwick. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational regimes. This paper describes the status of the RAL Front End Test Stand which consists of five main components: a 60 mA H- ion source, a low energy beam transport, a 324 MHz Radio Frequency Quadrupole accelerator, a high speed beam chopper and a comprehensive suite of diagnostics. The aim is to demonstrate production of a 60 mA, 2 ms, 50 pps, chopped H- beam at 3 MeV. | ||
| TUPAN112 | Slow-Wave Chopper Structures for Next Generation High Power Proton Drivers | 1637 |
|
Funding: Work supported by CCLRC/RAL/ASTeC and the European Community Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract No. RII3-CT-50295)
A description is given of slow-wave chopper structures for the 3.0 MeV, 60 mA, H- MEBT lines of the CERN Linac 4 and RAL Front-End Test Stands (FETS). Transmission line properties and transverse E-field uniformity for the original European Spallation Source (ESS) designs* have been refined by modelling static, and time dependent electromagnetic fields in the 3D CST 'EM Studio', and 'Microwave Studio' codes**. In addition, the original compact, radiation hard, vacuum compatible designs have been simplified and reconfigured to be compatible with standard NC machining practice. Transmission line properties in the frequency and time domain, together with E-field uniformity in the axial and transverse planes, are presented.
* M. A. Clarke-Gayther, 'Slow-wave electrode structures for the ESS 2.5 MeV fast chopper', Proc. of the 2003 Particle Accelerator Conference (PAC), Portland, Oregon, USA, p. 1473-1475.** www.cst.com |
||
| TUPAN113 | Injection Studies on the ISIS Synchrotron | 1640 |
|
||
| The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. The multi-turn charge-exchange injection process strongly affects transverse beam distributions, space charge forces, beam loss and therefore operational intensity. The evolution of longitudinal distributions and subsequent trapping efficiency is also intimately linked with injection. Optimising injection is therefore a key consideration for present and future upgrades. Work is now under way looking at this process in more detail, and relates closely to other transverse space charge studies on the ring. This paper presents work including: space charge simulations of the present machine and comparison with observations; assessment of related loss mechanisms; and study of optimal painting schemes. Plans and preparations for more detailed experimental work are also summarised. | ||
| TUPAN114 | RF Design Options for a 180 MeV H- Linac for Megawatt Beam Facilities | 1643 |
| Future projects like a neutrino factory or an advanced spallation neutron source require high power proton accelerators capable of producing beams in the multi-MW range. The quality of the beam delivered to the target is very much dictated by the accelerator front end and by the lower energy linac. Prompted by the Front End Test Stand (FETS) under construction at RAL, a new 180 MeV H- linac is being considered as a possible replacement for the aging current 70 MeV ISIS injector, and the same linac has also been included in designs for the proton driver for a possible UK Neutrino Factory. In this paper, different RF design options are analysed and a general layout for the new linac is presented based on two accelerating structures to raise the beam energy from 3 to 180 MeV: a 324 MHz Drift Tube Linac (DTL) making use of commercial Toshiba klystrons, followed by Side Coupled Linac (SCL) with a triple frequency jump at the transition between the two structures. | ||
| TUPAN115 | Comparative Study of Beam Dynamics in LINAC4 using CERN and RAL MEBT (Medium Energy Beam Transport) Lines | 1646 |
|
||
|
Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" program (CARE, Contract No. RII3-CT-2003-506395). CERN and RAL are working in parallel to develop Front Ends for future particle accelerators. At CERN the Front End will be part of LINAC4, a potential replacement for the Linac2 accelerator, whilst at RAL the Front End is intended to demonstrate that a high current, high quality chopped beam is achievable and that the design could be used as part of a Proton Driver for a future Neutrino Factory. The two Front End designs have many similarities and basically consist of four main components: an H- ion source, a Low Energy Beam Transport (LEBT) matching into a Radio-Frequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) line with a fast beam chopper. The beam choppers are different in the two designs and it is important to compare the effectiveness of the two methods of operation. This paper describes a simulation study of high intensity beam dynamics and beam transport when the RAL and CERN MEBT designs are each fed into the same CERN structure for LINAC4. |
||
| TUPAN117 | Progress on Dual Harmonic Acceleration on the ISIS Synchrotron | 1649 |
|
||
| The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the most intense pulsed, spallation, neutron source. The accelerator consists of a 70 MeV H- linac and an 800 MeV, 50 Hz, rapid cycling, proton synchrotron. The synchrotron beam intensity is 2.5·1013 protons per pulse, corresponding to a mean current of 200 μA. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities with harmonic number 2. Four additional, harmonic number 4, cavities have been installed to increase the beam bunching factor with the potential of raising the operating current to 300μA. The dual harmonic system has now been used operationally for the first time, running reliably throughout the last ISIS user cycle of 2006. This paper reports on the hardware commissioning, beam tests and improved operational results obtained so far with dual harmonic acceleration. |