KAERI, Daejon
Uniform irradiation is very important for many kinds of experiments of proton beam utilization. In general, scanning magnet have been used for the uniform irradiation of high energy proton beam in the type of wobbler scanning, raster scanning, spiral scanning, etc. In the case of using magnets, it is not easy and needs high cost to install and operate because the magnet size and power become bigger with increase of beam energy accordingly. In this paper, we proposed simpler method and apparatus for uniform irradiation using 2D motional stage. It is composed of two motion systems for X- and Y- direction motion and goniostage. The maximum area is 20cm x 20cm and the incident angle can be controlled from +15 to -15 degree. Maximum sample weight have to be less than 5kg. In this paper, preliminary results for simple wobbler scanning is shown when the proton energy and beam current are about 40MeV and 1~10 nA respectively. The uniform scanning area was checked by using GAF film, MD-55 or HD-810. The stage can be used for the beam alignment and beam profile measurement at any position of beam line.
CERN, Geneva
Force transducers based on strain and capacitive gauges have been developed and used for monitoring the coil pre-stress during assembly and excitation of magnet models. This paper will summarize and compare the new techniques of mechanical measurements use at CERN for the New Inner Triplet Project. Furthermore the paper will give a comparison of the gauge performances (Creep effects, temperature effects, etc.) and will present the performances of the new data acquisition system developed at CERN to measure simultaneously the strain gauges, the capacitive gauges and other external parameters for the magnet.
LBNL, Berkeley, California
Fermilab, Batavia
BNL, Upton, Long Island, New York
Advanced superconductors such as Nb3Sn are being considered for future magnet upgrades of the Large Hadron Collider (LHC) at CERN. The US LHC Accelerator Research Program (LARP) has developed a large bore (120mm) Nb3Sn IR quadrupole (HQ) capable of reaching 15 T at its conductor and a gradients of 199T/m at 4.4K and 219T/m at 1.9K. HQ is addressing coil alignment and accelerator field quality in a shell-based mechanical structure. In this paper we summarize the fabrication, assembly and initial test results of the 1 m long two-layer magnet.
Kyushu University, Center for Accelerator and Beam Applied Science, Fukuoka
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
Kyushu University, Fukuoka
KURRI, Osaka
KEK, Ibaraki
SAGA, Tosu
150 MeV FFAG accelerator is under construction at Center for Accelerator and Beam Applied Science on Ito Campus to promote activities in all related scientific, medical, engineering and educational field at Kyushu University. In this paper, status of the development of hardware and the results of the beam commissioning of the injector are described.
INFN- Sez. di Padova, Padova
INFN/LNL, Legnaro (PD)
INFN-Torino, Torino
In the framework of the IFMIF/EVEDA project, the RFQ is a 9.8 m long cavity, with very challenging mechanicals specification. In the base line design, the accelerator tank is composed of 18 modules that are flanged together. The construction procedure of each module foresees the horizontal brazing of the four electrodes and then the vertical brazing of the flanges. A RFQ prototype, composed of 2 modules, aimed at testing all the mechanical construction procedure is under construction. In this article, the progress of the prototype construction and the progresses in the design and engineering phase, as well the description of all the fabrication phases is reported.
CERN, Geneva
The Linac4 RFQ will accelerate the H- beam from the ion source to the energy of 3 MeV. The RFQ is composed of three sections of 1 meter each, assembled by means of ultra high vacuum flanges and an adjustable centering ring. The complete 3-m long RFQ will be supported isostatically over 3 points like a simple beam in order to minimise the maximum deflection. The ridge line, used to feed the RF power into the RFQ, will be supported via springs and its position adjusted in such way that no strain is introduced into the RFQ at the moment of its connection. The mechanical design has been done at CERN where the modules are completely manufactured, heat treated and brazed also. In that way, all of the processes are carefully controlled and the influence, notably of the heat treatments, has been understood in a better way. Since 2002 several four vanes RFQ modules have been brazed at CERN for the TRASCO and IPHI projects. A two-step brazing procedure has been tested. This technique is actually used for the assembly of the CERN Linac4 RFQ. This paper describes the design, the mechanical procedures adopted for machining and assembly and the first results obtained.
Imperial College of Science and Technology, Department of Physics, London
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
This paper will present the mechanical engineering design for a 324 MHz 4-vane RFQ, which has been developed for the Front End Test Stand (FETS) project based at the Rutherford Appleton Laboratory (RAL) in the UK. The design criteria will be discussed along with particular design features of the RFQ including the tuners, vacuum ports, main body cooling pocket design and the support / alignment structure. Different techniques for creating the RF and vacuum seal between major and minor vanes are also discussed.
JASRI/SPring-8, Hyogo-ken
RIKEN/SPring-8, Hyogo
The University of Tokyo, Nuclear Professional School, Ibaraki-ken
We are developing a single-shot and non-destructive 3D bunch charge distribution (BCD) monitor based on Electro-Optical (EO) sampling with a manner of spectral decoding for XFEL/SPring-8. For fine beam tuning, 3D-BCD is often required to measure in real-time. The main function of this bunch monitor can be divided into longitudinal and transverse detection. For the transverse detection, eight EO-crystals surround the beam axis azimuthally, and a linear-chirped probe laser pulse with a hollow shape passes thorough the crystal. The polarization axis of the probe laser should be radially distributed as well as the Coulomb field of the electron bunches. Since the signal intensity encoded at each crystal depends on the strength of the Coulomb field at each point, we can detect the transverse BCD. In the longitudinal detection, we utilize a broadband square spectrum (> 400 nm at 800 nm of a central wavelength) so that the temporal resolution is < 30 fs if the pulse width of probe laser is 500 fs. In order to achieve 30-fs temporal resolution, we use an organic EO material, DAST crystal, which is transparent up to 30 THz. We report the first experimental results of this 3D-BCD monitor.
KEK, Ibaraki
MELCO SC, Tsukuba
J-PARC, KEK & JAEA, Ibaraki-ken
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation (<30 micrometers with 1 sec averaging), (3) beam based alignment.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
J-PARC, KEK & JAEA, Ibaraki-ken
The J-PARC RCS is an M-Watt class rapid cycling synchrotron and it has delivered an intensive beam to the neutron target and the MR. In order to overcome large space charge effect, its physical aperture is designed to be more than 250mm in diameter. Even though its chamber size is very large, the BPM system gives precise data to determine beam optics parameters of the ring. For this purpose, only relative positions and resolutions are important. However, for much higher intensity, the absolute beam position and accurate COD correction are indispensable. We have carefully installed the BPM and measured the position with respect to the quadrupole magnet (QM) nearby. But it is also necessary to estimate its absolute position by using beam. If each QM could be controlled independently, the simple beam based alignment technique can be utilized, but it is not the case for RCS. There are seven families of QM, and only each family can be controlled at one time. We developed a new technique by expanding the simple method for the case of multiple QM focusing changed simultaneously, and applied to the J-PARC RCS. The paper describes this method and discussed about experimental results.
ICEPP, Tokyo
KEK, Ibaraki
University of Tokyo, Tokyo
In this paper, we describe a system design and current status of Shintake beam size monitor. Shintake monitor is a laser-based beam diagnostics tool, which provides a non-invasive measurement of transverse beam sizes. The interaction target probing the electron beam is interference fringes build up by the two coherent lasers that have narrow bandwidth and long coherent length. A scale of the target structure corresponds to approximately one fourth of the laser wave length, and the smallest measurable size reaches down to several tens of nanometers. The monitor we described here is installed at the virtual interaction point of the ATF2 beam line, which is built to confirm the proposed final focus system for Future Linear Colliders. We adopt second harmonics of Nd:YAG laser of 532 nm wavelength, and phase stabilization feedback system to allow to measure the designed beam size of about 37 nm. To widen a measurable range up to about 5 microns (wire scanner's range), we also prepare three crossing modes that change an effective wavelength for the fringes. The monitor is used to measure a focus size during the tuning process. The system is based on the Shintake monitor for FFTB.
University of Tokyo, Tokyo
KEK, Ibaraki
ICEPP, Tokyo
ATF2 is the final focus test facility for ILC to realize and demonstrate nanometer focusing. One of the goals of the ATF2 is a demonstration of a compact final focus system based on the local chromaticity correction. A designed beam size at the focal point is to be 37 nm in vertical. To achieve the goal, a beam size monitor capable of nanometer beam size measurement is inevitably needed. Shintake monitor satisfies the demands, and is installed at the virtual interaction point of the ATF2. Shintake monitor is a beam size monitor which uses laser interference fringe pattern to measure beam size. The beam test for the Shintake monitor was successful in measurement of signal modulation with the laser interference fringe pattern in November 2009. In April 2010, beam size of less than 1 micron was achieved. We have studied the error sources, and evaluated the total error to be less than 10% for 1 minute measurement. This paper is about the evaluation of the Shintake monitor performance by analyzing beam tests data. Most systematic error sources are well understood, so that we can estimate accuracy of beam size measurement when the beam size reaches 37nm.
CERN, Geneva
The CLIC main beam quadrupoles need to be stabilized to 1.5 nm integrated R.M.S. displacement at 1 Hz. The choice was made to apply active stabilization with piezoelectric actuators in a rigid support with flexural guides. The advantages of this choice are the robustness against external forces and the possibility to make fast incremental nanometre positioning of the magnet with the same actuators. The study and feasibility demonstration is made in several steps from a single degree of freedom system (s.d.o.f.) with a small mass, a s.d.o.f. with a large mass, leading to the demonstration including the smallest (type 1) and largest (type 4) CLIC main beam quadrupoles. The paper discusses the choices of the position and orientation of the actuators and the tailored rigidities of the flexural hinges in the multi degree of freedom system, and the corresponding MIMO control system. The compatibility with the magnet support and micrometer alignment system is essential. The status of the study and performed tests will be given.
CERN, Geneva
The commissioning of the beam transfer systems for LHC included detailed aperture measurements in the injection regions and for the beam dump systems. The measurements, mainly single pass, were made using systematic scans of different oscillation phases and amplitudes, and the results compared with the expectations from the physical aperture model of the LHC. In this paper the measurements and results are presented and compared with the specified apertures in these critical areas.
CERN, Geneva
TRIUMF, Vancouver
In 2008, the SPS-to-LHC transfer line operation allowed for the first time to perform beam measurements in the last part of the lines and into the LHC. Beam parameters were measured and compared with expectation. Discrepancies were observed in the dispersion matching into the LHC, and also in the vertical phase advance along the line. In 2009, extensive theoretical and simulation work was performed in order to understand the possible sources of these discrepancies. This allowed establishing an updated model of the beam line, taking into account the importance of the full magnetic model, the limited dipole corrector strengths and the precise alignment of beam elements. During 2009, beam time was allocated in order to perform further measurements, checking and refining the optical model of the transfer line and LHC injection region and validating the different assumptions. Results of the 2009 optics measurements and comparison with the beam specification and model are presented.
CERN, Geneva
Phase II collimators will complement the existing system to improve the expected high RF impedance and limited efficiency of Phase I jaws. An international collaborative effort has been launched to identify novel advanced materials responding to the very challenging requirements of the new collimators. Complex numerical calculations simulating extreme conditions and experimental tests are in progress. In parallel, an innovative modular design concept of the jaw assembly is being developed to allow fitting in alternative materials, minimizing the thermally induced deformations, withstanding accidents and tolerate high radiation doses. Phase II jaw assembly is made up of a molybdenum back-stiffener ensuring high geometrical stability and a modular jaw split in threes sectors. Each sector is equipped with a high-efficiency independent cooling circuit. Beam position monitors (BPM) are embedded in the jaws to accelerate setup time and improve beam monitoring. An adjustment system will permit to fine-tune the jaw flatness just before commissioning the system. A full scale collimator prototype is being manufactured by CERN workshops to validate each feature of the new design.
SLAC, Menlo Park, California
The Phase II upgrade to the LHC collimation system calls for complementing the 30 high robust Phase I graphite secondary collimators with 30 high Z Phase II collimators. The Phase II collimators must be robust in various operating conditions and accident scenarios. This paper reports on the final construction and testing of the prototype collimator to be installed in the SPS (Super Proton Synchrotron) at CERN. Bench-top measurements have demonstrated the device is fully operational and has the mechanical and vacuum characteristics acceptable for installation in the SPS.
JAI, Oxford
CERN, Geneva
Fermilab, Batavia
We present the current status of the beam tracking simulations of the Compact Linear Collider (CLIC) from the exit of the damping ring to the interaction point, including the ring to main linac (RTML) section, main linac, beam delivery system (BDS) and beam-beam interactions. This model introduces realistic alignment survey errors, dynamic imperfections and also the possibility to study collective effects in the main linac and the BDS. Special emphasis is put on low emittance transport and beam stabilization studies, applying beam based alignment methods and feedback systems. The aim is to perform realistic integrated simulations to obtain reliable luminosity predictions.
Royal Holloway, University of London, Surrey
Serpentine is a Python library, written for the purpose of simulating charged particle accelerators. It has been written to allow for the simulation of both rings and single-shot machines in a light-weight way (i.e. without requiring significant computational resources for typical calculations, such as the determination of transfer matrices, or matching of Twiss parameters), and has been structured to be highly modular (i.e. allowing extension of the simulations to include effects not already included in the base installation). Through the use of the Universal Accelerator Parser (UAP), Serpentine has no need for a new lattice representation, and allows access to any lattice format understood by UAP. The operation of this code on several complex accelerator designs is demonstrated.
ELETTRA, Basovizza
PSI, Villigen
CERN, Geneva
FERMI@ELETTRA and PSI-XFEL are 4th Generation Light Sources that require high quality electron beam at the entrance of the undulator chains. In this context, a specially developed X-band structure with integrated alignment monitors will be used to mitigate the nonlinearities in the longitudinal phase space due to the second order RF time curvature and the second order momentum compaction term of chicane compressor. The knowledge of the transverse and longitudinal short range wakefields in the X-band structure is essential to evaluate the beam quality in terms of longitudinal energy spread and transverse kick spread. We have used the ABCI code to numerically evaluate the transverse and longitudinal wake potentials for short bunches in this structure.
ISSP/SRL, Chiba
JAEA/ERL, Ibaraki
KEK, Ibaraki
In ERLs, superconducting cavities accelerate low-emittance beams with high-gradient standing-wave RF fields. If alignment error of the cavities is considerable, they can harmfully affect the beam trajectory and quality because the cavities have strong transverse focusing. Achieving high alignment accuracy of the cavities is difficult compared with the other ERL elements such as magnets because the cavities are contained in cryomodules. Therefore we studied effects of the alignment error of main superconducting cavities with analytical approaches and simulations, using a one-loop model of the compact ERL as an example. In this paper, we present the effects of alignment error of main superconducting cavities on ERLs and their correction.
KEK, Ibaraki
Akita University, Akita
Profile shape measurements detecting profile slope angle, which corresponds to the differential of the profile shape, have been used for evaluating profile shapes highly precisely. They are hardly affected by scanning error in measurement and considered to have advantages for long distance measurements. Here, profile measurement using a level was adopted for straightness alignment of the KEK e-/e+ injector linac, considering the straightness alignment as a profile shape measurement. The slope angles between the alignment base plates of the linac could be detected with reproducibility of 10 micro-rad (σ) by sequential measurement interval of 1 to 2 m. The reproducibility of the straightness derived from the angle measurements was 42 micrometer (σ) for 69 m of the measurement distance and agreed well with the estimated value based on our error propagation model. These results show that straightness reproducibility of better than 1 mm (2-σ) can be achieved for 500 m of the KEK e-/e+ injector linac by sampling interval of 2m, and for 10 km of the ILC linac by sampling interval of 20 cm.
KEK, Ibaraki
A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the KEKB injector linac. The new alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the next generation of B-factories. A new laser optics with Airy pattern (so-called Airy beam) has been developed and the laser propagation characteristics in vacuum has been systematically investigated at a 82-m-long straight section of a beam line of the injector linac. The laser-based alignment measurement based on the new laser optics has been carried out with a measurement resolution of ±0.1 mm level by using a previously-used laser detection system. The experimental results are reported along with the basic design of the new laser-based alignment system.
KEK, Ibaraki
A new laser-based alignment system is under development at the KEKB injector linac. We are revisiting our alignment system because the previous alignment system has become obsolete. The new alignment system is again required to increase the stability of the electron- and positron-beam injection towards next-generation of B-factories. It is similar to the previous one, which comprises a laser-diode system and quadrant photodetectors installed in vacuum light pipes. A displacement of a girder unit of the accelerating structure can be precisely measured in the direction of the laser-ray trace, where the laser light must stably propagate up to 500-m-long downstream without any orbital and beam-size fluctuation. A novel approach in which a two-beam-interference laser-light propagates in the vacuum light pipe, has been designed to increase the alignment precision based on the quadrant photodetector measurement. The propagating laser spot sizes can be narrowed due to the two-beam interference over the Rayleigh-range limit. The design of the new laser-based alignment system is summarized along with some experimental results in this report.
CERN, Geneva
A prerequisite for a successful nanometre level magnet stabilization and pointing system is a low background vibration level. This paper will summarize and compare the ground motion measurements made recently in different accelerator environments at e.g. CERN, CESRTA and PSI. Furthermore the paper will give the beginning of an inventory and characterization of some technical noise sources, and their propagation and influence in an accelerator environment. The importance of the magnet support is also mentioned. Finally, some advances in the characterization of the nanometre vibration measurement techniques will be given.
KIT, Karlsruhe
Karlsruhe Institute of Technology (KIT), Karlsruhe
CERN, Geneva
The monochromaticity and intensity of synchrotron light emitted by undulators strongly depend on the undulator field quality. For the particular case of superconductive undulators it was shown recently that their field quality can be significantly improved by an array of coupled high temperature superconductor loops attached to the surface of the superconductive undulator. Local field errors induce currents in the coupled closed superconducting loops and, as a result, the hereby generated magnetic field minimizes the field errors. In previous papers the concept was described theoretically and a proof-of-principle experiment was reported. This paper reports results of the first quantitative measurement of the phase error reduction in a 12-period short model undulator equipped with a full-scale induction shimming system.
ELETTRA, Basovizza
RIAL VACUUM S.p.A, Parma
The FERMI@Elettra project at the ELETTRA Laboratory of Sincrotrone Trieste (ST), currently under construction, will be comprised of a linear accelerator and two Free-Electron-Laser beamlines (FEL1, FEL2). In order to deliver high-intensity VUV and soft X-ray pulses, permanent magnet undulators with 9 mm minimum variable gap will be used. The adopted vacuum chambers will have a 7 by 25 mm2 elliptical internal cross-section. While manufacturing the vacuum chamber in aluminum helps reducing the resistive wall wakefield effects, the chamber inner wall surface quality is strongly correlated to the surface roughness wakefield component. We report on the results of the study to improve the wall surface finish and lower the roughness periodicity. The chamber manufacturing status and its alignment mechanism is also presented.
CERN, Geneva
Cockcroft Institute, Warrington, Cheshire
Fermilab, Batavia
JAI, Oxford
The CLIC BDS tuning, alignment and feedbacks studies have been typically performed independently and only over particular sections of the BDS. An effort is being put to integrate all these procedures to realistically evaluate the luminosity performance.
CERN, Geneva
Cockcroft Institute, Warrington, Cheshire
JAI, Oxford
SLAC, Menlo Park, California
The CLIC Conceptual Design Report must be ready by 2010. This paper aims at addressing all the critical points of the CLIC BDS to be later implemented in the CDR. This includes risk evaluation and possible solutions to a number of selected points. The smooth and practical transition between the 500 GeV CLIC and the design energy of 3 TeV is also studied.
PSI, Villigen
The application of various optics correction techniques at the SLS allows to reduce the vertical emittance to <3 pm.rad corresponding to an emittance coupling of <0.05 %. Beam sizes can be measured with a resolution of ~0.5 um allowing to resolve vertical beam sizes close to the quantum radiation limit of 0.55 pm.rad. The application of beam-based alignment/ calibration techniques on magnet girders (remotely controlled), quadrupoles and sextupoles can be used to center the beam in all relevant optical elements at a minimum expense of vertical dipole corrector strength. Furthermore a fast orbit feedback based on a high resolution digital BPM system allows to stabilize the closed orbit up to ~90 Hz and to perform precise orbit manipulations within this bandwidth. Furthermore the top-up operation mode guarantees very stable conditions for the various beam-based measurements. These conditions make the SLS an excellent "test-bed" for future damping ring optimization.
KEK, Ibaraki
Linear accelerator systems with superconducting RF technology have become increasingly important to reach high-quality, high current beam conditions required by the high-energy physics and photon science communities. The International Linear Collider, for instance, calls for very challenging (beam conditions). Similarly, the XFEL requires (beam conditions) and future ERLS require (high average current). In this talk, we review the needs and challenges of SCRF linac beam physics and technology for present and future applications.
CERN, Geneva
PSI, Villigen
PSI-XFEL and Elettra-Fermi-require a X-band RF structure. As CLIC is pursuing a program for producing and testing x-band high-gradient RF structures, a collaboration between PSI, Elettra and CERN, has been established to build a multipurpose X-band accelerating structure. This paper focuses on its engineering design which is based on disk-shaped cells bonded together by different technologies (diffusion bonding, vacuum brazing and laser beam welding). The accelerating structure consists of 2 coupler subassemblies and 73 disks, and include wake field monitor waveguides. The engineering study also comprises the external cooling system, consisting of two parallel cooling circuits, and the tuning system, allowing for the fine-tuning by means of cell deformations. The engineering solution for installation and sealing of wake field monitor feed-through devices inside the accelerating structure RF-cavity is also proposed.
SLAC, Menlo Park, California
CERN, Geneva
KEK, Ibaraki
A CERN-SLAC-KEK collaboration on high gradient X-band structure research has been established in order to demonstrate the feasibility of the CLIC baseline design for the main linac stably operating at more than 100 MV/m loaded accelerating gradient. Several prototype CLIC structures were successfully fabricated and high power tested. They operated at 105 MV/m with a breakdown rate that meets the CLIC linear collider specifications of < 5·10-7/pulse/m. This paper summarizes the fabrication technologies including the mechanical design, precision machining, chemical cleaning, diffusion bonding as well as vacuum baking and all related assembly technologies. Also, the tolerances control, tuning and RF characterization will be discussed.
KEK, Ibaraki
University of Fukui, Faculty of Engineering, Fukui
Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture
The two electrostatic septa are one of the most important device for the slow extraction in 50GeV proton synchrotron. We have developed the thin ribbon type septum in order to reduce the beam loss. If alignment of ribbons is poor, the effective thickness seen from the beam become large, and it would increase the beam-hitting rate. The alignment of ribbon over 1.5m long septa was measured by a laser-focus displacement meter. The achieved effective thickness of septa is estimated to be 0.075mm and 0.080mm respectively. We will report a high voltage conditioning and a performance under beam commissioning.
NSC/KIPT, Kharkov
NESTOR facility that is under construction in NSC KIPT (Kharkov, Ukraine) consists of compact 225 MeV electron storage ring, 100 MeV linear accelerator-injector, laser optical system and radiation channel. To provide effective and cheap survey and alignment system for compact facility is crucial task in order to achieve designed X-ray parameters (X-ray intensity up to 1012 phot/s). In the article the survey and alignment strategy of Compton generator NESTOR is described. The system uses traditional triangulation method and provides the accuracy of technological equipment alignment equal to 100 mkm.
Fermilab, Batavia
The NOνA project will upgrade the existing Neutrino at Main Injector (NuMI) project beamline at Fermilab to accommodate beam power of 700 kW. The Medium Energy (ME) graphite target assembly is provided through an accord with the State Research Center of Russia Institute for High Energy Physics (IHEP) at Protvino, Russia. The effects of proton beam energy deposition within beamline components are considered as thermal stability of the target carrier assembly and alignment budget are critical operational issues. Results of finite element thermal and structural analysis involving the target carrier assembly is provided with detail regarding the target's beryllium windows.
mcgee@fnal.gov
INFN-Ferrara, Ferrara
IHEP Protvino, Protvino, Moscow Region
UNIFE, Ferrara
Università dell'Insubria & INFN Milano Bicocca, Como
INFN/LNL, Legnaro (PD)
PNPI, Gatchina, Leningrad District
JINR, Dubna, Moscow Region
INFN MIB, MILANO
CERN, Geneva
Enrico Fermi Institute, University of Chicago, Chicago, Illinois
INFN-Trieste, Trieste
INFM-CNR, Istituto Nazionale di Fisica della Materia - Consiglio Nazionale delle Ricerche, Brescia
New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators.
The UA9 collaboration
USTC/NSRL, Hefei, Anhui
In order to meet the increasing requirements of synchrotron radiation users, an upgrading plan of hefei light source is undergoing by National Synchrotron Radiation Laboratory (NSRL). The emittance of storage ring is reduced from 166nm.rad to 36nm.rad. In this paper, we study the beam close orbit distortions' (COD) sensitivity to the field and alignment errors in magnets. Estimation of the COD from various error sources is investigated. The distribution of beam position monitors and the location of correctors are reported in the paper. Simulation proves that COD can be corrected down to 50 microns level. In the same time the corrector strengths are weaker enough in the correction scheme.
BINP SB RAS, Novosibirsk
Fermilab, Batavia
One of the possible ways to increase luminosity of hadron colliders is the compensation of beam-beam tune-spread with an electron lens (EL). At the same time, EL as an additional nonlinear element in the lattice can increase strength of nonlinear resonances so that its overall effect on the beam lifetime will be negative. Time-consuming numerical simulations are often used to study the effects of the EL. In this report we present a simplified model, which uses analytical formulae derived for certain electron beam profiles. Based on these equations the idealized shapes of the compressed tune spread can be rapidly calculated. Obtained footprints were benchmarked against several reference numerical simulations for the Tevatron in order to evaluate the selected configurations. One of the tested criteria was the so-called "folding" of the compensated footprint, which occurs when particles with different betatron amplitudes have the same tune shift. Also studied were the effects of imperfections, including misalignment of the electron and proton beams, and mismatch of their shapes.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
One of the major challenges for the International Linear Collider (ILC) damping rings is the attainment of the 2 pm vertical emittance specification. To achieve such an ultra-low vertical emittance a highly effective diagnostics and correction system is needed. However, since both BPMs and correctors have also negative impacts on the design (cost, complexity, impedance), it is important to understand how the number and locations of both these components affect the correction. In this paper we present the results of simulations for the Technical Design Phase baseline damping rings lattice (DCO4), aimed at understanding the effectiveness of orbit, dispersion, and coupling correction for different design and operation scenarios.
SLAC, Menlo Park, California
We use measured or simulated magnetic fields for dipoles and quadrupoles to build a lattice model for SPEAR3. In a non-symplectic approach the phase space coordinate mapping on the fields is based on Runge-Kutta integration of the equation of motion. In a symplectic approach we approximate the fields with proper fringe field models. Complication of the use of rectangular gradient dipoles in SPEAR3 is considered. Results of the model is compared to measurements on the real machine.
CERN, Geneva
The CLIC study is a site independent study exploring technological developments to extend linear colliders into the Multi-TeV colliding beam energy range at reasonable cost and power consumption. A conceptual design report (CDR) of an electron-positron Compact LInear Collider (CLIC) with a 3 TeV center-of-mass collision energy is presently being prepared including results of 25 years of R&D to address the feasibility of its novel and promising technology, especially in an ambitious Test Facility, CTF3. The R&D is performed by a multi-lateral CLIC/CTF3 collaboration strong of 37 volunteer institutes from 19 countries from which the outstanding work and results are reported.