| Paper | Title | Page |
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| MOPLS108 | Liquid Metal Target for ILC | 816 |
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| We considered the Hg target for gamma/positron conversion suitable for usage in ILC project. Positron scheme generation with undulator allows usage thin Hg jet confined in profiled duct with rectangular cross-section. | ||
| MOPLS109 | Operational Experience with Undulator for E-166 | 819 |
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| We represent results of operation of 2.54 mm period, K=0.2, up to 30 Hz undulator used in E-166 experiment for polarized positron production. One peculiarity is in usage of Ferrofluid for cooling. | ||
| MOPLS113 | Commissioning of the ALTO 50 MeV Electron Linac | 825 |
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| The ALTO 50 MeV electron linac is dedicated to the production of neutron-rich radioactive nuclei using the photo-fission process and the optimisation of the target-ion source system for SPIRAL 2 and Eurisol projects. A description of the accelerator consisting in 3 Mev injector (old test station of LAL), LIL accelerating structure, RF power plant, beam line, control system and diagnostics will be given. Specified and measured beam parameters will be compared to show the performance for the photo-fission and eventually other applications. | ||
| MOPLS114 | Construction of the Probe Beam Photo-injector of CTF3 | 828 |
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| The paper describes the HF and dynamic beam modelling performed onto the 3 GHz / 2,5 cells photo-injector of the future CTF3 (CLIC Test Facility 3) probe beam linac, whose goal is to demonstrate the feasibility of the 30 GHz accelerating sections in the framework of the CLIC project. The Probe Beam Photo-Injector (PBPI) conception is inspired from the drive beam photo-injector already designed by LAL (Orsay, France) and actually tested in our laboratory. However, the design of PBPI has been simplified with respect to the previous because the charge per bunch is 4 times lower and the number of bunches several orders of magnitude smaller. The internal geometry and the coupling system of the PBPI have been designed with 2D (SUPERFISH) and 3D (HFSS, ANSYS) codes. A detailed analysis of the dissymmetry (induced by the coupling system) of the accelerating field component has been performed. Based on the modified design, PARMELA simulations showed that the technical specifications are fulfilled. The vacuum issue has been also carefully investigated, and NEG (Non Evaporated Getter) technology has been adopted in order to reach the 10-10 mbar pressure inside the structure. | ||
| MOPLS115 | A Spin Rotator for the ILC | 831 |
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| A spin rotator featuring an optic axis with straight vision is presented. This rotator utilizes three bends, two solenoid pairs and two correction devices. These correctors, named reflectors, are mandatory for removing the cross plane coupling introduced by the solenoids. It is shown how the solenoids have to be set up to achieve longitudinal IP polarization taking into account non-zero crossing angles at the interaction region and a linac following the curvature of the earth. Furthermore, the stability requirements for mechanical and electrical imperfections are analyzed. | ||
| MOPLS116 | Status Report on the Harmonic Double-sided Microtron of MAMI C | 834 |
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The Mainz Mikrotron MAMI is a cascade of three racetrack microtrons, delivering since 1991 a high quality 855MeV, 100muA cw electron beam for nuclear and radiation physics experiments. An energy upgrade of this machine to 1.5GeV by adding a Harmonic Double-Sided Microtron (HDSM)* as a fourth stage is well under way. Here we give a review of the experiences gained during fabrication and testing of the main components of the HDSM and report the status of its construction. Initial operation of the machine is expected for the first half of 2006. After a period of commissioning in diagnostic pulse mode with low beam power (10ns, high intensity bunch trains with a repetition rate of max. 10kHz), soon the first nuclear physics experiments will be started.
*A. Jankowiak et al. "Design and Status of the 1.5 GeV-Harmonic Double Sided Microtron for MAMI", Proceedings EPAC2002, Paris, p. 1085. |
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| MOPLS118 | Magnetic Modelling of a Short-period Superconducting Helical Undulator for the ILC Positron Source | 840 |
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| A positron source utilising undulators is now defined as the baseline option for the International Linear Collider (ILC). The ILC requires a short period undulator, as close to 10mm as possible, that is capable of producing 10 MeV photons. The HeliCal collaboration in the UK has undertaken a programme to design, develop and produce a prototype undulator. As part of the programme, the group has used the OPERA software package to perform the magnetic design of the undulator. The design has addressed several issues, including the effect of magnetic material for the undulator former, optimal winding geometry, the magnetic flux inside the superconductor and its variation with undulator period and the winding bore. This paper summarizes the results of both the 2d and the 3d magnetic simulations. | ||
| MOPLS120 | Mitigation of Emittance Dilution due to Transverse Mode Coupling in the L-band Linacs of the ILC | 843 |
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| The main L-band linacs of the ILC accelerate 2820 bunches from a center of mass of 10 GeV to 500 GeV (and in the proposed later upgrade, to 1 TeV). The emittance of the vertical plane is approximately 400 times less than that of the horizontal plane. Provided the vertical and horizontal mode dipole frequencies are degenerate, then the motion in each plane is not coupled. However, in reality the degeneracy will more than likely be removed with the eigen modes lying in planes rotated from the x and y planes due to inevitable manufacturing errors introduced in fabricating 20,000 cavities. This gives rise to a transverse coupling in the horizontal-vertical motion and can readily lead to a dilution in the emittance in the vertical plane. We investigate means to ameliorate this emittance dilution by splitting the horizontal-vertical tune of the lattice. | ||
| MOPLS121 | The DAFNE Beam Test Facility: from 1 to 10 Milliards of Particles | 846 |
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| The DAFNE Beam Test Facility is operating since 2002, providing electrons, positrons and photons from the single particle up to 1010 particleS per spill and from 20 to 750 MeV. During these years, the facility has hosted tens of high energy test and experiments coming from all Europe, operating in a wide spread of multiplicity and energy. Operation performance and parameters, tools and diagnostics, as well as the main results obtained, are presented. | ||
| MOPLS123 | Performance of the FONT3 Fast Analogue Intra-train Beam-based Feedback System at ATF | 852 |
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| We report on the design and testing of the 3rd generation Feedback On Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). The all-analogue FONT3 electronics was designed to have an ultra-short latency of c. 10ns. We describe the design of the BPM signal processor, feedback circuit and kicker-driver amplifier. We report on deployment of FONT3 at the Accelerator Test Facility (ATF) at KEK, where it was tested with the 56ns-long electron bunchtrain extracted from the ATF damping ring. Feedback, with delay-loop operation, on the beam was demonstrated with a latency close to design. We comment on the applicability of this technology to ILC, as well as future warm-RF based linear colliders, such as CLIC. | ||
| MOPLS124 | The KEK Injector Upgrade for the Fast Beam-Mode Switch | 855 |
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| The KEK linac is a 600-m-long linear accelerator with maximum energy 8-GeV electron and 3.5-GeV positron, and it is used as an injector for 4-rings (KEKB e-/ e+, PF, PF-AR). To increase the operation efficiency, we have an injector upgrade plan for the quasi-simultaneous injection. In this paper, we will present the operation scheme and the construction of a new beam transport line in detail. | ||
| MOPLS128 | Status of the Fatigue Studies of the CLIC Accelerating Structures | 858 |
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| The need for high accelerating gradients for the future Compact Linear Collider imposes considerable constraints on the materials of the accelerating structures. The surfaces exposed to high pulsed RF currents are subjected to cyclic thermal stresses possibly resulting in surface break up by fatigue. Since no fatigue data exists in the literature up to very large numbers of cycles, a comprehensive study has been initiated. Low cycle fatigue data (up to 108 cycles) has been collected by means of a pulsed laser surface heating apparatus. The surface damage has been characterized by SEM observations and roughness measurements. High cycle fatigue data (up to 1011 cycles) at various stress ratios have been collected in high frequency bulk fatigue tests using an ultrasonic apparatus. It is found that the appearance of surface fatigue damage in the laser experiments, and of fatigue cracks in the bulk specimen, happen at similar stress levels for similar numbers of cycles. This allows the two experimental techniques to be connected and to predict the surface damage at a high number of cycles. Up-to-date fatigue data for selected high conductivity, high strength Cu alloys are presented. | ||
| MOPLS129 | Integration of the PHIN RF Gun into the CLIC Test Facility | 861 |
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| CERN is a collaborator within the European PHIN project, a joint research activity for Photo injectors within the CARE program. The scope of this project is to build an RF Gun equipped with high quantum efficiency Cs2Te cathodes and a laser to produce the nominal beam for the CLIC Test Facility (CTF3). The nominal beam for CTF3 has an average current of 3.5 A, 1.5 GHz bunch repetition frequency and a pulse length of 1.5 us (2310 bunches) with quite tight stability requirements. In addition a phase shift of 90 deg is needed after each train of 140 ns for the special CLIC combination scheme. This RF Gun will be tested at CERN in fall 2006 and should be integrated as a new injector into the CTF3 linac, replacing the existing injector consisting of a thermionic gun and a subharmonic bunching system. The paper studies the optimal integration into the machine trying to optimize transverse and longitudinal phase space of the beam while respecting the numerous constraints of the existing accelerator. The presented scheme uses emittance compensation and velocity bunching to fulfill the requirements. | ||
| MOPLS130 | Implications of a Curved Tunnel for the Main Linac of CLIC | 864 |
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| Preliminary studies of a linac that follows the earth's curvature are presented for the CLIC main linac. The curvature of the tunnel is modeled in a realistic way by use of geometry changing elements. The emittance preservation is studied for a perfect machine as well as taking into account imperfections. Results for a curved linac are compared with those for a laser-straight machine. |