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| THPRI001 | Design of a High Luminosity Tau/Charm Factory | 3757 |
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The design of a high luminosity Tau/Charm Factory has been accomplished by the INFN-LNF Laboratory in Frascati in collaboration with the Consortium Nicola Cabibbo Laboratory. The target luminosity is 1035 cm-2 ses−1 at 4.6 GeV in the center of mass. This design is a natural evolution of the SuperB B-Factory, that was aimed to be built in the Rome Tor Vergata University campus as an Italian Flagship Project. The Tau/Charm design keeps all the features that made SuperB a state-of-the art accelerator, such as the “large Piwinski angle and crab waist sextupoles” collision scheme, the super squeezed beams, and the polarized electron beam. As a plus, it will be possible to collect data at high luminosity in a large energy range (2 to 4.6 GeV c. m.), with a peak luminosity target of 1034 cm-2 ses−1 at 2 GeV. The possibility to extend the Linac for a SASE-FEL facility is also taken into account. A Conceptual Design Report* was published in September 2013. In this paper the design principles and the project features are reviewed.
* Tau/Charm Factory Accelerator Report, INFN Report INFN-13-13/LNF, September 2013, arXiv:1310.6944 [physics.acc-ph] |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI001 | |
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| THPRI002 | DAΦNE General Consolidation and Upgrade | 3760 |
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| In the first six months of 2013 the KLOE detector has been upgraded inserting new detector layers in the inner part of the apparatus, around the interaction region. The long shutdown has been used to undertake a general consolidation program aimed at improving the Φ-Factory operation stability and reliability and, in turn, the collider uptime. In this context several systems have been revised and upgraded, new diagnostic elements have been installed, some critical components have been modified and the interaction region mechanical support structure design has been developed to improve its mechanical stability and to deal with the weight added by the new detector layers. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI002 | |
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| THPRI003 | Beam-beam Simulation Study for CEPC | 3763 |
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| CEPC is an Circular Electron Positron Collider proposed to carry out high precision study on Higgs bosons. It is similar to TLEP project , the luminosity and beam lifetime may be determined by the beamstrahlung effect. We try to check the resonability of the machine parameters with weak-strong and strong-strong simulation. At the same time we also do some cross-check between different codes. We wish the work could help determine the beam parameters which could achieve design luminosity. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI003 | |
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| THPRI004 | FCC-ee/CepC Beam-beam Simulations with Beamstrahlung | 3766 |
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| Beamstrahlung, namely synchrotron radiation emitted during the beam-beam collision, can be an important effect for circular high-energy lepton colliders such as FCC-ee (TLEP). In this paper we study beam-beam effects in the presence of energy spreading and bunch lengthening due to beamstrahlung. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI004 | |
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| THPRI005 | The Mechanical and Vibration Studies of the Final Focus Magnet-cryostat for SuperKEKB | 3770 |
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| Construction of the SuperKEKB has been progressed in KEK. The target luminosity of the SuperKEKB is 8×1035 cm-2s−1, which is 40 times larger than the KEKB. The vertical beam sizes of electron and positron must be squeezed to the level of 50 nano-meter at the interaction point. The beam final focus system for the SuperKEKB consists of 4-superconducting (SC) quadrupole doublets, 43 SC-correctors, 4 SC-compensation solenoids. The designs of the cryostats in the left and right side with respect to the beam interaction point are being studied with the progress of the magnet designs. In the design works, the support structure of each cryostat, strength of the cryostat components and support rods for supporting cold mass are investigated. As for the vibration issue, vibration properties of the superconducting quadrupole magnets due to the ground motion has been studied. Also vibration properties of the concrete bridges where the two cryostats will be placed in the interaction region were investigated and measured. We will present the cryostat designs and these vibration studies in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI005 | |
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| THPRI006 | Dynamic Aperture Study of SuperKEKB with Beam-beam Effect | 3773 |
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| The SuperKEKB is an asymmetric-energy double-ring collider to achieve 40 times higher luminosity than that of the KEKB B-factory. The strong non-linearity of both final focusing and beam-beam force, which are required to achieve such high luminosity, reduce dynamic aperture and limit Touschek beam lifetime. In order to achieve long enough beam lifetime for collision operation, we are studying the dynamic aperture under beam-beam effect. The study results of both dynamic aperture and Touschek beam lifetime are reported in this presentation. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI006 | |
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| THPRI007 | Lattice Optimization of BEPCII Collider Rings | 3776 |
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| BEPCII is a double ring e+e− collider operating in the tau-charm region. In March 2013, the peak luminosity achieves 7.0·1032 cm-2s-1 with a new lower alphap lattice. The beam-beam parameter is also increased from 0.033 to 0.04 with the new lattice. In this paper we'll review the lattice optimization history briefly and focus on the optimization of the lower alphap lattice. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI007 | |
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| THPRI008 | Interaction Region Lattice for FCC-ee (TLEP) | 3779 |
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Funding: The work is supported by the Ministry of Education and Science of the Russian Federation. FCC-ee (TLEP)* project is a high-luminosity e+e- collider and is an essential part of the Future Circular Collider (FCC) design study at CERN . FCC-ee is being designed to reach center-of-mass energy from 90 to 350 GeV with circumference of 80-100 km to study Higgs boson properties and perform precise measurements at the electroweak scale. It is also an intermediate step towards 100 TeV proton-proton collider built in the same tunnel. Some of the limiting factors of the new collider are total energy loss due to synchrotron radiation, beam lifetime degradation owing to beamstrahlung, geometry of the tunnel required to accommodate the successor. The present paper describes linear lattice of interaction region and results of nonlinear beam dynamics study. * M.~Koratzinos et al., ‘‘TLEP: A HIGH-PERFORMANCE CIRCULAR e+e− COLLIDER TO STUDY THE HIGGS BOSON'', IPAC2013, Shanghai, China, TUPME040 (2013) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI008 | |
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| THPRI010 | FCC-ee Final Focus with Chromaticity Correction | 3782 |
| SUSPSNE005 | use link to see paper's listing under its alternate paper code | |
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| A 100 km circular electron-positron collider is considered as one of the possible future high energy facilities. In order to achieve a high luminosity, strong beam focusing at the Interaction Point is used requiring the correction of the chromatic aberrations. In this paper we study preliminary designs of a Final Focus System for the TLEP collider with chromatic correction. Beam orbit stability and dynamic aperture calculations are also presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI010 | |
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| THPRI011 | Beam-machine Interaction at TLEP: First Evaluation and Mitigation of the Synchrotron Radiation Impact | 3785 |
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| In the framework of post-LHC accelerator studies, TLEP is a proposed high-luminosity circular e+e− collider, aimed at measuring the properties of the Higgs-boson H(126) with unprecedented accuracy, as well as those of the W boson, the Z boson and the top quark. In order to calculate the impact of synchrotron radiation, the latter has been implemented in the FLUKA code as new source term. A first account of escaping power as a function of the vacuum chamber shielding thickness, photoneutron production, and activation has been obtained for the 80km circumference 175 GeV (beam energy) TLEP option. Starting from a preliminary layout of the FODO cell and a possible dipole design, energy deposition simulations have been carried out, investigating the effectiveness of absorbers in the interconnections. The results provide inputs to improve the cell design and to support mechanical integration studies. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI011 | |
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| THPRI012 | Tuning of the Compact Linear Collider Beam Delivery System | 3788 |
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| Tuning the CLIC Beam Delivery System (BDS), and in particular the final focus, is a challenging task. In simulations without misalignments, the goal is to reach 120~\% of the nominal luminosity target, in order to allow for 10~\% loss due to static imperfections, and another 10~\% loss from dynamic imperfections. Various approaches have been considered to correct the magnet misalignments, including 1-1 correction, dispersion free steering (DFS), and several minimization methods utilizing multipole movers. In this paper we report on the recent advancements towards a feasible tuning approach that reach the required luminosity target in a reasonable time frame. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI012 | |
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| THPRI013 | A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV | 3791 |
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| An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI013 | |
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| THPRI014 | Modular Stand-Alone Pulse Current Measurement System for Kicker and Septa at BESSY II and MLS | 3794 |
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Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin. Pulse current measurement systems are introduced for all pulsed deflection magnets in the BESSY II and MLS storage rings which acquire data autonomously. The measured pulse currents are displayed locally or remotely as single values or graphs. The data acquisition systems utilize commercial PXI chassis by National Instruments (NI), controllers and 2-channel 14bit, 100MHz high-speed digitizer cards. Measurement routines are programmed with LabVIEW 2012. Special in-house custom made ‘CA-Lab’ client software provides interface for the independent systems to write values into pre-assigned process variables of the EPICS control system. The retrieved data can be displayed in the machine control system and stored in a data archive. This allows shot to shot assessment of the pulse currents for accelerator operation and troubleshooting as well as long term data evaluation in correlation with other relevant machine parameters. This report also describes the set-up for the pulse current measurements and the structured programming for the data acquisition. Limits of the applied measurement technique and experience with the information gained for the accelerator operation will be explained. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI014 | |
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| THPRI015 | DAΦNE Transfer Line for KLOE-2 Physics Run | 3797 |
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| The transfer lines of the DAΦNE accelerator complex have been revised and optimized in view of the forthcoming KLOE-2 physics run. The transfer lines consolidation activities involved low level systems, diagnostics tools and control system hardware modifications for the magnetic element switching polarity during the injection procedure. Transfer lines optics has been reviewed and optimized as well by a systematic study based on a MAD-X model. The work done determined a substantial improvement in the transfer lines stability and reproducibility, speeded up the injection procedure with a considerable reduction on the background hitting the experimental detector during the beam injection process. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI015 | |
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| THPRI016 | Pulse Based Data Archive System and Analysis for Current and Beam Loss Monitors in the J-PARC RCS | 3800 |
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| The data archive system in the J-PARC 25-Hz Rapid-Cycling Synchrotron (RCS) records the beam intensity and the beam loss monitor (BLM) pattern for all pulses. The system is based on the common memory and utilizes the timing system of the J-PARC. Although its time resolution is limited, it is useful to detect rare events or phenomena appearing with only higher accelerator repetition. Using these data, the stability of the beam intensity, particularly ion source can be examined. The relation between BLM patterns and its causes can be studied pulse-by-pulse basis and it would make use of future improvements. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI016 | |
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| THPRI019 | Reliability and Availability Modeling for Accelerator Driven Facilities | 3803 |
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| Accelerator driven facilities are and will have to be designed to a very high level of reliability and beam availability to meet expectations of the users and experiments. In order to fulfill these demanding requirements on reliability and overall beam availability, statistical models have been developed. We compare different statistical reliability models as well as tools in terms of their performance, capacity and user-friendliness. In addition we also benchmarked some of the existing models. We will present in detail a tool being used for LHC and LINAC4 which is based on the commercially available software package Isograph and a tool using Excel, which was developed in house for ESS-systems. The impact of an early reliability modeling on the design of mission critical systems will be presented as well. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI019 | |
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| THPRI020 | Availability Studies for Linac4 and Machine Protection Requirements for Linac4 Commissioning | 3807 |
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| Linac4 is one of the key elements in the upgrade program of the LHC injector complex at CERN, assuring beams with higher bunch intensities and smaller emittance for the LHC and many other physics experiments on the CERN site. Due to the demand of continuous operation, the expected availability of Linac4 needs to be carefully studied already during its design phase. In this paper an overview of the relevant systems impacting on Linac4 machine availability is given: the various system failure modes are outlined as well as their impact on the total yearly machine downtime. Machine Protection Systems (MPS) play a significant role in reducing the risk associated to each failure mode and are therefore important for reaching the target availability. The Linac4 MPS requirements, with particular focus on the different commissioning phases, are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI020 | |
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| THPRI021 | Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-triggering Lines | 3810 |
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| To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a reliability analysis to quantify its impact on LHC machine availability are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI021 | |
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| THPRI022 | The Accelerator Reliability Forum | 3813 |
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| A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum (http://reliability.forumotion.com). This contribution will describe the forum and advertise it's usage in the community. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI022 | |
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| THPRI024 | Finding Your Happy-User-Index | 3816 |
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| Reliability is defined as the ability of a system or component to perform its required functions under stated conditions for a specified period of time. If we are talking about accelerator reliability then we have to know what the required functions are. Many accelerator facilities restrict their analysis to the beam availability: how reliable is beam provided to the users? We will show that this metrics is often not fully adequate. Specific metrics can be much more useful to allow you to optimize your facility to the needs of your users. The three accelerator user facilities at PSI will serve as examples for these happy-user-indexes. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI024 | |
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| THPRI025 | Accelerator Reliability Reporting at the Swiss Light Source | 3819 |
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| Third generation light sources do aim for a very high reliability of the accelerator. This contribution describes the reliability reporting of the Swiss Light Source at the Paul Scherrer Institut, as it has been performed in the past decade. We will highlight the importance of a formal reporting on the accelerator reliability to support the long term optimization of the reliability of an accelerator facility. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI025 | |
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| THPRI026 | A Review on Accelerator Operator Training | 3822 |
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| Operators of accelerator facilities have to be trained in order to safely operate their machines. While the amount of training varies between the different types of accelerators, many best-practices could be applied to the training of operators for a variety of different facilities. The aim of our study is to survey the best-practices for operator training for a larger number of accelerator facilities. The results may provide useful insights to advance the training-plans for operators of particle accelerators. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI026 | |
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| THPRI027 | Automated Conditioning System for Siemens Novel Electrostatic Accelerator | 3825 |
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| Siemens has proposed a novel compact DC electrostatic tandem accelerator to produce protons of a few MeV and is currently commissioning a prototype at the Rutherford Appleton Laboratory. The geometry of the accelerator involves large surfaces which are exposed to high electric fields and therefore need long procedures for conditioning. An automated system for conditioning has been developed. It reacts quicker to breakdowns than a human operator could do, thus being more effective and also reduces the time spent by research staff on the conditioning. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI027 | |
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| THPRI028 | Acoustic Spark Localization for the 201 MHz RF Cavity | 3828 |
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Funding: Work supported by U.S. Department of Energy Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on the experiment setup for localizing sparks in an RF cavity by using piezoelectric transducers and on preparation for data collection on a 201.25 MHz vacuum cavity. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI028 | |
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| THPRI030 | Progress Towards Completion of the MICE Demonstration of Muon Ionization Cooling | 3831 |
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Funding: DOE, NSF, STFC, INFN, CHIPP and several others The Muon Ionization Cooling Experiment (MICE) at the Rutherford Appleton Laboratory aims to demonstrate ~10% ionization cooling of a muon beam, by its interaction with low-Z absorber materials followed by restoration of longitudinal momentum in RF linacs. MICE Step V will provide the flexibility for a thorough exploration and characterization of the performance of ionization cooling. Step V will include four RF cavities to provide 8 MV/m gradient in a strong magnetic field. This entails an RF drive system to deliver 2 MW, 1 ms pulses of 201 MHz frequency at 1 Hz repetition rate, the distribution network to deliver 1 MW to each cavity with correct RF phasing, diagnostics to determine the gradient and the muon transit phase, and development of the large diameter magnets required in order to keep the muons focused through the linacs. Progress towards the completion of Step V is described. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI030 | |
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| THPRI031 | Design and Commissioning of S-Band RF Station for AREAL Test Facility | 3834 |
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| The RF station has been designed and constructed for AREAL Linac. The constructional features and commissioning results of RF system are presented. The whole RF system is designed to work at 3GHz frequency. The linac includes an electron gun for 0.5-8 ps electron bunch production with 1-10 Hz repetition rate. For linac RF control system a Libera LLRF stabilization system is used. An important feature of the presented system is a high level synchronization of amplitude-phase characteristics which provide the required accuracy for particle acceleration and bunch formation. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI031 | |
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| THPRI032 | Study of a RF Gun with a Thermoionic Cathode | 3837 |
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The low energy part of our pre injectors* is made up of a 90 kV DC thermoionic triode gun, followed by a 500 MHz sub harmonic prebuncher and a 3 GHz prebuncher. These two cavities are respectively fed with 500 W, a modulation of ± 25 kV, and 90 W corresponding to a ± 10 kV. The gun grid is modulated within a 500 MHz signal. The initial 1 ns phase extension at the gun level is reduced, at the buncher entry, to 40 ps for 75% of the gun current. This study proposes to replace the gun and the two cavities by a RF gun integrated in a modulated cavity at 200 MHz followed by a drift in order to bunch the beam. This study will compare the beam dynamics simulations for these two cases.
*A. Setty et al, "Design and Construction of Turnkey Linacs as Injectors for Light Sources", Proceedings IPAC 2012, USA, Louisiana, May 2012. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI032 | |
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| THPRI033 | Design of New Buncher Cavity for Relativistic Electron Gun for Atomic Exploration – REGAE | 3840 |
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| The Relativistic Electron Gun for Atomic Exploration, REGAE, is a small electron accelerator build and operated at DESY. Its main application is to provide high quality electron bunches for time resolved diffraction experiments. The RF system of REGAE contains different parts such as low level RF, preamplifier, modulator, phase shifter, and cavities. A photocathode gun cavity to produce the electrons and a buncher cavity to compress the electron bunches in the following drift tube. Since the difference between the operating mode of the existing buncher and its adjacent mode is too small, the input power excites the other modes in addition to the operating mode which affects the beam parameters. A new buncher cavity is designed in order to improve the mode separation. Furthermore the whole cavity is modeled by a circuit which can be useful especially during the tuning process. Beam dynamics simulations have been performed in order to compare the new designed cavity with the old one which declare that the effects of the adjacent modes on the beam parameters are decreased. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI033 | |
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| THPRI035 | Design and Simulation of Side Coupled Six MeV Linac for X-Ray Cargo Inspection | 3844 |
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| Using in X-ray cargo inspection is one of most applications of linear accelerators. This paper represents design and simulation of Side Coupled Six MeV cavity. The electromagnetic simulation of structure was carried out in the SUPERFISH and CST Microwave studio. 2.3 MW input power is considered according to MG5193 magnetron. The coupling coefficient is calculated equal to 3% for stabilization of accelerator operation against environmental and mechanical errors effects. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI035 | |
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| THPRI038 | Simulation Study of Electron Gun for Six MeV Linac for X-Ray Cargo Inspection | 3847 |
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| Electron guns are designed in different models. Output beam quality and efficiency of the linear accelerator for each application depends on choosing the suitable model of electron gun. The most common types are diode and triode electron guns. Simulation Study of diode electron gun of Six MeV Linac for X-Ray Cargo Inspection represented in this article. Vaughan analytical method was used to obtain the initial dimensions. In final stage, CST Particle Studio software used to obtain the dimensional details. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI038 | |
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| THPRI040 | Study of Geometrical Parameters and their Tolerances in Optimization of Accelerating Cells of Side Coupled Linac | 3850 |
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| After choosing the suitable geometry for accelerating cavity, evaluation of geometrical parameters effects on radio frequency characteristics is essential. In this paper after study of priority of geometrical parameters in optimization of accelerating cells of Side Coupled Linac, according to obtained results, new design of s-band accelerating cavity is suggested. By frequency sensitivity study of new dimensions, we can choose best technique to tune the accelerating cavity during magnetic coupling-hole adjustment. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI040 | |
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| THPRI041 | Twenty Years of Operation of the Elettra RF System | 3853 |
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| Six thousand hours per year is the typical running scheduled time of the user-dedicated Elettra facility and twenty years is a significant amount of operating hours for the RF system. Failure and weak points of the installed equipment is discussed as well as the up-time statistic. The effectiveness of the predictive versus the extraordinary maintenance is presented. The gained operational experience has allowed the planning of the priorities to refit the installed components within a reasonable budget, in compliance with the user-operation time schedule and following the technical need of upgrading to improve the RF system performance. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI041 | |
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| THPRI042 | Design and RF Test of Damped C-Band Accelerating Structures for the ELI-NP Linac | 3856 |
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| The linac energy booster of the European ELI-NP proposal foresees the use of 12 traveling wave C-Band structures, 1.8 m long with a field phase advance per cell of 2pi/3 and a repetition rate of 100 Hz. Because of the multi-bunch operation, the structures have been designed with a damping of the HOM dipoles modes in order to avoid beam break-up (BBU). They are quasi-constant gradient structures with symmetric inputs couplers and a strong damping of the HOM in each cell. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce their cost. In the paper we shortly review the whole design criteria and we illustrate the low and high power RF test results on prototypes that shown the feasibility of the structure realization and the effectiveness of the HOM damping. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI042 | |
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| THPRI043 | Thermal-mechanical Analysis of the RF Structures for the ELI-NP Proposal | 3860 |
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| The room temperature RF structures in the ELI-NP Linac will operate in multi-bunch with high repetition rate (100 Hz). For these reasons they are subject to some kW of power dissipated on the internal cavities surfaces. The resulting thermal deformation of the cavities shapes could imply variations in their electromagnetic fields. To limit these effects and optimize the cooling design, a fully coupled ElectroMagnetic- Thermal-Mechanical analysis has been performed on the S-Band Radiofrequency Gun and on the C-Band multi-cell structures. In the paper the study done in Ansys Workbench with HFSS and Ansys Mechanical is reviewed | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI043 | |
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| THPRI044 | Vacuum Waveguide System for SPring-8 Linac Injector Section | 3863 |
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| An SF6 waveguide system for the injector section of SPring-8 linac has been replaced in a vacuum waveguide system including a newly developed vacuum circulator and an isolator. This paper describes developed RF components, a waveguide configuration and an RF conditioning of the system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI044 | |
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| THPRI045 | Development of a 1.3-GHz Buncher Cavity for the Compact ERL | 3866 |
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| In a high-brightness injector of the Compact ERL (cERL), a 1.3-GHz buncher cavity is used to compress the electron bunches which are produced at a 500-kV photocathode DC electron gun. An rf voltage required is about 130 kV. To elongate the lifetime of the photocathode of the DC gun which is located beside the buncher cavity, an extremely-low pressure of about 10-9 Pa is required in the buncher cavity under operating conditions. In order to achieve such low pressures, we have developed a normal-conducting cavity which included several measures to reduce the outgas from the cavity components, together with careful rf designs to avoid any problems due to multipactor discharges or to other problems. With the developed cavity, we achieved a vacuum pressure of about 2·10-9 Pa under rf operations at an rf voltage of about 100 kV. The buncher cavity was installed in the cERL, and it worked very well; we could demonstrate to compress the bunch length from 10 ps (FWHM) to 0.5 ps (rms) using the buncher cavity. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI045 | |
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| THPRI046 | Air-cooled Magnetic Alloy Cavity for J-PARC Doubled Rep.-rate Scenario | 3869 |
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| The upgrade project of the J-PARC MR (Main Ring) is in progress to deliver the beam power of 750 kW based on doubled repetition-rate scenario. The present RF section will be occupied by 9 sets of new magnetic alloy, FT3L, cavity using the direct water cooling scheme. The direct water cooling requires dedicated high-quality cooling water. These cavities will be used for the fundamental RF for acceleration. The second harmonic RF is necessary to increase the bunch length. This allows to enlarge the beam current, and to relax the space charge effects during the injection. Thanks to the high impedance FT3L, the power loss in the second harmonic RF system becomes moderate. The air cooled cavity is designed to fit in any space in the MR where the dedicated water is not available. This paper reports the design of the second RF system, technical issues to produce the magnetic alloy cores to fit the air cooling, and construction of the system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI046 | |
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| THPRI047 | Large-aperture Travelling-wave Accelerator Structure for Positron Capture of SuperKEKB Injector Linac | 3872 |
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| Comparing to the previous KEKB, the four-times higher charge of 4 nC per bunch is required for the injector linac of SuperKEKB. Not only a flux concentrator will be introduced but also the physical aperture of the downstream six 2m-long accelerator structures was increased as large as 30mm in diameter. We call these structures as LAS, “Large Aperture S-band” structure. The resultant higher RF group velocity of about 3% makes the acceleration gradient lower. In the nominal acceleration system, a 40MW klystron with SLED feeds four 2m-long accelerator structures producing 20MV/m acceleration field. The acceleration gradient higher than 14 MV/m is required for the very first two LAS structures to suppress the satellite bunches. This gradient is obtained by feeding only two LAS structures. Initially, ten LAS structures were installed and the RF processing has partly started. In the present paper, we firstly describe the acceleration system design and then present the processing characteristics through the RF processing without beam and with beam. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI047 | |
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| THPRI048 | Design of an Accelerating Tube for a Standing-wave Accelerator based on Genetic Algorithm’s Optimal Calculation | 3875 |
| SUSPSNE090 | use link to see paper's listing under its alternate paper code | |
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| A compact medical standing-wave (SW) electron accelerating tube has been designed that operating frequency is 2998MHz, operating mode is π/2, final energy is 6MeV and beam current is 100mA based on genetic algorithm (GA)’s optimal calculation. It employed a bi-periodic structure with nose cone shape. We performed the simulation experiment which proved that GA was feasible and gave a set of geometric parameter with higher shunt impedance. We performed tuning of the whole tube by CST MICROWAVE STUDIO and SUPERFISH and calculation of beam dynamics by ASTRA and Parmela in this paper. The total length of the tube is less than 300mm. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI048 | |
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| THPRI049 | Engineering Design of the RF Input Couplers for C-ADS RFQ | 3878 |
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| A new coupler with the special ceramic window has been developed at IMP, CAS (Institute of Modern Physics, Chinese Academy of Sciences), operating at 30 kW/162.5 MHz in CW mode for an one-meter prototype cavity, which can provide all kinds of experiences to the real four-meter cavity including EM simulation, power conditioning, cooling consideration and so on. Now, the beam experiments on prototype cavity have been completed and the results show the simulation and the measurements of coupler were in the good agreement. The special bowl-type ceramic window can promote S parameter and reduce sparking risk for beam commissioning stably. A detailed electromagnetic design and measured results of the coupler will be presented in the paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI049 | |
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| THPRI050 | Calculation and Design of the Re-buncher Cavities for the LIPAc Deuteron Accelerator | 3881 |
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Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project AIC-A-2011-0654 Two re-buncher cavities are necessary for the LIPAc (Linear IFMIF Prototype Accelerator), presently being built at Rokkasho (Japan). They are placed at the Medium Energy Beam Transport (MEBT) line to longitudinally focus a 5 MeV CW deuteron beam. Due to the strong space charge and the compactness of the beamline, the cavity has several space restrictions. In order to minimize the power loss, an IH-type cavity with 5 gaps was selected. It provides an effective voltage of 350 kV at 175 MHz with a power loss of 6.6 kW. First, electromagnetic calculations have been done with HFSS to compute the resonant frequency, the S-parameters, the electric and magnetic field maps, the power losses and the proper geometry for a magnetic input coupler and a pickup probe. Then, a mechanical Ansys model has been used to analyze the stresses and deformations due to vacuum, the cooling circuit and the temperature distribution, taking into account the power losses imported from the electromagnetic model. Finally, the fluid dynamics in the cooling circuits of the stems has been carefully studied. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI050 | |
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| THPRI051 | Fabrication and Tests of the Re-buncher Cavities for the LIPAc Deuteron Accelerator | 3884 |
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Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project AIC-A-2011-0654 Two re-buncher cavities will be installed at the Medium Energy Beam Transport (MEBT) of the LIPAc accelerator, presently being built at Rokkasho (Japan). They are IH-type cavities with 5 gaps and will provide an effective voltage of 350 kV at 175 MHz. The cavity consists of a cylindrical main body and two endplates in stainless steel with an internal copper coating. The stems and drift tubes are machined from bulk OFE copper. The fabrication techniques for the cooling pipes, the input coupler and the pick-up are presented. Material choices and fabrication process are discussed. The first re-buncher is already fabricated. RF low power tests have been made to measure resonant frequency, S-parameters and Q-factor before and after the copper plating. The electric field map has also been measured with the bead-pull method. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI051 | |
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| THPRI052 | Design, Fabrication and Tests of the Second Prototype of the Double-Length CLIC PETS | 3887 |
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Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project FPA2010-21456-C02-02 The future collider CLIC is based on a two-beam acceleration scheme, where the drive beam provides to the main beam the RF power through the Power Extraction and Transfer Structures (PETS). The technical feasibility of some components is currently being proved at the CLIC Experimental Area (CLEX). Two double- length CLIC PETS will be installed in CLEX to validate their performance with beam. The first prototype was produced and validated in 2012. This paper is focused on the engineering design, fabrication and validation of the second prototype. Taking into account the results of the first prototype, some modifications have been included in the design to ease fabrication and assembly. The fabrication techniques are very similar to the ones used for the first prototype. Mechanical measurements on single parts and different assembly stages will be reported. The industrialization feasibility will be also analyzed. Finally, several tests such as vacuum tightness and RF measurements with low power have been realized to validate the device. These results are compared with the first prototype ones. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI052 | |
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| THPRI053 | Ferrite Material Characterization in a Static Bias Field for the Design of a Tunable Cavity | 3890 |
| SUSPSNE088 | use link to see paper's listing under its alternate paper code | |
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| During the development of ferrite-loaded accelerating cavities, the electromagnetic properties of the dispersive ferrite material need to be known. We describe a coaxial short-circuit measurement technique to measure the complex permeability of toroidal-shaped samples (127mm outer and 70mm inner diameter) that are exposed to an external magnetic bias field. The external magnetic bias field is applied perpendicular to the RF magnetic field. With this method it is possible to characterize the frequency dependence of the permeability for a frequency range of 1-100MHz. The dependence of the permeability on the external magnetic bias is presented for the ferrite G-510 from Trans-Tech Inc. and the material characterization is shown in the same frequency range. The measurement results are verified by simulations of the measurement set-up. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI053 | |
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| THPRI054 | Permittivity and Permeability Measurement Methods for Particle Accelerator Related Materials | 3893 |
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| For the special requirements related to particle accelerators, knowledge of the different material parameters of dielectrics and other materials are needed in order to carry out simulations during the design process of accelerator components. This includes also properties of magnetically biased ferrites of which usually little information is available about material characteristics, especially in magnetic bias fields. Several methods of measurement are discussed and compared of which some require delicate sample preparation whereas others can work with unmodified material shapes that makes those methods also suited for acceptance checks on incoming materials delivered by industry. Applications include characterization of different materials, as absorbers in which dielectric losses play an increasing role, as well as low frequency measurements on ferrites that are used for tunable cavities. We present results obtained from both broadband and resonant measurements on different materials determined in the same sample holder. Where possible, the results were confirmed with alternative methods. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI054 | |
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| THPRI055 | The New 118 MHz Normal Conducting RF Cavity for SIAM Photon Source at SLRI | 3896 |
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| The Siam Photon Source (SPS) is the 1.2 GeV second generation light source in Thailand. It is managed by the Synchrotron Light Research Institute (SLRI). The institute is located inside the campus of Suranaree University of Technology (SUT), which is approximately 20 km from the city of Nakhon Ratchasima (or normally called Korat). Korat is 250 km north-east of Bangkok. Two insertion devices (IDs) have been installed in the SPS storage ring during June to August 2013. These IDs require additional electrical field energy from RF cavity to compensate electron energy loss in the storage ring. The existing RF cavity has been pushed to its maximum capability and the new RF cavity is in the procurement process. The design and study of the new RF cavity will be presented. Electromagnetic fields of the cavity are studied together with the effects to electron beam instabilities. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI055 | |
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| THPRI056 | A New Debunching Cavity for the ISIS H− Injector | 3899 |
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| The energy range of the ISIS 70MeV H− injected beam is reduced using an RF debunching cavity. The existing cavity consists of a mild steel vacuum vessel containing a water-cooled copper shell into which RF power is fed. The unit is made up of components designed for the 50 MeV Proton Linear Accelerator (PLA) which used to occupy the Rutherford Appleton Laboratory (RAL) site between 1957 and 1969. The component drawings date back to the late 1960s. Due to its age, complexity and a lack of spares, there is a need for a modern solution. This paper documents the development of a new debunching cavity for the ISIS neutron source. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI056 | |
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| THPRI058 | RF Delivery System for FETS | 3902 |
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| The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. In this experiment, the first stages necessary to produce a very high quality, chopped H− ion beam as required for the next generation of high power proton accelerators (HPPAs) are designed, built and tested. HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An RF system outline, circulator high power tests, RF amplifiers tests, waveguide run with shielding and couplers design are presented and discussed in this paper. Experimental measurements of the system’s circulator and RF Amplifiers high power test will be presented as part of the system testing results. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI058 | |
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| THPRI059 | Field Emission Study of RF cavity in Static Magnetic Field | 3905 |
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| The RF cavity performance in solenoid magnetic field is crucial for the muon ionization cooling. Previous experiments have shown that the strong external magnetic field can significantly lower the maximum achievable RF voltage in the cavity. The mechanism of this performance degradation has been studied both analytically and experimentally, but so far no conclusive cause has been determined yet. In this paper, we propose an experiment to study the effect of a static B field on the field emission in the RF cavity, which hasn't been investigated before, and which can contribute to the cavity performance degradation in the solenoid field. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI059 | |
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| THPRI060 | Conceptual Design of an Electromagnetic Driven Undulator Based Positron Target System for ILC | 3908 |
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| There have been intense activities on development of the fast spinning Ti wheel positron target for ILC in the last few years. As in many high power target design, it requires solutions for many technical challenges, such as vacuum, thermal stress and radiation damage control, just to name a few. Due to the unique beam timing structure, in this paper, we present a target system based on a electromagnetic mechanical system that drives a bullet type Ti slug (~ 1.4x1.4x10 cm, weigh ~ 50 g) as the target system. The mechanism is similar to a reloadable EM rail gun driven projectiles. The system can be compact, vacuum isolated, and ease of cooling. Conceptual design layout and parameter estimations are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI060 | |
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| THPRI061 | Perpendicular Biased Ferrite Tuned Cavities for the Fermilab Booster | 3911 |
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| The aging Fermilab Booster RF system needs an upgrade to support future experimental program. The important feature of the upgrade is substantial enhancement of the requirements for the accelerating cavities. The new requirements include enlargement of the cavity beam pipe aperture, increase of the cavity voltage and increase in the repetition rate. The modification of the present traditional parallel biased ferrite cavities is rather challenging. An alternative to rebuilding the present Fermilab Booster RF cavities is to design and construct new perpendicular biased RF cavities, which potentially offer a number of advantages. An evaluation and a preliminary design of the perpendicular biased ferrite tuned cavities for the Fermilab Booster upgrade is described in the paper. Also it is desirable for better Booster performance to improve the capture of beam in the Booster during injection and at the start of the ramp. One possible way to do that is to flatten the bucket by introducing second harmonic cavities into the Booster. This paper also looks into the option of using perpendicularly biased ferrite tuners for the second harmonic cavities. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI061 | |
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| THPRI062 | CW Room Temperature Re-buncher for the PIP-II Linac Front End | 3914 |
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| At Fermilab there is a plan for improvements to the Fermilab accelerator complex aimed at providing a beam power capability of at least 1 MW on target. The essential element of the plan (the Proton Improvement Plan II – PIP-II) is a new 800 MeV superconducting linac. The PIP-II linac includes a room temperature front-end and high energy part based on five types of superconducting cavities used to cover the entire velocity range required for beam acceleration. The room temperature front end is composed of an ion source, low energy beam transport line (LEBT), radio frequency quadrupole (RFQ), and a medium energy beam transport line (MEBT). The paper reports RF design of the re-buncher for MEBT along with thermal analysis of the cavity. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI062 | |
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| THPRI064 | Plasma Chemistry in a High Pressure Gas Filled RF Test Cell for use in a Muon Cooling Channel | 3917 |
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| Filling an RF cavity with a high pressure gas prevents breakdown when the cavity is placed in a multi-Tesla external magnetic field. A beam of particles traversing the cavity, be it muons or protons, ionizes the gas, creating an electron-ion plasma which absorbs energy from the cavity. In order to understand the nature of this plasma loading, a variety of gas species, gas pressures, dopants, and cavity electric fields were investigated. Plasma induced energy loss, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times were measured. The results for hydrogen, deuterium, helium, and nitrogen, doped with dry air will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI064 | |
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| THPRI065 | Effects of Beam Loading and Higher-order Modes in RF Cavities for Muon Ionization Cooling | 3921 |
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| Envisioned muon ionization cooling channel is based on vaccum and/or gas-filled RF cavities of frequencies of 325 and 650 MHz. In particular, to meet the luminosity requirement for a muon collider, the muon beam intensity should be on the order of 1012 muons per bunch. In this high beam intensity, transient beam loading can significantly reduce the accelerating gradients and deteriorate the beam quality. We estimate this beam loading effect using an equivalent circuit model. For gas-filled cavity case, the beam loading is compared with plasma loading. We also investigate the excitation of higher-order modes and their effects on the performance of the cavity. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI065 | |
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| THPRI066 | Design of a 1.3 GHz Two-cell Buncher for APEX | 3924 |
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Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The design of a 1.3 GHz buncher cavity for the APEX project, a MHz repetition rate high-brightness photoinjector, is presented. The buncher cavity operates at 240 kV in CW mode, and it compresses the 750 keV beam from APEX gun through ballistic compression. Compared with a single cell design, a two-cell cavity doubles the shunt impedance to 7.8 MΩ, which greatly relaxes the requirements for both RF amplifier and cavity cooling. Coupler design, multipacting analysis, HOM analysis and thermal analysis will be presented in this paper. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI066 | |
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| THPRI070 | Tuner System Simulation and Tests for the 201-MHz MICE Cavity | 3927 |
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Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program. The frequency of MICE cavities is controlled by pneumatic tuners as their operation is impervious to large magnetic fields. The mechanical and RF transfer functions of the tuner were simulated in ANSYS. The first of these tuning systems was assembled and tested at Fermilab. The mechanical response and the RF tuning transfer function have been measured and compared with simulation results. Finally the failure of different actuators has been simulated and tested to predict the operational limits of the tuner. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI070 | |
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| THPRI071 | Instrumentation for Characterizing 201-MHz MICE Cavity at Fermilab | 3930 |
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| A 201-MHz single cavity module is installed in the Mucool Test Area (MTA) of Fermilab to test the performance of the cavity at the design parameters for the International Muon Ionization Cooling Experiment (MICE) particularly in multi-Tesla external magnetic fields. To monitor various aspects of the cavity and to understand detailed physics involved in RF breakdown and multipacting, numerous instrumentation is installed on the cavity module and also in the experimental hall, which includes thermocouples, infrared sensors, electron pickups, fiber light guides, and radiation detectors. In this paper, we will present details of each diagnostic and initial test results. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI071 | |
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| THPRI073 | Achieving Higher Energies via Passively Driven X-band Structures | 3933 |
| SUSPSNE089 | use link to see paper's listing under its alternate paper code | |
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| Due to their higher intrinsic shunt impedance X-band accelerating structures significant gradients with relatively modest input powers, and this can lead to more compact particle accelerators. At the Colorado State University Accelerator Laboratory (CSUAL) we would like to adapt this technology to our 1.3 GHz L-band accelerator system using a passively driven 11.7 GHz traveling wave X-band configuration that capitalizes on the high shunt impedances achievable in X-band accelerating structures in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. Here we provide the design details of the X-band structures that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structure while driven solely by the beam from the L-band system. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI073 | |
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| THPRI074 | Colorado State University (CSU) Accelerator and FEL Facility | 3937 |
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| The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI074 | |
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| THPRI075 | S-Band Structure Study for the MaRIE Project | 3940 |
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Funding: Work was supported by the US Department of Energy through the LANL/LDRD Program. The Matter-Radiation Interactions in Extremes (MaRIE) facility proposed at LANL utilizes a 20-GeV electron linac to drive a 50-keV XFEL. Experimental requirements drive a need for multiple photon bunches over time durations of about 10 microsecond produced by a bunch train of interleaving 0.1 nC very low-emittance bunches with 2-nC electron bunches. The linac is required not only to provide high gradient and high efficient acceleration, but also a controlled wakefield profile to maintain the beam quality. In this paper, we explore the feasibility of using the S-Band technology to meet such acceleration requirements. We will present the design optimization and comparison of S-Band structures based on different design considerations. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI075 | |
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| THPRI076 | Laser Triggered RF Breakdown Study Using an S-band Photocathode Gun | 3943 |
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| A laser triggered RF breakdown experiment was carried out with an S-band photocathode gun at Tsinghua University for attempting understanding of the RF breakdown processes. By systematic measurement of the time dependence of the breakdown current at the gun exit and the stored RF energy in the cavity, one might gain insight into the time evolution of RF breakdown physics. A correlation of the stored energy and field emission current has been analysed with an equivalent circuit model. Experimental details and analysis methods are reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI076 | |
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| THPRI077 | Electric Field Enhancement Study using an L-band Photocathode Gun | 3946 |
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| RF breakdown in high gradient accelerating structures is a fundamental problem that is still needed better understanding. Past studies have indicated that field emission, which is usually represented by electric field enhancement (i.e. β) produced from the Fowler-Nordheim plot, is strongly coupled to the breakdown problem. A controlled surface study using a high gradient L-band RF gun is being carried out. With a flat cathode, the maximum electric field on the surface reached 103 MV/m. And electric field as high as 565 MV/m on the surface was achieved by a pin-shaped cathode. The field enhancement factor was measured at different surface field during the conditioning process. Initial results of the study are presented in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI077 | |
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| THPRI078 | Experimental Study of Surface RF Magnetic Field Enhancement Caused by Closely Spaced Protrusions | 3949 |
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| The RF magnetic field enhancement between two closely spaced protrusions on a metallic surface has been studied theoretically. It is found that a large enhancement occurs when the field is perpendicular to the gap between the protrusions. This mechanism could help explain the melting that has been observed on cavity surfaces subjected to pulsed heating that would nominally be well below the melting temperature of the surface material. To test this possibility, an experiment was carried out in which a pair of copper “pins” was attached to the base plate of an X-band cavity normally used to study pulsed heating. Melting was observed between the pins when the predicted peak temperature was near or exceeded the copper melting temperature. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI078 | |
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| THPRI079 | RF BREAKDOWN IN A GAS-FILLED TE01 CAVITY | 3952 |
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| An L-band (1.3 GHz) TE01 mode pillbox cavity has been designed to study rf breakdown in gas. Since there are no surface electric fields, effects from the electron interaction with the surface should not be present as in the DC breakdown case. A CCD camera was used to measure the integrated light pattern through holes in the cavity, and an ultrafast diode was used to observed the evolution of the plasma during breakdown. Some preliminary results of the tests are presented in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI079 | |
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| THPRI080 | The New Design for Capture Cavity of CEBAF | 3955 |
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| In CEBAF, the electron beam from the injector must be sufficiently relativistic to match a 1 GeV recirculated beam in the first linac. The electron beam is produced with a ~130 keV electron gun, then accelerated by a room temperature, graded-beta standing wave linac, capture section, from 130 keV to 510 keV before enters two 5-cell superconducting RF cavities for further acceleration. Present capture cavity is a 5-cell side-coupled cavity. We designed a new slot-coupled cavity which has lower power consumption and simpler structure. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI080 | |
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| THPRI081 | A Transverse Electron Target for Heavy Ion Storage Rings | 3958 |
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| A transverse electron target already constructed is under investigation for the application in storage rings at the FAIR facility. Using a sheet beam of free electrons in a crossed beam geometry promises a high energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width of 5 mm in the interaction region with electron densities of up to 109 electrons/cm3. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV and a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions. Also the ion optical behaviour of the target was investigated numerically. The target is integrated in a test bench to study the performance of the electron gun and the electron beam optics. The installed volume ion source delivers light ions and molecules for characterization of the target performance by measuring charge changing processes. Subsequently the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements. An overview of the project status will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI081 | |
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| THPRI082 | Power Upgrade Studies for the ISIS-TS1 Spallation Target | 3961 |
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| ISIS is one of the world's most powerful spallation neutron sources for the study of material structures and dynamics. Currently ISIS has two spallation targets, TS1 operating at proton beam powers of up to 200kW, and TS2 operating to 45kW. This paper focuses upon an upgrade study of TS1 with the goal of increasing the ultimate operating power to 1 MW and beyond. During this study we have taken into consideration the necessity of maintaining the spallation neutron pulse width at current values. The increased heat deposition was monitored and the target plates dimensions were modified to take this into account. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI082 | |
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| THPRI083 | Target Design for the ISODAR Neutrino Experiment | 3964 |
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| This paper focuses on the design of a high-intensity antineutrino source from the production and subsequent decay of Li8. The Geant4 code is used to calculate the anti-neutrino flux that can be obtained along with the production of undesirable contaminants. We present in this paper the optimised design for the target, moderators, reflector and shielding. Engineering issues associated with this design are also discussed in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI083 | |
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| THPRI084 | Testing Results of the Prototype Beam Absorber for the PXIE MEBT | 3967 |
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Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H− bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. A prototype of the absorber was manufactured from molybdenum alloy TZM, and tested with an electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototype and key testing results. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI084 | |
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| THPRI085 | Target Station Design for the Mu2e Experiment | 3970 |
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Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. The Mu2e experiment at Fermilab is devoted to search for the conversion of a negative muon into an electron in the field of a nucleus without emission of neutrinos. One of the main parts of the Mu2e experimental setup is its Target Station in which negative pions are generated in interactions of the 8-GeV primary proton beam with a tungsten target. A large-aperture 5-T superconducting production solenoid (PS) enhances pion collection, and an S-shaped transport solenoid (TS) delivers muons and pions to the Mu2e detector. The heat and radiation shield (HRS) protects the PS and the first TS coils. A beam dump absorbs the spent beam. In order for the PS superconducting magnet to operate reliably the sophisticated HRS was designed and optimized for performance and cost. The beam dump was designed to absorb the spent beam and maintaining its temperature and air activation in the hall at the allowable level. Comprehensive MARS15 simulations have been carried out to optimize all the parts while maximizing muon yield. Results of simulations of critical radiation quantities and their implications on the overall Target Station design and integration will be reported. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI085 | |
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| THPRI086 | Beam Dumps of the New LCLS-II | 3973 |
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Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515. In 2013 the design of the new LCLS-II new hard X-FEL facility at the SLAC National Accelerator Laboratory was rescoped to operate two parallel variable gap undulator lines at repetition rates up to 1MHz and above. A new superconducting RF structure will be installed in the first third of the SLAC two-mile Linac to provide a few hundred kWof beam power at energies of up to 4 GeV. This paper describes the radiological aspects of the dumps that are being designed for the end of the electron beam lines. A layered arrangement of shielding materials is being optimized to reduce instantaneous dose leakage to occupied areas, minimum cool-down time to access the tunnel, and impact to equipment and to the environment. Calculations deal with numerous constraints, as legacy beam components will be used, and the existing tunnel structure was designed for beam powers fifty times below those envisaged for LCLS-II. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI086 | |
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| THPRI087 | Magnet Design for the Target System of a Muon Collider/Neutrino Factory | 3976 |
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| The Target System and Pion Decay Channel for a Muon Collider/Neutrino Factory utilizes a string of solenoid magnet to capture and transport the low-energy pions whose decay provides the desired muon beams. The magnetic field strength at the target is 15-20 T, "tapering" down to 1.5-3 T in the Decay Channel. The superconducting coils which produce these fields must have substantial inner radius to accommodate internal shielding against radiation damage by secondary particles. A significant fraction of the primary beam energy is transported into the Decay Channel via protons, and the Decay Channel includes a magnetic chicane to provide a beam dump for these. The design of the various coils in this scenario is reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI087 | |
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| THPRI088 | Energy Deposition in the Target System of a Muon Collider/Neutrino Factory | 3979 |
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| Most of the energy of the primary proton beam of Muon Collider/Neutrino Factory would be deposited in the superconducting coils that provide a solenoid-magnet transport channel for secondary particles, unless those coils are protected by massive internal shielding. Studies are reported of energy deposition in such shielding, with the goal of permitting 10 years operational life at 4-MW beam power. The graphite target should be able to withstand the "thermal shock" induced by the pulsed beam; further study is needed to confirm this. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI088 | |
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| THPRI089 | Carbon Target Optimization for a Muon Collier/neutrino Factory With a 6.75 GeV Proton Driver | 3982 |
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| The first phase of a Muon Collider/Neutrino Factory program may use a 6.75-GeV proton driver with beam power of only 1 MW. At this lower power it is favorable to use a graphite target (replaced quarterly) with beam and target tilted slightly to the axis of the 15-20 T pion-capture solenoid around the target. The low-energy proton beam is significantly deflected by the magnetic field, requiring careful optimization, reported here, of the beam/target configuration. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI089 | |
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| THPRI091 | Machine Protection Considerations for BERLinPro | 3985 |
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Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association The Berlin energy-recovery-linac project BERLinPro at the HZB is a 50 MeV ERL test facility, which addresses physical and technological questions for future superconducting rf based high brightness, high current electron beam sources. The combination of a 100 mA cw beam, electron bunches with normalized emittances lower than 1 mm mrad and the magnet optics of BERLinPro leads to power densities capable to harm the accelerator components within microseconds if total beam loss occurs. Furthermore, continuous beam loss on the level of 10-5 has to be controlled to avoid activation and to protect the SRF, beam diagnostics and other infrastructure components. In this paper, we present the evaluation of the required key parameters of the BERLinPro machine protection system and present its first conceptual design. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI091 | |
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| THPRI093 | CSCM: EXPERIMENTAL AND SIMULATION RESULTS | 3988 |
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| The copper-stabilizer continuity measurement - or CSCM - was devised to obtain a direct and complete qualification of the continuity in the 13 kA bypass circuits of the LHC, especially in the copper-stabilizer of the busbar joints and the bolted connections in the diode-leads. The circuit under test is brought to ~20 K, a voltage is applied to open the diodes, and the low-inductance circuit is powered with a pre-defined series of current profiles. The profiles are designed to successively increase the thermal load on the busbar joints up to a level that corresponds to worst-case operating conditions at nominal energy. In this way, the circuit is tested for thermal runaways in the joints - the very process that could prove catastrophic if it occurred under nominal conditions with the full circuit energy. Surveillance software and a numerical model were devised to carry out the analysis and ensure complete protection of the circuit from over-heating. A type test of the CSCM was successfully carried out in April 2013 on one main dipole and one main quadrupole circuit of the LHC. This paper describes the analysis procedure, the numerical model, and results of this first type test. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI093 | |
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| THPRI094 | MadX Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation | 3991 |
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| Quench tests with stored beam were performed in 2013 with one of the LHC main focusing quadrupoles to experimentally verify the quench levels for beam losses in the time scales from a few milliseconds to several seconds. A novel technique combining a 3-corrector orbital bump and transverse-damper kicks was used for inducing the beam losses. MadX tracking simulations were an essential step for determining the spatial and angular beam loss distributions during the experiment. These were then used as input for further energy-deposition and quench-level calculations. In this paper the simulated beam-loss distributions for the respective time scales and experimental parameters are presented. Furthermore the sensitivity of the obtained loss-distributions to the variation of key input parameters, which were measured during the experiment, is discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI094 | |
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| THPRI095 | Testing Quality and Metrics for the LHC Magnet Powering System throughout Past and Future Commissioning | 3995 |
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| The LHC magnet powering system is comprised of thousands of individual components to assure a safe operation when operating with stored energies as high as 10GJ in the superconducting LHC magnets. Each of these components has to be thoroughly commissioned following interventions and machine shutdown periods to assure their protection function in case of powering failures. As well as a dependable tracking of test executions it is vital that the executed commissioning steps and applied analysis criteria adequately represent the operational state of each component. The Accelerator Testing (AccTesting) framework in combination with a domain specific analysis language provides the means to quantify and improve the quality of analysis for future campaigns. Dedicated tools were developed to analyse in detail the reasons for failures and success of commissioning steps in past campaigns and to compare the results with newly developed quality metrics. Observed shortcomings and discrepancies are used to propose additional verification and mitigation for future campaigns in an effort to improve the testing quality and hence assure the overall dependability of subsequent operational periods. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI095 | |
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| THPRI096 | Use of Silicon Carbide as Beam Intercepting Device Material: Tests, Issues and Numerical Simulations | 3998 |
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| Silicon Carbide (SiC) stands as one of the most promising ceramic material with respect to its thermal shock resistance and mechanical strengths. It has hence been considered as candidate material for the development of higher performance beam intercepting devices at CERN. Its brazing with a metal counterpart has been tested and characterized by means of microstructural and ultrasound techniques. Despite the very positive results, its use has to be evaluated with care, due to the strong evidence in literature of large and permanent volumetric expansion, called swelling, under the effect of neutron and ion irradiation. This may cause premature and sudden failure of components, and can be mitigated to some extent by operating at high temperature. For this reason limited information is available for irradiation below 100°C, which is the typical temperature reached in intercepting devices like dumps or collimators. This paper describes the brazing campaign carried out at CERN, the results, and the theoretical and numerical approach used to characterize the extent of the swelling phenomenon with radiation, as well as the p+ irradiation test program to be conducted in the next future. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI096 | |
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| THPRI097 | A Retrospective View to the Magnet Interlock Systems at CERN | 4001 |
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| Several thousands of both, superconducting and normal conducting magnets are in charge of guiding the particle beams in CERN’s accelerator complex. In order to protect the magnet and powering equipment from damage, dedicated magnet interlock and protection systems are deployed throughout the various accelerators and transfer lines. These systems have worked extremely well during the first years of LHC operation, providing highly dependable interlocking of magnet powering based on industrial COTS components. This paper reviews the performance of the more than 70 individual installations during the first LHC running period and compares the operational experience with the initial expectations of dependability. Additional improvements required to address specific operational needs and observed shortcomings are presented. Finally, we review the existing magnet interlock infrastructure in the LHC injector complex and the ongoing renovation works during the first long shutdown. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI097 | |
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| THPRI098 | Brazing and Helium Leaking Test for High Heat Load Components in the Taiwan Photon Source | 4004 |
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| Taiwan Photon Source is the second accelerator constructed by National Synchrotron Radiation Research Center (NSRRC). With 3GeV, 500mA, this facility will generate extremely high synchrotron radiation and most of the power load will be shadowed at front end in order to shape final confining beam size for beam lines users. The high heat load components are known to be the critical parts to absorb the unwanted energy. In order to practically distribute high density power along each high heat load components, several absorbers are introduced. Namely, primary mask, main mask, photon absorber and slits. The manufacturing process such as UHV chemical cleaning, brazing and helium leaking test will be described in this report. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI098 | |
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| THPRI099 | Constructing and Installation of TPS Front End | 4007 |
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| National Synchrotron Radiation Research Center (NSRRC) in Taiwan is completing the construction of Taiwan Photon Source (TPS) synchrotron accelerator project. This 3GeV, 500mA beam current 3rd generation synchrotron accelerator will have total of 7 insertion device beam lines at day one. Corresponding front ends have been design and fabricated. Installation and craning is underway. Current status of frond end are reported and presented in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI099 | |
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| THPRI100 | Distributed Cooling System for the AREAL Test Facility | 4010 |
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| Following the design specifications of the Advanced Research Electron Accelerator Laboratory (AREAL), a reliable distributed cooling system for the AREAL linear accelerator has been developed. The cooling system provides a high accuracy temperature control for the electron gun, klystron and the magnets. The main requirements and technical solutions for various accelerator components cooling units are presented, including the local and remote control. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI100 | |
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| THPRI101 | Coupler Kick and Cavity Tilt Effects on Emittance Preservation in Linear Accelerators | 4013 |
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| The effects of the coupler kick and the cavity tilts on the beam dynamics in long linear accelerator are studied. The dispersive and wakefield caused beam emittance dilution are evaluated analytically using two particle model of the beam. The numerical simulations for the European XFEL project are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI101 | |
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| THPRI102 | Energy Effciency of Particle Accelerators - A Networking Effort within the EUCARD² Program | 4016 |
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Funding: EuCARD² is co-funded by the partners and the European Commission under Capacities 7th Framework Programme, Grant Agreement 312453 EuCARD² is an Integrating Activity Project for coordinated Research and Development on Particle Accelerators, co-funded by the European Commission under the FP7 Capacities Programme. Within the network EnEfficient we address topics around energy efficiency of research accelerators. The ambitious scientific research goals of modern accelerator facilities lead to high requirements in beam power and beam quality for those research accelerators. In conjunction with the user’s needs the power consumption and environmental impact of the research facilities becomes a major factor in the perception of both funding agencies and the general public. In this Network we combine and focus the R&D done individually at different research centers into a series of workshops. We cover the topics “Energy recovery from cooling circuits “, “Higher electronic efficiency RF power generation“, “Short term energy storage systems”, “Virtual power plants” and “Beam transfer channels with low power consumption”. Our network activities are naturally open to external participants. With this work we will introduce our energy efficiency topics to interested participants and contributors from the whole community. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI102 | |
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| THPRI103 | Improvement of the Run-time of 35 mbar Helium Gas Pumping Units for the Superconducting Linear Accelerator S-DALINAC | 4019 |
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Funding: Work supported by DFG through SFB 634 The superconducting Darmstadt linear accelerator S-DALINAC has been designed to provide electron beams of up to 130 MeV for nuclear and astrophysical experiments. The accelerating cavities are operated in a liquid helium bath at 2 K. To achieve this temperature the cryostat has to be pumped down to a pressure of 35 mbar which was done by a system of pumping units connected in series, when the accelerator started its operation in 1991. In 2005 this system was replaced by four parallel switched pumping stations. In the first three years of their operation, the reliability of the accelerator was very poor due to repeated breakdowns of the pumping stations caused by overheating. In addition the high temperatures lead to an early decay of the gaskets used. The problem was solved by installing oil cooling systems and more appropriate shaft sleeves at the pumping stations. We will report on the technical efforts we made and thereby further increased the availability of the accelerator significantly. Also we will give a review on our experiences in maintenance procedures. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI103 | |
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| THPRI104 | Design and Fabrication of Bunch Compressor Support System for PAL XFEL | 4022 |
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| Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Bunch compressor support systems are developed to be used for the linear accelerator tunnel. The support system design is based on an asymmetric four-dipole magnet chicane in which asymmetry and variable R56. can be optimized. This flexibility is achieved by allowing the middle two dipole magnets to move transversely. Moving system consist of servo motor, rodless ball screw actuator and linear encoder. In this paper, we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI104 | |
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| THPRI105 | Determination of Magnetic Multipoles using a Hall Probe | 4025 |
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| In this work we present a method that allows determining the harmonic content of the magnetic field generated by an accelerator magnet using a Hall probe bench. The method is based on measuring the three components of the magnetic field on a cylindrical surface parallel to the longitudinal axis of the magnet. Such a measurement is accomplished by carrying out a series of on-the-fly scans for a series of straight lines whose transversal coordinates lay on a circle. The Fourier decomposition of the magnetic field along a circle at a given longitudinal position yields the harmonic terms of the field at a reference radius equal to the circle’s radius. As a result the method provides the longitudinal dependence of the harmonic terms, and in particular it allows analyzing their behavior in the fringe field region. We present an example of the application of this method to the measurement of a quadrupole of the Storage Ring of ALBA. A comparison with the integrated results provided by a rotating coil bench is also shown. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI105 | |
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| THPRI106 | Specialized Technical Services at ESS | 4028 |
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| The European Spallation Source (ESS), a world class lab for neutron science currently under construction in Lund, Sweden requires a number of technical services that extend across the various project areas (accelerator, target and neutron science). These services include: cryogenics, vacuum and technical electrical and cooling systems. This effort constitutes more than 70 million Euros of construction cost. Rather than have separate support groups in each of the project areas, ESS has created a Specialized Technical Services group within the Accelerator Division to provide these services. This approach permits standardization, development of synergies and improved communication. The STS group also provides cryomodule testing and accelerator infrastructure and installation to the accelerator project. This paper describes the scope of work, current design status and future plans for Specialized Technical services at ESS. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI106 | |
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| THPRI108 | Manufacturing and Inspecting Supporting Tables for Front End in Taiwan Photon Source | 4031 |
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| Taiwan Photon Source is the second accelerator constructed by National Synchrotron Radiation Research Center with energy 3 GeV and 500 mA beam current. In order to install and support front end components those table are designed and constructed. The results of manufacturing and inspecting tables are one of the primary factors that will directly affect the final confining aperture to the end usres. Those supporting table has six types and are all designed and simulated by Solidworks. Different alignment and measurement tools are utilized to inspect these tables. In addition, some results of final post-installation measurement and vibration test are also reported. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI108 | |
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| THPRI109 | Auto-alignment Status of the Taiwan Photon Source | 4034 |
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| Taiwan Photon Source (TPS) is a new 3-GeV ring under construction at NSRRC in Taiwan. There are hundreds of magnets placed on girders that must be aligned correctly to keep the electronic beam in the desire orbit. Due to the reasons of manpower, set up time, accuracy of adjustment, deformation of the floor, and limited space, an auto-alignment girder control system was designed to meet this requirement. The auto-alignment test was completed with one double-bend cell at NSRRC. The Auto-alignment process will be tested with some sections of magnet girders to confirm the control system and the algorithm in the TPS. The status and test results will be described in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI109 | |
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| THPRI111 | Higher Order Mode Absorbers for High Current ERL Applications | 4037 |
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| Efficient damping of the higher-order modes (HOMs) of the superconducting cavities is essential for any high current linac, especially for the proposed energy recovery linac at Cornell that aims for high beam currents and short bunches. This contribution will present the design and first result on the HOM absorbers built for the Main Linac Cryomodule (MLC). | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI111 | |
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| THPRI112 | Basic Research on RF Absorbing Ceramics for Beam Line HOM Absorbers | 4040 |
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| Higher Order Mode (HOM) absorbers for future high current machines have been a challenging component for many years. Even though many different materials are commercially, none of them seems to fully qualify for accelerator applications. Some of them are brittle or chippy, others porous, have small bandwidth of absorption, a high dc resistivity leading to charge-up or are unreliable in terms of batch to batch variations. Alfred University and Cornell University have recently partnered in developing a dedicated absorber ceramic material that tries to overcome these limitations. We will report on results from small samples of different compositions we produced based on SiC, graphene and graphite. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI112 | |
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| THPRI113 | Spallation Neutron Source Cryogenic Test Facility Horizontal Test Apparatus Operation | 4043 |
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Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The Spallation Neutron Source (SNS) has built Superconducting Radio Frequency (SRF) processing and testing facilities to support improvement programs and future upgrades. The Cryogenic Test Facility (CTF) system is capable of delivering liquid helium at 4.5K to different test apparatus in support of SRF testing. This paper describes the final stages of fabrication, commissioning and the initial operation of the Horizontal Test Apparatus (HTA). The HTA allows for cold testing of single jacketed medium-beta or high-beta SRF cavities. Heat loads, capacities, and other performance data collected during operation will be presented. Cavity testing lifecycle for plasma processing research and development will be discussed. System changes to allow for 2K helium operation in the HTA will also be addressed. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI113 | |
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| THPRI114 | Apparatus and Technique for Measuring Low RF Resistivity of Tube Coatings at Cryogenic Temperatures | 4046 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. An in-situ technique for coating stainless steel vacuum tubes with Cu was developed to mitigate the problems of wall resistivity that leads to unacceptable ohmic heating of superconducting magnets cold bore and electron cloud generation in RHIC that can limit future machine luminosity enhancement. Room temperature RF resistivity of 10 μm Cu coated stainless steel RHIC beam tube has conductivity close to copper tubing. Before coating the RHIC beam pipe with copper, it is imperative to test the Cu coating’s conductivity at cryogenic. A folded quarter wave resonator structure has been designed and built for insertion in a cryogenic system to measure RF resistivity of copper coated RHIC tubing at liquid helium temperatures. The design is based on making the resonator structure out of a superconducting material such that the copper coating is the most lossy material. RHIC tubing samples prepared with different magnetron sputtering deposition modes are to be optimized by iterative processes. Additionally, this device can also be used for the development of better, cheaper SRF cavities and electron guns. The apparatus and its design details will be presented. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI114 | |
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| THPRI115 | Measuring and Aligning Accelerator Components to the Nanometre Scale | 4049 |
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| First tests have shown that the precision and accuracy required for linear colliders and other future accelerators of 10 micrometers cannot be reached with a process based on independent fiducializations of single components. Indeed, the systematic and random errors at each step add up during the process with the final accuracy of each component center well above the target. A new EC-funded training network named PACMAN (a study on Particle Accelerator Components Metrology and Alignment to the Nanometer scale) will propose and develop an alternative solution integrating all the alignment steps and a large number of technologies at the same time and location, in order to gain the required precision and accuracy. The network composed of seven industrial partners and nine universities and research centers will be based at CERN where ten doctoral students will explore the technology limitations of metrology. They will develop new techniques to measure magnetic and microwave fields, optical and non-contact sensors and survey methods as well as high accuracy mechanics, nano-positioning and vibration sensors. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI115 | |
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