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| MOPPC013 | Optics and Lattice Optimizations for the LHC Upgrade Project | 151 |
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| The luminosity upgrade of the LHC collider at CERN is based on a strong focusing scheme to reach lowest values of the beta function at the collision points. Several issues have to be addressed in this context, that are considered as mid term goals for the optimisation of the lattice and beam optics: Firstly a number of beam optics have been developed to establish a baseline for the hardware R&D, and to define the specifications for the new magnets that will be needed, in Nb3Sn and in NbTi technology. Secondly, the need for sufficient flexibility of the beam optics especially for smallest β* values has to be investigated as well as the need for a smooth transition between the injection and the collision optics. Finally the performance of the optics based on flat and round beams has to be compared and different ways have to be studied to optimise the chromatic correction, including the study of local correction schemes. This paper presents the status of this work, which is a result of an international collaboration, and summarises the main parameters that are foreseen to reach the HL-LHC luminosity goal. | ||
| MOPPD077 | Studies for an Alternative LHC Non-Linear Collimation System | 544 |
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Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program. A LHC nonlinear Betatron cleaning collimation system would allow larger gap for the mechanical jaws, reducing as a consequence the collimator-induced impedance, which may limit the LHC beam intensity. In this paper, the performance of the proposed system is analyzed in terms of beam losses distribution around the LHC ring and cleaning efficiency in stable physics condition at 7TeV for Beam1. Moreover, the energy deposition distribution on the machine elements is compared to the present LHC Betatron cleaning collimation system in the Point 7 Insertion Region (IR). |
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| MOPPR044 | Optics and Emittance Studies using the ATF2 Multi-OTR System | 879 |
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Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction. |
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| MOPPR064 | Development of a Turn-by-Turn Beam Position Monitoring System for Multiple Bunch Operation of the ATF Damping Ring | 930 |
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| An FPGA-based monitoring system has been developed to study multi-bunch beam instabilities in the damping ring (DR) of the KEK Accelerator Test Facility (ATF). The system utilises a stripline beam position monitor (BPM) and a single-stage down-mixing BPM processor. The system is designed to record the horizontal and/or vertical positions of up to three bunches in the DR with c. 150ns bunch spacing, or the head bunch of up to three trains in a multi-bunch mode with bunch spacing of 5.6 ns. The FPGA firmware and data acquisition software allow the recording of turn-by-turn data. An overview of the system and performance results will be presented. | ||
| MOPPR065 | A Low-latency Sub-micron Resolution Stripline Beam Position Monitoring System for Single-pass Beamlines | 933 |
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| A low-latency, sub-micron resolution stripline beam position monitoring system has been developed for use in single-pass beamlines. The fast analogue front-end signal processor is based on a single-stage RF down-mixer and is combined with an FPGA-based system for digitisation and further signal processing. The system has been deployed and tested with beam at the Accelerator Test Facility at KEK. Performance results are presented on the calibration, resolution and stability of the system. A detailed simulation has been developed that is able to account for the measured performance. | ||
| MOPPR066 | Study of Transverse Pulse-to-Pulse Orbit Jitter at the KEK Accelerator Test Facility 2 (ATF2) | 936 |
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Funding: FPA2010-21456-C02-01 For future linear colliders the precise control and mitigation of pulse-to-pulse orbit jitter will be very important to achieve the required luminosity. Diagnostic techniques for the orbit jitter measurement and correction for multi-bunch operation are being addressed at the KEK Accelerator Test Facility 2 (ATF2). In this paper we present recent studies on the vertical jitter propagation through the ATF2 extraction line and final focus system. For these studies the vertical pulse-to-pulse position and angle jitter have been measured using the available stripline beam position monitors in the beamline. The cases with and without intra-train orbit feedback correction in the ATF2 extraction line are compared. |
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| TUPPR017 | Nonlinear Post-Linac Energy Collimation System for the Compact Linear Collider | 1846 |
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Funding: FPA2010-21456-C02-01 The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed to provide protection of the Beam Delivery System (BDS) against off-energy and mis-steered beams. The conventional baseline design consists of a two stage spoiler-absorber scheme. The CLIC energy collimators are required to withstand the impact of a full bunch train. This condition makes the energy collimator design very challenging, since the collimators have to deal with a total beam power of 14 MW at nominal energy and intensity. The increase of the transverse spot size at the collimators using nonlinear magnets could be a potential solution to guarantee the survivability of the collimators. In this paper we present an alternative nonlinear optics design for the CLIC energy collimation system. Possibilities for its optimization are discussed in view of performance simulation results. |
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| TUPPR030 | Thermo-mechanical Analysis of the CLIC Post-Linac Energy Collimators | 1882 |
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Funding: FPA2010-21456-C02-01 The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed for passive protection of the Beam Delivery System (BDS) against mis-steered beams due to failure modes in the main linac. In this paper, a thermo-mechanical analysis of the CLIC energy collimators is presented. This study is based on simulations using the codes FLUKA and ANSYS when an entire bunch train hit the collimators. Different failure mode scenarios in the main linac are considered. Moreover, we discuss the results for different collimator materials. The aim is to improve the collimator design in order to make a reliable and robust design so that it survives without damage from the impact of a full bunch train in case of likely events generating energy errors. |
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| WEPPP068 | Latest Performance Results from the FONT5 Intra-train Beam Position and Angle Feedback System at ATF2 | 2864 |
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| A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-to-bunch time scales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. The latest results from beam tests at ATF2 will be presented, including the system latency and correction performance. | ||