| Paper | Title | Other Keywords | Page |
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| MOPGW069 | Recent Beam Performance Achievements with the Pb-Ion Beam in the SPS for LHC Physics Runs | injection, target, optics, luminosity | 250 |
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| In the SPS, which is the last accelerator in the LHC ion injector chain, multiple injections of the Pb-ion beam have to be accumulated. On this injection plateau the beam suffers from considerable degradation such as emittance growth and losses. This paper summarises the achievements on improving the beam parameters and maximising the performance of the Pb-ion beam for the LHC physics run in 2018. The results are discussed in view of the target beam parameters of the LHC injectors upgrade project, which is being deployed during the presently ongoing long shutdown. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW069 | ||
| About • | paper received ※ 12 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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| TUPMP013 | New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of J-PARC RCS | vacuum, injection, radiation, damping | 1255 |
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| One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP013 | ||
| About • | paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| TUPMP053 | Test Results of the Low-Stored-Energy -80 kV Regulator for Ion Sources at LANSCE | linac, power-supply, ion-source, controls | 1369 |
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Funding: Work supported by the U. S. Department of Energy. The H− ion source at the LANSCE accelerator facility uses an 80 kV accelerating column to produce an H− ion beam. A regulated power supply maintains the source and support equipment racks at -80kV with respect to local ground. As the facility’s H− beam currents have been increased, voltage droop on the regulated -80 kV power supply has become one of the limiting factors on beam current. The previous regulator used a standard 120kV DC HV supply and a high power planar triode in series to regulate the voltage down to 80 kV and to stop the flow of current during an arcdown of the -80 kV accelerating column. In 2018 we devised a method of using a pair of standard, 50 kV capacitor charging supplies to produce the required 80 kV with minimal stored energy and significantly better voltage regulation over the beam pulse. This configuration has been tested on the Ion Source Test Stand and is being considered for installation on the main LANSCE linac. We will present the design, modeling and measured results of the new system as compared with the performance of the previous system. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP053 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| TUPTS030 | The New High Field Septum Magnets for Upgrading of Fast Extraction in Main Ring of J-PARC | operation, extraction, septum, power-supply | 2001 |
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| The J-PARC Main Ring (MR) is working on imporved beam to 750 kW by shorting the repetition period from 2.48 s to 1.3 s which we call 1Hz operation. There are fout high field septum magnet along the fast extraction line in the MR, and these will be improved to the new magnets which can operate 1Hz frequency. The new high field septa will be installed in 2021. In this poster we will report about the performance of these new septum magnets. These high field septum magnets are called Septum 30(SM30), 31(SM31), 32(SM32), 33(SM33). We will replace SM30, SM31, and SM32. One reasons of cethe replacement is installation of a large-size quadrupole magnet to upsteam postion of the septa. We need to change the longitudinal length of the septa. Second is large aperture of the beam duct for reduction of beam loss by the collision of the halo of the proton beam to the duct. The new high field SM30, SM31 and SM32 have large aperture. and the material of the beam ducts for extraction line are ceramics for reduction of amount of heat generation by eddy current on the surface of the duct. The maetial of the circulating duct are titanium for reduction of radioactivation. On the other hand, the power supply will not be replaced, then the current power supplies will be used for these new septa. The new SM30, SM31, and SM32 were produced in 2015. The first test operation of SM31 were conduced with 2.48 s repein 2015, and we have meaured the magnetic field without problem. In 2018, we conduced the first 1Hz operation with SM30. The minimum repetition period of the operation was 1.16 s without any problem. We measuered magnetic fields in the gap of the pole and in the circulating beam duct. In this report we will report the detail of the results of the operation and field measurement. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS030 | ||
| About • | paper received ※ 26 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| WEPMP034 | Characterisation of SPS Slow Extraction Spill Quality Degradation | quadrupole, dipole, target, extraction | 2403 |
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| The main physics users of the Super Proton Synchrotron (SPS) are the experiments installed in the North Area (NA). They are supplied with slowly extracted protons or heavy ions, exploiting a third integer slow extraction to provide a 4.8 s spill. High duty cycle and constant particle flux are the main requirements. Frequent super cycle changes induce variation of the spill macro structure which directly deteriorate the final spill quality. In this paper, the source of such an effect are investigated. Results of both beam based measurements and direct magnetic measurements on the SPS reference magnets are presented. Finally, a possible strategy to counteract this effect is discussed, in order to try to remove the super cycle changes variation as cause for spill quality deterioration. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP034 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| WEPRB068 | Ka-Band Linearizer Studies for a Compact Light Source | wakefield, klystron, impedance, FEL | 2976 |
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Funding: This project has received funding from the European Union’s Horizon2020 research and innovation programme under grant agreement No 777431. The CompactLight project is currently developing the design of a next generation hard X-ray FEL facility, based on high-gradient X-band (12 GHz) structures, bright electron photo-injectors, and compact short period undulators. However, to improve the brightness limitations due to the non-linear energy spread of the electron bunches, a K-band (36 GHz) linearizer is being considered to provide a harmonic compensation during the bunch compression. In this paper, we analyze the feasibility of such linearizer. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB068 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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| THPGW044 | Highly Stable Linearly Polarized Arbitrary Temporal Shaping of Picosecond Laser Pulses | laser, controls, polarization, experiment | 3682 |
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This paper reports the study and demonstration of a new variable temporal shaping method capable of generating linearly polarized picosecond laser pulses with arbitrary predefined shapes, which are highly desired by various applications including low emittance high brightness electron bunch generation in photocathode guns. It is found that both high transmittance and high stability of the shaped pulses can be achieved simultaneously when crystals are set at specific phase delay through the fine control of the crystal temperature. Such variable temporal shaping technique may lead to new opportunities for many potential applications over a wide range of laser wavelengths, pulse repetition rates, time structures and power levels, etc. In addition, a new double-pass variable shaping method is also proposed and could significantly simplify the shaper structure and reduce the cost.
*liufangming@pku.edu.cn |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW044 | ||
| About • | paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| THPRB071 | Beam-Based Measurements on Two ±12.5 kV Inductive Adders, together with Striplines, for CLIC Damping Ring Extraction Kickers | kicker, extraction, damping, storage-ring | 3970 |
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| The CLIC study is investigating the technical feasibil-ity of an electron-positron linear collider with high lumi-nosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems, each of which consists of a set of striplines and two inductive adders, must provide ex-tremely stable field pulses. The DR extraction kicker system is the most demanding: specifications require a field uniformity within ±0.01% and pulses up to 900 ns flattop duration, at ±12.5 kV and 309 A, with ripple and droop of not more than ±0.02 % (±2.5 V), with respect to a reference waveform. Two prototype inductive adders have been designed and built at CERN, and have been tested with prototype striplines installed in the storage ring of the ALBA Synchrotron Light Source, in Spain. The stability of the kicker system, including the modulators, has been evaluated from the beam-based measure-ments and is reported in this paper. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB071 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| THPRB073 | Laboratory Measurements on Two ±12.5 kV Inductive Adders with ±0.02% Waveform Stability for CLIC Damping Ring Extraction Kickers | kicker, extraction, damping, collider | 3978 |
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| The CLIC study is investigating the technical feasibil-ity of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. Each DR extrac-tion kicker system consists of a set of striplines and two pulse modulators. Specifications for this system require that the modulator produce pulses of 900 ns flattop dura-tion, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to a reference waveform. Inductive adder topology has been chosen for the pulse modulators. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed, built and tested at CERN. This paper presents the measurements of the stability of these adders for two different waveforms: a flat-top waveform and a controlled decay waveform, the latter of which is required to generate flat-top total field for the CLIC DR extraction stripline kicker. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB073 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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| THPRB078 | Performance Validation of the Existing and Upgraded PS Injection Kicker | kicker, injection, simulation, operation | 3994 |
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| The CERN PS injection kicker KFA45 will be upgraded in the framework of the LHC Injector Upgrade (LIU) project to allow for injection of 2 GeV proton beams. This paper summarizes the recent efforts to validate beam based waveform measurements, Pspice simulations and current waveform measurements by direct magnetic field measurements in the aperture of the existing system. The magnetic probe, associated measurement hardware design and measurements results are discussed. The paper concludes with a performance comparison and an outlook to future waveform tuning possibilities. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB078 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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