Paper | Title | Page |
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MOZZPLM2 | A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution | 37 |
SUSPFO046 | use link to see paper's listing under its alternate paper code | |
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Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster. |
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Slides MOZZPLM2 [2.618 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZZPLM2 | |
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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MOPTS046 | Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC | 960 |
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We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS046 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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MOPTS048 | Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1 | 968 |
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J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS048 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | |
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TUXXPLS2 | Negative Muonium Ion Production With a C12A7 Electride Film | 1175 |
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Funding: This work was supported by OSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707. Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H− formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented. |
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Slides TUXXPLS2 [2.680 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS2 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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TUPRB117 | Disk and Washer Coupled Cavity Linac Design and Cold-Model for Muon Linac | 1924 |
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Funding: This work was supported by JSPS KAKENHI Grant Numbers JP15H03666, JP 16H03987, JP18H03707. A disk and washer (DAW) coupled cavity linac (CCL) has been developed for a middle velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.3 to 0.7 at an operational frequency of 1296 MHz. In this poster, the cavity designs, beam dynamics designs, and the cold-model measurements will be presented. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB117 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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TUPTS027 | Progress of J-PARC LINAC Commissioning | 1990 |
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After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS027 | |
About • | paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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WEPGW033 | Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire | 2543 |
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A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H− beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H− beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033 | |
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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WEPGW042 | Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment | 2571 |
SUSPFO052 | use link to see paper's listing under its alternate paper code | |
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Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP15H05742, JP16H03987, JP16J07784, JP18H03707 and JP18H05226. The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW042 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
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THPTS022 | The Realization of Iterative Learning Control for J-PARC LINAC LLRF Control System | 4155 |
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The beam current of j-parc linac was planned to increase to 60 mA. The stronger beam current will lead to higher beam loading effect. Due to the low Q factor of cavity in high β section of linac, the traditional PID feedback & feedforward control method may have to face huge challenges. In order to make the system run better at 60 mA, the iterative learning control (ILC) method was put forward to use in LLRF control system. All the ILC operations are done in EPICS-PC. By installing the PyEpics module, we can use python programs to realize the data interaction between EPICS system and PC and further realize the ILC algorithm. In this paper, the architecture of ILC methods will be introduced. The performance of ILC method will be reported. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS022 | |
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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