| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| TUYAA01 | High Currents Effects in DAΦNE | vacuum, impedance, feedback, electron | 82 |
|
|||
| DAΦNE, the Italian lepton collider, operates routinely with high intensity electron and positron colliding beams. The high current multi-bunch beams are stored in two independent rings, each of them 97 m long, and are distributed in 100 ’ 110 contiguous buckets out of the 120 available, spaced by only 2.7 ns. Since its construction, DAΦNE has been operated in different configurations which, overall, allowed to store current up to 1.4 A and 2.45 A in the positron and in the electron beam respectively. Still today DAΦNE holds the record for the highest electron beam current ever stored in particle factories and modern synchrotron radiation sources. The DAΦNE experience in terms of beam dynamics optimization aimed at achieving the high intensity beams is presented, with special emphasis on the e-cloud related issues, which represent the dominant effect limiting the positron beam current. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYAA01 | ||
| About • | paper received ※ 24 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||
| TUYAA03 | Impedances and Collective Effects for JLEIC | impedance, electron, dipole, proton | 90 |
|
|||
|
Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. JLEIC is the high luminosity and high polarization electron-ion collider (EIC) currently under design at Jefferson Lab. Its luminosity performance relies on the beam stability under high-intensity electron and ion beam operation. The impedance budget analysis and the estimations of beam instabilities are currently underway. In this paper, we present the update status of our back-of-envelope estimations for these collective instabilities, and identify area or parameter regimes where special attentions for instability mitigations are required. |
|||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYAA03 | ||
| About • | paper received ※ 22 October 2018 paper accepted ※ 08 March 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||
| WEYAA02 | Large Scale Superconducting RF Production | SRF, niobium, FEL, collider | 251 |
|
|||
| The efficient plug to beam power conversion promised by the use of Superconducting RF to accelerate particle beams is still the driving force to pursue the development of this technology. Once the effective gain reached the level to pay for cryogenics, big physics laboratories started to believe on SRF, investing resources and proposing large challenging projects. Since then the cooperation with industry has been crucial to transform e few lab results into reliable SRF cavities and related ancillaries. This process started in the eighties and reached the actual paradigm with the realization of the European XFEL. All the new large scale projects in construction or proposed should start from the analysis of this experience and move forward from there. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEYAA02 | ||
| About • | paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||
| WEYAA03 | SRF System for KEKB and SuperKEKB | operation, controls, HOM, LLRF | 256 |
|
|||
| Eight superconducting accelerating cavities were operated for more than ten years at the KEKB. Commisioning operation of SuperKEKB is ongoing and those cavities are also used to accelerate the electron beam of 2.6 A. There are some issues to address the large beam current and to realize stable operation. One issue is a large HOM power of 37 kW expected to be induced in each cavity module. To cope with the HOM power issue, we have installed an additional HOM damper to the downstream of the cavity module. Another issue is degradation of Q values of the cavities during the ten years operation. Cause of the degradation was particle contamination. To clean the cavity surface, high pressure rinsing (HPR) is an effective way. Therefore we have developed a horizontal HPR. In this method, a nozzle for water jet is inserted horizontally into the cavity module without disassembly of the cavity. We applied the horizontal HPR to our degraded cavities. The RF performances of those cavities have been successfully recovered. In this report, present status of our cavity will be presented. Additionally, LLRF control issues for SuperKEKB will be introduced. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEYAA03 | ||
| About • | paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||
| WEPAB04 | KEKB/SuperKEKB Cryogenics Operation | controls, superconducting-cavity, operation, cryogenics | 276 |
|
|||
| KEKB/SuperKEKB cryogenics operation will be introduced. KEKB was built in the tunnel of the TRISTAN accelerator. The TRISTAN accelerator was operated from 1986 to 1995. The superconducting acceleration cavities were installed in 1988 to increase the beam energy. The cryogenic system for superconducting cavities was also established simultaneously. In 1989 superconducting cavities were added, and cryogenic systems were also enhanced from 4kW to 6.5kW. KEKB took over many facilities from TRISTAN. The cryogenic system for superconducting cavities is one of them. This old refrigerator is used also in SuperKEKB. In operation of the cryogenic system, it is necessary to cool down the equipment from room temperature. In KEKB, its cooling rate of cavities are limited to 2.5~3K/h. In the steady state, the pressure and the liquid level in the superconducting cavity cryomodule should be kept constant. To keep the condition in the cryomodule stably, the sum of the heat generated by RF and the heater is controlled as constant. In KEKB/SuperKEKB, superconducting magnets are also used. They have their own refrigerator. In the workshop, they are also introduced. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEPAB04 | ||
| About • | paper received ※ 24 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||
| WEPAB05 | Conceptional design of CEPC Cryogenic system | cryogenics, collider, cryomodule, booster | 282 |
|
|||
| The CEPC has two rings, the booster ring and the collider ring. There are 432 superconducting cavities in total. In the booster ring, there are 96 ILC type 1.3 GHz 9-cell superconducting cavities; eight of them will be packaged in one 12-m-long module. There are 12 such modules. In the collider ring, there are 240 650 MHz 2-cell cavities; six of them will be packaged in one 11-m-long module. There are 40 of them. All the cavities will be cooled in a liquid-helium bath at a temperature of 2K to achieve a good cavity quality factor. The cooling benefits from helium II thermo-physical properties of large effective thermal conductivity and heat capacity as well as low viscosity and is a technically safe and economically reasonable choice. The 2K cryostat will be protected against heat radiation by means of two thermal shields cooling with 5-8K helium as well as 40-80K helium from a refrigerator. There are 4 cryo-stations along the 100km circular collider with the physical design of double ring. Generally, each cryo-station is supplied from a common cryogenic plant, with one refrigerator and one distribution box. The cooling capacity of each refrigerator is 18kW @ 4.5K. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEPAB05 | ||
| About • | paper received ※ 10 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||