IPAC2015 - List of Authors (Ady, M.)

Paper	Title	Page
WEPHA009	Propagation of Radioactive Contaminants Along the Isolde Beamline	3115
	R. Kersevan, M. Ady, A. Dorsival, A. Gottberg, M. Maietta, G. Vandoni CERN, Geneva, Switzerland
	The vacuum system of RIB facilities is entirely hermetical, with storage of effluents and controlled release to atmosphere after a decay time. In Isolde, distributed primary pumping is sectorized in three parts, but all effluents are conveyed together in a unique tank. Thus, highly contaminated gas from the target and front end may be mixed with less contaminated gas from the beam transfer lines. This study aims at analysing and quantifying the distribution and propagation of neutral rare gas radioactive isotopes along the Isolde beam-line by numerical simulation (steady-state and time resolved Test-Particle Monte-Carlo, Molflow+) and experimental means. The time-resolved Monte-Carlo integrates decay time for the propagating species. To measure the distribution of contaminants, sampling filters are installed at the exhaust of the vacuum turbo-molecular pumps. Comparison between simulation and experiment shows excellent agreement, confirming the pertinence of the Monte-Carlo tool to radioactive species propagation. The filtering effect of magnetic sectors, the RFQ Cooler, and Buncher on the propagating neutral isotopes are quantified.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA009
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WEPHA011	Photodesorption and Electron Yield Measurements of Thin Film Coatings for Future Accelerators	3123
	R. Kersevan, M. Ady, P. Chiggiato CERN, Geneva, Switzerland T. Honda, Y. Tanimoto KEK, Tsukuba, Japan
	The performance of future accelerators could be limited by electron cloud phenomena and high photodesorption yields. For such a reason, the study of secondary electron and photodesorption yields of vacuum materials is essential. The eradication or mitigation of both secondary electron and molecule desorption could strongly reduce the beam scrubbing time and increase the availability of nominal beams for experiments. Surface modifications with the desired characteristics can be achieved by thin-film coatings, in particular made of amorphous carbon and non-evaporable getters (NEG). In the framework of a new collaboration, several vacuum chambers have been produced, and different coatings on each of them have been applied. The samples were then irradiated at KEK’s Photon Factory with SR light of 4 keV critical energy during several days, allowing the measurement of the photodesorption yield as a function of the photon dose. This paper presents the experiment and briefly summarizes the preliminary photodesorption and photoelectron yield data of different coatings. The results can be used for future machine design with similar conditions, such as the FCC-hh.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Propagation of Radioactive Contaminants Along the Isolde Beamline

3115

R. Kersevan, M. Ady, A. Dorsival, A. Gottberg, M. Maietta, G. Vandoni
CERN, Geneva, Switzerland

The vacuum system of RIB facilities is entirely hermetical, with storage of effluents and controlled release to atmosphere after a decay time. In Isolde, distributed primary pumping is sectorized in three parts, but all effluents are conveyed together in a unique tank. Thus, highly contaminated gas from the target and front end may be mixed with less contaminated gas from the beam transfer lines. This study aims at analysing and quantifying the distribution and propagation of neutral rare gas radioactive isotopes along the Isolde beam-line by numerical simulation (steady-state and time resolved Test-Particle Monte-Carlo, Molflow+) and experimental means. The time-resolved Monte-Carlo integrates decay time for the propagating species. To measure the distribution of contaminants, sampling filters are installed at the exhaust of the vacuum turbo-molecular pumps. Comparison between simulation and experiment shows excellent agreement, confirming the pertinence of the Monte-Carlo tool to radioactive species propagation. The filtering effect of magnetic sectors, the RFQ Cooler, and Buncher on the propagating neutral isotopes are quantified.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPHA011

Photodesorption and Electron Yield Measurements of Thin Film Coatings for Future Accelerators

3123

R. Kersevan, M. Ady, P. Chiggiato
CERN, Geneva, Switzerland
T. Honda, Y. Tanimoto
KEK, Tsukuba, Japan

The performance of future accelerators could be limited by electron cloud phenomena and high photodesorption yields. For such a reason, the study of secondary electron and photodesorption yields of vacuum materials is essential. The eradication or mitigation of both secondary electron and molecule desorption could strongly reduce the beam scrubbing time and increase the availability of nominal beams for experiments. Surface modifications with the desired characteristics can be achieved by thin-film coatings, in particular made of amorphous carbon and non-evaporable getters (NEG). In the framework of a new collaboration, several vacuum chambers have been produced, and different coatings on each of them have been applied. The samples were then irradiated at KEK’s Photon Factory with SR light of 4 keV critical energy during several days, allowing the measurement of the photodesorption yield as a function of the photon dose. This paper presents the experiment and briefly summarizes the preliminary photodesorption and photoelectron yield data of different coatings. The results can be used for future machine design with similar conditions, such as the FCC-hh.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)