http://www.cnr.it/ontology/cnr/individuo/prodotto/ID177031

Photon reflectivity distributions from the LHC beam screen and their implications on the arc beam vacuum system (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Photon reflectivity distributions from the LHC beam screen and their implications on the arc beam vacuum system (Articolo in rivista) (literal)

Anno

2004-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1016/j.apsusc.2004.05.271 (literal)

Alternative label

N. Mahne (1); V. Baglin (2); I.R. Collins (2); A. Giglia (1); L. Pasquali (3); M. Pedio (1); S. Nannarone (3); R. Cimino (4) (2004)
Photon reflectivity distributions from the LHC beam screen and their implications on the arc beam vacuum system
in Applied surface science; ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, AMSTERDAM (Paesi Bassi)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

N. Mahne (1); V. Baglin (2); I.R. Collins (2); A. Giglia (1); L. Pasquali (3); M. Pedio (1); S. Nannarone (3); R. Cimino (4) (literal)

Pagina inizio

221 (literal)

Pagina fine

226 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url

http://www.sciencedirect.com/science/article/pii/S0169433204007676 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

235 (literal)

Rivista

Applied surface science (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali

5 (literal)

Note

ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

(1) TASC-INFM, SS 14, Km 163.5, Basovizza, Trieste, Italy; (2) CERN CH-1211, Geneva 23, Switzerland; (3) Università di Modena e Reggio E.-41100, Modena, Italy; (4) LNF-INFN 00044, Frascati, Italy (literal)

Titolo

Photon reflectivity distributions from the LHC beam screen and their implications on the arc beam vacuum system (literal)

Abstract

In particle accelerators with intense positively charged bunched beams, an electron cloud may induce beam instabilities and the related beam induced electron multipacting (BIEM) can result in an undesired pressure rise. In a cryogenic machine such as the large hadron collider (LHC), the BIEM will introduce additional heat load. When present, synchrotron radiation (SR) may generate a significant number of photoelectrons, that may play a role in determining the onset and the detailed properties of the electron cloud related instability. Since electrons are constrained to move along field lines, those created on the accelerator equator in a strong vertical (dipole) field cannot participate in the e-cloud build-up. Therefore, for the LHC there has been a continuous effort to find solutions to absorb the photons on the equator. The solution adopted for the LHC dipole beam screens is a saw-tooth structure on the illuminated equator. SR from a bending magnet beamline at ELETTRA, Italy (BEAR) has been used to measure the reflectivities (forward, back-scattered and diffuse), for a flat and a saw-tooth structured Cu co-laminated surface using both white light SR, similar to the one emitted by LHC, and monochromatic light. Our data show that the saw-tooth structure does reduce the total reflectivity and modifies the photon energy distribution of the reflected photons. The implications of these results on the LHC arc vacuum system are discussed. © 2004 Elsevier B.V. All rights reserved. (literal)

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