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Title: Magnetic Frequency Response of HL-LHC Beam Screens

Abstract

Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained. Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected impact of different beam screen layouts for the most relevant HL-LHC insertion magnets. A welldefined post-processing technique is used to derive the frequency response of the different multipoles from multi-physics Finite Element Method (FEM) simulation results. In addition, a well approximated analytical formula for the low-frequency range of multi-layeredmore » beam screens is presented.« less

Authors:
 [1];  [1];  [1];  [2];  [1]
  1. CERN
  2. Fermilab
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1409341
Report Number(s):
FERMILAB-PUB-17-443-AD
1636694
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Trans.Nucl.Sci.
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS

Citation Formats

Morrone, M., Martino, M., De Maria, R., Fitterer, M., and Garion, C.. Magnetic Frequency Response of HL-LHC Beam Screens. United States: N. p., 2017. Web.
Morrone, M., Martino, M., De Maria, R., Fitterer, M., & Garion, C.. Magnetic Frequency Response of HL-LHC Beam Screens. United States.
Morrone, M., Martino, M., De Maria, R., Fitterer, M., and Garion, C.. Thu . "Magnetic Frequency Response of HL-LHC Beam Screens". United States. doi:. https://www.osti.gov/servlets/purl/1409341.
@article{osti_1409341,
title = {Magnetic Frequency Response of HL-LHC Beam Screens},
author = {Morrone, M. and Martino, M. and De Maria, R. and Fitterer, M. and Garion, C.},
abstractNote = {Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained. Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected impact of different beam screen layouts for the most relevant HL-LHC insertion magnets. A welldefined post-processing technique is used to derive the frequency response of the different multipoles from multi-physics Finite Element Method (FEM) simulation results. In addition, a well approximated analytical formula for the low-frequency range of multi-layered beam screens is presented.},
doi = {},
journal = {IEEE Trans.Nucl.Sci.},
number = ,
volume = ,
place = {United States},
year = {Thu Oct 12 00:00:00 EDT 2017},
month = {Thu Oct 12 00:00:00 EDT 2017}
}