collective effects and beam measurements in particle accelerators
DESCRIPTION
Collective Effects and Beam Measurements in Particle Accelerators. beam diagnostics and fundamental limitations to the performance of high-intensity accelerators. http://ab-abp-rlc.web.cern.ch/ab-abp-rlc/. See also slides on Measurements, ideas, curiosities. Wakefield for a pill-box cavity. - PowerPoint PPT PresentationTRANSCRIPT
Name Event DateName Event Date11
F. Ruggiero Univ. “La Sapienza”, Rome, 20–24 March 2006CERN
Collective Effects and Beam Collective Effects and Beam Measurements in Particle Measurements in Particle
AcceleratorsAcceleratorsbeam diagnostics and fundamental beam diagnostics and fundamental
limitations to the performance of high-limitations to the performance of high-intensity acceleratorsintensity accelerators
See also slides on Measurements, ideas, curiosities
http://ab-abp-rlc.web.cern.ch/ab-abp-rlc/
Name Event DateName Event Date22
F. Ruggiero Collective Effects and Beam MeasurementsCERN
Wakefield for a pill-box Wakefield for a pill-box cavitycavity• Animation showing a bunch of charged Animation showing a bunch of charged
particles moving on the cavity axis and the particles moving on the cavity axis and the corresponding electric field lines computed corresponding electric field lines computed by the program ABCIby the program ABCI
• Courtesy Andreas Wagner Courtesy Andreas Wagner http://awagner.home.cern.ch/awagner/http://awagner.home.cern.ch/awagner/
Name Event DateName Event Date33
F. Ruggiero Collective Effects and Beam MeasurementsCERN
TRISIM3D simulation of a LEP TRISIM3D simulation of a LEP bunchbunch
EE = 22 GeV, = 22 GeV, QQss = 0.092, = 0.092, II = 0.3 = 0.3 mA mA • 3-dimensional computer simulation of single 3-dimensional computer simulation of single
bunch collective effects in particle acceleratorsbunch collective effects in particle accelerators• top and side view of the particle distribution turn top and side view of the particle distribution turn
by turn, over 60 turnsby turn, over 60 turns • Courtesy Andreas Wagner Courtesy Andreas Wagner
http://awagner.home.cern.ch/awagner/http://awagner.home.cern.ch/awagner/
Name Event DateName Event Date44
F. Ruggiero Collective Effects and Beam MeasurementsCERN
CERN Linac4CERN Linac4layout and parameterslayout and parameters
DTL CCDTL SCL
3MeV 40MeV 90MeV 160MeV
Drift TubeLinac
352 MHz13.4 m3 tanks5 klystrons4 MW
Side Coupled Linac
704 MHz28 m20 tanks4 klystrons12 MW
Cell-Coupled Drift TubeLinac352 MHz25.3 m24 tanks8 klystrons6.5 MW
Duty cycle:0.1% phase 1 (Linac4)3-4% phase 2 (SPL)(RF design: 15%)
4 different structures, (RFQ, DTL, CCDTL, SCL) 2 frequencies
Total Linac4: 80 m, 18 klystrons
current: 40 mA (avg. in pulse), 65 mA (bunch)
CHOPPERRFQ
Chopper
352 MHz3.6 m
Radio FrequencyQuadrupole
352 MHz6 m1 Klystron1 MW
H-
3MeV95keV
Courtesy A. LombardiCourtesy A. Lombardi
Name Event DateName Event Date55
F. Ruggiero Collective Effects and Beam MeasurementsCERN
Instabilities in a LinacInstabilities in a Linac
Courtesy A. LombardiCourtesy A. Lombardi
=Longitudinal to transverse phase advance
Tra
nsv
ers
e t
une d
epre
ssio
n
Name Event DateName Event Date66
F. Ruggiero Collective Effects and Beam MeasurementsCERN
Intra-Beam Scattering Intra-Beam Scattering (simplified formulae by K. Bane, EPAC 2002)(simplified formulae by K. Bane, EPAC 2002)
• For the LHC, the average For the LHC, the average dispersion invariant is dispersion invariant is <<HHxx>~0.03 m, >~0.03 m, avav~100 m, ~100 m, and the Coulomb logarithm and the Coulomb logarithm (log)~24(log)~24
• Note that the transverse IBS Note that the transverse IBS growth rate is about growth rate is about proportional to the particle proportional to the particle density in the 6D phase density in the 6D phase space space NNbb/(/(zz
x
2δ
avb
2p
3δz
2/33IBSz
1
)log(
8 H
cNr
x2δ
IBSz
IBSx H
IBS growth times for IBS growth times for long super-bunches in long super-bunches in the LHC as a function of the LHC as a function of the rms momentum the rms momentum spread spread