Estimations for of Optical Stochastic Cooling of Protons and Lead Ions in LHC

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Estimations for of Optical Stochastic Cooling of
Protons and Lead Ions in LHC
A. Zholents, M. Zolotorev
LBNL, Berkeley, 4/26/2006
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How it works
kicker
S. van der Meer, 1968
number of particles in the sample
good mixing
bad mixing
g
amplifier
DL 1/bandwidth
p
pick-up
L
b
D. Möhl, Stochastic Cooling for Beginners, CERN
optimal gain
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Cooling rate
g
1
2
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OSC obeys the same principles as the microwave
stochastic cooling, but explores a superior
bandwidth of optical amplifiers, 1014 Hz
Fluorescence and absorption spectra of Tisapphire
microwave slicing
sample length 10 cm
100 THz
rel. units
optical slicing
sample length 10 mm
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Undulator as a kicker
Electron trajectory through undulator
-
S
e
N
Light
S
N
N
S
N
S
Magnetic field in the undulator

Undulator period
Laser wavelength
peak field
period
Undulator parameter
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Undulator options for LHC
Protons
Lead ions
optical wavelengh (microns)
optical wavelengh (microns)
Bpeak 15 T
Bpeak 15 T
10 T
10 T
undulator period (m)
undulator period (m)
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Beam parameters (provided by Wolfram Fischer )
The rms energy spread is 1.1e-4 for for
both protons and lead ions. protonsZ1,A1 gamma
7461 Nb1.15e11 protons/bunch bunch
spacing25ns rms transverse emittance3.75mm.mrad
rms bunch length7.55 cm leadZ82,A208 gamma29
63 Nb0.7e7 ions/bunch bunch spacing125ns rms
transverse emittance1.5 mm.mrad rms bunch
length7.94cm
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Square of inverse damping time shown in a number
of passes through cooling system txtE is assumed
Average amplifier power
relative bandwidth
rms energy spread
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Lead ions
Damping time, sec
Undulator period-7 m field 10 T, number of
periods 3
Amplifier average power (W)
Damping time for protons 5 hours at 1kW
amplifier power
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Needs for RD

• Bypass optics
• Optical amplifier
• Proof-of-principle with electrons