Elias Métral, APC meeting, 09/06/20051/15 E. Métral (10 min) AMPLITUDE AND POWER SPECTRA...
-
Upload
beryl-ball -
Category
Documents
-
view
215 -
download
0
Transcript of Elias Métral, APC meeting, 09/06/20051/15 E. Métral (10 min) AMPLITUDE AND POWER SPECTRA...
Elias Métral, APC meeting, 09/06/2005
1/15
E. Métral (10 min)E. Métral (10 min)
AMPLITUDE AND POWER SPECTRA
COMPARISON BETWEEN DIFFERENT TYPES
OF LONGITUDINAL BUNCH PROFILES
FOR THE SPS MKE KICKER HEATING
This is a follow-up of the APC presentation of Jan Uythoven on 17/09/04 (presented at RLC meeting on 01/10/04)
Theory Comparison with measured spectra in 2003 and 2004 (given
by Jan Uythoven)
Elias Métral, APC meeting, 09/06/2005
2/15
APC presentation of Jan Uythoven on 17/09/04 (1/2)APC presentation of Jan Uythoven on 17/09/04 (1/2)
Bump
Elias Métral, APC meeting, 09/06/2005
3/15
For the operational scenarios presented at APC
on 03/10/03 only (afterwards real measured spectra were used)
APC presentation of Jan Uythoven on 17/09/04 (2/2)APC presentation of Jan Uythoven on 17/09/04 (2/2)
Elias Métral, APC meeting, 09/06/2005
4/15
THEORY (1/5)THEORY (1/5)
1.5 1 0.5 0.5 1 1.5
0.5
1
1.5
2
2/b
4bb density Line
density amplitude Parabolic
density line Parabolicdensity amplitudeGaussian
bunch bag-Water
Elias Métral, APC meeting, 09/06/2005
5/15
200 400 600 800
0.2
0.4
0.6
0.8
1
MHzf
spectrumAmplitude
ns7.0
4bdensity amplitude Parabolic
density line Parabolic
density amplitudeGaussian
bunch bag-Water
THEORY (2/5)THEORY (2/5)
Bumps
Elias Métral, APC meeting, 09/06/2005
6/15
200 400 600 800
0.2
0.4
0.6
0.8
1
MHzf
spectrumPowerTHEORY (3/5)THEORY (3/5)
The bumps disappear in the power spectra
Elias Métral, APC meeting, 09/06/2005
7/15
Computation of the power loss in the case of a broad-band resonator impedance (fit used by Elena Shaposhnikova for the longitudinal impedance of 1 SPS MKE kicker, Chamonix XIII, p. 47)
200 400 600 800
1000
2000
3000
4000
5000
6000
kΩ6sR
0.95QMHz600rf
MHzf
lZRe
THEORY (4/5)THEORY (4/5)
Elias Métral, APC meeting, 09/06/2005
8/15
THEORY (5/5)THEORY (5/5)
Average power deposited per unit length [W/m] from theory
Parabolic amplitude density = 893 Parabolic line density = 677 Gaussian amplitude density = 605 Water-bag bunch = 530
Power (Parabolic amplitude density) = 1.48 × Power (Gaussian) Power (Parabolic line density) = 1.12 × Power (Gaussian) Power (Water-bag bunch) = 0.88 × Power (Gaussian)
ns7.04 b
p/b102.1 11bN
bunches724 M
m 1.66 length Kicker L
LZIMP SBlossbloss /2
1
00 rumPowerSpectRe2p
lSBloss fpfpZZ
0feNI bb
Elias Métral, APC meeting, 09/06/2005
9/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (1/6)
200 400 600 800
0.2
0.4
0.6
0.8
103@8p4secSpectrum20
MHzf
spectrumAmplitude
ns9.0
density amplitude Parabolic
Elias Métral, APC meeting, 09/06/2005
10/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (2/6)
200 400 600 800
0.2
0.4
0.6
0.8
103@16p8secSpectrum20
MHzf
spectrumAmplitude
?ns85.0
Elias Métral, APC meeting, 09/06/2005
11/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (3/6)
200 400 600 800
0.2
0.4
0.6
0.8
104@17secSpectrum20
MHzf
spectrumAmplitude
ns7.0
The bump is well fitted here
Elias Métral, APC meeting, 09/06/2005
12/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (4/6)
200 400 600 800
0.2
0.4
0.6
0.8
104@34secSpectrum20
MHzf
spectrumAmplitude
ns7.0
The bump is well fitted here
Elias Métral, APC meeting, 09/06/2005
13/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (5/6)
Spectrum2003@8p4sec = 509 Spectrum2003@16p8sec = 958 Spectrum2004@17sec = 593 Spectrum2004@34sec = 590
Average power deposited per unit length [W/m] from measured spectra
~600 W/m for 2004, with more stable spectra
Elias Métral, APC meeting, 09/06/2005
14/15
Comparison with measured spectra in 2003 and 2004 (given by Jan Uythoven) (6/6)
For 472 bunches, Jan finds ~600 W/m before acceleration In good agreement with the previous estimates
Elias Métral, APC meeting, 09/06/2005
15/15
CONCLUSIONCONCLUSION
Good agreement between Jan and myself
The estimates of Jan are made using the real measured spectra (one cannot do better than that if the spectra measurement is reliable)
~600 W/m are found for 472 bunches, with 1.21011 p/b, using either the measured spectrum or the measured bunch length (0.7 ns rms) assuming a Gaussian distribution
No bumps appear in the amplitude spectrum for a Gaussian bunch, but these bumps are not important for the power loss as they disappear in the power spectrum!