Upload
hayden-sellers
View
16
Download
0
Embed Size (px)
DESCRIPTION
SPS IMPEDANCE ESTIMATES BY LUC VOS IN 1986 and 2003. E. Métral. How different are our predictions (for the vertical impedance) compared to the ones from L. Vos? What are the remaining contributors to the vertical impedance?. - PowerPoint PPT Presentation
Citation preview
Elias Métral, Informal SPS impedance meeting, 12/12/2007 1/?
E. Métral E. Métral
SPS IMPEDANCE ESTIMATES
BY LUC VOS IN 1986 and 2003
How different are our predictions (for the vertical impedance) compared to the ones from L. Vos?
What are the remaining contributors to the vertical impedance?
Elias Métral, Informal SPS impedance meeting, 12/12/2007 2/?
from L. Vos (CERN-AB-2003-088 (ABP))
Lepton cavities, all kickers IN
3 MKE OUT
2 MKA OUT, partial shielding
1 MKA, 3 MKE, MKLP, lepton cavities OUT, all shielding
1 MKE OUT
5 MKE IN
4 MKE IN
Only dipolar impedance here!!! L. Vos made an assumption for the
quadrupolar term!!!
Elias Métral, Informal SPS impedance meeting, 12/12/2007 3/?
L. Vos considered that the vertical coherent tune shift is made up for 1/3 by the quadrupolar tune shift and for 2/3 by the collective tune shift (i.e. from the dipolar impedance)
Summary for the vertical impedance:
Vos’ assumptions
Total imped. meas. by Helmut [M/m]
Dipolar imped. (only) meas. by
Helmut assuming factor 2/3 [M/m]
Dipolar imped. (only) computed by Vos assuming factor 2/3 [M/m]
Dipolar imped. (only) meas. quoted
by Vos assuming factor 2/3 [M/m]
2001 19.1 12.7 10 12.2
2002 8.7 8.4 - 10
2003 22.2 14.8 15
2006 23.6 15.7 20
Elias Métral, Informal SPS impedance meeting, 12/12/2007 4/?
Measurements from Helmut predicts an increase of the total impedance of 4.5 M/m or 3 M/m for the dipolar impedance (assuming the factor 2/3!) between 2001 and 2006
Our prediction for the total impedance increase is 5.2 M/m or 3.5 M/m for the dipolar impedance (assuming the factor 2/3!)
Vos’ prediction is 15 M/m for the total impedance increase or 10 M/m for the dipolar impedance (assuming the factor 2/3!)
I think one can explain better the impedance increase since 2001
However, one has to look in detail to Vos’ estimate of the impedance in 2001, which seems quite close to the meas. from Helmut, to try and identify our missing contributors
Conclusions and outlook (1/2)
Elias Métral, Informal SPS impedance meeting, 12/12/2007 5/?
Conclusions and outlook (2/2)
from L. Vos (CERN SPS/86-21(MS))