1. A.KOLOMIETS & A.KOVALENKO
TO CRYSTAL GONIOMETER FOR LHC
PRELIMINARY SIMULATION
A.KOLOMIETS & A.KOVALENKO
CERN, 21 OCTOBER 2016

2. CRYSTAL GONIOMETER FOR LHC PRELIMINARY SIMULATION (BRIEF SUMMARY)
A.KOLOMIETS & A.KOVALENKO
CERN, AUGUST 2016
A.KOLOMIETS & A.KOVALENKO
CERN, AUGUST 2016

3. OUR MODEL AND CST- CALCULATIONS OF LONGITUDINAL IMPEDANCE
PARKING POSITION
MODEL USED IN FEBRUARY 2016

4. Silicon strip position = 1.45 mm from the beam axis
MODULS OF LONGITUDINAL IMPEDANCE
OPERATIONAL POSITION
z = 120 mm
WL = mm
Silicon strip position = 1.45 mm from the beam axis

5. OPERATIONAL POSITION
z = 120 mm
WL = mm
NO Silicon strip

6. COMPARISON OF OUR CALCULATED with PREVIOUSLY WIRE MEASURED DATA ( bottom)

7. Silicon strip position = 47mm from the beam axis
MODULES OF LONGITUDINAL IMPEDANCE
PARKING POSITION
z = 120 mm
WL = mm
Silicon strip position = 47mm from the beam axis

8. Source beam shifted -5 mm from the axis
MODULES OF LONGITUDINAL IMPEDANCE
OPERATIONAL POSITION
z = 120 mm
WL = mm
Source beam shifted -5 mm
from the axis

9. CRYSTAL GONIOMETER IMPEDANCE
SIMULATION OF SEPTEMBER 2016

10. Longitudinal Impedance
WL=50000 mm

11. Transverse Impedance Zx dip
Trans. Impedance (Ohm/m)
Frequency (GHz)
Frequency, GHz

12. Transverse Impedance Zx quad
Trans. Impedance (Ohm/m)
Frequency (GHz)

13. Transverse Impedance Zx gen ( Zx dip + Zx quad = Zx gen )
Trans. Impedance (Ohm/m)
Frequency (GHz)

14. TRANSVERSE IMPEDANCE
DIRECT CALCULATION OF TRANSVERSE IMPEDANCE DON’T PROVIDE THE CST SIMULATION PACKAGE
THE ANALITICAL PROCEDURE IS PRESENTED IN SEVERAL PAPERS PUBLISAHED BY THE CERN TEAMS
FOLLOWING TO C.ZANINNI et al (IPAC2012) WE TESTED SOME PROCEDURE HOW IT COULD BE POSSIBLE TO DO WITHIN THE CST USING POSTPROCESSING PROCEEDURES, NEVERTHELESS IT HAS TO BE VERYFIED FURTHER.
AS IT WAS AGREED AT THE MEETING OF AUGUST 17TH IT IS NECESSARY TO USE APPROVED AT CERN IMPEDANCE GROUP PROCEDURE FOR THAT.

16. ΔQ = [(βeI0) /(4σz√π ω0 Q0 γm0)]∙ Im{-ZT eff },
For the first estimates of influence a crystal collimation device in the LHC ring the results published by CERN are used, namely: formula of vertical tune shift due to the resistive wall impedance presented by S.Persitelli.
ΔQ = [(βeI0) /(4σz√π ω0 Q0 γm0)]∙ Im{-ZT eff },
where:
 charge of electron e = , K
beam current I0, A
particle revolution frequency ω0 , s-1
particle relative velocity β
Lorenz factor γ
proton rest mass m0 = 1.67∙10 – 28, kg
rms bunch length σz , m
betatron tune Q0

17. parameter
unit
design value
Length of the orbit *) m
26659
Maximum proton energy
TeV
7.0
Maximum dipole field T
8.33
Number of dipoles
1232
Maximum gradient
T/m
Number of quadrupoles
386
Total number of magnets
9300
Number of RF cavities
8 per beam
Beam injection energy
0.4
Proton beam radius
16∙10-6
Number of bunches
2808
Number of protons/bunch:
at the first stage of operation
after upgrade
1.1∙1010
1.1∙1011
The ring filling time s
450
Number of revolutions per s
11.245∙103
Current per beam A
0.54
0.85
Bunch sizes (rms), z/x,y mm
120/0.159
Betatron tunes
~ 60
Emittance (normalized)
3.75∙10-6
Beam lifetime h
~ 10
Luminosity :
@ 0.54 A
@ 0.85 A
cm-2∙s-1
1.0∙1034
2.5∙1034

20. Modeling of the goniometer resonant frequencies
September 2016

21. Computer model

22. Mode 1
f = GHz
 E
 H

23.  E
Mode 2
f = GHz
 H

24.  E
 H
Mode 3
f = GHz

25.  E
 H
Mode 4
f = GHz

26.  E
 H
Mode 5
f = GHz

27.  E
 H
Mode 6
f = 0.831GHz

28.  H
 E
Mode 7
f = GHz

29.  E
Mode 8
f = GHz
 H

30. Mode 9
f = GHz
 E
 H

31. GONIOMETER INSIDE MOVABLE SCREENNIG PART OF THE BEAM PIPE
test

32. COMPUTER MODEL

33. LONGITUDINAL IMPEDANCE
Импеданс (Ом)
FREQUENCY, GHz)

34. TRANSVERSE IMPEDANS in Х plane (dipolar), Ohm/m
FREQUENCY, GHz)

35. TRANSVERSE IMPEDANS in Х plane (quadrupolar), Ohm/m
FREQUENCY, GHz)

36. SUMMARY
SET OF MODEL CALCULATIONS OF THE EXISTING CRYSTAL COLLIMATION GONIOMETER IMPEDANCE WAS PERFORMED.
THE OBTAINED DATA MAKE IT POSSIBLE TO ESTIMATE TOLERABLE SAFE PARAMETERS (THE LHC BEAM INTENSITY LEVEL) OF THE EXISTING DEVICE USING AFTER FINAL AGREEMENT OF THE CALCULATION PROCEEDURE
THE ANALYSIS OF FREQUENCY SPECTRA AND THE E/H FIELD DISTRIBUTION INSIDE THE GONIOMETER SHOWED A POSSIBLE WAY OF ITS FURTHER IMPROVEMENT
THE WORK IS IN PROGRESS