TO CRYSTAL GONIOMETER FOR LHC PRELIMINARY SIMULATION A

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

CRYSTAL GONIOMETER FOR LHC PRELIMINARY SIMULATION (BRIEF SUMMARY) A. KOLOMIETS & A. KOVALENKO CERN, 16 -25 AUGUST 2016

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

MODULS OF LONGITUDINAL IMPEDANCE OPERATIONAL POSITION z = 120 mm WL = 50000 mm Silicon strip position = 1. 45 mm from the beam axis

OPERATIONAL POSITION z = 120 mm WL = 50000 mm NO Silicon strip

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

MODULES OF LONGITUDINAL IMPEDANCE PARKING POSITION z = 120 mm WL = 50000 mm Silicon strip position = 47 mm from the beam axis

MODULES OF LONGITUDINAL IMPEDANCE OPERATIONAL POSITION z = 120 mm WL = 50000 mm Source beam shifted -5 mm from the axis

CRYSTAL GONIOMETER IMPEDANCE SIMULATION OF SEPTEMBER 2016

Longitudinal Impedance WL=50000 mm

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

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

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

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 (IPAC 2012) 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 17 TH IT IS NECESSARY TO USE APPROVED AT CERN IMPEDANCE GROUP PROCEDURE FOR THAT.

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 = [(βe. I 0) /(4σz√π ω0 Q 0 γm 0)]∙ Im{-ZT eff }, where: charge of electron e = 1. 6 10 -19 , K beam current I 0, A particle revolution frequency ω0 , s-1 particle relative velocity β Lorenz factor γ proton rest mass m 0 = 1. 67∙ 10 – 28, kg rms bunch length σz , m betatron tune Q 0

parameter unit design value m 26659 Te. V 7. 0 T 8. 33 Length of the orbit *) Maximum proton energy Maximum dipole field Number of dipoles Maximum gradient 1232 T/m Number of quadrupoles 386 Total number of magnets 9300 Number of RF cavities Beam injection energy Proton beam radius 8 per beam Te. V 0. 4 m Number of bunches 2808 Number of protons/bunch: at the first stage of operation after upgrade The ring filling time 1. 1∙ 1010 1. 1∙ 1011 s Number of revolutions per s Current per beam Bunch sizes (rms), z/x, y 16∙ 10 -6 450 11. 245∙ 10 3 A 0. 54 0. 85 mm 120/0. 159 Betatron tunes ~ 60 Emittance (normalized) m 3. 75∙ 10 -6 Beam lifetime h ~ 10 Luminosity : @ 0. 54 A @ 0. 85 A cm-2∙s-1 1. 0∙ 10 34 2. 5∙ 10 34

Modeling of the goniometer resonant frequencies September 2016

Computer model

E H Mode 1 f = 0. 192 GHz

E H Mode 2 f = 0. 238 GHz

E H Mode 3 f = 0. 601 GHz

E H Mode 4 f = 0. 708 GHz

E H Mode 5 f = 0. 801 GHz

E H Mode 6 f = 0. 831 GHz

E H Mode 7 f = 0. 932 GHz

E H Mode 8 f = 1. 186 GHz

E H Mode 9 f = 1. 195 GHz

GONIOMETER INSIDE MOVABLE SCREENNIG PART OF THE BEAM PIPE • test 10. 2016

COMPUTER MODEL

Импеданс (Ом) LONGITUDINAL IMPEDANCE FREQUENCY, GHz)

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

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

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