PTC-ORBIT code for CERN machines (PSB, PS, SPS)

PTC-ORBIT code for CERN machines (PSB, PS, SPS) current status … Alexander Molodozhentsev (KEK) Etienne Forest (KEK) Group meeting, CERN June 1, 2011

Alexander Molodozhentsev (KEK) What is this code? • PTC Etienne Forest (KEK) • ORBIT  SNS-BNL code (Jeff Holmes, SNS) Idea to ‘glue’ these two codes was generated by A.Molodozhentsev and discussed during the HB ICFA06 Workshop • PTC-ORBIT combined code (from 2007, KEK-SNS) … use for J-PARC Main Ring to study the space-charge effects in combination with the machine resonances …  compiled for the KEK super computers (Hitachi & IBM, 2007 ) and for the CERN CLIC cluster (CERN, November 2010) MADX-PTC  convenient way to prepare realistic machine description including user’s matching procedures …

Alexander Molodozhentsev (KEK) Why PTC-ORBIT ? • PTC lattice representation • Comprehensive lattice analysis • RF cavities (acceleration) • NEW !…Time dependent magnets Real machine with field Imperfections and alignment data ORBIT node PTC as the tracker (6D integrator) • ‘ORBIT’ staff: • - Injection foil. • Space charge model. • Transverse and • longitudinal impedance. • Feedback for stabilization. • Aperture and collimation. • Electron cloud model. Main feature: Common environment for the single particle dynamics (lattice analysis and resonance compensation) and multi particle dynamics (collective effects).

Alexander Molodozhentsev (KEK) Lattice preparation #1: • MADX lattice without zero-length elements and without cutting • Time variation of the rectangular bending magnets  with the fringe field effect … vertical focusing QUADRUPOLE with zero quadrupole component … (added to MADX) … • Alignment errors & high-order field components of the ring magnets … • Required matching procedure … by MADX … • Proper setting the RF cavities … by MADX … • Example for RF: BR.C02 : RFCAVITY, VOLT:=0.008, HARMON:=1, L:=1.0, LAG:=0, no_cavity_totalpath;

Alexander Molodozhentsev (KEK) Lattice preparation #2 (PTC): • Cut the lattice using some method (PTC: EXACT=FALSE or TRUE) • Fit all machine parameters you would normally fit using your matching routines (MADX or PTC). • Examine the resulting lattice functions and also some short term dynamic aperture. • If ALL is fine, reduce the number of cuts and/or the sophistication of the method and go back to step #1. • If something is wrong, increase the number of cuts and/or sophistication of the method and go back to step #1. • After a having oscillated between different lattice representations, make a decision and call that “the lattice”  PTC ‘FLAT’ file.

Alexander Molodozhentsev (KEK) Lattice preparation #3 (PTC): … by MADX-PTC • Method … EXACT=Exact or False Drift-Kick-Drift or Matrix-Kick-Matrix • Integration … order of the integration … for PTC-ORBIT • LMAX … maximum distance between the space-charge nodes in the machine • THINLENS … The parameter THINLENS describes an approximate integrated quadrupole strength for which a single thin lens should be used. ……… lmax 1.0d0 fuzzylmax 0.10 THINLENS 0.1 PRINT FLAT FILE PSB_PTC_ORBIT_FLAT.TXT Example (from PTC script thin4.xtx): Flat file with proper setting the machine elements and machine parameters !!!

Alexander Molodozhentsev (KEK) Notes #1(3): # 1 Flat file preparation (MADX-PTC) with proper setting the machine elements and machine parameters # 2 STATIC RF cavities  No need to prepare the RF tables (all information should be in FLAT file) # 3 PTC-ORBIT script preparation … # 3.1 read flat file # 3.2 read (or generate) the 6D particle distribution # 3.3 space charge module (if you want to use it) # 3.4 define the tracking conditions # 3.5 tracking module with the beam analysis # 3.6 … saving data for the continues tracking …  Off-line USER analysis of the obtained results …

Alexander Molodozhentsev (KEK) Notes #2(3): # 3.4 define the tracking conditions to activate the ‘time-variation’ option of PTC for different type of the machine magnets for the PTC-ORBIT tracking  NEW feature of the PTC !!!

Alexander Molodozhentsev (KEK) Notes #3(3): time0.txt ‘time’ instead of ‘path_length’ Cavity  ON Modulation  ON PTC flags … Modulation … set_xsm.txt Definition: initial time and units ramp_psb_bs.txt BS_ramp.txt scaling Number of multipole components Multipole index Name of element time b1 a1 B0/(B) scaling

Alexander Molodozhentsev (KEK) PTC-ORBIT Code setting & test • CERN PS Booster (with C.Carli) • CERN PS (with S.Gilardoni) • CERN SPS (with H.Bartosic)

Alexander Molodozhentsev (KEK) CERN_PS Booster Checking … always should be done be before any studied to avoid nonsense ! • Longitudinal single particle motion  (1) NO acceleration (2) WITH acceleration • Chicane (time variation) • Quadrupole magnets (QD3&QD14) time variation during the chicane decay • SINGLE PARTICLE MOTION !!! Before you start some multi particle tracking …

Alexander Molodozhentsev (KEK) CERN_PS Booster • Different PTC models: EXACT= TRUE or FALSE ? … checking the linear chromaticity CONCLUSION: Exact=FALSE could be used for the PSB study as basis … … should be checked … ~ 5% < 1% (*) … ‘path-length’ instead of Time (**) … ‘Time’ instead of ‘path-length’

Alexander Molodozhentsev (KEK) CERN_PS Booster PTC-GINO interface ‘Single harmonic’ RF cavity

Alexander Molodozhentsev (KEK) CERN_PS Booster:longitudinal / RF cavity ON (“+cavity” in time0.txt) PTC-ORBIT by using the PTC flat filewith proper setting the RF cavities for the machine NO CHICANE … Single particle tracking

Alexander Molodozhentsev (KEK) CERN_PS Booster: setting the injection chicane including the edge focusing effect of the PSB bump magnets (NO kickers for the transverse painting) CHICANE -45.607 mm

Alexander Molodozhentsev (KEK) MADX_PTC • MADX matching inside the PTC universe (made with Piotr Skowronski): • … matching the working point • … vertical beta-beating correction by QD3&QD14 PTC: twiss analysis (at the QM positions) ~ 30% ~ 10%

Alexander Molodozhentsev (KEK) CERN_PSB:Chicane and QD3&14 variation Just EXAMPLE … (NOT REALISTIC CASE !) “BS” table “QM” table 1 msec 1 msec FAST variation of the BS-strength (< 2 synchrotron periods / VRF=8kV)

Alexander Molodozhentsev (KEK) CERN_PSB Initial particle coordinates: matched to the chicane height at the beginning of the chicane’s decay X [mm] s 1 msec X(t) PTC-ORBIT: modulation  ON (by using “BS” table) RF cavity  ON Single particle tracking FAST variation of the BS-strength (< 2 synchrotron periods / VRF=8kV)

Alexander Molodozhentsev (KEK) CERN_PSB REALISTIC CASE ! LONG (~ 10 synchrotron periods) variation of the CHICANE strength without adjustment the RF system ‘Matched’ (to COD) initial single particle

Alexander Molodozhentsev (KEK) CERN_PSB REALISTIC CASE ! #1 Kicker magnets variation keeping maximum strength of bump magnets #2 Bump magnets variation from maximum to zero (during ~ 5 msec) #2 #1 PTC-ORBIT: modulation  ON (by using “KS&BS” tables) RF cavity  ON ( without adjustment ) Single particle tracking

Alexander Molodozhentsev (KEK) CERN_PSB  READY FOR REAL ACTION !!!

Alexander Molodozhentsev (KEK) CERN_PS • Longitudinal single particle motion • Chicane (time variation)

Alexander Molodozhentsev (KEK) CERN_PS What should be done in addition? • Independently from PTC-ORBIT … • MADX matching with the machine realistic lattice • clean lattice to avoid the ‘zero’ length elements • ….

Alexander Molodozhentsev (KEK) CERN-PS: longitudinal / RF cavity ON PTC-GINO interface COD outside of the chicane ‘Single harmonic’ RF cavity

Alexander Molodozhentsev (KEK) CERN_PS: longitudinal / RF cavity ON PTC-ORBIT Single particle tracking

Alexander Molodozhentsev (KEK) CERN_PS • Exact model: TRUE or FALSE ? … checking the linear chromaticity CONCLUSION: Exact=TRUE is needed for the PS study ~ 22% ~ 5% * … ‘path_length’ instead of ‘time’

Alexander Molodozhentsev (KEK) CERN_PS: Chicane variation(‘matched’ condition) Time table for BS_40 X [mm] X(t) s REALISTIC 1msec TREV ~ 2.3 sec PTC-ORBIT: modulation  ON RF cavity  ON Single particle tracking

Alexander Molodozhentsev (KEK) CERN_PS: Chicane variation MAX Chicane:fractional tunes (x) 0.129409999999942 (y) 0.296639999999998 END of modulation:fractional tunes (x) 0.129487939990263 (y) 0.293684605278531 PTC-ORBIT: modulation  ON RF cavity  ON TWISS analysis

Alexander Molodozhentsev (KEK) CERN_PS: Chicane variation(6D : ‘matched’ condition) REALISTIC Time table for BS_40 1msec TREV ~ 2.3 sec PTC-ORBIT: modulation  ON RF cavity  ON Multi particle tracking

Alexander Molodozhentsev (KEK) CERN PS  READY FOR REAL ACTION !!!

Alexander Molodozhentsev (KEK) CERN SPS  Basic staff without any time-dependent magnets …

Alexander Molodozhentsev (KEK) CERN SPS MADX-PTC

Alexander Molodozhentsev (KEK) CERN SPS  READY FOR REAL ACTION !!!

Alexander Molodozhentsev (KEK) Important step:  DEVELOP (or USE) the realistic machine model, based on the existing experience of the machine operation … • Comprehensive analysis of the lattice resonances, obtained from the machine modeling … • compare with the real machine operation for the • ‘zero’ beam intenisty • extensive study of the combined effects of the machine resonances and the coherent effects (like the low energy space charge …)

Alexander Molodozhentsev (KEK) Thanks for your attention …

PTC-ORBIT code for CERN machines (PSB, PS, SPS)