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

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 ? Real machine with field Imperfections and alignment data PTC lattice representation  Comprehensive lattice analysis  RF cavities (acceleration)  NEW !… Time dependent magnets 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)

… 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. Lattice preparation #3 (PTC): Alexander Molodozhentsev (KEK) ……… 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 !!!

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 set_xsm.txt ramp_psb_bs.txtBS_ramp.txt PTC flags … Definition: initial time and units Modulation … Name of element time b1a1 Number of multipole components scaling Multipole index B 0 /(B  ) ‘time’ instead of ‘path_length’ Cavity  ON Modulation  ON 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 Exact=TRUEExact=FALSE Q x = Q y = Qx/Qx/ (*) (**) – Qy/Qy/ (*) (**) (*) … ‘path-length’ instead of Time CONCLUSION: Exact=FALSE could be used for the PSB study as basis … … should be checked … (**) … ‘Time’ instead of ‘path-length’ ~ 5% < 1% 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 file with proper setting the RF cavities for the machine Single particle tracking Alexander Molodozhentsev (KEK) NO CHICANE …

CERN_PS Booster:  setting the injection chicane including the edge focusing effect of the PSB bump magnets (NO kickers for the transverse painting) CHICANE 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 1 msec Just EXAMPLE … (NOT REALISTIC CASE !) “BS” table“QM” table FAST variation of the BS-strength (< 2 synchrotron periods / V RF =8kV) Alexander Molodozhentsev (KEK)

CERN_PSB PTC-ORBIT: modulation  ON (by using “BS” table) RF cavity  ON Single particle tracking 1 msec Initial particle coordinates: matched to the chicane height at the beginning of the chicane’s decay X [mm]  X(t) s FAST variation of the BS-strength (< 2 synchrotron periods / V RF =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) #1 #2 Single particle tracking PTC-ORBIT: modulation  ON (by using “KS&BS” tables) RF cavity  ON ( without adjustment ) 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 … o MADX matching with the machine realistic lattice o clean lattice to avoid the ‘zero’ length elements o …. Alexander Molodozhentsev (KEK)

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

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

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

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

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

CERN_PS: Chicane variation (6D : ‘matched’ condition) Multi particle tracking REALISTIC Time table for BS_40 T REV ~ 2.3  sec 1msec PTC-ORBIT: modulation  ON RF cavity  ON Alexander Molodozhentsev (KEK)

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

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

CERN SPS MADX-PTC Alexander Molodozhentsev (KEK)

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

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 … Alexander Molodozhentsev (KEK)