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Status of the CLIC Decelerator and Test Beam Line simulation framework

Status of the CLIC Decelerator and Test Beam Line simulation framework. Erik Adli , University of Oslo and CERN, June 28, 2010. CLIC Decelerator and TBL simulation.

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Status of the CLIC Decelerator and Test Beam Line simulation framework

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  1. Status ofthe CLIC Decelerator and Test Beam Line simulationframework Erik Adli, University of Oslo and CERN, June 28, 2010

  2. CLIC Decelerator and TBL simulation Background: the last fewyearsextensive beam physics studies for the CLIC decelerator and the TBL has beenperformed, mainlyusingthetrackingcode PLACET. The scripts have nowbeencleaned up and madeavailable for everyoneoncvs (placetrepository), and thusput under versioncontrol. Placetrepository: https://savannah.cern.ch/projects/placet/ Decelerator dir: placet-development/examples/clic/decelerator/

  3. Simulationscope: decelerator and TBL ~ 25 m, 8 FODO cells +, 16 PETS ~ 1000 m, 500 FODO cells, 1500 PETS • Example TBL studies: • Optics and transport • Instrumentation design • Wakefields • Online model • -> TBL comissioning and physics studies • Exampledecelerator studies: • PETS/wakefield studies • Alignment studies • Instrumentation studies • Failure studies • -> CLIC CDR Was found best to use a common simulation framework for the two machines.

  4. Implementation philosophy USER OPTIONS AND PARAMETERS • Uses PLACET core functionality (defining beam, wakes, lattices and tracking) • Decelerator scripts, in TCL and octave, calls placet core • Options and parameters deemed useful for new users and "clean" are extracted in separate file DECELERATOR SCRIPTS (TCL and Octave) PLACET CORE (C and C++) Note: decelerator beam uses different placet core commands for beam, cavity and wake definitions. • For studies I have performed: consideration whether it has been worth clearing things up and make it (will it be useful and understandable?)

  5. Implementation details def_pets.tcl user_options.tcl def_beam.tcl PLAECET CORE main.tcl advanced_options.tcl loop_main.tcl multisim.m user_tblbeamline.tcl def_lattice.tcl online_exchange • "3-layer structure" : • to redo well-defined studies already prepared: only "user_" files need to be touched • for new studies other script files might need to be touched • for some new studies changes in the placet core will be ineluctable

  6. Implementation details: user file user_options.tcl # DECELERATOR AND TBL scripts # E. Adli # basic user options # which machine to simulate (uncomment a single choice) # a 1050 m long decelerator sector set mysimname clic12 # the Test Beam Line, including matching and instrumentation sections #set mysimname tbl12 ... # inital normalized emittance [m] set emitt_x 150.0e-6 set emitt_y 150.0e-6 # bunch length [um] set sigma_z 1000 # number of random machines to simulate (random misalignment is applied for each machine) set n_machines 1 # default machine rms misalignments [um], [urad] set sigma_quad 20 set sigma_quad_yp 1.0e3 set sigma_bpm 20 set sigma_bpm_yp 1.0e3 set sigma_pets 100 set sigma_pets_yp 1.0e3 set sigma_quad_roll 0.0 set sigma_bpm_roll 0.0 # 1: force all misalignments to zero (perfect machine) set zero_all_misalignments 1 . . . Will go through a few examples of studies performed with these scripts, which have been "cleaned up" into user options.

  7. Implementation details: multisim.m multisim.m . . % SET QUAD STRENGTH JITTER scale_Q = 1+randn(1,length(Q))*$quad_strength_jitter; Qy_nominal = placet_element_get_attribute("$mysimname", Q, "y"); if( length(P) > 0 ), placet_element_set_attribute("$mysimname", P(P_failed), "e0", -1.0); end; % drive wedges PETS placet_element_set_attribute("$mysimname", Q, "y", Qy_nominal.+jitter_Qy); % y jitter placet_element_set_attribute("$mysimname", Q, "strength", Qstrength_nominal.*scale_Q); % strength jitter placet_element_set_attribute("$mysimname", Q(Q_failed), "strength", Qstrength_nominal(Q_failed)*$quad_fail_current_reduction); placet_element_set_attribute("$mysimname", B, "resolution", 0); [E0, BEAM] = placet_test_no_correction("$mysimname", "$beamname1", "None", 1); % final beam in centre quad y0 = placet_element_get_attribute("$mysimname", B, "reading_y") + placet_element_get_attribute("$mysimname", B, "y"); losses_NC += placet_element_get_attribute("$mysimname", Q, "aperture_losses"); . . placet_element_set_attribute("$mysimname", B, "resolution", $bpm_resolution); placet_element_set_attribute("$mysimname", Q, "strength", Qstrength_nominal ); % restore quads placet_element_set_attribute("$mysimname", Q, "y", Qy_nominal ); % restore quads. if( length(P) > 0 ), placet_element_set_attribute("$mysimname", P, "e0", PETS_nominal); end; % restore PETS y0_NC += y0; Core of the decelerator script is the placet-octave based "multisim.m" which handles beamline modifications and tracking, within one clear and compact script.

  8. First users The scripts have already been shared with : • CERN BE/BI (M. Olvegaard); TBL instrumentation • CERN BE/RF (R. Lillestoel); TBL steering • CERN TE/EPC (M. Jonker): in progress • IFIC Valencia (J. Garrigos, A. Faus-Golfe): in progress

  9. A few examples

  10. PETS wake fields user_options.tcl . . # scaling factors for RQ, Q and w. All modes scaled simultainously. Scalong factor of 1: nominal PETS parameters set RQ_scaling_factor [expr 1.0e-0] set w_t_scaling_factor [expr 1.0e-0] set Q_t_scaling_factor [expr 1.0e-0] set beta_t_scaling [expr 1.0e-0] #set Q_t_scaling_factor $loop_param2 . . # MAIN BEAM: static beam offset and jitter beam offset (in y) in quantities of sigma_y (total is partioned over available modes) set static_mainbeam_offset [expr 0.0] #set static_mainbeam_offset [expr 0.0/1.944582] #set static_mainbeam_offset [expr ($loop_param1-1)/10.0] set jitter_mainbeam_offset_total 0.0 . . . For changes of modes: def_pets.tcl

  11. Alignment user_options.tcl . . . # default machine rms misalignments [um], [urad] set sigma_quad 20 set sigma_quad_yp 1.0e3 set sigma_bpm 20 set sigma_bpm_yp 1.0e3 set sigma_pets 100 set sigma_pets_yp 1.0e3 set sigma_quad_roll 0.0 set sigma_bpm_roll 0.0 # 1: force all misalignments to zero (perfect machine) set zero_all_misalignments 0 # BPM resolution [um] set bpm_resolution 2.0 # mover corrector step size [um] set corrector_step_size 1 # performing tracking with selected correction schemes (1: selected, multiple schemes can be selected, and the machine will then apply them in the order marked below) set track_no_correction 1 set track_1to1_correction 0 set track_DFS_correction 0 . .

  12. Alignment (more) Generate full R-matrix once, save, and re-load for further studies Load/save corrected machines for further studies Validity at discretion of user.... user_options.tcl . . . # load R-matrix if exists, save R-matrix when generated set do_multisim_load_save_R 1 # load and save machines set do_multisim_load_mach 0 set do_multisim_save_mach 0 . . . # Options to use only a sub-set of BPMs and/or correctors # use every n'th BPM for correction (1: use all BPMs) set B_BBA_interval 1 # use every m'th QUAD for correction (1: use all quads) set Q_BBA_interval 1 # use every k'th QUAD/BPM combo for correction (1: use all combos) - if > 1 above B and Q are IGNORED set QB_BBA_interval 1 #set QB_BBA_interval $loop_param2 # if 0: use corr-BPM 1 3 5 7 9 .... if 1: use corr-BPM 1 2 4 6 8 ... # note: first BPM is in front of a F-quad (DEFOC in y), therefore best effect in y when starting using 2 4 6 set BBA_interval_start2 0 . . . Correct using sub-set of BPMs and/or correctors (automatically extracting relevant information from full R-matrix). For full flexibility in BPM/corrector choice: manipulate vector in : multisim.m

  13. Failure modes user_options.tcl . . . # component failure # number of quads failed set n_failure_quad 0 # fail N quads in series for each failure (in total: n_failure_quadxquadfail_in_series are failed) set quadfail_in_series 1 # effect of failure: reduction of current the following fraction of original current [-] set quad_fail_current_reduction 0.0 # fraction of BPMs failed (e.g. 0.9: 90%) set n_failure_BPM_percent 0 . . .

  14. Optics studies (example TBL) user_options.tcl . # save lattice geometry set savelattice_active 1 # save multisim beta for lowest energy particle set savebeta_multisim_active 1 .

  15. TBL online exchange user_options.tcl . . . . # TBL online exhange? # 0: use nominal ctf3 parameters, for baseline studies # 1: read tbl magnet currents, initial energy and initial energy from files (for online use in CTF3) set tbl_online_exchange 0 . . . Calculate response matrices and transfer matrices (TBI) for the TBL, including the effect of the PETS. Exchanging files using the standard(?) CTF3 method with "virtual.currents". Expected found in online_exchange folder: virtual.currents virtual.energies virtual.beamcurrentes TBL response matrix

  16. TBL spectrometer user_options.tcl . . . # TBL options } elseif { $mysimname == "tbl12" } { set activate_power_optimization 0 # default current [A] set initial_current [expr 28.0e-0] # default decelerator initial energy [GeV] set initial_energy 0.150 # default power [MW] set requested_PETS_power 135.0 # default maximum energy spread [-] set requested_E_spread 0.55 . . . # indicate where a PETS is installed (0: no PETS in this slot, 1: PETS installed in this slot) #set tbl_PETS_list "1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0" set tbl_PETS_list "1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1" . . . Simulated beam at spectrometer dump location after 8 PETS.

  17. Simulation parameters user_options.tcl . . . . # number of bunches to simulate (to reach steady-state, at least 20 for clic and at least if { $mysimname == "clic12" } { set n_bunches_sim 50 } elseif { $mysimname == "tbl12" } { #set n_bunches_sim 240 set n_bunches_sim 60 # full CTF3 train length #set n_bunches_sim 1680 # TBL: beam is converted to a particle beam before the spectrometer set n_particle_beam 50000 NB: number of particles simulated and length of simulated train might need to be changed for some studies. Default is a short train (~ x 2 longer than transient). TBL: might want to simulate full train length TBL: particle beam dumped, number of particles can be specified For other simulation-techincal changes there are also some options in : advanced_options.tcl

  18. How to run

  19. To get started 1) run the main script, e.g. cd ...../decelerator/results/ placet-octave ../dec_scripts/main.tcl 2) change parameters and options (each option well documented in the file) ../dec_scripts/user_options.tcl 3) retrieve data in the main dump-file (matlab/octave format), using matlab or octave load "../results/decsimdata.1.1.1.1.1.dat" 3b) examples of data in dump-file plot(Bs, y0_NC) % BPM y-readings at each BPM plot(Qs, env_NC(1:end-1)) % 3-sigma beam envelope at each quadrupole plot(b0nc(:,1), b0nc(:,3), 'x') % beam energy profile and, please see: • decelerator/README.txt (decelerator get started doc) • PLACET.pdf (standard placet manual)

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