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Acceleration issue in PTC-Orbit debugged

Acceleration issue in PTC-Orbit debugged. E.Benedetto Space Charge meeting, 29/8/2013. Outline. The issue The proposed solution Examples Influence on our (PSB) simulations. The issue.

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Acceleration issue in PTC-Orbit debugged

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  1. Acceleration issue in PTC-Orbit debugged E.Benedetto Space Charge meeting, 29/8/2013

  2. Outline • The issue • The proposed solution • Examples • Influence on our (PSB) simulations

  3. The issue • PTC was not communicating to ORBIT the increase of energy (momentum, beta, gamma, etc..) imposed through the PTC RF tables. • How we noticed it ( Vincenzo’s presentation 18/7/2013): • showAccelerate(fio) (pure Orbit command) output not showing increase of Energy and Beta • Still had the doubt (=hope) it was just a wrong output…

  4. Acceleration issues: • Orbit seems to not recognize the acceleration imposed through PTC RF tables showaccelerate(fio) PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

  5. The proposed solution • Changes in the PTC source file Sq_orbit_ptc.f90 two subroutines: • ORBIT_up_grade_mag: called every turn before entering the RF cavity to update the RF freq. (for the new BETA0) and where the new revolution freq. is passed to Orbit. • energize_ORBIT_lattice: called at the very beginning to set the correct RF cavity freq. (and revolution freq.) • The proposal is to modify at these 2 location and pass to Orbit not only the new revolution frequency, but also the new energy, momentum, beta, gamma, etc..

  6. subroutine energize_ORBIT_lattice(t) implicit none real(dp), optional :: t type(fibre), pointer :: p type(work) werk,travail real(dp) e_in,t0,freqs integer i logical found found=.false. freqs=1.e38_dp werk=0 travail=0 t0=x_orbit_sync(6) ! read from the initial_settings file and multiplied by clight if(present(t)) t0=t if(fill_patch) then write(6,*) " filling patches with t= x0 from main program " t0=t0_main endif write(6,*) "energize at time ", t0,t0/clight write(6,*) "Initial Frequency of First Cavity", paccfirst%mag%c4%freq call find_acc_energy(paccfirst,t0,e_in,my_true) ! new ! call find_acc_energy(paccfirst,x_orbit_sync(6),e_in,.false.) call find_energy(werk,kinetic=e_in) p=>paccfirst%parent_layout%start do i=1,paccfirst%parent_layout%n travail=p if(p%mag%kind==kind4) then p%mag%c4%freq = p%mag%c4%freq*werk%beta0/travail%beta0 p%magp%c4%freq = p%mag%c4%freq if(p%mag%c4%freq<freqs)then freqs=p%mag%c4%freq found=.true. endif call find_acc_energy(paccfirst,t0,e_in,my_true) !new endif p=werk p=>p%next enddo if(freqs/=0.and.found) then my_ORBIT_LATTICE%ORBIT_OMEGA=twopi*freqs/CLIGHT ! EB beginning - added by Elena Benedetto - to have correct energy already at the beginning my_ORBIT_LATTICE%ORBIT_P0C=werk%P0C my_ORBIT_LATTICE%ORBIT_kinetic=werk%kinetic my_ORBIT_LATTICE%orbit_beta0=werk%beta0 my_ORBIT_LATTICE%orbit_brho=werk%brho my_ORBIT_LATTICE%orbit_energy=werk%energy my_ORBIT_LATTICE%orbit_gamma=1.0_dp/werk%gamma0i ! EB end - added by Elena Benedetto else write(6,*) " cavity with frequency problems ", freqs,found stop endif write(6,*) "Final Frequency of First Cavity", paccfirst%mag%c4%freq write(6,*) "Initial and Final beta0 ",travail%beta0,werk%beta0 write(6,*) "Starting time of simulations =",t0/clight ," and kinetic energy =",my_ORBIT_LATTICE%ORBIT_kinetic end subroutine energize_ORBIT_lattice The same is done in the ORBIT_up_grade_mag subroutine

  7. Test #1: showAccelerate(fio) output Same job, with the new compiled version, vs. the old one, i.e. PTC11012012-ORBIT10 • New: • Energy, beta0 are updated • Elepsed time takes into account the beta0 increase • Old: • Energy, beta0 stay constant • Elapsed time increases linearly with #turns

  8. Test #2: SpaceCharge diagnostics Same job, with the new compiled version, vs. the old one, i.e. PTC11012012-ORBIT10 Perveance~ l/(b2 g3) ~ It can be seen as the “coefficient” of the space charge force • New: • Perveance/l decreasing • Old: • Perveance/lconstant

  9. Implications for PSB simulations • d(Brho)/dt=10 Tm/s PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

  10. Implications for PSB simulations Same job, with the new compiled version, vs. the old one, i.e. PTC11012012-ORBIT10 • In 7000 turns (d(Brho)/dt=10 Tm/s): • Energy: 160MeV  170.9 MeV • Beta: 0.5197  0.533 • Perveance/l/rp ~A*1/(b2g3): 1.064  1.154 Horizontal emittance Vertical emittance # turns # turns

  11. FINAL_SETTINGS issue • Small differences (with acceleration) between: • Elapsed time in Orbit diagnostics (e.g. showAccelerate(fio)) • FINAL_SETTINGS.txt file if only 1 long simulation • FINAL_SETTINGS.txt file resulting from “continuous tracking” • Differences between 1) and 2,3) understood: “Orbit time” is simply the sum over #turns of (2pR/bc) • But 2) and 3) should be exactly the same!!! • 3) getting closer to 1) for jobs of 1turn each • See example next page

  12. FINAL_SETTINGS issue

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