1. PTC-ORBIT issues for PSB simulations V. Forte – E. Benedetto – M. Martini S.c. meeting (18/07/2013)

2. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) OUTLINE We observed different “strange” behaviours in PTC-ORBIT simulations that should be fixed or, at least, explained by the code developers: Acceleration issues RF issues Aperture related spikes No-coincidence (and coincidence) of solutions

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

4. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) The energy path described in the table is the following…

5. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) Acceleration issues: ORBIT diagnostics Statistical Twiss + dynamic energy (from RF table) Fixed Twiss (from Twiss PTC table) + dynamic energy (from RF table) Fixed Twiss (from Twiss PTC table) + static energy (160 MeV) Orbit seems to not recognize the acceleration imposed through PTC RF tables The Orbit diagnostics confirm the hypothesis. In fact these are similar to post-processing calculations using fixed Twiss and a constant 160 MeV kinetic energy Horizontal RMS emittance Vertical RMS emittance

6. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) Acceleration issues: Orbit seems to not recognize the acceleration imposed through PTC RF tables This can cause problems in: Diagnostics (  p/p calculation…) Space charge computation MUST BE FIXED!

7. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) RF table definition: In case of acceleration (Bdot ≠ 0), the longitudinal phase space is (artificially?!) shifted by PTC in order to use  0 as a fixed point. While, without acceleration, this is a direct consequence of the equations (0 stable phase), it shouldn’t be in case with acceleration.

8. 8 kV (h=1) + 8 kV (h=2) in phase without acceleration PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) The +time command must be used for space charge simulations and causes a shift of  in phase.

9. 8 kV (h=1) + 8 kV (h=2) in phase without acceleration (swapped sign in PTC-ORBIT) PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) For this reason the sign of the voltages must be swapped. 8 (h=1) & 8 (h=2) in phase -> -8, -8

10. 8 kV (h=1) + 8 kV (h=2) in phase with acceleration PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) For this reason the sign of the voltages must be swapped 8 (h=1) & 8 (h=2) in antiphase -> -8, +8 8 (h=1) & 8 (h=2) in phase -> -8, -8

11. 8 kV (h=1) + 6 kV (h=2) in phase with acceleration PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

12. 8 kV (h=1) + 8 kV (h=2) in antiphase without acceleration SFP @ 1.047 rad ~ 60 deg Synch.period ~ 482 turns Synch. period ~ 712 turns PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

13. 8 kV (h=1) + 8 kV (h=2) in antiphase with acceleration SFP @ 1.365 rad ~ 78 deg Synch. period ~ 482 turns Synch. period ~ 780 turns PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) The sign of the voltages must be swapped 8 (h=1) & 8 (h=2) in antiphase -> -8, +8

14. 8 kV (h=1) + 6 kV (h=2) in antiphase without acceleration SFP @ 0.8568 rad ~ 49 deg Synch. period ~ 655 turns Synch. period ~ 745 turns PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

15. 8 kV (h=1) + 6 kV (h=2) in antiphase with acceleration PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013)

16. RF table definition: In case of acceleration (Bdot ≠ 0), the longitudinal phase space is (artificially?!) shifted by PTC in order to use  0 as a fixed point. While, without acceleration, this is a direct consequence of the equations (0 stable phase), it shouldn’t be in case with acceleration -> (0,0) is not a solution of the equations anymore. This can cause problems in: Defining complex energy paths (i.e. acceleration->static energy) without transition (i.e. from acceleration to static energy) mismatch Longitudinal matching is possible only after single particle tracking to be sure of the bucket position(trick) The way this shift is performed must be analytically clear!

17. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) Aperture-dependent spikes

18. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) No-coincidence of solutions

19. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) No-coincidence of solutions

20. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) coincidence of solutions (without apertures)

21. PTC-ORBIT issues for PSB simulations - V. Forte – E. Benedetto – M. Martini - S.c. meeting (18/07/2013) CONCLUSIONS We observed different “strange” behaviours in PTC-ORBIT that should be fixed or, at least, explained by the code developers. Solutions (or explanations) should be provided soon to avoid slacks in simulations.