2. Space Charge meeting – CERN – 09/10/2014
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Space Charge meeting – CERN – 09/10/2014
Vincenzo Forte
Thanks to:
E. Benedetto, M. McAteer, F. Schmidt

3. From ABP/LIS meeting 04/11/2013
Intensities and tunes
From ABP/LIS meeting 04/11/2013
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

4. Initial beam characteristics and simulations set up
Transverse planes
ex rms (normalized)
(+/− )
ey rms (normalized)
(+/− )
Simulations set up
S.c. method
2.5D direct space charge (128x128 & 64x64 mesh grids)
Nr. of initial m.p.
500e3
Longitudinal plane
Peak Voltage (h=1 & h=2)
8 kV & 8 kV
Relative phase
0 deg (short bunch)
Dp/p
2e-3
B. factor
0.25
ez rms (eVs)
0.17
Full length (ns)
~400
Intensity
1.7e12 p.
Energy (MeV)
160
From ABP/LIS meeting 04/11/2013
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

5. Improving the optics: closed orbit matching and correction
The measured CODs
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

6. Improving the optics: closed orbit matching and correction
Vertical COD
Without COD correction
With COD correction
13 vertical DVTs ->
DVT=COD matching component
+ COD correction component (from real machine values)
Thanks M. McAteer
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

7. Without COD correction
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

8. Without COD correction – intensity evolution
From ABP/LIS meeting 04/11/2013
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

9. Without COD correction: the vertical transverse profiles…
only shift
shift
Simulations with direct space charge
Simulations without space charge
beam deformation
no beam deformation
The beam loses Gaussianity already after 5 ms!
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014

10. With COD correction
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 06/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

11. With COD correction – intensity evolution
Boundaries shape -> rectangle x=[-61, 61] mm y=[-29.5, 29.5] mm
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 06/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

12. With COD correction: The vertical transverse profiles…
Measurements
Simulation without space charge
Simulation with space charge (boundaries)
Simulation with direct
space charge
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

13. With COD correction - RMS emittances
Vertical
Horizontal
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 06/10/2014

14. The losses distribution along the machine (simulated BLMs)
Without COD correction
With COD correction
Direct space charge simulation (the one with boundaries is on-going)
Simulation with boundaries
Period 2 & 6
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014

15. Vertical plane (considering the max FFT amplitude)
The effect of the space charge model with boundaries. The coherent tune shift
Vertical plane (considering the max FFT amplitude)
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

16. The effect of the space charge model with boundaries.
The incoherent tune shift
direct space charge
with boundaries
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014

17. With COD correction and random quad field errors – intensity evolution
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

18. The effect of the chromaticity on the losses
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

19. The effect of the chromaticity on the losses
A new MD will be performed in the next days to confirm the results.
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

20. The effect of the chromaticity on the losses
Footprint with DQy=-6.66 (turn 0)
Footprint with DQy=-0.47 (turn 0)
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014

21. Summary and conclusions
A dynamic tune scan toward the vertical integer resonance (Qy=4) in the PSB has been presented.
At first, an improvement in the optics model has been performed, through the use of the DVT steerers, to create an equivalent model in terms of COD.
Case1: With the new model, without COD correction, the simulations show great results in case the direct space charge module is added.
Case 2: with a COD correction (the same as in the machine) is applied, the simulations underestimate the losses in case the direct space charge module is considered, while they overestimate the losses using the space charge module with boundaries.
The qualitative behaviour of the transverse vertical profiles is reproduced in terms of beam deformation (toward a parabolic-like during the cycle).
The presence of the boundaries has effects both in the coherent tune and in the incoherent tune shifts.
10 Simulations with randomly distributed errors (10 different seeds) show the same results in a sigma span similar to the real errors, as measured by M. McAteer (s=7e-4 for dk1)
Simulations with chromaticity correction performed through the harmonic sextupoles family (XNOH0) show that, as expected, this may have a role in the losses induced by incoherent tune spread (to be confirmed through new MDs).
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 06/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

22. Appendix
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 06/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

23. Improving the optics: closed orbit matching and correction
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013

24. Improving the optics: closed orbit matching and correction
PSB (PTC-Orbit) 160MeV space charge simulations with improved optics model: the vertical dynamic integer case.
Vincenzo Forte – Space Charge meeting – CERN – 09/10/2014
PSB space charge studies update
Vincenzo Forte – BE-ABP/LIS meeting – CERN - 04/11/2013