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

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

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

Initial beam characteristics and simulations set upTransverse planes

ex rms (normalized)

2.6757 (+/− 0.0844)

ey rms (normalized)

5.0542 (+/− 0.4521)

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 (@C500)

1.7e12 p.

Energy (MeV) 160

Simulations set up

S.c. method

2.5D direct space charge (128x128 & 64x64 mesh grids)

Nr. of initial m.p.

500e3

From ABP/LIS meeting

04/11/2013

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

Improving the optics: closed orbit matching and correction

The measured CODs

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

Improving the optics: closed orbit matching and correction

Without COD correction With COD correction

Thanks M. McAteer

Vertical COD

13 vertical DVTs -> DVT=COD matching component + COD correction component (from real machine values)

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

Without COD correction

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

Without COD correction – intensity evolution

From ABP/LIS meeting

04/11/2013

Without COD correction: the vertical transverse profiles…

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Sim

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no beam deformation

shift

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

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

With COD correction

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

With COD correction – intensity evolution

Boundaries shape -> rectangle x=[-61, 61] mm y=[-29.5, 29.5] mm

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

With COD correction: The vertical transverse profiles…

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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

With COD correction - RMS emittances

Vertical

Horizontal

Direct space charge simulation (the one with boundaries is on-going)

Simulation with boundaries

With COD correction

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

The losses distribution along the machine (simulated BLMs)

Period 2 & 6

Without COD correction

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

The effect of the space charge model with boundaries. The coherent tune shift

Vertical plane (considering the max FFT amplitude)

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

The effect of the space charge model with boundaries. The incoherent tune shift

with boundariesdirect space charge

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

With COD correction and random quad field errors – intensity evolution

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

The effect of the chromaticity on the losses

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

The effect of the chromaticity on the losses

A new MD will be performed in the next days to confirm the results.

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

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 – 06/10/2014

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 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

Appendix

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

Improving the optics: closed orbit matching and correction

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

Improving the optics: closed orbit matching and correction