PTC-ORBIT Studies for the CERN LHC Injectors Upgrade Projectepaper.kek.jp/HB2012/talks/weo1b05_talk.pdf · 2013. 4. 28. · PTC-ORBIT(MPI) Multi-turn injection for the CERN PS Booster

PTC-ORBIT Studies for the CERN LHC Injectors

Upgrade Project KEK: A.Molodozhentsev, E.Forest

CERN: G. Arduini, H. Bartosik, E.Benedetto, C.Carli, V.Forte, M.Fitterer, S.Gilardoni, M.Martini,

E.Metral, N.Mounet, F.Schmidt, R.Wasef

Outline Motivation Computational tools ‘Space-charge’ convergence study Machine study and the code benchmarking ‘Dynamic’ simulations of the Multi-turn injection for the CERN PS Booster Observation of the space charge effects for CERN PS and SPS Conceptual design of the CERN RCS

A.Molodozhentsev (KEK), ICFA HB12 workshop Beijing, China, September 17-21, 2012

Motivation CERN LHC (25nsec) beam upgrade scenario (LIU request)


Motivation


Space charge detuning estimations for the LHC Injectors

Computational tools


‘Space-charge’ convergence study


Space charge detuning for CERN PS-Booster (160MeV)

2D histogram

QV

QH 4 4.5

4

4.5

QH/QV=4.26/4.43

PTC-ORBIT(MPI)

‘Space-charge’ convergence study

RMS emittance evolution Evolution of the ‘halo’ part of the beam

RMS and 99% emittance evolution for different sets of the ‘space charge’ module of the code for the case of the lattice tunes QH / QV = 4.26 / 4.43 (CERN PS Booster)


2.5D 2.5D

PTC-ORBIT(MPI)

Machine studies (MD-2012) and the PTC-ORBIT code benchmarking

LHC25 beam Bf ~ 0.4


Motivation: reproduce the measured beam evolution

at 160MeV by the PTC-ORBIT tracking

Foot print QH/QV=4.18/4.23

4.5 4

4

4.5

Measured beam profile ‘Tomoscope’ image

Generated beam profile

Generated and measured transverse beam profile at the 160MeV energy

H V

-20 20 -10 10

PTC-ORBIT(MPI)

Machine studies (MD-2012) and the PTC-ORBIT code benchmarking

CERN PS-Booster

MD2

CERN PS-Booster H

V MD3


… taken into account the random

error of the quadrupole strength of the PS Booster magnets

MD5

… including the random TILT of the PS Booster quadrupole magnets

[1,-1,0]

Linear coupling of the PS Booster:

QMIN 0.008

[1,0

,4] r

eson

ance

[2

,-2,0

] res

onan

ce

Accuracy of the RMS emittance measurements should be improved …

lattice with RANDOM errors { K1}QM #1: ‘ideal’ lattice #2 : 1Sigma = 1.0 10-3 (relative value) #3 : 1Sigma = 5.0 10-3

Up to 1Sigma = 4.28 10-5 rad

#2

#3

#1

Multi-turn injection for the CERN PS Booster with LINAC4

Significant improvement of the efficiency of the MT injection by using the H- stripping injection in the H-plane

Control over both transverse emittances Effects of the edge-focusing of the

‘slow’ bump-magnets, changing during the chicane reduction



0.000 0.001 0.002 0.003 0.004 0.005

-0.779

-0.778

-0.777

-0.776

-0.775

-0.774

-0.773

Qua

drup

ole

stre

ngth

[T/m

2 ]

Time [sec]

0 1000 2000 3000 4000 5000 6000

-80

-60

-40

-20

0

Hor

izon

tal c

hica

ne h

eigh

t [m

m]

Number of Turns

Begining of the MT Injection

End of the MT Injection

Lattice tunes: QH /QV =4.28/4.45 QV could be above 4.5 … Compensation the V beta-beating effect Active compensation scheme by

using 2 independent families of quads Reduction of the V-beta beat: 35% 5% Dynamic changing the quad strength

during the chicane’s fall from MAX ( -80mm) to ZERO


#1 #2

V beta-beating around CERN PS Booster: #1 – before; #2 – after the ‘active’ correction

X-PX

<X> vz Nturns

KQ vz Time

PTC-ORBIT(MPI)


Capture efficiency ~ 98%, Bf ~ 0.6

Double harmonic RF system with the longitudinal stacking of the bunches


Particle distribution after 5520t

[rad]

W [G

eV]

PTC-ORBIT (space charge ON)

PTC-ORBIT(MPI)



0 1 2 3 4 5 6

1.20

1.25

1.30

1.35

1.40

1.45

Nor

mai

lzed

RM

S em

ittan

ce [u

m]

Time[msec]

H

V

0 1 2 3 4 5 6

6.0

6.5

7.0

7.5

8.0

8.5

9.0

Nor

mai

lzed

RM

S e

mitt

ance

[um

]

Time[msec]

V

H

Transverse emittance evolution (NO FOIL) V OFF-set ( 3mm) to control the Vertical emittance Space Charge effects ON (adapted grid) … 35.2e10ppb Incoherent space charge detuning < -0.5, Lattice tune QH / QV = 4.27 / 4.58

Effects of FOIL, Aperture limitation, machine imperfections should be analyzed

RMS Normalized Emittance 99% Normalized Emittance

PTC-ORBIT(MPI)

CERN PS: space charge effects and machine resonances

Tune scan at the energy 2.0GeV Typical tune-spread H,V ~(-0.18, -0.28)

Emittance growth near the [0,1,6] resonance has been studied experimentally … for the code benchmarking

Resonance Driving Terms: ‘pencil’ beam (LHC-INDIV) different horizontal kick strength

‘Realistic’ machine description by using the measured field nonlinearities of the PS magnets … … in progress … to reproduce the experimental observations.


S.Gilardoni talk

CERN PS: space charge effects and machine resonances

0.2 0.4 0.6 0.8 1Frequency

0.002

0.004

0.006

0.008

0.01

edutilpmA

Resonanse_Basis

Observation of the [1,-1,0] resonance turn-by-turn data acquisition …

Turn-by-Turn data analysis

Linear coupling resonance observation (NO correction)

‘LHC-INDIV’ beam


[1,-1,0] resonance observation

CERN SPS: space charge effects and machine resonances

• Tune scan for the Q20 SPS optics at 26GeV • Single bunch : 2.5-2.7e11 p/b • Normalized RMS emittance: 1.2 m in both planes • The incoherent space charge detuning: QH -0.15, QV -0.25.


New scan

NO RMS emittance growth

NO RMS emittance growth

H.Bartosik talk

Losses !

RCS conceptual design Motivations (including the space charge at injection): alternative to the CERN PS Booster upgrade (160MeV-2GeV, 10Hz) effect the beam envelope modulations on the emittance growth effect of the super-periodicity

Qy -0.4

V [

m]

V [

m]

Variation of the beam size can lead to the emittance growth: the ‘TRIPLET’ features smallest variation of the transverse emittance compared to the ‘DOUBLET’ and the ‘FODO’ cell

‘Triplet’

‘FODO’ ‘Triplet’

Lattice tune above 2Qy=7 Including the Vertical

beta-beating correction …

Symmetry 1

Emittance growth due to excitation of ‘systematic’ resonances:

‘weak’ symmetry breaking in one cell with correcting the beat-beat


PTC-ORBIT(MPI)

Injection

ExtractionRF

Conclusions

The performed benchmarking between the measured and simulated beam evolution for the CERN PS Booster at 160MeV shows very good agreement Optimization of main PS Booster setting has been performed to simulate the multi-turn injection process Data accumulation for the further study of the space charge effects for the LHC Injectors has been started to

perform extensive simulations during the ‘Shut-Down-1’ period



Documents

PTC-ORBIT Studies for the CERN LHC Injectors Upgrade Projectepaper.kek.jp/HB2012/talks/weo1b05_talk.pdf · 2013. 4. 28. · PTC-ORBIT(MPI) Multi-turn injection for the CERN PS Booster