ptc-orbit code for cern machines (psb, ps, sps) alexander molodozhentsev (kek) etienne forest (kek)...

PTC-ORBIT code for CERN machines

(PSB, PS, SPS)

Alexander Molodozhentsev (KEK)Etienne Forest (KEK)

Group meeting, CERN June 1, 2011

current status …

What is this code?

PTC Etienne Forest (KEK)

ORBIT SNS-BNL code (Jeff Holmes, SNS)Idea to ‘glue’ these two codes was generated by A.Molodozhentsev

and discussed during the HB ICFA06 Workshop

PTC-ORBIT combined code (from 2007, KEK-SNS)

… use for J-PARC Main Ring to study the space-charge effects in combination with the machine resonances …

compiled for the KEK super computers (Hitachi & IBM, 2007 ) and for the CERN CLIC cluster (CERN, November 2010)

MADX-PTC convenient way to prepare realistic machine description including user’s matching procedures …

Alexander Molodozhentsev (KEK)

Why PTC-ORBIT ?Real machine with fieldImperfections andalignment data

PTC lattice representationComprehensive lattice analysis RF cavities (acceleration) NEW !…Time dependent magnets

ORBIT nodePTC as the tracker (6D integrator)

‘ORBIT’ staff:- Injection foil.- Space charge model.- Transverse and longitudinal impedance.- Feedback for stabilization.- Aperture and collimation.- Electron cloud model.

Main feature:Common environment for the single particle dynamics (lattice analysis andresonance compensation) and multi particle dynamics (collective effects).


Lattice preparation #1: MADX lattice without zero-length elements and

without cutting Time variation of the rectangular bending magnets with the fringe field effect … vertical focusing

QUADRUPOLE with zero quadrupole component … (added to MADX) …

Alignment errors & high-order field components of the ring magnets …

Required matching procedure … by MADX … Proper setting the RF cavities … by MADX … Example for RF:

BR.C02 : RFCAVITY, VOLT:=0.008, HARMON:=1, L:=1.0, LAG:=0, no_cavity_totalpath;


Lattice preparation #2 (PTC): Cut the lattice using some method (PTC: EXACT=FALSE or

TRUE)

Fit all machine parameters you would normally fit using your matching routines (MADX or PTC).

Examine the resulting lattice functions and also some short term dynamic aperture.

If ALL is fine, reduce the number of cuts and/or the sophistication of the method and go back to step #1.

If something is wrong, increase the number of cuts and/or sophistication of the method and go back to step #1.

After a having oscillated between different lattice representations, make a decision and call that “the lattice” PTC ‘FLAT’ file.


… by MADX-PTC Method … EXACT=Exact or False

Drift-Kick-Drift or Matrix-Kick-Matrix Integration … order of the integration

… for PTC-ORBIT LMAX … maximum distance between the space-charge nodes in the machine THINLENS …

The parameter THINLENS describes an approximate integrated quadrupole strength for which a single thin lens should be used.

Lattice preparation #3 (PTC):


………lmax1.0d0fuzzylmax0.10THINLENS0.1

PRINT FLAT FILEPSB_PTC_ORBIT_FLAT.TXT

Example (from PTC script thin4.xtx):

Flat file with proper settingthe machine elements and machine parameters !!!

Notes #1(3):

# 1 Flat file preparation (MADX-PTC) with proper setting the machine elements and machine parameters

# 2 STATIC RF cavities No need to prepare the RF tables (all information should be in FLAT file)

# 3 PTC-ORBIT script preparation …

# 3.1 read flat file # 3.2 read (or generate) the 6D particle distribution # 3.3 space charge module (if you want to use it) # 3.4 define the tracking conditions # 3.5 tracking module with the beam analysis # 3.6 … saving data for the continues tracking …

Off-line USER analysis of the obtained results …


Notes #2(3):

# 3.4 define the tracking conditions to activate the ‘time-variation’ option of PTC for different type of the machine magnets for the PTC-ORBIT tracking NEW feature of the PTC !!!


Notes #3(3):time0.txt

set_xsm.txt

ramp_psb_bs.txt BS_ramp.txt

PTC flags …

Definition: initial time and units

Modulation …

Name of element

timeb1 a1

Number of multipole components

scaling

scaling

Multipoleindex

B0/(B)

‘time’ instead of ‘path_length’Cavity ONModulation ON


PTC-ORBIT Code setting & test

CERN PS Booster (with C.Carli)

CERN PS (with S.Gilardoni)

CERN SPS (with H.Bartosic)


CERN_PS Booster

Checking … always should be done be before any studied to avoid nonsense !

Longitudinal single particle motion (1) NO acceleration (2) WITH acceleration Chicane (time variation) Quadrupole magnets (QD3&QD14) time variation during the chicane decay SINGLE PARTICLE MOTION !!! Before you start some multi

particle tracking …


CERN_PS Booster Different PTC models: EXACT= TRUE or FALSE ?

… checking the linear chromaticity

Exact=TRUE Exact=FALSE

Qx= 4.2797

Qy = 4.4497

Qx/ -3.471 (*)

(**) – 6.678-3.647- 7.017

Qy/ -7.3023 (*)

(**) -14.049-7.115-13.69

(*) … ‘path-length’ instead of Time

CONCLUSION:Exact=FALSE could be usedfor the PSB study as basis …… should be checked …

(**) … ‘Time’ instead of ‘path-length’

~ 5%

< 1%


CERN_PS Booster

PTC-GINO interface

‘Single harmonic’ RF cavity


CERN_PS Booster: longitudinal / RF cavity ON (“+cavity” in time0.txt)

PTC-ORBIT by using the PTC flat file with proper setting the RF cavities for the machine

Single particle tracking


NO CHICANE …

CERN_PS Booster: setting the injection chicane including the edge focusing effect of the PSB bump magnets (NO kickers for the transverse painting)

CHICANE-45.607 mm


MADX_PTC

0 20 40 60 80 100 120 140 1602

4

6

8

10

12

14

16

18

20

22

NO Chicane YES Chicane YES BB correction YES Chicane NO BB correction

Bet

a_Y

[m]

s [m]

0 20 40 60 80 100 120 140 160-35-30-25-20-15-10

-505

101520253035

s [m]

BetaY Beating CORRECTEDBeatY NO Beat Correction

Bet

aY_B

eat [

%]

MADX matching inside the PTC universe (made with Piotr Skowronski): … matching the working point … vertical beta-beating correction by QD3&QD14

PTC: twiss analysis (at the QM positions)

~ 30%

~ 10%


CERN_PSB: Chicane and QD3&14 variation

0.0000 0.0002 0.0004 0.0006 0.0008 0.0010

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20 BS variation

b1 [m

-1]

Time [sec]

0.0000 0.0002 0.0004 0.0006 0.0008 0.0010

-0.7675

-0.7670

-0.7665

-0.7660

-0.7655

-0.7650

-0.7645

-0.7640

Time [sec]

QD3 time variation

b2 [m

-2]

1 msec 1 msec

Just EXAMPLE … (NOT REALISTIC CASE !)

“BS” table “QM” table

FAST variation of the BS-strength (< 2 synchrotron periods / VRF=8kV)


CERN_PSB

0 200 400 600 800 1000 1200-50

-40

-30

-20

-10

0

Middle of chicane

Chi

cane

hei

ght [

mm

]

Number of Turns

PTC-ORBIT: modulation ON (by using “BS” table) RF cavity ON Single particle tracking

1 msec

0 200 400 600 800 1000 1200-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0 OUTSIDE of Chicane

X p

ositi

on o

utsi

de th

e ch

ican

e [c

m]

Number of Turns

Initial particle coordinates: matched to the chicane height at the beginning of the chicane’s decay

X [mm]

X(t)

s

FAST variation of the BS-strength (< 2 synchrotron periods / VRF=8kV)


CERN_PSB

-0.0010 -0.0005 0.0000 0.0005 0.0010-0.0010

-0.0005

0.0000

0.0005

0.0010 NO {BS-KS} CHICANE

dE [G

eV]

Phase [deg]

-0.15 -0.10 -0.05 0.00 0.05 0.10 0.15

0.00000

0.00005

0.00010

0.00015

0.00020

YES {BS-KS} CHICANE

dE [G

eV]

Phase [deg]-1000 0 1000 2000 3000 4000 5000 6000 7000 8000

-81.8

-81.6

-81.4

-81.2

-81.0

-80.8 YES {BS-KS} CHICANE

X [m

m]

Number of Turns

REALISTIC CASE !

LONG (~ 10 synchrotron periods)variation of the CHICANE strengthwithout adjustment the RF system

‘Matched’ (to COD) initial single particle


-1000 0 1000 2000 3000 4000 5000 6000 7000 8000

-80

-60

-40

-20

0

20

X [m

m]

Number of Turns

{BS-KS} CHICANE modulation

-0.04 -0.02 0.00 0.02 0.04-0.00010

-0.00005

0.00000

0.00005

0.00010

dE [G

eV]

Phase [deg]

{BS-KS} CHICANE modulation

CERN_PSB REALISTIC CASE !

#1 Kicker magnets variation keeping maximum strength of bump magnets#2 Bump magnets variation from maximum to zero (during ~ 5 msec)

#1

#2


PTC-ORBIT: modulation ON (by using “KS&BS” tables) RF cavity ON ( without adjustment )


CERN_PSB

READY FOR REAL ACTION !!!


CERN_PS

Longitudinal single particle motion Chicane (time variation)


CERN_PS

What should be done in addition?

Independently from PTC-ORBIT …

o MADX matching with the machine realistic latticeo clean lattice to avoid the ‘zero’ length elementso ….


CERN-PS: longitudinal / RF cavity ON

COD outside of the chicane

PTC-GINO interface

‘Single harmonic’ RF cavity


CERN_PS: longitudinal / RF cavity ON

-0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-0.0020

-0.0015

-0.0010

-0.0005

0.0000

0.0005

0.0010

0.0015

0.0020 PTC-ORBIT

p/p

PHASE [rad]

PTC-ORBIT Single particle tracking


CERN_PS Exact model: TRUE or FALSE ?

… checking the linear chromaticity

Exact=TRUE Exact=FALSE

Qx= 6.1294

Qy = 6.2966

Qx/ * -5.2353 -6.43

Qy/ * -6.9503 -7.29

* … ‘path_length’ instead of ‘time’

CONCLUSION:Exact=TRUE is neededfor the PS study

~ 22%

~ 5%


CERN_PS: Chicane variation(‘matched’ condition)

0 100 200 300 400 500 600 700-5

0

5

10

15

20

25

30

35

40

Chi

cane

Hei

ght n

ear B

S2

[mm

] ("

node

_104

5")

Number of Turns


0.0000 0.0002 0.0004 0.0006 0.0008 0.0010

0.000

0.005

0.010

0.015

0.020 BS_40

b1 [m

-1]

Time [sec]

Time table for BS_40

TREV ~ 2.3 sec

1msec

PTC-ORBIT: modulation ON RF cavity ON

REALISTIC

X [mm]

X(t)

s


CERN_PS: Chicane variation

0 100 200 300 400 500 600 70010

12

14

16

18

20

22

24

26 MAX Chicane END_Modulation

Bet

a_Y

[m]

Ring Position [m]

TWISS analysis

MAX Chicane: fractional tunes (x) 0.129409999999942 (y) 0.296639999999998

END of modulation: fractional tunes (x) 0.129487939990263 (y) 0.293684605278531



CERN_PS: Chicane variation(6D : ‘matched’ condition)

0.0000 0.0002 0.0004 0.0006 0.0008 0.0010

0.000

0.005

0.010

0.015

0.020 BS_40

b1 [m

-1]

Time [sec]

Multi particle tracking

REALISTICTime table for BS_40

0 100 200 300 400 500 600 700-5

0

5

10

15

20

25

30

35

40 pos_#1045

Bea

m c

entro

id o

bser

vatio

n [m

m]

Number of TurnsTREV ~ 2.3 sec

1msec



CERN PS



Basic staff without any time-dependent magnets …

CERN SPS


CERN SPS

MADX-PTC


CERN SPS



Important step: DEVELOP (or USE) the realistic machine model,

based on the existing experience of the machine operation …

Comprehensive analysis of the lattice resonances, obtained from the machine modeling …

compare with the real machine operation for the‘zero’ beam intenisty

extensive study of the combined effects of the machine resonances and the coherent effects (like the low energy space charge …)


Thanks for your attention …


ptc-orbit code for cern machines (psb, ps, sps) alexander molodozhentsev (kek) etienne forest (kek)...

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