Injection path for MR &particle losses at MR_SCR

Alexander MolodozhenstevKEK

MR commissioning groupJanuary 17, 2006

Schematic layout of Injection Path for MR

Circulating beam

Beam from RCS

QDXQFPQDTQFR

BP

1

BP

2

BP

3

Mag

net

Sep

tum

Kic

ker

ma

gn

ets

Scheme of the INJECTION path (April, 2005) … SAD data

70 75 80 85 90 95-0.025

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

COD during INJECTION

Circulating Beam

QFR QDT QFP

BP#3 BP#2 BP#1

OPMS: 3-2-1

INJECTION:Bumps & OPMS

x [m

]

z [m]

Time pattern (h=9) 1st batch

~ 1 msec~ 200 turns

2nd batch 3rd batch 4th batch

40 msec~ 7’435 turns

OPMS

BP

Opposite Field Magnet Septum – PULSE (sinusoidal)Bump Magnets – like DC

~850nsec

~ 120 msec

Parameters of the INJECTION beam-line (SAD data)

Elements Strength (k0L)

[rad]

Effective Length

[m]

BP1 0.0024269618 0.20

BP2 -0.0063929115 0.50

BP3 0.0020820796 0.20

OPMS5 -0.01649460 0.35

OPMS4 0.03298920 0.70

OPMS3 -0.01649460 0.35

Elements representation (for MAD & ORBIT)

Elements Eff.Length [m] Theta [rad] E1 [rad] E2 [rad]

BP1 0.20 0.00242269 0.0 0.0024

BP2 0.50 -0.0063929 -0.0023 -0.0041

BP3 0.20 0.00208207 0.0021 0.0

OPMS5 0.35 -0.0164946 -0.0023 -0.0142

OPMS4 0.70 0.03298920 0.0142 0.0187

OPMS3 0.35 -0.0164946 -0.0187 0.0023

QFP 1.76 … as quadrupole

QFR 0.86 … as quadrupole

QDT 1.86 … as COMBINED function BM plus Edge Focusing:

xCOD ~ 0.02m, e1=-0.002, e2=+0.002

* Edge focusing effect will lead to the vertical beta-beating

INJECTION_Path_MR Lattice parameters

Qx = 22.4279 (22.4281)Qy = 20.8227 (20.8199)x,max = 40.715m (40.812m)y,max = 33.922m (33.257m)Dx,max = 3.072m (3.057m)

With OMS

ORIGINAL

Without OMS

Qx = 22.4281Qy = 20.8195x,max = 40.818my,max = 33.197mDx,max = 3.057m

D:\Alex\Work\2005\MR\MAD\mad050509I_for_ORBIT_YES_Inj_Bump\Teapot_ORBIT_Tracker\22428_20819\Yes_CCSX\Test#3_COD\Check_Dec05\DR_Short\INJD_short.mad

Vertical -beating ~ 2…3 % (without quadrupole components of OMS)

Simulation approach #1

#1 … Lattice with BP & OMS (rectangular pulse) & CFQDT:: 200 turns#2 … Lattice with BP & --- & CFQDT :: 7’235 turns

Simulation approach #2

• RCS 0.6MW beam (v050906/Transverse:: 95254mp)• RCS_MR Beamline Collimator :: 54 mm.mrad (90935mp)• Matched beam at MR_SCR position for Qx=22.428, Qy=20.82 including injection

dogleg• Sextupole magnets for chromaticity correction are ON

• Uniform Longitudinal distribution: = ± 60 degree (Bf = 0.3), p/p = ± 0.002• MR scraper acceptance = 70 mm.mrad• RF:: h=9; VRF= 140 / 91 kV• Beampipe:: Rectangular shape / size(X,Y) = ± 70 mm• NFFT: 100×100 / Nbin: 512 / z < 1.5m

• INJECTION DOGLEG:: Bump Magnets (1,2,3) + Opposite Field Magnet Septums (1,2,3) + Combined Function QDT

• Different conditions for Bump Magnets and Opposite Field Magnet Septums…(#1: DC for ALL; #2: DC for Bumps and PUSLE for Opposite MS; #3: only DC Bumps)

• Overall number of turns = 2’000.

NO Injection Dogleg

MRSCR=70 mm.mrad

99% emittance LOST particles

V

H

Case 1: DC for ALL elements of INJECTION dogleg

V

H

99% emittance LOST particles

2000 turns BP & OMS & CFQDT …

Case 2: DC for Bump-magnets and PULSE for OMS of INJECTION dogleg

V

H

99% emittance LOST particles

200 turns BP & OMS & CFQDTplus 1800 turns BP & CFQDT …

Footprint for case #2

4Qx

= 9

0

4Qy = 83

4Qx=

89

2Q x–2Q y

=3

3Qx=

67

Qx+2Q

y=64

-Qx+2Q y

=19

Only Space-Charge resonancesand Normal Sextupole resonancesare indicated

Qx

Qy

Red – Space Charge resonancesBlue – Normal Sextupole resonances

after 2000turns

Case 1_2: DC for ALL elements of INJECTION dogleg

NO CC_Sextupoles, dp=0

99% emittance LOST particles

2000 turns BP & OMS & CFQDT …

NO_CCSX:: dp/p = 0 NO influence of Normal Sextupole Resonances

99% Emittance behavior during the injection process (MR_SCR70)

V

H

Particle losses at MR_SCR70 during injection process

1.63%

0.92%

0.35%

0.10 %

120msec40msec 80msec

1st batch

2nd batch

3rd batch

4th batch

Budget of MR particle lossesSingle bunch power of the case of 0.6MW beam from RCS (h=9, 8 bunches) is 3.56kW.

Power of the lost beam at the injection energy for each batch …

1 batch 2 batch 3 batch 4 batch

~ 116 W ~ 66 W ~ 25 W ~ 7.2 W

Total power of the lost beam at the injection energy for 8 bunches ~ 214 W (120msec injection time) … < 450W !!!

Injection time:: 120 msec

RCS_Beam (TR::v050906, LD::Uniform)MR_SCR_Acceptance = 70 π mm.mrad (CLM54 in RCS_MR_BeamLine)

… continue

(1) Introduction of realistic field-error of the MR magnets

(2) Introduction of misalignment of MR magnets (excitation of skew-resonances)