N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

•Introduction•1. Electrostatic simulations with MAFIA

BPM for damping wiggler BPM for “standard” vacuum chamber

•2. Simulations with Microwave Studio (MWS) Coupling between BPM-buttons

EM Simulations for PETRA3

EM Simulations for PETRA3

N. Baboi, DESY, Hamburg

BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

PETRA3PETRA3

Energy: 6 GeV Emittance: 1nm rad Current: 100 mA Bunches: 40 / 960

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

BPMs for PETRA3BPMs for PETRA3

235 BPMs (buttons) for various chamber sections

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Monitor Constant 1/KMonitor Constant 1/K

DLDRULUR

DLULDRUR

LR

LRH

)()(

DLDRULUR

DLDRULUR

DU

DUV

)()(

UR

DR

UL

DL

HHKx VVKy

)0,0(1

yxxK H

H

)0,0(1

yxyK V

V

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

1. Electrostatic Simulations (MAFIA)1. Electrostatic Simulations (MAFIA)

• Electrostatic calculation 1 V at one button calculate field distribution monitor constant K

• through reflections field for all 4 buttons• combine these fields H and V KH and KV

coupling factor between beam and BPM-pickups • = voltage at middle of BPM for 1 V at one button (in %)

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

1a. BPM for Damping Wiggler1a. BPM for Damping Wiggler

chamber: 30 x 120

distance between buttons = 24 mmdistance between buttons = 24 mm

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

BPM for Damping Wiggler: Coupling

BPM for Damping Wiggler: Coupling

coupling 10%

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

BPM for Damping Wiggler: Monitor Constant

BPM for Damping Wiggler: Monitor Constant

H

V

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

BPM for Damping Wiggler: Monitor Constant (2)

BPM for Damping Wiggler: Monitor Constant (2)

Buttondistance

1/Kx [mm-1]

1/Ky

[mm-1]Coupling

[%]

20 0.074 0.070 12

24 0.083 0.061 10

31 0.093 0.045 7

1/KH = 0.08 mm-1

1/KV = 0.06 mm-1

For 1 mm resolution need 8·10-5 resolution in V

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

1b. “Standard” Chamber1b. “Standard” Chamber

R. Wanzenberg

1/KH = 0.059 mm-1

for = 55 deg

1/KV = 0.056 mm-1

for = 55 deg

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

2. Coupling between Buttons: UR – UL MAFIA-S: Electrostatic Simulation

2. Coupling between Buttons: UR – UL MAFIA-S: Electrostatic Simulation

buttondefined as vacuum

~0.9e-4V

coupling to beam: 23%coupling to button ≈ 0.009%

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between Buttons: UR – DR MAFIA-S: Electrostatic Simulation

Coupling between Buttons: UR – DR MAFIA-S: Electrostatic Simulation

buttondefined as vacuum

~0.12V

coupling to button ≈ 10%BUT measurement (Neumann): -45dB -> 0.6%!

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between ButtonsMicrowave Studio: S-parameters

Coupling between ButtonsMicrowave Studio: S-parameters

(normalized to 50 Ohm)

good agreement to measurements

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between ButtonsMicrowave Studio: Time Domain

Coupling between ButtonsMicrowave Studio: Time Domain

port 1port 3

port 2port 4

electric(or magnetic)boundaries

source

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between ButtonsTime Domain – Results

Coupling between ButtonsTime Domain – Results

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

1-4: ports5: discrete port (source)

1-4: ports5: discrete port (source)

port 1

port 2

port 3

port 4

discreteport 5

(S-Param, 10kpractically I-source)

electric boundaries

Coupling between Buttons“Beam” Simulation

Coupling between Buttons“Beam” Simulation

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between Buttons “Beam” Simulation - Results

Coupling between Buttons “Beam” Simulation - Results

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between Buttons “Beam” Simulation - Results (2)

Coupling between Buttons “Beam” Simulation - Results (2)

Current / Voltage

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Coupling between Buttons “Beam” Simulation - Results (3)

Coupling between Buttons “Beam” Simulation - Results (3)

worst case: other buttons are short-circuited => no difference!

Effect of other buttons

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

3. Error Analysis: BPM for Straight Section

3. Error Analysis: BPM for Straight Section

chamber: 94 x 9415 mm buttons (Meggitt)

5deg error in UR and DL pickups

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Preliminary: BPM for Straight Section: Monitor Constant

Preliminary: BPM for Straight Section: Monitor Constant

Without error With 5 deg error 10% error

N. Baboi, DESYN. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006BPM Workshop, Lüneburg, Nov. 30, 2006

Preliminary: BPM for Straight SectionsFields without/with angle error

Preliminary: BPM for Straight SectionsFields without/with angle error

5deg angle error