N. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006 Introduction 1. Electrostatic simulations with...

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


PETRA3PETRA3

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


BPMs for PETRA3BPMs for PETRA3

235 BPMs (buttons) for various chamber sections


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


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 %)


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

chamber: 30 x 120

distance between buttons = 24 mmdistance between buttons = 24 mm


BPM for Damping Wiggler: Coupling

BPM for Damping Wiggler: Coupling

coupling 10%


BPM for Damping Wiggler: Monitor Constant

BPM for Damping Wiggler: Monitor Constant

H

V


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


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


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%


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%!


Coupling between ButtonsMicrowave Studio: S-parameters

Coupling between ButtonsMicrowave Studio: S-parameters

(normalized to 50 Ohm)

good agreement to measurements


Coupling between ButtonsMicrowave Studio: Time Domain

Coupling between ButtonsMicrowave Studio: Time Domain

port 1port 3

port 2port 4

electric(or magnetic)boundaries

source


Coupling between ButtonsTime Domain – Results

Coupling between ButtonsTime Domain – Results


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


Coupling between Buttons “Beam” Simulation - Results

Coupling between Buttons “Beam” Simulation - Results


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


Current / Voltage




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

Effect of other buttons


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


Preliminary: BPM for Straight Section: Monitor Constant

Preliminary: BPM for Straight Section: Monitor Constant

Without error With 5 deg error 10% error


Preliminary: BPM for Straight SectionsFields without/with angle error

Preliminary: BPM for Straight SectionsFields without/with angle error

5deg angle error

N. Baboi, DESY BPM Workshop, Lüneburg, Nov. 30, 2006 Introduction 1. Electrostatic simulations with...

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