LOLA setup

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LOLA setup mulated LOLA measurement*: no transverse beam dimen imaging: entrance-LOLA to OTR mulated LOLA measurement*: gaussian transverse shap about coupler kick (=CK) measurements 16 th June 2010, see s2e-meeting in Oct. imulated LOLA measurement*: no emittance but CK Simulated LOLA Measurements mulated LOLA measurement*: gaussian transv. + CK simulated LOLA measurement*: CSR + CK ut reconstruction method of filamentary phase space summary

description

Simulated LOLA Measurements. LOLA setup. imaging: entrance-LOLA to OTR. about reconstruction method of filamentary phase space. simulated LOLA measurement * : no transverse beam dimensions. simulated LOLA measurement * : gaussian transverse shape. about coupler kick (=CK). - PowerPoint PPT Presentation

Transcript of LOLA setup

Page 1: LOLA setup

LOLA setup

simulated LOLA measurement*: no transverse beam dimensions

imaging: entrance-LOLA to OTR

simulated LOLA measurement*: gaussian transverse shape

about coupler kick (=CK)

* measurements 16th June 2010, see s2e-meeting in Oct.

simulated LOLA measurement*: no emittance but CK

Simulated LOLA Measurements

simulated LOLA measurement*: gaussian transv. + CK

simulated LOLA measurement*: CSR + CK

about reconstruction method of filamentary phase space

summary

Page 2: LOLA setup
Page 3: LOLA setup

LOLA setup

LOLA L = 3.826 m; 2.856 GHzDrift L = 2.693 mBend L = 0.447 m; 5 degDrift L = 0.131 mBend L = 0.447 m; 5 degDrift L = 4.481 mOTR 17.5 µm / pixel

Page 4: LOLA setup

LOLA setup

field expansion in LOLA close to axis(for symmetry PEC in xz-plane and PMC in yz-plane)

tj

yzEzE

yz

y exp0

Re

,

0,tr,E

tj

xzB

zB

xz

x

exp0Re

,

0,

tr,B

with 0,0,, xyyz BjEE

2

0,0,0,

0,0,

0,,

,0,0,

, 0ReRe Oe

vByEBjvBEe

vByExvBvBE

xvBtj

yxyx

zxytj

yxyz

yxzzxy

yxz

BvE

we need the transverse field on axis: zBzE xy 0,0, ,

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LOLA setup

approach with

(Panofsky-Wenzel theorem)

zjkxy ezEcBE 0ˆ

0,0,

ck

0

and slowly compared to cell length zE

dzzEedzeeszEV sjkzcjszjk

yˆˆ 00

cvz

0yv

dzzEyecjV sjk

zˆ0

LOLA cavity, in reasonable approximation:

yeV

cK

MW MV 1.6 PVy

1

1

1

1

1

1

22

2

2

2

2

2

16200010000010000210000000000001

syyxx

LKKLK

KKLL

L

syyxx

with

Page 6: LOLA setup

energy calibration; theoretically:

streak calibration; theoretically:

MWGeV23.17

pixelfsec PS

510007.2pixel

d

imaging: entrance-LOLA to OTR

LOLA L = 3.826 m; 2.856 GHzDrift L = 2.693 mBend L = 0.447 m; 5 degDrift L = 0.131 mBend L = 0.447 m; 5 degDrift L = 4.481 mOTR 17.5 µm / pixelfull imaging function entrance-LOLA to OTR

Page 7: LOLA setup

imaging: entrance-LOLA to OTR

LOLA L = 3.826 m; 2.856 GHzDrift L = 2.693 mBend L = 0.447 m; 5 degDrift L = 0.131 mBend L = 0.447 m; 5 degDrift L = 4.481 mOTR 17.5 µm / pixel

streak (Vy) with positive sign:

MeV 700

MV 30

yVexample:

streak with negative sign, “time” axis flipped:

“energy” axis“time” axis

desired effect

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imaging of long phase space to “time” & “energy” is not changed by sign of streaksignificant “time” “energy” crosstalk for large streakno crosstalk horizontal phase space to “time”crosstalk horizontal to “energy” does not change with sigh of streakcrosstalk vertical to “time” & “energy” flips with sigh of streaksymmetric vertical phase space LOLA picture does not change with sign of streak

imaging: entrance-LOLA to OTR

streak (Vy) with positive sign:

MeV 700

MV 30

yVexample:

streak with negative sign, “time” axis flipped:

“energy” axis“time” axis

desired effect

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about reconstruction of filamentary phase space

based on the assumption of an filamentary phase space, a reconstructionmethod from two measurements with different sign of streak is proposed:

none of the errors, mentioned on the last transparency, is correctedby this method!

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real LOLA measurement

streak with both signs:

weak difference!symmetric vertical phase space?

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simulated LOLA measurement: no transverse beam dimensions

black = long. phase spaceblue = LOLA simulation

all pictures: full OTR screen in pixels

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(PLOLA=25MW)simulated LOLA measurement: no transverse beam dimensions

black = long. phase spaceblue = LOLA simulation

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simulated LOLA measurement: gaussian transverse shape

μm 0 yx

μm 1 yx

μm 1x

μm 1y

μm 0μm 1

y

x

μm 1μm 0

y

x

(design optics, emittance = 1um)

black = long. phase spacecolor = LOLA simulation

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simulated LOLA measurement: gaussian transverse shape

so far no difference for vz=+-1

μm 1x

μm 1y

μm 1μm 0

y

x

μm 0 yx μm 0μm 1

y

x

μm 1 yx

black = long. phase spacecolor = LOLA simulation

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about coupler kick

horizontal & vertical parameters vs. length at BC2 entrance(TW mode, ACC1 145 MV, 4.7 deg, ACC39 20MV, -144.7 deg)

coupler kicks with numbers as on the next page

Page 16: LOLA setup

about coupler kick

numbers:

TESLA cavity in pure traveling wave operation (my old MAFIA calculation before 2005, Qe=2.5E6)3rd harmonic cavity in pure SW operation (fields from E. Gjonaj)

TESLA Cavityupstream = (54.8+13.0i)10-6

(22.4+14.1i)10-6

downstream = (26.8+19.0i)10-6

( 41.1+ 6.0i)10-6

Page 17: LOLA setup

about coupler kick

TESLA Cavityupstream = (54.8+13.0i)10-6

(22.4+14.1i)10-6

downstream = (26.8+19.0i)10-6

( 41.1+ 6.0i)10-6

numbers:

other numbers: (s2e-meeting Mai 2007)

upstream = (57.1+ 6.6i)10-6

(41.43.5i)10-6

z_pen = 6 mm, forward backwarddownstream = (25.0+51.5i)10-6 (52.3 8.1i)10-6

( 32.2+ 5.2i)10-6 ( 32.4+ 5.8i)10-6

z_pen = 8 mm, forwarddownstream = ( 0.5+53.7i)10-6 (39.233.6i)10-6

( 32.4+ 5.1i)10-6 ( 33.0+ 5.6i)10-6

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upstream(57.8+ 7.0i)10-6

(25.151.4i)10-6

downstream(41.03.5i)10-6

( 36.5+ 5.4i)10-6

TESLA Cavityupstream = (54.8+13.0i)10-6

(22.4+14.1i)10-6

downstream = (26.8+19.0i)10-6

( 41.1+ 6.0i)10-6

upstream(57+ 7i)10-6

(23+52i)10-6

downstream(42 3i)10-6

( 30+ 5i)10-6

upstream(68.8+ 3.7i)10-6

(48.3 3.4i)10-6

downstream(36.5+66.1i)10-6

( 41.0+14.5i)10-6

numbers:

more other numbers:

but the geometry is probably different

about coupler kick

Page 19: LOLA setup

about coupler kick

used for the following: (TW mode, ACC1 145 MV, 4.7 deg, ACC39 20MV, -144.7 deg)

ACC13

ACC39

time dependent part: same order of magnitude!

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simulated LOLA measurement: no emittance but coupler kick

design optics

only CK before BC2 is considered here

it depends on cavity phases & amplitudes and on TW/SW modus

for short bunches CK of cavities after BC2 negligible, butprobably not for on-crest measurement (needed to determinethe uncompressed bunch length)

with self effects: perturbation approach

Page 21: LOLA setup

simulated LOLA measurement: no emittance but coupler kick

absolut only time dependent part of CKtransverse due to CK

different

black = long. phase spaceblue = LOLA simulation

phi = 7.5 deg

Page 22: LOLA setup

simulated LOLA measurement, no emittance but coupler kickonly time dependent part of CK

transverse due to CK hor.+vert. CK vert. CKhor. CK

black = long. phase spaceblue = LOLA simulation

phi = 7.5 deg

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simulated LOLA measurement, no emittance but coupler kickonly time dependent part of CK

transverse due to CK hor.+vert. CK vert. CKhor. CK

black = long. phase spaceblue = LOLA simulation

phi = 8.0 deg

Page 24: LOLA setup

simulated LOLA measurement, gaussian transverse + CK

black = long. phase spacecolor = LOLA simulation

phi = 7.5 deg phi = 8.0 deg

starts from design optics (emittance=1um)

transverse transverse

Page 25: LOLA setup

simulated LOLA measurement, CSR-transverse + CKhorizontal CSR; starts from design optics (emittance=1um)

black = long. phase spacecolor = LOLA simulation

phi = 7.5 deg phi = 8.0 deg

transverse transverse

Page 26: LOLA setup

simulated LOLA measurement, CSR-transverse + CK

BUT long bunch, low compressionphi = 5.0 deg

transverse

this difference has not been observed

black = long. phase spacecolor = LOLA simulation

Page 27: LOLA setup

log-book:

index = 10

density profile density profile

slice energy slice energy

single measurement 20 measurements averaged

slope 1 slope 2 (z-flipped)z

E

z/c

E/E

real LOLA measurement phi = 5.0 deg

small difference!???: vertical distribution nearly symmetric

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no vert. CK

simulated LOLA measurement, CSR-transverse + horizontal CKhorizontal CSR; starts from design optics (emittance=1um)

phi = 5.0 deg phi = 8.0 deg

transverse transverse

no vert. CK

same picture for both streaks, no error in time measurement

Page 29: LOLA setup

right direction, but not enough

“time” measurement:only crosstalk from vertical phase space

CK still unknown; horizontal part depends on cavity operation

vertical CK perhaps overestimated

summary

“energy” measurement:significant crosstalk from “time” meas. for strong streakcrosstalk from hor. & vert. phase-spacevert. phase space: sign flips with streak

CK affects LOLA measurementhorizontal “energy” measurementvertical “energy” and “time”

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Simulated LOLA measurement, CSR-transverse + CKhorizontal CSR; starts from design optics (emittance=1um)

black = long. phase spacecolor = LOLA simulation

phi = 7.5 deg phi = 8.0 deg