Emittance Measurements and Related Experimental Results 15th ATF2 Project Meeting, January 24 2013M....

M. Woodley

Emittance Measurements and Related Experimental Results

15th ATF2 Project Meeting, January 24 2013 1/44

M. Woodley15th ATF2 Project Meeting, January 24 2013 2/44

Outline• emittance measurements

– charge dependence– coupling correction

• kicker issues• BS3X issues• vertical dispersion correction with correctors• beta matching in EXT upstream of OTRs

– in inflector– in coupling correction section

• other issues• Summary, Continuing Work, Mitigation


Emittance MeasurementIssues:• do we believe the OTR measurements?• how stable/reproducible are the measurement results?• what about charge and bunch length correlations?


QF

9X

QK

1X

Q

D10

X

QF

11X

QK

2X

Q

D12

X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

QF

17X

QK

4X

QD

18X

QF

19X

QD

20X

QF

21X

EXT Diagnostics Section

165 170 175 180 185 1900

5

10

15

20

25

30

35

40

Ver

tical

Bea

m S

ize

(um

)

S (m)

OTR Vertical Emittance MeasurementDecember 14, 2011 07:44

Wire Scanner Measured Vertical Beam SizesDecember 14, 2011 09:30(MW1X σy value ignored)

black circles = WSblue circles = OTR


0 2 4 6 8 10 12 14 16 18 200.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65ICT = 0.4446 +- 0.0051

ICT

Meas #

November 6, 2012

0 1 2 3 4 5 6 7 8 9 10 1120

21

22

23

24

25

26

27

28

29EmitY = 25.4122 +- 0.2439 pm

Em

itY (

pm)

Meas #0 1 2 3 4 5 6 7 8 9 10 11

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65ICT = 0.4967 +- 0.0082

ICT

Meas #

November 29, 2012

(e10

)(e

10)


0 1 2 3 4 5 6 7 8 9 10 1123

23.5

24

24.5

25

25.5

26

26.5

27

ICT

Cor

rect

ed E

mitY

(pm

)

Meas #

EmitY = 25.2738 +- 0.1437 pm @ ICT = 0.45 (chisq=1)

0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.6520

21

22

23

24

25

26

27

28

29

30EmitY vs ICT

ICT (e10)

Em

itY (

pm)

p0= 16.4+- 1.261

p1= 19.73+- 2.707

RMS= 0.42 pm

NDF= 8 chisq/N = 0.391

rho = 1.001

EmitY = 16.4 ± 1.3 pm @ ICT = 0ΔEmitY/ΔICT ≈ 2 pm/109

November 29, 2012

0.35 0.4 0.45 0.5 0.5514

16

18

20

22

24

26

28

30EmitY vs ICT

ICT (e10)

Em

itY (

pm)

November 6, 2012

EmitY = 13.3 ± 3.5 pm @ ICT = 0ΔEmitY/ΔICT ≈ 3 pm/109

0 1 2 3 4 5 6 7 8 9 10 115

10

15

20

25

30EmitY = 26.9659 +- 0.5466 pm @ ICT = 0.45 (chisq=1)

ICT

Cor

rect

ed E

mitY

(pm

)

Meas #

~ 30 minutes


6.25

9.76

14.06

3.51

σy (μm)

ICT (1010)

εy (pm)

βy = 2.56 m

DR XSR σy vs ICT

“by eye”linear fit:

0.07 pm / 109

in EXT:2 pm / 109

November 6, 2012


ICT = 5x109

DR RF = 0.29 MV

εx = 1.87 nmBx = 1.05εBx = 1.96 nm

εy = 30.1 pmBy = 1.01εBy = 30.4 pm

ICT = 5x109

DR RF = 0.20 MV

εx = 1.77 nmBx = 1.08εBx = 1.93 nm

εy = 28.8 pmBy = 1.00εBy = 28.9 pm

Emittance vs Bunch Length (December 21 2012 owl)


Coupling CorrectionIssues:• do we believe the OTR beam tilt measurements?• do measured beam tilts respond to coupling correction?


250 300 350 400 450 500 550 600 650 700250

300

350

400

450

500

550

600

650

700

750OTR2X X VS ZH9X Expected Pos

ZH9X Expected Pos /um

OT

R2X

X /

um

p0= 8.922+- 8.079p1= 0.9918+-0.01692

RMS= 7.75 umNDF= 9

chisq/N = 1.081rho = 1.010

OTR2X beam tilt … is it real? Check measured response to ZH9X

X

Y

OTR0X before corrections OTR0X after dispersion correction OTR0X after coupling correction


Extraction KickerIssues:• multipole fields (quadrupole/sextupole): are they real?• what’s the correct voltage?• is the kicker rolled?• what’s inside? (field linearizer? metal or plastic electrode

restraint?)


Field Simulation (May 26, 2005)C. Pappas, SLAC

1 2 3 4

0.75" Ф0.827" Ф

0.5"0.75" 1.3"1.0"

0.0625"

0.591" Ф

electrodeceramicchamber

scale: 1.14" (figure) ≈ 0.75" (actual)

±25σx

ceramic chamber

DIMAD SBEND parameters:

L = 0.4 m ANGLE = 5.0e-3 rad K1 = -1.846929e-1 m-2

K2 = -3.824591e+1 m-3

M. Woodley

0 10 20 30 40 50 60-5

-4

-3

-2

-1

0

1

2

3

4

5

X

(m

m)

S (m)

KE

X1

QM

6RQ

M7R

BS

1XB

S2X

BS

3X

BH

1X

BH

2X

BH

3X

KE

X2

QS

1X

Q

F1X

QD

2X

Q

F3X

QF

4X

Q

D5X

QF

6X

Q

S2X

QF

7X

QD

8X

QF

9X

QK

1X

Q

D10

X

Q

F11

X

Q

K2X

QD

12X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

Q

F17

X

Q

K4X

QD

18X

QF

19X

QD

20X

QF

21X

QM

16F

F

Q

M15

FF

QM

14F

F

Q

M13

FF

QM

12F

F

Q

M11

FF

QD

10B

FF

Q

D10

AF

F

QF

9BF

F

Q

F9A

FF

QD

8FF

QF

7FF

SF

6FF

0 10 20 30 40 50 60-5

-4

-3

-2

-1

0

1

2

3

4

5

Y

(m

m)

S (m)

KE

X1

QM

6RQ

M7R

BS

1XB

S2X

BS

3X

BH

1X

BH

2X

BH

3X

KE

X2

QS

1X

Q

F1X

QD

2X

Q

F3X

QF

4X

Q

D5X

QF

6X

Q

S2X

QF

7X

QD

8X

QF

9X

QK

1X

Q

D10

X

Q

F11

X

Q

K2X

QD

12X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

Q

F17

X

Q

K4X

QD

18X

QF

19X

QD

20X

QF

21X

QM

16F

F

Q

M15

FF

QM

14F

F

Q

M13

FF

QM

12F

F

Q

M11

FF

QD

10B

FF

Q

D10

AF

F

QF

9BF

F

Q

F9A

FF

QD

8FF

QF

7FF

SF

6FF

what we expected to see (no kicker multipoles) …

bad BPMs

… what we observed


Orbit Bump Study (February 2010): bump vertically through KEX2

bad BPMs

M. Woodley

what we expected to see (with predicted kicker multipoles) …

… what we observed

0 10 20 30 40 50 60-5

-4

-3

-2

-1

0

1

2

3

4

5

Y

(m

m)

S (m)

KE

X1

QM

6RQ

M7R

BS

1XB

S2X

BS

3X

BH

1X

BH

2X

BH

3X

KE

X2

QS

1X

Q

F1X

QD

2X

Q

F3X

QF

4X

Q

D5X

QF

6X

Q

S2X

QF

7X

QD

8X

QF

9X

QK

1X

Q

D10

X

Q

F11

X

Q

K2X

QD

12X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

Q

F17

X

Q

K4X

QD

18X

QF

19X

QD

20X

QF

21X

QM

16F

F

Q

M15

FF

QM

14F

F

Q

M13

FF

QM

12F

F

Q

M11

FF

QD

10B

FF

Q

D10

AF

F

QF

9BF

F

Q

F9A

FF

QD

8FF

QF

7FF

SF

6FF

0 10 20 30 40 50 60-4

-3

-2

-1

0

1

2

3

4

X

(m

m)

S (m)

KE

X1

QM

6RQ

M7R

BS

1XB

S2X

BS

3X

BH

1X

BH

2X

BH

3X

KE

X2

QS

1X

Q

F1X

QD

2X

Q

F3X

QF

4X

Q

D5X

QF

6X

Q

S2X

QF

7X

QD

8X

QF

9X

QK

1X

Q

D10

X

Q

F11

X

Q

K2X

QD

12X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

Q

F17

X

Q

K4X

QD

18X

QF

19X

QD

20X

QF

21X

QM

16F

F

Q

M15

FF

QM

14F

F

Q

M13

FF

QM

12F

F

Q

M11

FF

QD

10B

FF

Q

D10

AF

F

QF

9BF

F

Q

F9A

FF

QD

8FF

QF

7FF

SF

6FF

bad BPMs


Orbit Bump Study (February 2010): bump vertically through KEX2

M. Woodley

set ZH3X/ZH4X/ZH5X X-bump; scan ZV5X/ZV6X/ZV7X Y-bump; find X-bump setting where Y-bump closes

at this point the quadrupole field seen by the beam in KEX2 has the value predicted by POISSON for the vacuum chamber center

we observed that BSM background increased at X-bump = -1.5 mm, so we set X-bump back to zero … KEX2 horizontally misaligned?

should scan X-bump and observe BSM background to locate center of KEX2 vacuum chamber (in X)

ΔX ΔY

ΔX = +3 mm

ΔX = +1 mm

ΔX = 0

ΔX = -1.5 mm



Δεy/εy0 (%) ≈ 60.4 × [ΔYkicker1 (mm)]2

Vertical emittance growth (ηy corrected)

12 pm -> 20 pm @ +- 1 mm


QK1X[K1]

QK2X[K1]

QK3X[K1]

QK4X[K1]

Simulation of vertical offset in KEX1

• coupling due to sextupole component blows up vertical emittance

• coupling corrected with QK skew quads (after vertical dispersion correction)

• pattern of QK strengths is not what we observe (QK1X is relatively weak)

• more in Edu Marin’s presentation …

-20 -10 0 10 200

50

100QK1X

-20 -10 0 10 200

50

100QK2X

-20 -10 0 10 200

20

40

60QK3X

I (A)-20 -10 0 10 200

20

40

60

80QK4X

I (A)

Nov/Dec 2012 QK*X SET-file values

simulations by Edu Marin

M. Woodley

-800 -700 -600 -500 -400 -300 -200 -100 00

50

100

150

200

250

300

350

400

450dX/dV = -0.5085 um/V

X BS

3X (

um)

KEX (V)

V

x

RcVcRx

1212

1,,

R12 = 4.7329 mm/mraddX/dV = -0.5085 mm/kV

dθ/dV = -0.1074 mrad/kVθ0 = -5 mrad V0 = 46.5 kV

(SLAC NDR KEX: 0.1158 mrad/kV)

Horizontal orbit position at BS3X center estimated by

back-propagation from EXT BPM measurements

(QF1X-QF4X) … courtesy of Yves Renier

8 μm

112 μm

215 μm

315 μm

415 μm

0 V

-200 V

-400 V

-600 V

-800 V

ΔX @ BS3X (from orbit fit) ΔVKEXΔX

ATF2 feedback

measurement: 2012/12/07 Owl Shift



EXT Orbit (Corrected) vs KEX VoltageDecember 13, 2012 Day Shift

40 45 501520

1540

1560

1580

1600

BS

1X (

A)

KEX (kV)40 45 50

2540

2560

2580

2600

BS

3X (

A)

KEX (kV)

40 45 50-1.5

-1

-0.5

0

0.5

ZV

1X (

A)

KEX (kV)40 45 50

-0.4

-0.2

0

0.2

0.4

ZV

2X (

A)

KEX (kV)

KEX1 steers vertically?inferred roll is ~100 mrad (!)

… or something else?


BS3X Skew Quadrupole (?)Issues:• origin of observed anomalous vertical dispersion in EXT/FF?

– measured vertical dispersion in DR at extraction point is small• we have had problems with BS3X in the past

– BS3X had to be physically rolled ~ -4 mrad (March 17, 2010)

M. Woodley

140 150 160 170 180 190 200 210 220 230

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

Modeledηy0 = -13.2 mmη′y0 = -14.2 mr

140 150 160 170 180 190 200 210 220 230

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

ModeledBS3X skew quad

KL = -0.03 m-1

IIDX = -5.8 A

12 pm 39 pm

Measured

Δμy(BS3XIP) = 101.8°


NOTE: ηx = 179 mm @ BS3X

M. Woodley

140 150 160 170 180 190 200 210 220 230-100

-50

0

50

100

DY

(m

m)

S (m)

Modeledηy0 = -13.2 mmη′y0 = -14.2 mr

140 150 160 170 180 190 200 210 220 230-100

-50

0

50

100

DY

(m

m)

S (m)


KL = -0.03 m-1

IIDX = -5.8 A

12 pm 39 pm

Measured

Δμy(BS3XIP) = 101.8°


zoom in …


Measured

IQS = -0.951 A

140 150 160 170 180 190 200 210 220 230-100

-50

0

50

100

DY

(m

m)

S (m)

IQS = -0.834 A


KL = -0.03 m-1

IIDX = -5.8 A

Measured

IQS = -0.474 A

140 150 160 170 180 190 200 210 220-200

-150

-100

-50

0

50

100

150

200

DY

(m

m)

S (m)

IQS = -0.500 A


KL = -0.03 m-1

IIDX = -5.8 A

either use QS Σ-knob to correct EXT (IP-phase) …

… or use QS Σ-knob to correct FF (FD-phase)


BS3X Skew Sextupole (?)Issues:• anomalous vertical dispersion amplitude depends on extraction

kicker voltage• X position dependent skew quadrupole field skew sextupole

M. Woodley

ΔKEX = -200 V

140 150 160 170 180 190 200 210 220-800

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

KLBS3Xskew = -0.03215 m-1

Measured Modeled

ΔKEX = 0 (KEX = 50000 V)

140 150 160 170 180 190 200 210 220-800

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

KLBS3Xskew = -0.03517 m-1

Measured Modeled


M. Woodley

ΔKEX = -400 V KLBS3Xskew = -0.03094 m-1

140 150 160 170 180 190 200 210 220-800

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

Measured Modeled


140 150 160 170 180 190 200 210 220-800

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

Measured Modeled


M. Woodley


140 150 160 170 180 190 200 210 220-800

-600

-400

-200

0

200

400

600

DY

(m

m)

S (m)

Measured Modeled


-800 -700 -600 -500 -400 -300 -200 -100 0-0.036

-0.034

-0.032

-0.03

-0.028

-0.026

-0.024BS3Xskew VS dKEX

dKEX /V

BS

3Xsk

ew /

1/m

p0=-0.03493+-0.0004444p1=-1.058e-05+-9.071e-07

RMS=0.000444 1/mNDF= 3

rho = -0.989

BS3Xskew = 0 @ KEX = 46.7 kV

KEX lower voltage0 50 100 150 200 250 300 350 400 450

-0.036

-0.034

-0.032

-0.03

-0.028

-0.026

-0.024BS3Xskew VS BS3X X

BS3X X /um

BS

3Xsk

ew /

1/m

p0=-0.03513+-0.0004623p1=2.081e-05+-1.799e-06

RMS=0.000448 1/mNDF= 3

rho = 0.989

BS3Xskew = 0 @ BS3X X = +1.7 mm

toward DR (to the left)

M. Woodley

Set EXT Kicker Voltage to 46 kV

45.5 45.6 45.7 45.8 45.9 46 46.1 46.2 46.3 46.4 46.5350

400

450

500

550

600

650

700

750V0 = 45.936 +- 0.038

|DY

| (um

)

EXT_DKICKER (kV)

QD10B (FB off)

QD4A (FB off)QD10B (FB on)

QD4A (FB on)

49.1 49.2 49.3 49.4 49.5 49.6 49.7 49.8 49.9 50 50.1350

400

450

500

550

600V0 = 46.519 +- 0.046 (kV)

|DY

| (um

)

EXT_DKICKER (kV)

QD10B (FB on)

QD4A (FB on)

Dec 7 (KEX @ 50 kV) Dec 12 (KEX @ 46 kV)



Vertical Dispersion CorrectionIssues:• can’t simultaneously correct vertical dispersion in EXT (at OTRs …

IP-phase) and in FF (FD-phase) using the QS Σ-knob• presence of KEX2 prevented use of vertical dipole correctors for

“other phase” vertical dispersion correction– emittance growth when off axis vertically in KEX2 (sextupole)– but … KEX2 is now gone (using BKX dipole instead)

• can now use both QS Σ-knob and vertical dipole correctors for vertical dispersion correction

M. Woodley

140 150 160 170 180 190 200 210 220-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

Orb

it (u

m)

S (m)

ZV3X: ΔI = +0.096 A

140 150 160 170 180 190 200 210 220-250

-200

-150

-100

-50

0

50

100

150

200

250

DY

(m

m)

S (m)

ZV3X: ΔI = +0.096 A

140 150 160 170 180 190 200 210 220-5000

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

Orb

it (u

m)

S (m)

ZV11X: ΔI = +0.049 A

140 150 160 170 180 190 200 210 220-250

-200

-150

-100

-50

0

50

100

150

200

250

DY

(m

m)

S (m)

ZV11X: ΔI = +0.049 A


Simulation

M. Woodley

Monday Day Shift, December 17, 2012

before correction after correction

QS*X : -1.050 A -0.113 A (ΔI = +0.937 A) … correct IP-phase ηy

ZV3X : +0.172 A +0.047 A (ΔI = -0.125 A) … correct FD-phase ηy

ZV11X : +0.201 A +0.229 A (ΔI = +0.028 A) … correct FF orbit



Beta MatchingIssues:• beta matching to FF using FF matching quads can’t be verified

easily (QMs are downstream of OTRs)• changing the matching quad strengths can be painful (steering, … )• matching in EXT inflector wasn’t possible given the constraints of

the double kicker system– but … KEX2 is now gone (using BKX dipole instead)– still need to hold dispersion fixed

• matching between inflector and OTRs means changing optics of coupling correction system– maybe not so bad given coupling correction algorithm (see

following presentation by Edu Marin … )


before β-match

εx = 1.37 nmBx = 2.26εBx = 3.11 nm

εy = 36.1 pmBy = 1.52 εBy = 55.1 pm

(set12dec11_1908)

after β-matchεx = 1.60 nmBx = 1.24εBx = 1.99 nm

εy = 40.6 pmBy = 1.05 εBy = 42.6 pm

QF9X : 36.027 32.936 ( -8.6%)QD10X : 56.860 66.116 ( +16.3%)QF11X : 46.638 35.836 ( -23.2%)QD12X : 46.230 48.314 ( +4.5%)

(set12dec11_2012)

Beta Matching (December 11 2012 swing)

M. Woodley

name match0 match1 match2 match3 design

file 054152 061717 080625 084346

EmitX 1.7894 1.8228 1.7587 1.5860

BmagX 1.1946 1.0013 1.0026 1.0076 1.0000

EmBmX 2.1376 1.8251 1.7633 1.5981

BetaX 4.7239 6.0386 6.4327 6.2257 6.3052

AlphaX -2.8890 -4.2795 -4.6550 -4.5596 -4.4943

EmitY 28.4846 25.7572 30.8175 28.2300

BmagY 1.2000 1.3489 1.0554 1.0034 1.0000

EmBmY 34.1808 34.7439 32.5253 28.3262

BetaY 9.1308 9.4923 7.1151 6.0766 6.1903

AlphaY 4.4037 4.8369 3.2854 2.6087 2.5763

QF1X 50.682 50.947 50.812 50.812 49.024

QD2X 42.865 43.035 43.312 43.312 42.865

QF3X 30.497 30.724 30.800 30.800 30.498

QF4X 30.863 30.710 30.636 30.636 30.864

QD5X 41.940 42.083 41.995 41.995 41.940

QF6X 52.983 52.753 52.692 52.692 51.556

QF7X 54.600 54.524 57.931 57.931 54.601

QD8X 26.862 26.850 27.005 27.005 26.863

QF9X 34.701 36.133 36.027 36.027 34.702

QD10X 52.965 51.764 56.860 56.860 52.964


Beta Matching (December 12 2012 owl)

0

1

2

3

X Y


0 5 10 15 20 25 30 35 40 45 500

2

4

6

8

10

12

14

16

sqrt

(Bet

a)

S (m)

fit

0 5 10 15 20 25 30 35 40 45 500

2

4

6

8

10

12

14

16sq

rt(B

eta)

S (m)

fit

25 30 35 40 45 500

1

2

3

4

5

6

7

sqrt

(Bet

a)

S (m)

SQ

207.6°87.1°

89.9°90.0°

SQ SQ SQ

56.7°112.5°

25 30 35 40 45 500.5

1

1.5

2

2.5

3

3.5

4

4.5

sqrt

(Bet

a)

S (m)

SQ

180.0°90.0°

89.9°90.0°

SQ SQ SQ

90.2°90.0°


MB2XIssues:• we were blind to the extraction trajectory between KEX1 and QF1X• two special button-type BPMs exist in this area

– MB1X at location of DR BPM 20 (between QM6R1 and QM7AR)– MB2X between septa BS2X and BS3X

• Glen hooked MB2X up to a spare channel in the stripline BPM DAQ system


DRextraction

kicker

extractionsepta

MB1X(button)

MB2X(button)

MQF1X(stripline)

MB2X: top left button(stripline BPM system)

Y

X

~ ICT


Additional Issues


Effect of DR orbit feedback

DR FB ON

DR FB OFF and DR correctors were reset.

emittance increasedue to orbit feedback?


Summary,Continuing Work,

Mitigation

M. Woodley15th ATF2 Project Meeting, January 24 2013

Summary (1)• multi-OTR EXT emittance measurements are reliable and stable

– measured beam tilt (coupling) values are believable and correspond to real X-Y coupling

• extracted vertical emittance is strongly dependent on bunch charge– 2-3 pm per 109 … much larger than observed in DR ( < 0.1 pm per 109 … IBS prediction?)– OTR camera gains were adjusted for low charge … optimized? other OTR systematics?– best vertical emittance observed during November-December running was 21 pm @ 109 e-/bunch

• extracted vertical emittance appears to be independent of DR RF voltage (bunch length)

• measured beam tilt (coupling) values are believable and correspond to real X-Y coupling– zeroing all 4 measured beam tilts minimizes projected vertical emittance

• observed KEX1 quadrupole/sextupole field components agree with (a) POISSON field simulation– tracking simulations indicate that vertical beam offset in KEX1 might not be a source of emittance growth– not sure exactly what’s inside either SLAC kicker

• KEX1 calibration measured with two independent methods– for 5 mrad (nominal) kick at 1.269 GeV: 46.5 kV (from orbit dependence); 46.7 kV (from vertical dispersion)

41/44


Summary (2)• anomalous vertical dispersion in EXT/FF is well modeled by a skew quadrupole field at BS3X

– strength of inferred skew quadrupole depends on horizontal beam position in BS3X, consistent with a skew sextupole field there with strength K2L = 16 m-2 … for comparison, K2L for SD4FF is ~ 15 m-2

• both phases of vertical dispersion (IP and FD) can be corrected with a combination of QS Σ-knob and vertical dipole correctors ZV3X and ZV11X beta matching can be done more reliably using EXT inflector quads and/or coupling correction section quads– leave FF matching quads alone

• button-type BPM MB2X (between extraction septa BS2X and BS3X) is now reading out through the stripline BPM DAQ system– still needs to be calibrated– could imagine setting KEX1 to nominal voltage and using X reading as “gold” value

42/44


• model horizontal orbit sensitivity of vertical emittance due to assumed BS3X skew sextupole field– after coupling correction, does pattern of QK strengths match observations?

• model horizontal orbit sensitivity of vertical kick due to assumed BS3X skew sextupole field– can we reproduce Okugi-san’s vertical steering (ZV1X and ZV2X) vs KEX1 voltage measurement?

• model the propagation of projected vertical emittance around the (coupled) Damping Ring– if εy = 12 pm at XSR source point (mid-store), is it 12 pm at the extraction kicker (last turn)?

• put KEX1 on a mover and try to measure vertical emittance vs KEX1 Y position?

43/44

Continuing Work


• reduce Damping Ring vertical emittance– use new DR laserwire to confirm XSR measurements

• run at low charge … 109 e-/bunch or less– performance of diagnostics?

• understand charge dependence of vertical emittance– why is charge dependence of εy at OTRs > 20 times what is observed in DR?

– is this a wakefield? why doesn’t εy depend on DR RF voltage?

• we’ve been measuring vertical emittance blowup in EXT since before ATF2 was proposed– the only part of the system common to both ATF and ATF2 is the DR extraction system (6 m of beamline starting at

KEX1 and ending at BS3X)– maybe we should rip open the entire system and physically look for anything wrong?

• fix the slow DR circumference (energy) drift– should be better now that DR air conditioner is working again– install a small 4 dipole chicane for circumference adjustment (controlled by an energy feedback)?

44/44

Mitigation?


Extra Slides


Date Nwire Emit (nm) BMAG

Dec 14 2010 4 1.784 ± 0.130 1.10 ± 0.04

Dec 9 2010 4 1.686 ± 0.102 1.08 ± 0.05

Nov 2010 (?) EXT kicker controller replaced

May 18 2010 4 1.905 ± 0.078 1.08 ± 0.03

Apr 21 2010 4 1.212 ± 0.065 1.26 ± 0.03

Mar 17 2010 BS3X rolled ~4 mrad (CCW)

Feb 25 2010 4 1.868 ± 0.336 1.15 ± 0.12

Feb 17 2010 4 negative

Feb 3 2010 4 1.626 ± 0.095 1.10 ± 0.06

Jan 28 2010

Date Nwire Emit (pm) BMAG

Dec 14 2010 5 27.6 ± 1.8 1.09 ± 0.04

Dec 9 2010 4 29.3 ± 3.1 1.05 ± 0.02

Nov 2010 (?) EXT kicker controller replaced

May 18 2010 5 11.7 ± 2.3 1.43 ± 0.25

Apr 21 2010 5 15.4 ± 2.0 1.78 ± 0.17

Mar 17 2010 BS3X rolled ~4 mrad (CCW)

Feb 25 2010 5 22.08 ±0.9 1.19 ± 0.03

Feb 25 2010 5 38.33 ± 1.1 1.10 ± 0.02

Feb 17 2010 5 22.6 ± 1.4 1.15 ± 0.04

Feb 3 2010 5 16.1 ± 0.7 1.06 ± 0.03

Jan 28 2010 5 31.6 ± 1.2 1.03 ± 0.01

Horizontal EXT Emittance Measurements Vertical EXT Emittance Measurements

46/44


OTR Vertical Emittance MeasurementDecember 14, 2011 07:44

name sigt sigd sig----- ------- ------- -------OTR0X 17.00 2.54 16.80OTR1X 13.44 2.90 13.12OTR2X 19.18 5.77 18.29OTR3X 17.53 3.26 17.22 Vertical emittance parameters at OTR0X-------------------------------------------------------energy = 1.2817 GeVemit = 49.7560 +- 3.8167 pmemitn = 124.7989 +- 9.5732 nmemitn*bmag = 139.1183 +- 14.3102 nmbmag = 1.1147 +- 0.0582 ( 1.0000)bmag_cos = -0.0976 +- 0.0000 ( 0.0000)bmag_sin = 0.4310 +- 0.0000 ( 0.0000)beta = 6.2274 +- 0.6272 m ( 6.1903)alpha = 3.0722 +- 0.3470 ( 2.5763)chisq/N = 1.0000 Propagated vertical spot sizes-----------------------------------OTR0X = 17.6 um ( 16.8 +- 1.4)OTR1X = 12.5 um ( 13.1 +- 0.9)OTR2X = 18.8 um ( 18.3 +- 1.3)OTR3X = 16.9 um ( 17.2 +- 1.3)

165 170 175 180 185 1900

5

10

15

20

25

30

35

40

Ver

tical

Bea

m S

ize

(um

)

S (m)

QF

9X

QK

1X

Q

D10

X

QF

11X

QK

2X

Q

D12

X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

QF

17X

QK

4X

QD

18X

QF

19X

QD

20X

QF

21X



sigt sigd sigw sig------- ------- ------- ------- 19.50 2.76 2.50 19.14 19.40 5.81 2.50 18.34 13.60 3.18 2.50 12.98 29.50 3.70 2.50 29.16 Vertical emittance parameters at MW0X-------------------------------------------------------energy = 1.2817 GeVemit = 42.9533 +- 3.4254 pmemitn = 107.7395 +- 8.5918 nmemitn*bmag = 114.9045 +- 10.4024 nmbmag = 1.0665 +- 0.0409 ( 1.0000)bmag_cos = 0.3468 +- 0.0000 ( 0.0000)bmag_sin = -0.0229 +- 0.0000 ( 0.0000)beta = 8.8918 +- 0.9843 m ( 6.1903)alpha = 3.6762 +- 0.4276 ( 2.5763)chisq/N = 1.0000 Propagated vertical spot sizes-----------------------------------MW0X = 19.5 um ( 19.1 +- 1.4)MW2X = 18.0 um ( 18.3 +- 1.4)MW3X = 13.5 um ( 13.0 +- 1.0)MW4X = 27.5 um ( 29.2 +- 2.2)

165 170 175 180 185 1900

5

10

15

20

25

30

35

Ver

tical

Bea

m S

ize

(um

)

S (m)

QF

9X

QK

1X

Q

D10

X

QF

11X

QK

2X

Q

D12

X

QF

13X

QD

14X

QF

15X

QK

3X

Q

D16

X

QF

17X

QK

4X

QD

18X

QF

19X

QD

20X

QF

21X


Wire Scanner Vertical Emittance MeasurementDecember 14, 2011 09:30(MW1X σy value ignored)


0 2 4 6 8 10 12 14-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

Y

(m

m)

S (m)

KE

X1

QM

6R

QM

7R

BS

1X

BS

2X

BS

3X

BH

1X

QS

1X

Q

F1X

QD

2X

QF

3X

ZV

100R

X

ZV

1X

ZV

2X

ZV

3X

BS3X roll = 4.66 mrad

BS3X roll = 4.66 mradIzv1 = -6.918 (-6.976) ampIzv2 = 1.270 ( 0.965) ampchi2 = 0.3102

Observed that first 2 EXT vertical correctors (ZV1X and ZV2X) needed to be strong to properly launch into EXT (since before EXT rebuild for ATF2 … )

• hypothesize that correctors are compensating for a kick error in extraction channel• simulate error kick by rolling individual elements; use ZV1X and ZV2X to correct orbit• find error that gives best fit to actual ZV1X/ZV2X values → BS3X septum magnet roll• BS3X was physically rolled ~ -4 mrad (March 17, 2010) to relieve ZV1X and ZV2X• projected vertical emittance in EXT before coupling correction was improved

(~20-40 pm before → ~10-20 pm after)

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4SET-file values (April 2009 - May 2010)

ZV

2X C

urre

nt (

A)

ZV1X Current (A)

before March 17, 2010

after March 17, 2010


3

4

5x 10

4

DK

ICK

ER

1500

1600

BS

1X

2500

2550

2600

2650

BS

3X

-2

-1

0

ZH

9R

Apr May Jun Jul0

5

10

BK

X

Oct Nov Dec Jan

Apr 21εy = 15.4 pm

May 18εy = 11.7 pm

SET-file History (Apr-Dec, 2010)

KEX controllerreplaced

fastkicker

fastkicker

Dec 9εy = 29.3 pm

Dec 14εy = 27.6 pm


2010 2011 2012 201335

40

45

50

Time

EX

T-D

KIC

KE

R (

kV)

DR Extraction Kicker Historic Setpoint Data (from SET-files)

εy = 12 pmMay 18 2010

εy = 15 pmApril 21 2010

Emittance Measurements and Related Experimental Results 15th ATF2 Project Meeting, January 24 2013M....

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