Main Injector Lambertson Aperture Scans

David Johnson and Ming-Jen Yang

March 17, 2006

Motivation and Data Collection

• The goal is to document the loss free apertures through the Main Injector Lambertson regions prior to the installation of the WQB wide aperture quads.

• The expected increase in circulating beam aperture in the Lambertson regions is due to: – the increase in beam pipe dimensions of the WQB on the inside

of the ring, – the shifting of the Lambertson septa to the radial outside (which

will also require new Lambertson flanges and the re-alignment of the upstream end of the transfer line.

• The wide aperture quad (4”) will allow the extracted beam to be farther to the outside of the ring without loss on the quad pole tip.

LM520A (61-0)LN520B (61-1)LN520C (61-2/2)*LN520D (61-3/4)*LN520E (61-45)*

LM521A (61-5)LN521B (61-6/6) *LN522A (61-7/7)*

LM

522B

(61-

8)

LM

522C

(61-

9)

LM

522D

(61

-10)

LM

522E

(61

-11)

LM

522F

(62

-0)

LM

522G

(62

-1)

LM

522H

(62

-2)

Q523Q522

Q521

Q520

Q522

Q521

V701Q701 LAM52C LAM52B

LAM52A

ES52B ES52A K520A,B

LM

701

(P1)

H522 TAR521

*Goes to chassis 2 w / beamline integrators – reset / hold timers I:LMNUMR and I:LMNUMH The numbers in parenthesis are the house - slot number and the number after the “/” is the slot in crate 2

LM

523

(62-

3)

MI-52 Loss Monitor Placement

LM607A(63-7)

LM607B(63-8) LM608A(63-9)

LM608 B(63-10)

LM

608

C(6

3-11

)

LM

608

D(6

4-0)

LM

608

E(6

4-1)

LM

608

F(6

4-2)

LM

608

G(6

4-3)

LM

608

H(6

4-4)

Q609 Q608

Q607Q608

V101Q101 LAM60C LAM60B

LAM60A H608 RF cavities

MI-60 Loss Monitor Placement Around NuMI Lambertsons

LM on Lambertson Flange

LM on conduit

LAM60

LM

Q60

8

LA

M61

A

LAM60 – NuMI Loss Monitors

LAM61B

V10

0

Q101

LM

609(

64-5

)

Q620 Q619V101 Q101LAM60CLAM60B

MI-62 Loss Monitor Placement

LM

619B

(64

-4)

Q620LAM60AH620Q621

LM

619C

(64

-5)

LM

6 19 D

(64

-6)

LM

619E

(64

-7)

LM

619F

(64

-8)

LM

620A

(64

-9)

LM

620B

(64

-10)

LM

620C

(64

-11)

LM

620D

(65-

0)

LM621 (65-1)

LM

619A

(64

-3)

pbars

Beta and Beam width Variance Across Lambertson

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9

Location

Bet

a [m

]

10.0

12.0

14.0

16.0

18.0

20.0

22.0

Bea

m w

idth

(6

) [m

m]

Beta X

Beta Y

Width Y

Width X

LAM1U LAM1D QUAD BPM LAM2U LAM2D LAM3U LAM3D

ASSUME 10 -mm-mr 95% normalized

Data Collection

• Injection scans were performed using a dedicated 8 GeV $2E cycle.

• Extraction scans (MI52 and MI60) were performed on low intensity stacking and NuMI cycles.

• First turn data was taken by aborting the beam after only one pass thru the Lambertson region of interest. The loss monitor “sample and hold” event, $2C, was set to measure the peak of the loss monitor response.

• Data on beam intensity, positions, loss and magnet currents were taken using I90.

• Data was transferred to excel for data analysis

Expectations• What apertures are expected through

Lambertsons?– Field Free: 60 mm loss free (1/2 MI beam pipe if septum

edge is located on MI centerline)– Field Region: 50 mm loss free (on axis) due to 50 mm

field region aperture. Expect first loss on outside of ring to occur on the Lambertsons either side of the quad

• What aperture is expected vertically in MI beam pipe?– The inside dimension of MI beam pipe is ~47mm

• For 20 and = 55m, 6 = 26.4 mm => +/-10.3mm free aperture

Summary of Aperture Scan Data Sets• MI40 8 Gev

– Horizontal scan Field and Field Free region with 1st turn H402:3– Vertical scan of Field Free close to notch (V401:4)– Horizontal scan of Field region (only toward septum) K400

• MI52 8 Gev– Horizontal scan Field region with 1st turn KPS5S– Horizontal scan Field Free circulating using H522:3– Horizontal scan Field Free and Field region 1st turn using H522:3

• MI52 120 Gev– Horizontal scan Field Free region using H522:3– Vertical scan of Field Free region using V521:4– Horizontal scan of Field region using KPS5S and H522:3

• MI60 8 Gev– Horizontal scan Field Free region 1st turn H608:3 – Horizontal scan Field Free (and Field) region 1st turnH608:3

• MI60 120 Gev– Horizontal scan Field region KPS6S– Horizontal scan of Field Free region (only toward septum) circulating H608:3

• MI62 8 Gev– Horizontal scan Field Free (and Field) region 1st turn H620:3

Summary of LAM40 Scan• Assume 10 beam• 8 Gev First turn using protons (060201)

– Field Free Region • Centroid of 8 Gev beam at HP402 is -27.8 mm• Inside loss start -41.3 mm on HP402 as seen on LM402G• Loss on septum starts at -11 on HP402 or +16.8 mm motion from

the nominal• Loss free aperture ~30 mm+ 16mm beam size -> ~46 mm

– Field Region• Beam strikes loss monitors LM402F,G,and H septum first on both

sides of the field region• The edge of loss free region based upon the upstream loss monitors

is 33.6 and 57.6 which gives a width of 24 mm + beam width which would eb ~ 40 mm

LAM40 First Turn Scan

-2

0

2

4

6

8

10

12

-30 -10 10 30 50 70

Delta calc position LAM40A us (mm)

loss

LM401BLM402ALM402BLM402CLM402DLM402ELM402FLM402GLM402H

Nominal position HP402 = -27 .805 mm

26 mm~24 mm

MI40 Position CalibrationsMI40 Position calibrations

-60

-40

-20

0

20

40

60

80

100

-40 -20 0 20 40 60 80

Calculated position at HP LAM402A

Po

siti

on

[m

m]

x_HP402

d HP402

HP_LAM42aNominal Circulating Beam Position

Field Free Region

Field Region

Summary of LAM52 Scans

• Assume 10 beam ,then 6 would be ~16 mm at entrance to 1st Lambertson

• Calculate aperture relative to position at entrance to first Lambertson HP_LAM52A

• 8 Gev First turn Field Free (060130)– Centroid of 8 Gev beam is -22.7 mm at LAM52A– Inside loss start -44 mm on beam pipe– Outside loss starts -6 mm on septum – Loss free aperture 38 mm + beam size (~16mm)-> ~ 54 mm

• 8 Gev Circulating Field Free (060131)– Inside loss starts at -39 mm– Outside loss (septum) first loss -12 mm– Loss free aperture 24 mm + beam size (~16mm) -> ~40 mm

• 120 Gev Field Free(060223)– Centroid circulating beam -13 mm– First loss seen on LM522A at -1.65 mm– No loss seen on inside beam pipe – Vertical scan

Aperture of LAM62C 8 Gev 1st Turn

LAM62 8 Gev 1st turn LAM62C Aperture

-2

0

2

4

6

8

10

12

-70 -50 -30 -10 10 30 50 70

Calc position LAM62C (proton upstream)

loss

(vol

ts)

'LAM619B: upstream V901

LAM619C: between V901 and LAM62C

LM619D: upstream 1/3 LAM62C

nominal positionat LAM62C

~99% LM619C = 17.4 mm (17.4 -4 ) = +/- 3

Base LM619D = 25.3 mm(25.3-4) = +/- 4.8

e = 10 at =28 = 2.2 mm 6 = 13.2 mm e = 20 6 = 18.8 mm

Back scatter from LAM62C septum

99 mm + 9.6 = 120 mm (physical aperture MI pipe ~120 mm)

steel septum located at +5 mm w rt MI centerline

Aperture 8 Gev First Turn LAM52

0

0.5

1

1.5

2

2.5

3

3.5

4

-50 -40 -30 -20 -10 0 10 20 30 40 50

HP LAM52A

I:LM521A

I:LN521B

I:LN522A

4 mm septum

Scrape at Q521 first in extraction region

Nominal 8 Gev position (-23mm)

2" Field Region

Loss free = 38 mm + 16 mm beam width = 54 mm

Beam Pipe

Notch

LAM52 Field Free 8 GeV First Turn Aperture

LAM52 Field Free 8 GeV Circulating ApertureField Free Circulating

0

1

2

3

4

5

6

7

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0

HP522 [mm]

Lo

ss [

v]

LN521B

LN522A

60 mm half aperture MI beam pipe

nominal positionHP522 = -27.0 mmLAM52 = -22.8 mm

22 mm

Inside beam pipe at Q522

Notch

4 mm septum

Comparison Between 1st turn and circulating aperture at LAM52

-3

-2

-1

0

1

2

3

4

5

6

-60 -50 -40 -30 -20 -10 0 10

HP LAM52A [mm]

LN

52

1B

[v

olt

s]

Circulating LN521B

First turn LN521B

H520 delta current

Circulating LM522B

24 mm circulating

38 mm 1st turn

99% beam width (6 ) ~ 16 mm at LN521B

NOTCH

Nominal

Lam52 8 Gev Field Region

LAM52 8Gev Field region Aperture

-10

10

30

50

70

90

110

-3 -2 -1 0 1 2 3 4 5

change in kicker voltage

-1

1

3

5

7

9

11

13

15

17

19

HP522TOR702 (norm)LN521B Lamb faceLM521A ds Q521 on beampipeLN520E

22 mm + 13.5 mm = 35.5 mm

SEPTUM

Radial outside

Summary of LAM60 Scans

• Assume 10 beam• 8 Gev First turn Field Free (060130)

– Centroid of 8 Gev beam is -32 mm– Inside loss start -46 mm beam pipe– Outside loss starts -14 mm on septum as seen by LM608F– Loss free aperture 24mm+beam size -> ~37mm

• 8 Gev First Turn Field Free (060131)– Inside loss starts at -40 mm– Outside loss (septum) first loss -18 mm– Loss free aperture17mm+beam size (~16mm) -> ~34mm

• 120 Gev Field Free and Extraction (060223)– Centroid circulating beam -23 mm– First loss seen at -3 mm – Centroid of extracted beam +17.5 mm – First loss seen on LM608A at 11.4 mm

LAM608 1st Turn 8 GeV Aperture

0

2

4

6

8

10

12

-60 -50 -40 -30 -20 -10 0 10 20 30

HP608 reading [mm]

Lo

ss [

volt

s] LM608A

LM608B

LM608C

LM608F

LM608H

Nominal 8 Gev Position

SEPTUM

LM607B disconnected

LAM608 8 GeV 1st Turn Beam Aperture Scan

LAM608 8 GeV Horizontal 1st Turn Beam Aperture Scan

0

2

4

6

8

10

12

-80 -60 -40 -20 0 20 40

Delta Position from Nominal HP(LAM60A) mm {beta= 52m}

Lo

ss [

v]

-60

-40

-20

0

20

40

60

Po

siti

on

HP

608

[mm

]

I:LM607B

LM608A

LM608B

HP608

+/-3 sigma beam ~ 13.5 mm ; no loss aperture in FF region 17+13.5 mm ~30.5 mmThe expected septum width is 13.5mm + 4 mm (min) ~17.5 mm effective thicknessWe measure a width of about 32 mm based upon LM607B at the upstream of LAM60A

FField Region

Field Free Region

Trajectory thru LAM60120 Gev H608:3 closed bump

-25

-20

-15

-10

-5

0

5

2740 2750 2760 2770 2780 2790 2800 2810 2820

di s tanc e f r om 604

max bump ampli tude

star t of loss

cir culating position at extr action

HP 608

LAM60LAM61A

LAM61B

2 mm off set to outside

120 GeV Field Region Scan

-2

0

2

4

6

8

10

12

8 10 12 14 16 18 20 22

HP 608 [mm]

I :LM607B

I:LM608A

I:LM608B

I:LM608C

I:LM608D

I:LM608E

I:LM608F

I:LM608G

I:LM608H

I:LM609

Nominal extr action P osi tion

3 of 40

3 of 10

outside

120 GeV Field Region Scan

-2

0

2

4

6

8

10

12

8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13

HP 608 [mm]

I :LM607B

I:LM608A

I:LM608B

I:LM608C

I:LM608D

I:LM608E

I:LM608F

I:LM608G

I:LM608H

I:LM609

LAM608 120 Gev Field Region Scan

LAM608 120 Gev Field Free Region Scan

120GeV scan fi eld f ree

-2

0

2

4

6

8

10

12

-25 -20 -15 -10 -5 0

HP 608

I :LM607B

I:LM608A

I:LM608B

I:LM608C

I:LM608D

I:LM608E

I:LM608F

I:LM608G

120GeV scan fi eld f ree

-2

0

2

4

6

8

10

12

-5 -4 -3 -2 -1 0

HP 608

I :LM607B

I:LM608A

I:LM608B

I:LM608C

I:LM608D

I:LM608E

I:LM608F

I :LM608G

Position of 120 Gev Beam at HP608

Sigma 20 ~ 1.2 mm

Shows a movement of 5mm

Summary of LAM62 Scan• 8 Gev First turn using protons (060201) Assume 10 beam

– Field Free Region • Centroid of 8 Gev beam at HP620 is -35.5 mm• Inside loss start -52 mm on HP620 as seen on LM620A and B• First loss seen on LM621 moving toward seputm at -19 mm on HP520 followed by LM620D with

LM619C• Loss free aperture 30 mm + 23 beam size -> ~53 mm

– Field Region• Lambertsons on at 8 Gev level-> bend protons up to hit the pole tip of Q620 which saturate loss

monitors close to quad and raises background due to backscatter on loss monitors farther upstream• When scanning from field region toward the septum, the beam strikes LAM62C septum first due to

septum offsets• Loss free width on LM619D is 21 mm followed by LM619E (both on LAM62C) and then on LM619C is

25 mm + beam size• Loss on LM619C is back scatter. This loss monitor is not saturated and will be used to estimate beam

size

– Beam Size Comments• Based upon beta at upstream end of LAM62C (28m) the sigma for a 10 should be 2.2 mm and 6

sigma should be 13.2mm.• Use the non saturated LM619C loss monitor to estimate beam size by scanning the beam across the

septum of LAM62C.• Beam extends to about 21 mm full width which gives a 11.5mm half width which implies beam

extends out to 5.3 .

Cartoon of LAM62 Layout

Q620LAM62A LAM62C

LAM62B

2.54mm

5mm

Field free region

LM61

9C

LM61

9D

LM62

0A

LM62

0B

LM62

0D

pPBARS

Circulating Field Free Region

Extraction Field Region

protons

Pbars

Q622

Q620

Q618

LAM62 8 Gev Field Free Region

LAM62 8 Gev 1st turn Field Free Aperture

-2

0

2

4

6

8

10

12

-70 -50 -30 -10 10 30 50 70

Calc position HP620

loss

(vol

ts)

I:LM619A

I:LM619B

I:LM619C

I:LM619D

I:LM619E

I:LM619F

I:LM620A

I:LM620B

I:LM620C

I:LM620D

I:LM621

I:LM622

Backscatter from Vertical offset a quad pole tip

LM620 A&B on either side of quad

LM622 respond to losses on Q620

30 mm + 23 mm beam

nominal

LAM62 8 Gev 1st turn Field Free Aperture

-0.5

0

0.5

1

1.5

2

-70 -50 -30 -10 10 30 50 70

Calc position HP620

loss

(vo

lts)

I:LM619A

I:LM619B

I:LM619C

I:LM619D

I:LM619E

I:LM619F

I:LM620A

I:LM620B

I:LM620C

I:LM620D

I:LM621

I:LM622

Backscatter from Vertical offset a quad pole tip

LM620 A&B on either side of quad

LM622 respond to losses on Q620

30 mm + 23 mm beam

nominal

Beam size from LAM62C septum scan

Beam Distribution from Septum loss

-2

0

2

4

6

8

10

12

-30 -20 -10 0 10 20 30

Calc. position at upstream face of LAM62C [mm]

exp(-x^2/s^2)

LAM619C

exp(x^2/S^2)

LM619A

LM619B

Series6

Series7

baseline w idth 25 mm septum w idth 4 mm=> 21 mm beam full w idth => 11.5 mm beam half size=> 5.3 w here = 2.2 mm)

31 mm

= 2.2mm

25 mm

Summary of Horizontal Apertures

Location Energy Type Beam Size Nominal Width dS Nominal Width dS

LAM40 8 first -27.8 26 11.5 29LAM52 8 first/last -23 30 20 20.4 23 9

8 circ -23 24 11120 circ/last -13 11 23 6

LAM60 8 first -32.75 23.5 138 circ -32.75 17 10

120 circ/last -22 19 17.2 6LAM62 8 first -35 30 16 21

Field Free Field Region

Cross Section at Q608

Beam out to about 6.5 on circulating beam

Start loss with single pass beamStart loss with circulating beam

Beam out to ~ 4.5 on 1st turn beam

Assume 10 ~ 3.1 mm

+/-3 sigma beam at nominal HP608 position