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Optical Diagnostic Results of MERIT (Mercury Intense Target) Experiment at CERN

H. Park , H. Kirk, T.Tsang, K. McDonald, F. Ladeinde

NFMCC MeetingFermilab, Batavia, IL

March 18, 2008

Acknowledgments: DOE/BNL

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Talk Outline

● Optical Diagnostics Setup- Optics configuration with respect to beam, magnet, and Hg jet- Schematics of optical diagnostic setup

● Observation of Hg Jet Interacting with Proton Beam- B field effects to Hg jet break up and vertical splash velocity

● Image Processing For Analysis

● MHD Results- Hg jet size, Hg jet surface fluctuation, and longitudinal Hg jet velocity

● Beam Integrated MHD Results- Beam intensity threshold and intensity scan

● Conclusions

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Total 360 of beam shots performed.

Images for 227 beam shots collected.

MERIT beam shot summary website,

http://www.hep.princeton.edu/~mcdonald/mumu/target/hkirk/MERIT_Beam_Program_110607.pdf

Optics Configuration with respect to Beam, Magnet, and Hg Jet

Z=0

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Optical Diagnostics Setup : Laser Pulse Structure, Schematic Diragram

Viewport 2SMD Camera0.025 ~ 0.25 ms frame rate0.15 µs exposure

Viewport 4Olympus Encore Camera0.25 ~ 2 ms frame rate60 ~ 100 µs exposure

Viewport 1, 3FV Camera0.25 ~ 2 ms frame rate10~15 µs exposure

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Observation Results : Interaction of Hg Jet with 14 GeV Beam, Movie

5T, 16TP 10T, 12TP0T, 8TP

5T, 16TP 10T, 20TP0T, 4TP

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Observation Results: Beam/Hg Jet Interaction B=5T,P=16TP,E=14GeV, L=28cm

continuing at next page

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Obsevation Results: Beam/Hg Jet Interaction

Hg Jet Break Up Center

continuing at next page

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Observation Result: Beam/Jet Interaction

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Observation Results: Velocity of Splash with Interaction of 24GeV Beam

3.8TP, 10T

6TP, 5Tt=0 t=0.175 ms t=0.375 ms

V = 24 m/s

t=0.150 ms

t=0 t=0.175 ms t=0.375 mst=0.050 ms

V = 47 m/s

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10TP, 10T

20TP, 10Tt=0 t=0.175 ms t=0.375 ms

V = 54 m/s

t=0.075 ms

t=0 t=0.175 ms t=0.375 mst=0.050 ms

V = 65 m/s

Observation Results: Velocity of Splash with Interaction of 24GeV Beam

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MHD Results: Hg Jet In Magnetic Field, V=15m/s

0.4T 5T

10T 15T

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X: 1011 Y: 231Index: 55

RGB: 0.22, 0.22, 0.22

0 100 200 300 400 500 6000

50

100

150

Jet thickness, pixels

Num

ber o

f eve

nts

Viewport 3, 15m/s, 0T

400 450 500 550 600 650 700 750-1000

-900

-800

-700

-600

-500

-400

-300

-200

TIF Image Processing Method For Analysis

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Results: Hg Jet Width Along The Magnet Axis, V=15m/s

0 2 4 6 8 10 12 14 1602468

1012141618202224262830

Distance from nozzle, 30cmDistance from nozzle, 45cmDistance from nozzle, 60cm

Jet w

idth

, mm

Magnetic induction field, T

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Results: Distortion Ratio Along The Magnet Axis, V=15m/s

0 2 4 6 8 10 12 14 16

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Distance from nozzle, 30cm Distance from nozzle, 45cm Distance from nozzle, 60cm

Dis

tort

ion

ratio

, ro=

r_no

field

Magnetic induction field, T

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Results: Hg Jet Surface Fluctuations, V=15m/s

0 2 4 6 8 10 12 14 160.0

0.4

0.8

1.2

1.6

2.0

2.4

2.8

3.2

3.6

4.0

4.4

4.8

Su

rfac

e flu

ctua

tions

of j

et, m

m R

MS

Magnetic induction field, T

Distance from nozzle, 30cm, top surface Distance from nozzle, 30cm, bottom surface Distance from nozzle, 60cm, top surface Distance from nozzle, 60cm, bottom surface

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Results: Longitudinal Hg Jet Velocity In Magnetic Field, V=15m/s

0 2 4 6 8 10 12 14 1656789

1011121314151617181920

Lo

gitu

dina

l Hg

jet v

eloc

ity

Magnetic induction field, T

Distance from nozzle, 60cmNozzle velocity

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Results: Distributed Threshold, B=5T, 14GeV Proton Beam Program

4 6 8 10 120.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

D

isru

ptio

n le

ngth

, m

Beam intensity, TP

Harmonic 8Harmonic 16

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Results: Intensity Scan, Harmonic 16, 14GeV Proton Beam Program

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

0.275

0.300

0.325

D

isru

ptio

n le

ngth

, m

Beam intensity, m

B=0TB=5TB=10TB=15T

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Results: Intensity Scan, Harmonic 16, 24GeV Proton Beam Program

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

0.0000.0250.0500.0750.1000.1250.1500.1750.2000.2250.2500.2750.3000.3250.3500.3750.4000.425

D

isru

ptio

n le

ngth

, m

Beam intensity, TP

B=0TB=5TB=10TB=15T

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Results: Intensity Scan, 14GeV vs 24GeV Proton Beam

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32-0.050-0.0250.0000.0250.0500.0750.1000.1250.1500.1750.2000.2250.2500.2750.3000.3250.3500.3750.4000.425

E=14GeV E=24GeV

Dis

rupt

ion

leng

th,m

Beam intensity,TP

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Conclusions

1. It is observed that the splash begins at the bottom of jet and ends at the top of jet, which is consistent with the beam trajectory. This breakup could be the by-product of cavitation caused by the energy deposition of the proton beam.

2. The extent of the Hg jet breakup is influenced by the magnetic induction field. • The splash velocity increases as the beam intensity increases,

however, the magnetic induction field reduces the effect.• The extent of the Hg jet disruption length is suppressed by the magnetic induction field.

3. The 24GeV proton beam results in greater disruption length than the 14GeV proton beam. The intensity threshold for the 24GeV beam is lower than the 14GeV beam.

4. The magnetic induction field stabilizes the Hg jet flow. The fluctuations on the jet surface decreases as the magnetic induction field increases.

5. The jet size increases as it moves to downstream and it was same up to 10T but increases at 15T. The jet size at 10T was smaller than at 15T, which might be a result of B field induced elliptical distortion.

6. The longitudinal Hg jet velocity was not significantly affected by the magnetic induction field.