★★Electron RF Linacs for Industrial Applications_ICABU11_17_포스텍

Electron Linacs for Industrial Applications, S. H. Kim, Sept. 30, 2011, ICABU’11 1/32

Electron RF Linacs Electron RF Linacs

for Industrial Applicationsfor Industrial Applications**

S. H. KimS. H. Kim1)#1)#, H. R. Yang, H. R. Yang1)1), M. H. Cho, M. H. Cho1,2)1,2), W. Namkung, W. Namkung1,2)1,2), , Y. G. SonY. G. Son2)2), S. D. Jang, S. D. Jang2)2), S. J. Kwon, S. J. Kwon2)2), S. J. Park, S. J. Park2)2), ,

J. S. OhJ. S. Oh3)3), K. O. Lee, K. O. Lee4)4), and K. H. Chung, and K. H. Chung4)4)

1) Department of Physics, POSTECH2) Pohang Accelerator Laboratory, POSTECH3) National Fusion Research Institute4) Korea Accelerator and Plasma Research Association

The 15th International Conference on Accelerator and Beam UtilizThe 15th International Conference on Accelerator and Beam Utilization ation (ICABU(ICABU’’11)11)

2011. 9. 30.

Gyeongju TEMF Hotel, Gyeongju, Korea

* Work partly supported by MKE, Korea and POSTECH BK21 Program# [email protected]


ContentsContents

• Introduction– Industrial applications of electron RF linacs

• Development of L-band electron linac– High power linac for e-beam processing

– Design details

– Commissioning status

• Development of C-band electron linac– Compact linac for industrial X-ray sources

– Design details

– Commissioning status

• Summary


Electron Beam Processing

Applications of e-beam processing(E-BEAM Service, Inc.)

Irradiation processing office(LEONI Studer Hard)

IntroductionIntroduction


Re-locatable vehicle inspection and images by dual energy e-beam

(Smiths Detection)

Cargo inspection with 9-MeV e-beam(Rapiscan Systems)

Mobile vehicle inspection with 2.5 MeV e-beam(Tsinghua Tongfang)

Cargo Inspection



Varian Clinac (S-band) Mitsubishi IGRT (C-band)

Accuray Cyberknife (X-band)

Radiotherapy



Application Fields with RF Frequencies


Radiotherapy(6 – 9 MeV, < 1 kW)

E-beam Processing- Sterilization- Polymer Reforming(< 10 MeV, > 10 kW)

Cargo Inspection(3 – 9 MeV, ~ 1 kW)

Higher Beam Power

More Compact

L-band

S-band

C-band

X-band

FavorableRF Frequency

Industrial Applicationsof Electron Linac


L-band Accelerator System

LL--band: Overviewband: Overview

10-MeV, 30-kW e-beam accelerator

E-beam scanner

L-band 1.3-GHz, 25-MW pk, 60-kW avg.

Klystron with pulse tank

70-MW pk, 210-kW avg. inverter PS & pulse modulator

Installed at ACEP/KAPRA, Cheorwon


Depth-Dose Curve for Electron Beam

0.0

0.5

1.0

1.5

2.0

2.5

0 1 2 3 4 5 6

Areal Density (g/cm2)

Re

lati

ve

Do

se

Single Double

10 MeV5 MeV2 MeV

1 MeV

0.5 MeV

PAL/POSTECH2007/3/23

Limited by neutron production


Depth-dose Curve of Electron Beam


Schematic Diagram of Accelerator System

PB: Pre-buncher IP: Ion PumpPGV: Pneumatic Gate Valve PS: Phase ShifterATT: Attenuator BEM: Beam Energy MonitorBCM: Beam Current Monitor

Accelerating Column

ATT

Solenoid Magnet PS

Load

Modulator

PS

E-Gun

PGV

BEM

PB BCM

IP

IPIP

PGV

IP Controller

E-gun Heater PS

E-gun HV Pulser RF WindowRF Window

Klystron

Vacuum GaugeController

Cooling WaterDistributor

TemperatureController

RF Driver

Master Trigger


Steering Coil Controller

IP Controller

Beam Diagnostics System

Cooling Stand

Inverter

Beam Scanner



Accelerator Parameter

RF System Parameter

Operating Frequency 1.3 GHz

Pulsed RF Power 25 MW

Pulse Length 7 μs

Repetition Rate 350 Hz

Average RF Power 60 kW

E-gun Parameter

High Voltage - 80 kV

Pulsed Beam Current 1.6 A

Pulse Length 6 μs

Beam Parameter

Beam Energy 10 MeV

Pulsed Beam Current 1.45 A

Beam Transmission Rate 90%

Average Beam Power 30 kW

Accelerating Structure Parameter

Type of StructureConstant-

impedance

Shape of Cell Disk-loaded

Operating Mode 2π/3 mode

RF Filling Time 0.8 μs

Operating Temperature 40°C ± 1°C

Average Accelerating Gradients 4.2 MV/m

Beam Loading Factor - 4.7 MeV/A

Temperature Shift Factor - 2.3 MeV/°C

LL--band: Designband: Design


0-mode

π/3-mode

2π/3-mode

π-mode

Accelerating Column and Prototype Test


Cell Parameters

CavityPhase

velocity/ cGroup

velocity/ cAttenuation

coefficient (Neper/m)

1st buncher 0.65 0.0170 0.0538

2nd buncher 0.75 0.0167 0.0489

3rd buncher 0.88 0.0165 0.0442

4th buncher 0.92 0.0164 0.0431

5th buncher 0.98 0.0163 0.0415

Normal 1.00 0.0089 0.0756

Normal section (26 cells)Bunching section

(5 cells)

RF input coupler

RF output coupler

2.3 m

)( 2/2 pwz

)( 3/22 pwz

)(2 mz w

)(1 wz

)( 2/pwj

)( 3/2pwj

)( mwj

Shorting bar

Tapered W/G

W/G to Coax adapter Network analyzer

(Agilent E8362B)

1 2

Buncher and Normal cells

Coupler cells

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실험방법


Low Power Test of Actual Accelerating Column

Fig 3. PAL2# Accelerating Structure Phase Shift Measurement

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

4.00

5.00

0 5 10 15 20 25 30 35

Input Cavity Cell Number Output

RF

Ph

ase

dev

iati

on

[d

egre

es]

Phase shift for cavity cell Cumulative phase shift for per cell relative to No.0

Measurement of phase advance per cell

RF Reflection

RF Transmission



Beam Dynamics Simulation

0 50 100 150 200 250 3000

2

4

6

8

10

12

Longitudinal Distance (cm)

Av

erag

e B

eam

En

erg

y (

MeV

)

0 50 100 150 200 250 300-8

-4

0

4

8

12

Ele

ctri

c F

ield

(M

V/m

)


0 100 200 300 400 5000

5

10

15

20

25

30

Beam Envelope

Tan

sver

se C

oo

rdin

ate

(mm

)


Aperture Limitation

Focusing Magnetic Fields

Beam Envelope

Longitudinal E-field on the Axis

Beam Energy Distribution

0 50 100 150 200 250 3000

250

500

750

1000

1250

1500

Lo

ng

itu

din

al M

agn

etic

Fie

ld (

G)



* Calculated by the PARMELA code with RF profiles from the SUPERFISH code


Installation of Accelerating Column

E-gunPGV

Pre-buncher

Steering coil

Focusing solenoids

Accelerating column

BCM

RF windowVacuum system

Waterload

PGV

Solednoidslens



Klystron and Modulator System



Circuit Diagram of Klystron and Modulator

Peak forward voltage 50 kV max

Peak forward current 15 kA max

Average anode current 15 A max

Peak Charging Rate 33 kJ/sec

Output Voltage 45 kV

Average Output Power 30 kW

Number of Units 8 units

Thyratron

HVInverterPowerSupply

ZPFN, 15 Stage

1:13 Pulse TR

DINV DTAIL

RTAIL

RSNUB

CSNUB

REOLC

RINVRcharging

50 nF

2.2 μH

KlystronHeater P.S.168 V / 4.2 A

Cathode

Heater

6:1 Heater TR


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Klystron Diode Test

247.72 kV

Klystron beam voltage

Klystron beam current246.4 A

Load Impedance 1 kΩ

Load Voltage 247.72 kV

Load Current 246.4 A

Charging Voltage 42 kV

Pulse Width (70 %) 9.3 μs

Diode test with 220-Hz repetition rates

PFN voltage

LL--band: Commissioningband: Commissioning


Beam Acceleration

Input RF power

Output RF power

Output beam current

Input beam current


Depth-dose distribution of e-beam

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7 8

Areal density (g/cm̂2)

Deposit

dose

(A.U

.)

`

Dose distribution in scanning direction

0

1

2

3

4

5

0 10 20 30 40

Distance (cm)

Abso

rbed

dose

(kG

y)

`

Dose distribution in scanning direction

Dose distribution through penetrating depth (Al)

18.5 MW

1.5 A1.3 A

6 µs

RF and beam pulsed waveform


Commissioning Status

Parameters 1st Machine 2nd Machine

RF frequency 1.3 GHz 1.3 GHz

Input RF power 12 MW 12 MW

Pulse length 8 μs/ 7 μs 7 μs/ 6 μs

Repetition rate 183 Hz 350 Hz

E-gun HV 75 kV 66 kV

Pulsed beam current 1.1 A 1.1 A

Beam energy ~ 9 MeV ~ 9 MeV

Beam power 13 kW 21 kW

E-gun pressure < 3×10-8 Torr < 3×10-8 Torr

ACC pressure < 10-7 Torr < 10-7 Torr


0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40

2

4

6

8

10

12

Beam power

Pea

k po

wer

(M

W)

Beam current (A)

Transmitted RF power

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40

2

4

6

8

10

12

14

16

Bea

m e

nerg

y (M

eV)

Beam current (A)

Electron Linacs for Industrial Applications, S. H. Kim, Sept. 30, 2011, ICABU’11

Advanced Center for E-beam Processing/KPARA, Cheorwon

(http://www.ebeam.or.kr)

20/32

10 MeV e-beam accelerator

2 MeV e-beam accelerator

165 keV e-beam accelerator

Seoul

Cheorwon

Pohang

Busan


Schematic Diagram of Accelerator System

X-ray Target

RF Window

Magnetron

Cooling WaterDistributor

TemperatureControllerPeak 1.5 MW,

Average 1.2 kW max.

IP: Ion PumpBCM: Beam Current Monitor

E-Gun

E-gun Heater PS

Circulatorw/ Matched Load

Trigger

40 kV, 50 A

20 kV, 150 mA

Accelerating Column

Pulse Modulatorwith Transformer

IP Controller


CollimatorBCM

Ion Pump

CC--band: Overviewband: Overview

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C-band Accelerator System

Accelerating column

RF window

Ion pump with vacuum gauge

Inverter/ Modulator/ Control rack

Magnetron

Pulse tank

Circulator

CC--band: Overviewband: Overview


Accelerator Parameter

CC--band: Designband: Design

Beam Parameters

Species Electron

Pulsed Output Current 50 mA

Output Energy 4 MeV @ 50 mA

Loss Beam Power Ratio 6 %

Accelerating Structure Parameters

Type of StructureBi-periodic

On-axis Coupled

Operating Mode SW π/2 mode

Number of Cells 10

Size 7.4 cm × 30.7 cm

Beam Aperture Diameter 10 mm

Accelerating Gradients 13.3 MV/m

Q-factor 11000

Effective Shunt Impedance 90 MΩ/m

Inter-cell Coupling Constant 6 %

RF System Parameters

Operating Frequency 5 GHz (C-band)

Pulsed RF Power 1.5 MW

Pulse Length 4 μs

Repetition Rate Max. 200 Hz

E-gun Parameters

High Voltage 20 kV

Pulsed Input Beam Current 150 mA

Beam Diameter (at the waist)

4 mm


Accelerating Structure

• Type: Biperiodic,On-axis-coupled, π/2-mode SW structure

• Number of cells: 10

• Length: 306 mm

• Inner diameter: ~48 mm

• Beam aperture diameter: 10 mm

Bunching cells3 cells × 21 mmβph ph = 0.7

Tapered W/G

RF input couplerIntercell magnetic

coupling slot

Normal cells6 cells × 30 mmβph ph = 1



Accelerating Cavity

0.0 0.2 0.4 0.6 0.8 1.0

4800

4850

4900

4950

5000

5050

5100

5150

5200

5250

Normal Cell Bunching Cell

Fre

que

ncy

(M

Hz)

Phase advance /π

Measured dispersion relation

Network analyzer(Agilent E8362B)Network analyzer(Agilent E8362B)


Simulation of accelerating cavity

Prototype test


Low Power Test of Actual Accelerating Column

Step motor Cavity Tuning jig

Networkanalyzer

Reflection coefficient

Bead test and cavity tuning

In Smith Chart

Field flatness


Resonant frequency

• After brazing: 4998.86 MHz (20℃)• After tuning: 4999.46 MHz (20℃)

(*in air with humidity of 25%)

• Under vacuum: 4999.17 MHz (40℃)

Field errors in normal cells: 0.65%

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Circuit Diagram of Magnetron & Modulator

Dong-A 403

5GHz, 1.5MW Magnetron & Pulse Modulator SystemC-Band1.5MW Magnetron

Pulse Modulator

High VoltageSwitched ModePower Supply

Tyratron

Dr iver Circuit

Tyra tronHe ater Power

Supply

MagnetronHe ater

Power Supply

Magnetron Beam Voltage Monitor

Magnetron Beam Current Monitor

EOLC

Protection Diode

ThyratronE2V

CX1191D

Tail Clipper

SurgeDes piker

Pulse Transformer

1:4

ResistorDivider

Dong-A 403Output Voltage 25 kVCharging Rate Peak 5 kJ/s Average 4.0 kJ/s

High VoltageCoaxialCable

MagnetronPulse Transformer

Tank

SON. Yoongyu, '2003. November . 19

Frequency 5100 MHzOutput Power 1.5 MWRepetiton Rate 200 ppsEffic ieccy 52 %Beam Voltage 39 kVBeam Current 83 ARF Pulse Width 4.0 ms

Peak Power 3.6 MWCharging Voltage 22.5 kVPFN Output Voltage 11.25 kVPFN Output Current 382 AHV Pulse Width (70% Voltage) 4.0 msRepetition Rate 200 pps

Pulse Modulator 7 Stage PFN

PFN impedance 29.37 WTotal Capacitance 68.26 nFTotal Inductance 51.6 mHSingle Capacitance 10 nF

50 W

30 W

50 W

G2

G1

10 mH

6.3 V

12. 5 A

CPI SFD369

1 nF

25 W

P1

P2

M2

M1M3

M4

E1

E2

E3

E2-1 E4 E4-1CT-2

Electron GUN

He aterPowe r Supply

ElectronGUN

ResistorDivider

Gun Beam Voltage Monitor

Gun Beam Current Monitor

50 W

CT-1

BNC-1 BNC-2 BNC-3 BNC-4

Heater voltage : 6.3 +/_ 0.5 V(Max :6.8 V), 12.5 A

Heater v oltage : 5 V +/_ 1 V(Max: 6 V), 28 A

He ater voltage : 9 V+/_ 1 V(Max: 10 V), 1 0 A

FilterPCB

2 MW

Dump SW

8.6 mH

1 0 nF

DS2124

DS21 24

RF-Output

CathodeVane

Anode

Strap

HV Probe


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Magnetron Test

CC--band: Commissioningband: Commissioning

Modulator Pulse TR & RF Source System

PLC

CCPS

PFN

Mag. Input V (32 kV)

E-gun Input V (11.8 kV)

PFN Output V (8.4 kV)

HeaterP.S

24 26 28 30 32 34 36 38 400

10

20

30

40

50

60

70

80

90

RF output*50

Efficiency

Magnetron Current

RF

Out

put

(MW

), E

ffic

ienc

y (%

)

Mag

net

ron

Cur

rent

(A

)

Magnetron Voltage (kV)

24 26 28 30 32 34 36 38 40

24 26 28 30 32 34 36 38 40

0

10

20

30

40

50

60

70

80

90


High Power RF Conditioning

Avg. 1480 kWPeak 1570 kW

Avg. 93 kWPeak 123 kW

RF Fwd

RF Ref

Forward RF power

Reflected RF power

0

150

300

450

600

750

900

1050

1200

1350

1500

0 5 10 15 20 25 30 35 40 45 50

RF Conditioning Time (hour)

Inpur

RF

Pow

er (

kW

)

.

Pulse waveform

RF aging history



Beam Acceleration


0

5

10

15

0 10 20 30 40 50 60 70 80Longitudinal Position (cm)

Bea

m R

ad

ius

(mm

)

Operating Frequency 5 GHz

Pulsed RF Power 1.5 MW

Pulse Length 4 μs

Beam Energy 3.5 ~ 4.0 MeV

Pulsed Beam Current 50 mA / 150 mA

Beam Spot Size

(measured at 40 cm after the

end of accelerating column)

13 ~ 14 mm

4 μs

Beam Parameters

Beam size measured position

End of acc. column

Longitudinal Position (cm)

Rea

m S

ize

(mm

)

RF and beam pulsed waveform

Magnetronvoltage

Input RF power

Beam current

Beam measurement

Beam envelop calculated by PARMELA code

BCT

Gate valve

Beam profile measurement chamber


Characteristics of X-ray Attenuation

(Courtesy of Prof. C. Tang, ICABU’10)


Dual energy inspection→ Discrimination of materials


0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25 30 35 40 45 50Longitudinal Position (cm)

Bea

m R

adiu

s (c

m)

Beam envelop

Position of the cell

Design of New Accelerating Column

Parameters Previous New

Operating Frequency 5 GHz 5 GHz

Input RF Power (peak) 1.5 MW 1.5 MW

E-gun Voltage 20 kV 20 kV

Number of Cells 10 17

Length of Accelerating Column 30 cm 48 cm

Input Beam Current (pulsed) 150 mA 150 mA

Output Beam Energy 4 MeV 6 MeV

Output Beam Current (pulsed) 50 mA 80 mA

Iris Diameter 10 mm 8 mm

Average Accelerating Gradient 13.3 MV/m 13.8 MV/m

Beam Spot Size 5 mm 1.3 mm


Beam dynamics simulation for

new accelerating column(by PARMELA code)

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Summary

• PAL/POSTECH developed electron RF linacs for industrial applications.

• L-band accelerator was installed at ACEP/KAPRA and now serves electron beams to processing users. The beam power reaches to almost 20 kW.

• C-band accelerator was commissioned for X-ray imaging sources. In order to increase the beam energy, new accelerating column is being designed adopting RF focusing scheme.

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Thank you for your attention!

Documents

★★Electron RF Linacs for Industrial Applications_ICABU11_17_포스텍