Design Status of the PEFP RCS

HB2010, Morschach, Switzerland

J.H. Jang1) Y.S. Cho1), H.S. Kim1), H.J. Kwon1), Y.Y. Lee2)

1)PEFP/KAERI, 2)BNL

(www.komac.re.kr)

2

PEFP (proton engineering frontier project) Status

Expansion Plan of PEFP

Design Concept of the PEFP RCS (rapid cycling synchrotron)

Lattice Design and Beam Dynamics

Summary

Contents

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Project : Proton Engineering Frontier Project (PEFP)

21C Frontier Project, Ministry of Education, Science & Technology

Project Objectives :

1st : Developing & constructing a proton linear accelerator (100MeV, 20mA)

2nd : Developing technologies for the proton beam utilizations &

accelerator applications

3rd : Promoting industrial applications with the developed technologies

Project Period : 2002.7 – 2012.3 (10 years)

Project Cost : 128.6 B Won (Gov. 115.7 B, Private 12.9 B) (Gyoungju City provides the land, buildings & supporting facilities)

Overview of PEFP

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Output Energy (MeV) 20 100

Peak Beam Current (mA) 20 20

Max. Beam Duty (%) 24 8

Avg. Beam Current (mA) 4.8 1.6

Pulse Length (ms) 2 1.33

Max. Repetition Rate (Hz) 120 60

Max. Avg. Beam Power (kW) 96 160

Schematics of PEFP Linac & Beamlines

Features of the PEFP linac

• 50 keV Injector (Ion Source + LEBT)

• 3 MeV RFQ (4-vane type)

• 20 & 100 MeV DTL

• RF Frequency : 350 MHz

• Beam Extractions at 20 or 100 MeV

• 5 Beamlines for 20 MeV & 100 MeV

- Beam to be distributed to 3 BL via AC

Future

Extension

100 MeV Beamlines 20 MeV Beamlines

TR105 TR101 TR25 TR21

TR23 TR22 TR24 TR102 TR103 TR104

100 MeV 20 MeV 3 MeV

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Status of Accelerator Development

100 MeV Beam 20 MeV Beam

Step 3

(’08.04 ~ ’12.03)

Step 2

(’05.07 ~ ’08.03)

Step 1

(’02.07 ~ ’05.06)

RF RF RF RF RF

91~102 80~91 69~80 57~69 45~57

DTL103 DTL104 DTL105 DTL106 DTL107 MEBT

RF RF

33~45 20~33

DTL101 DTL102

RF

RFQ IS

RF

DTL21~DTL24

Control & Diagnostics

Operating 2010

Fully developed & integrated up to 20 MeV at KAERI site in Daejeon

The fabrication of tanks up to 91MeV has been finished.

Last tank will be fabricated in this fiscal year.

Completed

6

The Project Site

The land (440,000 m2) provided by Gyeongju municipal government.

(The capital of Shilla dynasty for 992 years, from BC 57 to AD 935.)

Seoul

KAERI (Daejeon) Gyeongju

Daegu

Pusan

Express Railway (KTX)

(New Gyeongju Station)

Free Way

(Gyeonju IC)

Phase

II

Phase

I

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The Site Plan

Proton Accelerator Research

Center

② ③

④

⑨

⑩

⑪

⑤

⑥ ⑦

①

⑫

⑧

⑦ Water Storages

⑧ Main Office Building

⑨ Regional Cooperation Center

⑩ Dormitory

⑪ Information Center

⑫ Sewage Plant

① Accelerator Tunnel

② Experimental Hall

③ Ion Beam Facility

④ Utility Building

⑤ Substation

⑥ Cooling Tower

1,100 m 450 m

40

0 m

Reserved for

the Future Expansion

Phase I

(2002~2012)

Phase II

(2012 ~) Express Railway (Under construction)

Phase - II

Phase - I

Gyeong-bu

Freeway

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PEFP 20 MeV Linac

Waveguide WR2300

Klystron for DTL 350 MHz 1 MW CW

LEBT 3 MeV RFQ

350 MHz 4-Vane

Injector

50 keV 40 mA 20 MeV DTL

4 -Tank 150-DT

Klystron for RFQ 350 MHz 1 MW CW

Beam Profile Target station

for user

Extracted first beam (July 2005)

Obtained operation license (June 2007)

- Avg. current: 0.1 A,

- Rep. Rate: 0.1 Hz, 4 hrs/week

Started beam service (June 2007)

Achieved design performance (May 2008)

4cm

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Target Station for 20-MeV beams (at KAERI site)

-30 -20 -10 0 10 20 30

0

1000

2000

3000

4000Data: Data1_B

Model: Gauss

Equation: y=y0 + (A/(w*sqrt(PI/2)))*exp(-2*((x-xc)/w)^2)

Weighting:

y No weighting

Chi^2/DoF = 26392.98749

R^2 = 0.98215

y0 354.12642 ± 24.15184

xc 0.00098 ± 0.07989

w 10.29726 ± 0.18919

A 44757.8051 ± 893.56993

N.O

of p

art

icle

s

X axis [cm]

1m

Gauss fit of Data1_B

External beam

DTL

QM (triplet)

Target

Lead shielding

Concrete

Shielding

Beam energy / current : 20-MeV, 1uA (average) – 20mA peak, 50us, 1Hz

Target room dimension : 0.6m(width)x2.6m(length)x1.8m(height)

External beam diameter : 10cm (1m transport after beam window)

Beam window : 0.5mm thick Al

Shielding : gamma-10cm thick lead, neutron – 15cm thick concrete

License issued at June, 2007 (May, 2008 for 1uA license)

Irradiated Samples

103

178155

0

50

100

150

200

2007 2008 2009

10

100-MeV DTL tanks

tank cell # length

(m)

energy

(MeV)

DTL101 34 6.738 33.1

DTL102 28 6.707 45.3

DTL103 25 6.792 57.3

DTL104 23 6.877 69.1

DTL105 21 6.778 80.4

DTL106 20 6.870 91.7

DTL107 19 6.880 102.6

The fabrication of tanks up to 91MeV (DTL101~DTL106)has been finished.

Last tank will be fabricated in this fiscal year.

DTL tanks at Gyeonju office

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Beam Lines

BL25

BL21 BL22

BL23

BL24

BL105

BL101 BL102

BL103

BL104

Beam

Line

Application

Field

Rep.

Rate

Avg.

Current

Irradiation

Condition

TR21 Semiconductor 60 Hz 0.6 mA Hor. Ext.

TR22 Bio-Medical

Application 15 Hz 60 A Hor. Ext.

TR23 Materials, Energy &

Environment 30 Hz 0.6 mA Hor. Ext.

TR24 Basic Science 15 Hz 60 A Hor. Ext.

TR25 Radio Isotopes 60 Hz 1.2 mA Hor. Vac.

Beam

Line

Application

Field Rep. Rate

Avg.

Current

Irradiation

Condition

TR101 Radio Isotopes 60 Hz 0.6 mA Hor. Ext.

TR102 Medical Research

(Proton therapy) 7.5 Hz 10 A Hor. Ext.

TR103 Materials, Energy &

Environment 15 Hz 0.3 mA Hor. Ext.

TR104 Basic Science

Aero-Space 7.5 Hz 10 A Hor. Ext.

TR105 Neutron Source

Irradiation Test 60 Hz 1.6 mA Hor. Vac.

QM AC Dipole 25 BM 45 BM

Designed by reflecting user’s requirements

Developed components, BM, QM, ACM, & Beam Instruments

AC magnet distributes proton beams to three target rooms

Fabricated at IHEP (China)

Beam Line magnets

at Gyeonju office

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Options of PEFP Expansion

▪ 1 GeV Linac + Acc. Ring

⇒ 2 MW Spallation Neutron Source

⇒ 250, 400, 1000 MeV Proton Beam

▪ 200 MeV Linac + 2 GeV RCS

⇒ 0.5 MW Spallation Neutron Source

⇒ 250 MeV Proton Beam

▪ 400 MeV Linac + 8 GeV PS

⇒ 8 GeV Proton Beam

Two Options Proposed by Science & TEchnology Policy Institute (Feb, 2009)

: in a research report on “Long-term Planning for Proton Engineering Frontier Project”

Option 2

Option 1

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Design concept of PEFP RCS

Purpose

• Spallation neutron source: energy > 1GeV

• Medical application, Radioisotope, Nuclear physics, etc: energy ~ 450 MeV

Design concept

• PEFP 100MeV linac: injector of the RCS

• Final energy of RCS: 1 GeV (initial stage)

• Beam power of 60 kW (initial stage)

• Beam power of 500kW through 3 upgrade stages: injection and extraction energies,

repetition rate

• Injection: charge exchange and painting

• Extraction: fast and slow extraction

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Upgrade Plan

- Injection energy: from 100 MeV to 200 MeV

- Extraction energy: from 1 GeV to 2 GeV

- Repetition rate: from 15 Hz to 30 Hz

Injection

Energy

(MeV)

Extraction

Energy

(MeV)

Repetition

Rates

(Hz)

RF

Voltage

(kV)

Output

Power

(kW)

Initial 100 1000 15 75 60

1 100 1000 30 140 120

2 100 2000 30 260 250

3 200 2000 30 250 500

- In the following contents, we will focus on the RCS design study in initial stage

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Design parameters of PEFP RCS (initial stage)

Beam power (kW) : 60

Injection energy (MeV) : 100

Extraction energy (MeV) : 1000

Injection type : Charge exchange

Extraction type : Fast & Slow

Repetition rate (Hz) : 15

Circumference (m) : 224.16

Lattice structure and cell number : FODO and 20

Number of dipole : 32

Dipole field at 1 GeV (T) : 0.56

Super-period : 4

Tunes of QX /QY : 4.39/4.29

T : 4.4

RF harmonic number : 2

Required RF voltage : 75 kV

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Lattice Design (1/2)

• Four-fold symmetry :

To reduce lower-order resonance

• FODO lattice : pseudo 20 fold symmetry

• Dispersion free long straight sections :

– Injection and Extraction

– RF system

– Collimator

• Arc straight sections with missing dipole :

– Momentum collimation

– Slow extraction

Fast Extraction

Injection

Slow Extraction

RF

Ac

ce

lera

tion

RF

Ac

ce

lera

tio

n

Lattice Structure of PEFP RCS

Momentum Collimation

Collimator

65.08 m

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Lattice Design (2/2)

• Lattice: FODO

• Beam optics: MAD8

- dispersion suppression in the straight sections

• Maximum beta functions: 18.3 m / 18.7 m

• Dispersion function < 6.0 m

• beta functions and dispersion function

in one super-period

• Physical acceptance: 560 mm-mrad

• Collimator acceptance: 350 mm-mrad

• Transverse emittance: 280 mm-mrad

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Closed Orbit Distortion and Correction

Parameters Values

Magnetic Field Error of BM (dB/B) =10^-4

Magnetic Field Error of QM (dB/B) =10^-4

Displacement Error dx = dy = ds= 0.3mm

Rotation Error dx, dy, dz = 1.0 mrad

• MAD8: MICADO method

• Number of used BPM : 40

• Number of used corrector magnets : 40

• Maximum orbit distortion before/after corrections :

±10mm / ± 1mm

• Statistical analysis to determine the specification of the

corrector magnets.

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Chromaticity Correction

• Natural chromaticity: -4.32 / -4.64

• Assuming momentum spread : ±1%

• Maximum tune spread due to chromaticity:

dQx = 0.043, dQy = 0.046

(This is very small compared with the

space charge tune shift of 0.2)

Horizontal

Vertical

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Dynamic Aperture Study

• DYNAP routine in MAD8

• Tracking Method: LIE Algebra Method

• p/p < 0.7 % ( Injection Simulation Result )

• Closed Orbit Distortion Effects

• Multipole Effects of Dipole Magnet

• Most dominant effects: COD

(After correction, DA is larger than the stable

region)

p/p

effects

COD

effects

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• Painting scheme: Correlated • Macro – particles number: 4.0*104

• Circumference [m] : 224.16 • Linac peak current [mA] : 20

• Injection energy [MeV] : 100 • Injection time [ms] : 0.349

• Machine tunes(Qx/Qy) : 4.39/4.28 • Foil Thickness : 200 μg/cm2

• Linac emittance [pi mm mrad] : 1.0 • Number of Turns Injected : 200

• Beam emittance [pi mm mrad] : 280 • Space Charge effect : YES

Injection

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Transverse Correlated Painting

• correlated painting: ORBIT code

• Spatial beam size of horizontal and vertical coordinate: 55mm

bump function

x-y

x-x’

y-y’

distribution

injectiont

ttf 1)(

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Acceleration Simulation (1/3)

Time structure of the RCS input beam: injection energy: 100 MeV

repetition rate: 15 Hz

Linac beam just before injection : One macro-pulse includes 400 mid-pulses ( h=2 )

[ Macro-Pulse ] [ Mid-Pulse ]

RCS beam just after injection : One pulse includes two bunches

bunch length of 500 ns ~ Chopping factor of 57%

[ Pulse ] [ Bunch ]

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Acceleration Simulation (2/3)

- This simulation is for the initial stage: ORBIT

- Magnetic field ramping: sinusoidal

- Peak accelerating voltage < 75 kV

- Synchronous phase < 35.3

particle distribution in longitudinal phase space

magnetic field ramping

peak voltage

sync. phase

18.7 kV

75.0 kV

- Energy (E): Gaussian with = 0.2 MeV

- Phase (): uniform in 103 degrees

( chopping factor = 57%)

Energy

Phase

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Acceleration Simulation (3/3)

- final energy = 1003 MeV

- final capture rate = 99.9 %

200 turns

(100.1 MeV, 100 %)

6000 turns

(210.5 MeV, 99.93 %)

2000 turns

(113.8 MeV, 99.96 %)

10000 turns

(362.5 MeV, 99.91 %) 31200 turns

(1003 MeV, 99.91 %)

18000 turns

(700 MeV, 99.91 %)

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Summary

RCS is an option for PEFP expansion.

1 GeV RCS with the 100MeV linac as an injector

- upgradable up to 2 GeV (STEPI result for PEFP future study)

- fast extraction for spallation neutron source

- slow extraction for medical application, RI facility, nuclear physics

- lattice design, beam dynamics calculation including acceleration : MAD, ORBIT

Further work

- 2GeV study with 200 MeV injection.

- beam transport line (linac to RCS, RCS to target) and extraction

- components design

- instability issues, slow extraction, etc.

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Thank you for your attention !!