RFQ Beam Dynamics Design for Large Science Facilities and

Chuan Zhang

Institute for Applied Physics, Goethe-University

zhang@iap.uni-frankfurt.de

52nd ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams

HB2012, Beijing, China, Sept. 17-21, 2012

RFQ Beam Dynamics Design for Large Science

Facilities and Accelerator Driven Systems

RFQ

RFQ

Background

Real Examples

Conclusion Design

Procedures

3 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Accelerators for Science & Applications

Plot: U. Amaldi & K. Bethge

© ENEA, 2001

700 years 106 years

© ENEA, 2001

700 yeears 106 yeeeeears

4 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Accelerator-Based Science Centers

RHIC 2000

SNS 2006

LHC 2008

FAIR 2017

5 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Accelerator-Driven Systems

MYRRHA 2023

China ADS 2032

6 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

“Everything is Hard at the Beginning”

Cycle Duty Intensity Peak

Space- Charge

Sparking / Cooling

Low Beam Losses (Hands-on Maintenance)

Good Beam Quality (Downstream HoM, Quenching)

Short Length (Costs)

Modest V

+ +

+ +

Pic: J-PARC

7 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

LANL Four-Section Procedure

K-T Condition: to maintain a constant beam density for an adiabatic bunching • Longitudinal small oscillation frequency • Separatrix length in cm

20

2

2

rMcqUB

8 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

The Shortcomings of the LANL Method

T.P. Wangler, Principles of RF Linear Accelerators (1998), pp.241

GB: beam bunching is not efficient (will lead to a long structure).

SH: could be an important source of unstable particles.

Constant B: deal with the longitudinal and tranverse planes separately;

and MOST IMPORTANT, it ignores the space-charge effects.

9 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

New Four Section Procedure

NFSP FSP

Balanced

Transverse focusing strength B

Transverse

C. Zhang et al., NIM-A 2008 & PRST-AB 2004

Accelerated

Softened

d

NFSP FSP

Longitudinal

-270 -180 -90 0 90-0.2

-0.1

0.0

0.1

0.2

(Wi -

Ws) /

Ws

[deg]

s

separatrix

10 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

FAIR: Facility for Antiproton and Ion Research

95 keV 3.0 MeV 70 MeV

FAIR p-linac

GSI Today

FAIR

11 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

FAIR Proton RFQ vs. SNS RFQ

Parameters SNS FAIR

Ion H- H+

Duty cycle [%] 6.2 0.0144

Ipeak [mA] ~60 (35) 45 70 100

f [MHz] 402.5 325.44

Win [MeV] 0.065 0.095

Wout [MeV] 2.5 3

U [kV] 83 80

intrans.,norm., rms [ mm mrad] 0.2 0.3

outtrans.,norm., rms [ mm mrad] 0.21

0.21 0.30 0.30

0.30 0.30

0.31 0.31

outlongi., rms [ MeV deg] 0.103 0.163 0.153 0.152

L [m] 3.7 3.2

Transmission [%] ~90 98.7 97.2 95.3

C. Zhang, A. Schempp, NIM-A 2009

SNS

Data: J. Staples

FAIR

For accelerated particles only

12 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Design Results of the FAIR Proton RFQ

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0 20 40 60 80 100 120 140 160 180 200 220Cell Number

εno

rm.,

rms

[π c

m m

rad

]

x, 100%

y, 100%

z, 100%

z, 99%

max.: (177, 0.4)

95

95.5

96

96.5

97

97.5

98

98.5

99

99.5

100

0 25 50 75 100 125 150 175 200 225 250 275 300 325 350

Z [cm]

Tota

l Bea

m T

rans

mis

sion

T [%

]

45mA, designed 70mA, unmatched 70mA, matched100mA, unmatched100mA, matched

C. Zhang, A. Schempp, NIM2009

19799 / 125202

LEBT Output Dist. Provided by L. Groening

13 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

( 2011 – 2014 )

( 2005 – 2010 )

European ADS Projects

Specifications XT-ADS EFIT MAX

Design current 5 mA 30 mA 5 mA

Beam trips >1s: < 5 per three-month

>1s: < 3 per year

>3s: < 10 per three-month

Time structure CW, with 200μs zero-current holes N. Pichoff, EPAC 2001

14 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Design of the EUROTRANS RFQ

30mA

30mA

5mA

Eth=2.16MeV for 65Cu(p, n)65Zn

Total losses: 0.106%

15 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

EUROTRANS: a Toy! MAX: a Real Boy !

Rp ~ f -1.5

H. Vernon Smith, LINAC 2000

9-Hour CW Operation @ LEDA

Plot: MAX Deliverable 2.1

Ek: 1.8

16 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

EUROTRANS RFQ vs. MAX RFQ

C. Zhang, H. Klein, H. Podlech et al., IPAC 2011, WEPS043

17 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Project X Injector Experiment & China ADS Injector II

PXIE at FNAL China ADS Project

Parameters PXIE China ADS

Ion type H- H+

Input energy [keV] 30 35

Output energy [MeV] 2.1 2.1

Duty factor [%] 100 100

Frequency [MHz] 162.5 162.5

Beam current [mA] 5 (nominal); 1-10 15 (nominal); 1-20

Input transverse emittance [ mm-mrad] 0.25 (norm. rms) 0.3 (norm. rms)

Transverse emittance growth [%] ≤10 ≤10

Output longitudinal emittance [keV-nsec] ≤0.8 ≤1.0

Transmission [%] 95 95

TWISS Parameter [%] ≤1.5 ≤1.5

18 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Evolutions of Main RFQ Parameters

19 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Beam Transport Simulations

20 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Conclusions

• The RFQ accelerator is the standard injector.

• Challenges to modern RFQs: • High beam intensity

• High duty factor even CW

• An efficient design method for modern RFQs, “New Four

Section Procedure”, has been developed:

• Applied for the designs of more than 20 RFQs: • Ion species: proton – uranium (A/q: 1 – 59.5)

• Frequency [MHz]: 36.136 – 352

• Peak beam intensity [mA]: 0 – 200 (300)

• Duty factor [%]: 0.0144 – 100

• Proven experimentally: • New EBIS RFQ for BNL

• New HLI RFQ for GSI

M. Okamura et. al., PAC 2009

21 HB2012, Beijing, China, Sept. 19, 2012 Chuan Zhang

Vielen Dank

Thank You