1. Beam dynamics simulation for HEBT at KHIMA Synchrotron System
Dong Hyun An, Heejoong Yim, Garam Hahn and Chawon Park*
(Korea Institute of Radiological & Medical Sciences)
Nov. 13th, 2014
International Conference on Accelerators and Beam Utilization

2. CONTENTS
Clinical requirements & Beam specification for clinical requirements
Layout of KIRAMS-Synchrotron system
Beam Transport System (HEBT)
- Specifications & components
- Requirements & Main features
Modulated sections
Boundary conditions
Electrostatic septum
Chopper
- Horizontal & Vertical lines
Error analysis
Beam loss analysis
Summary

3. Clinical Requirements
Clinical Requirements For Carbon Therapy
Carbon Beam Range : 3.0 to 27.0 g/㎠
Range Modulation Steps : 0.1~0.2 g/㎠
Additional Distal Dose Fall-Off : < 2 mm
Dose Rate for 1 liter : 2 Gy/min
Beam size at Isocenter : 4~10 mm FWHM
[1] Accelerator-related
Clinical Requirements 1
Beam particle species
proton, carbon-12 2
Beam Range
3.0 to 27.0
g/㎠ 3
Bragg peak modulation steps
0.1~0.2 4
Range adjustment
0.1 5
Adjustment/modulation accuracy
≤± 0.025 6
Distal dose fall-off (80%-20%)
(in addition to the intrinsic DFO)
< 2 mm 7
Average dose rate
(for treatment volume of 1000 ㎤)
Gy/min
[3] Irradiation-related
Clinical Requirements 13
Beam position step
0.1 ㎜ 14
Beam position accuracy
≤± 0.05 15
Delivery dose precision
≤± 2.5 % 16
Field Size
2x2 to 20x20 ㎠ 17
Field position accuracy
≤± 0.5 18
Field dimension step 1 19
Field size accuracy 20
Lateral penumbra (80%-20%)
(for each side at the phantom surface)
< 2 21
Field homogeneity (orthogonal) Rt
≤ 105 22
Field homogeneity (longitudinal) Rl
≤ 111 23
Field symmetry 24
Source to surface distance (SSD)
> 4 m
[2] HEBT-related
Clinical Requirements 8
Beam size (FWHM)
4 to 10 ㎜ 9
Beam size step 1 10
Beam size accuracy
≤± 0.20 11
Beam axis height (above floor)
120 ㎝ 12
Irradiation Room
1 H (scanning)
1 H+V (scanning)
1 H+V (SOBP)
1 H (scanning, Research)
Beam energy
Beam Intensity
Beam Size and Position

4. Beam Specifications for clinical requirements
items
Beam Specifications for KIRAMS 1
Beam particle species
proton, carbon-12
Type of ion
1H3+ for proton and 12C4+ for carbon at ECRIS 2
Beam Range
3.0 to 27.0
(without scatterers)
g/㎠
Energy range
60~230 MeV for proton
MeV/u for carbon
(with the consideration of 3-5 ㎝ scatterer) 3
Bragg peak modulation steps
0.1~0.2
Energy steps
>250 steps 4
Range adjustment
0.1
Energy adjustment
1.101~0.416 MeV for proton
2.030~0.878 MeV/u for carbon 5
Adjustment/modulation accuracy
≤± 0.025
Energy adjustment accuracy
≤± 0.274~0.104 MeV for proton
≤± 0.505~0.219 MeV/u for carbon 6
Distal dose fall-off (80%-20%)
(in addition to the intrinsic DFO)
< 2 ㎜
Energy spread
[1σ in Gaussian dist.]
< 0.15 % at 230 MeV for proton
< 0.13 % at 430MeV/u for carbon 7
Average dose rate
(for treatment volume of 1000 ㎤)
㏉/min
Beam intensity
Min./Max. No. of particles per spill
1x108 / 1x1010 for proton
4x106 / 4x108 for carbon
Nominal number of spills : 60 spills in 2~3 min 8
Beam size (FWHM)
4 to 10
4 to 10 ㎜ 9
Beam size step
1 ㎜ 10
Beam size accuracy
≤± 0.2
≤± 0.2 ㎜ 11
Beam axis height (above floor)
120 ㎝
Beam axis height
120 ㎝ 12
Irradiation Room
1 H (scanning)
1 H+V (scanning)
1 H+V (SOBP)
1 H (scanning, Research)
Beam energy
Beam Intensity
Beam Size and Position

5. Layout of KIRAMS-SYNC system
KIRAMS Synchrotron System
HEBT
RFQ
0.4 MeV/u
IH-DTL
7 MeV/u
ECRIS
8keV/u
for H3+ and 12C4+
MEBT
p and 12C6+
SYNCHROTRON
ACCELERATOR
Extraction
Injection
Treatment
Room 3 (H)
scanning
Room 2 (H+V)
Room 1 (H+V)
SOBP
Research
Room (H)
Stripper
Beam particle species
p, 12C
Type of ion
1H3+ for proton and 12C4+ for carbon at ECRIS
Beam Range
3.0 g/㎠ to 27.0 g/㎠
Energy range
MeV for proton
MeV/u for carbon
Dose rate
2 ㏉/min for 1 liter
Beam intensity
1x108 ~ 1x1010 protons/spill at Isocenter
4x106 ~ 4x108 carbons/spill at Isocenter
Nominal number of spills : 60 spills in 2~3 min
Beam size
4 to 10 ㎜ FWHM
Injection
Multi-turn injection
Field Size
20x20 ㎠
Extraction
RF-KO slow-extraction
Irradiation Room
Gating / 1 H (scanning), 1 H+V (scanning), 1 H+V (SOBP), 1 H (scanning, Research)
Machine Dimension
37.9 x 66.4 x 17.6(H) m

6. HEBT Specifications Treatment : 1 H, 2 H+V Research : 1 H
RFQ
0.4 MeV/u
IH-DTL
7 MeV/u
ECRIS
8keV/u
for H3+ and 12C4+
MEBT
p and 12C6+
SYNCHROTRON
ACCELERATOR
Extraction
Injection
Treatment
Room 3 (H)
scanning
Room 2 (H+V)
Room 1 (H+V)
SOBP
Research
Room (H)
Stripper
Treatment : 1 H, 2 H+V
Research : 1 H
Phase Shifter and Stepper
Beam Chopping system
Beam direction
Irradiation
Method
Ion
type
Beam
energy
Size at isocenter
Treatment room H1
H+V fixed beams
SOBP
proton
C-12
MeV
MeV/u
4-10 mm FWHM H2
Scanning H3
H fixed beams
Research room HR

7. HEBT Components Chopper system Phase shifter & stepper
Quantity of component determined after beam dynamics simulation
Family ID/Total N
Magnets
Dipole
1 / 3 [22.5 deg] 10
2 / 3 [30.0 deg] 3
3 / 3 [45.0 deg] 8
Quadrupole
1 / 2 [L=350] 62
2 / 2 [L=550] 17
H/V Corrector
1 / 1 22
Chopper 4
Monitors
Profile 23
Qualification 1

8. Requirements & Main Feature
Layout depends on the configuration of the required beam ports in the different treatment rooms
Two type of treatment mode: active + passive
H+V fixed beam lines provide larger flexibility in applying radiation fields from various angles during one fraction
Design based on PIMMS
Beam size at the iso center in any beam line can be changed by altering the strength of quadrupoles on the phase shifter (for horizontal plane) & stepper (for vertical plane) in common part of the main extraction line, while keeping all other magnets setting constant
Has a region for dispersion free separately
Beam delivery: in case of active scanning
Horizontal/vertical fast scanning system with magnets for pencil beam
Energy variation directly with the synchrotron
Thanks to modulated design, Flexibility is guaranteed adding a new treatment rooms in the future

9. Boundary conditions for extraction line design
Dispersion vector at the entry to the extraction line (ES) is determined by the characteristics of the bar of charge for different momentum in horizontal phase space
Even though there is difference among different momentum, the dispersion vector is not so significantly different and can be ignored the difference
For the lowest energy ( E=110 MeV/u with carbon beam)
beam is a segment of the extraction separatrix

10. Boundary conditions for extraction line design (cont’d)
Twiss functions at entry (ES in ring)
bx = 15 m
ax = 0
‘Free’ parameter
ex = 1.67 p mm mrad
‘Unfilled’ ellipse –’free’
by = m
ay =
Values from ring
ey,RMS = to
Carbon range from ring
(110 ~ 430 MeV/u)
ey,RMS = to
Proton range from ring
(60 ~ 230 MeV)
Dx =
Dx’ =
Determined by extraction geometry
Dy = 0
Dy’ = 0
by = 2 m, mx = np at isocenter
Twiss functions at Isocenter
bx = 5 m
ax = 0
According to medical specifications and earlier choice of ‘free’ parameters
by = 2 to 27 m
ay = 0
Dx = 0
Dx’ = 0
Dy = 0
Dy’ = 0
Control module for combined beam sizes:
Horizontal plane: By Variation of the horizontal phase advance (mx), since the beam is a segment of the extraction separatrix that is represented as a ‘diameter’ of an unfilled ellipse (due to slow extraction)
Vertical plane: By Adjustment of vertical beta function (by)
by = 27 m, mx = (n+1/2)p at isocenter

11. Twiss functions at matching section
ES to Matching section
For some value of momentum spread (Dp/p ~-0.5*10-3),
the central orbit will be asymmetric in the dispersion region
Dispersion and its derivative on horizontal phase space are determined by the disposition of the bars of charge for different momentum
In this section, module provides the correct matching of the beam from the extraction at the electrostatic septum
Betatron amplitude [m] vs. distance [m]
Horizontal beam envelopes [m]
Vertical beam envelopes [m]
Dispersion [m]
Electrostatic septum (ES)
Twiss functions at matching section
bx = 7 m
ax = 0
Free parameters
Range from “stepper”
by = 2 to 27 m
ay = 0
Dx = 0
Dx’ = 0
Dy = 0
Dy’ = 0

12. Chopper
Footprint of Beam
Chopper system is composed of the four fast dipole magnets which are interleaved at three-30 deg. bending magnets
Switch the beam on and off rapidly ( < 200 ms)
Switch the beam on and off without perturbing its position at the patient
Be fail safe in that the power-off state is also the beam-off state
@ Qualification monitor (QM)
(QIM + QPM) s x
Basic information for manufacturing chopper magnet
Parameters
Values
Unit
Comments
Name
CPM
Chopper Dipole
Type
Horizontal
Maximum rigidity
6.62 Tm
@ E = 430 MeV/u
Deflection angle
5.5
mrad
Effective length
200 mm
@ Max. field
= 0.18 T
Good field region (diameter) 80
Integrated field quality
< ± 2x10-3
3D field quality
No. of magnets 4
ea.

13. Twiss functions at each isocenter
Horizontal lines
Ex) Up to TR3 through horizontal common line
Horizontal lines are composed of the TR3, TR2, TR1 and Research room
composed of two 22.5 bending magnets and many focusing magnets on lattice design level
Include phase shifter and stepper in common section (named as ‘stepper’)
By changing the corresponding magnetic strength on each quadrupole, the clinically necessary beam width at isocenter is to be determined
Corresponding k (=g/(Br)) for each by, where mx (phase advance)= 6.0 p is set
Betatron amplitude [m] vs. distance [m]
Dispersion [m]
Horizontal beam envelopes [m]
Vertical beam envelopes [m]
*k (field strength) [1/m2] at each quadrupole in stepper mx = 6.0 p), for TR3 b 2 5 10 15 20 27
QPM-07
-1.409
-1.418
-1.424
-1.427
-1.428
-1.429
QPM-08
1.306
1.431
1.482
1.487
1.486
1.471
QPM-09
-2.488
-2.467
-2.449
-2.437
-2.430
-2.425
QPM-10
1.176
1.179
1.185
1.191
1.184
1.183
QPM-11
-1.831
-1.837
-1.834
-1.829
-1.824
-1.819
QPM-12
0.806
0.770
0.723
0.685
0.663
0.642
Twiss functions at each isocenter
bx = 5 m
ax = 0
According to medical specifications and earlier choice of ‘free’ parameters
by = 2 to 27 m
ay = 0
Dx = 0
Dx’ = 0
Dy = 0
Dy’ = 0
* In WinAgile code, the negative value of ‘k’ corresponds to the focusing quadrupole, vise versa

14. Twiss functions at each isocenter
Vertical lines
Betatron amplitude [m] vs. distance [m]
Dispersion [m]
Horizontal beam envelopes [m]
Vertical beam envelopes [m]
Ex) Up to TR1 through vertical common line
Vertical lines are composed of the TR2, TR1 room through vertical common line
includes few 22.5 and 45 bending magnets and many focusing magnets in lattice design
[3D layout of the vertical line up to IR1]
k (Field strength) [1/m2] at each quadrupole in stepper mx = 7.0 p), for TR1 b 2 5 10 15 20 27
QPM-07
-1.168
-1.184
-1.049
-1.046
-1.044
-1.041
QPM-08
1.640
1.660
1.568
1.615
1.645
1.672
QPM-09
-2.493
-2.515
-2.522
-2.526
-2.530
-2.537
QPM-10
2.985
2.984
2.976
2.955
2.929
2.911
QPM-11
-1.741
-1.751
-1.747
-1.756
-1.763
QPM-12
0.926
0.962
0.967
0.977
0.990
1.011
Twiss functions at each isocenter
bx = 5 m
ax = 0
According to medical specifications and earlier choice of ‘free’ parameters
by = 2 to 27 m
ay = 0
Dx = 0
Dx’ = 0
Dy = 0
Dy’ = 0
* In WinAgile code, the negative value of ‘k’ corresponds to the focusing quadrupole, vise versa

15. Error analysis (For static errors)
Error type
Tolerance (1 s)
Distribution (3 s)
Quadrupole alignment x,y,z
0.3 mm
Truncated Gaussian
Quadrupole tilt
0.3mrad
Bending alignment x,y,z
0.3mm
Bending tilt
Integrated dipole field error (ΔBL/BL)
0.001
Integrated quadrupole field error
Monitor reading error
±0.5mm
Flat
Need to correct the orbit due to various distortion elements
Using MAD-X code, simulations are performed with a sample of 1000 randomly generated machines
With a standard alignment technique, % of the machines after correction in the horizontal plane and 99.9 % in the vertical plane are within the allowed global closed orbit margin ( ±7.5 mm in both plane)
Excursion vs. distance up to IR2 through vertical common line
1000 randomly generated machines
Profile monitor
Corrector

16. Error analysis (For static errors)ES
Iso ROOM2 MS
Stepper VC V2
At iso-center
x-excursion vs. Distance
Monitor
Corrector
hc_crm_01
v2_crm_02 ES MS VC V2
1000 randomly generated machine
y-excursion vs. Distance

17. Error analysis (For static errors)
Basic information for manufacturing the steerer
Parameters
Values
Unit
Comments
Name
Corr
Type
H/V combined
Maximum rigidity
6.62 Tm
@ E = 430 MeV/u
Deflection angle 5
mrad
Effective length
300 mm
@ Max. field
= 0.11 T
Free aperture diameter 90
Good field region (diameter) 80
Integrated field quality
< ± 2x10-3
3D field quality
Field stability
500
ppm
No. of magnets 22
ea.
Maximum required kicking angles are estimated to have the value less than 3.5 mrad in both plane
Number of needed correctors for whole lines is to be 22

18. Error analysis (For dynamic errors)
As an unavoidable errors which can’t be corrected with steerer,
~10% of static error tolerance ( stability of Magnet Power supply etc.) are used
x-excursion vs. Distance
Monitor
Corrector
hc_crm_01
v2_crm_02 ES MS VC V2
y-excursion vs. Distance

19. Error analysis (For dynamic errors)
Excursion distributions from MS to Iso center through v2 line:
Contributed effect on orbit distortion by Dynamic errors are small and comparable with corrected one for static errors
Zoomed

20. Beam loss analysis with TRACK
Matching section to IR1 through v1 line ( carbon E = 430 MeV/u)
orbit margins: Applying 7.5 mm for horizontal- and vertical-plane respectively
Using beam pipe having 66 mm of inner diameter
Layout with MadX
In phase space
Transmission ratio:99.93 %

21. Geometric spec. of HEBT elements
Based on the beam optics study in the whole horizontal and vertical beam lines, the sizes of aperture are expected less than 30.5 mm and 29.5 mm for both plane
Horizontal
Vertical
General
remarks
Maximum beam size (x or y) [mm]
±23
±22
Closed orbit margin (Dx1, Dy1) [mm]
±7.5
Sagitta in dipoles (Dx2) [mm]
±14
Quadrupoles
Good field region [mm]
±30
Dipoles
±40
±25
Ex) longest line through V1
With TRACK

22. Summary
Lattice design was done for whole lines up to each treatment room with several lattice programs
Since the design applied the modulation scheme, Beam size at the iso center can be changed freely for both horizontal- and vertical-plane respectively
Chopper magnet system is utilized to control the beam stopping immediately
Error study was done with various error sources
Determined the specification and position of corrector and beam profile (position) monitors on HEBT line
Served the information for lattice components to manufacture the components
Real tracking analysis should be done with applying the real 3D fringe field of each magnet getting an information from specific magnet design

23. Thanks for your attention
HEBT
RFQ
0.4 MeV/u
IH-DTL
7 MeV/u
ECRIS
8keV/u
for H3+ and 12C4+
MEBT
p and 12C6+
SYNCHROTRON
ACCELERATOR
Extraction
Injection
Treatment
Room 3 (H)
scanning
Room 2 (H+V)
Room 1 (H+V)
SOBP
Research
Room (H)
Stripper
Thanks for your attention

24. Back up

25. Beam Intensity SYNCHROTRON ACCELERATOR Carbon Scanning Spread Proton
HEBT
RFQ
0.4 MeV/u
IH-DTL
7 MeV/u
ECRIS
8keV/u
for H3+ and 12C4+
MEBT
p and 12C6+
SYNCHROTRON
ACCELERATOR
Extraction
Injection
ηHEBT=0.95
ηcap=0.80
ηMEBT=0.95(C)
ηMEBT=0.90(p)
ηDTL=0.80
ηRFQ=0.80
ηLEBT=0.95
ηFOIL=0.95(C)
ηFOIL=0.90(p)
ηinj=0.23(C)
ηinj=0.11(p)
Ηacc=1.00
ηrebunch=0.90
ηstab=0.90
ηext=0.90
ηSCAN=0.7
ηSCAT=0.3 1 2 8 3 4 5 6 7 10 11 9 12 13
1. Isocenter, 2. Before irradiation, 3. After extraction, 4. After acceleration, 5. After capture, 6. After injection, 7. MTInjection, 8. After MEBT, 9. After FOIL, 10. After DTL, 11. After RFQ, 12. After LEBT, 13. ECR extraction
Isocenter
Carbon
Scanning
Spread
Proton
⑬ ECRIS extraction
Beam current :
No. of particles :
12C4+
122 euA
1.90x1014
285 euA
4.45x1014
H3+
328 euA
2.05x1015
765 euA
4.77x1015
⑫ After LEBT
1.81x1014
4.22x1014
1.94x1015
4.54x1015
⑪ After RFQ
1.45x1014
3.38x1014
1.56x1015
3.63x1015
⑩ After DTL
74 euA
1.16x1014
173 euA
2.70x1014
199 euA
1.24x1015
465 euA
2.90x1015
⑨ After FOIL
12C6+
1.10x1014
2.57x1014
proton
3.36x1015
7.84x1015
⑧ After MEBT
100 euA
1.04x1014
235 euA
2.44x1014
485 euA
3.02x1015
1130 euA
7.05x1015
⑦ MT Injection
[16turns]
3.67x109
8.57x109
[28turns]
1.87x1011
4.35x1011
⑥ After Injection
8.26x108
1.93x109
2.07x1010
4.82x1010
⑤ After Capture
7.42x108
1.74x109
1.86x1010
4.34x1010
④ After acceleration
6.69x108
1.56x109
1.67x1010
3.90x1010
③ After extraction[/spill]
6.02x108
1.41x109
1.51x1010
3.51x1010
② Before Irradiation
[/spill]
5.72x108
1.34x109
Scattered
1.43x1010
3.34x1010
① Isocenter[/spill]
4.00x108
1.00x1010

26. Time structure
Dipole Magnet
Extraction
RF cavity
Injection

27. Specifications of magnets (dipole)
For magnets having different bending angle, share the same cross-sectional yoke plates
Courtesy of Hyunwook Kim
(Engineering Team)

28. Specifications of magnets (quadrupole)
For magnets having different length, use the same cross-sectional yoke plate and coil structure
Courtesy of Hyunwook Kim (Engineering Team)