Upgrading of the accelerator facilities at Upgrading of the accelerator facilities at

iThemba Laboratory for Accelerator Based iThemba Laboratory for Accelerator Based

Sciences (iThemba LABS) to increase the Sciences (iThemba LABS) to increase the

production of radionuclidesproduction of radionuclides

Layout of the talk

� Overview of facilities at iThemba LABS which operates a 200 MeV

separated-sector cyclotron and two 8 MeV solid-pole injector

cyclotrons

� A flat-top system for the light-ion injector cyclotron (SPC1)

�An additional buncher for the transfer beam line

�A flat-top system for the separated-sector cyclotron (SSC)

�A new vertical beam line for radionuclide production

� Beam splitting and an additional horizontal beam line for radionuclide

production

�Diagnostic equipment for high-intensity beams:

� Non-destructive beam position monitors

� High intensity 50kW beam stop

Separated-Sector Cyclotron FacilitySeparated-Sector Cyclotron Facility

0 10 20 m

beambeamswingerswinger

SSCSSC

SPC1SPC1SPC2 SPC2

Polarized ion sourcePolarized ion source

ECR ion sourceECR ion source

RadioisotopeRadioisotopeproductionproduction

Neutron therapyNeutron therapy

electronicselectronics electronicselectronics

Proton therapyProton therapy

Nuclear Physics Exp. vaultsNuclear Physics Exp. vaults

Rf-system

Sector Magnet

Rf-system

Low Energy In

High Energy Out

The SSC•4 separate sectors

(SSC)

•Variable-energy

machine

•K = 200 MeV

•RF frequency : 7

to 26 MHz

Solid-pole injector cyclotron 1 (SPC1)•K = 8 MeV

•Internal PIG

ion source

•Radionuclide

production

•Radiotherapy

CYCLOTRON OPERATING SCHEDULE

0.0

0

2.0

0

4.0

0

6.0

0

8.0

0

10

.00

12

.00

14

.00

16

.00

18

.00

20

.00

22

.00

24

.00

M ONDAY

TUESDAY

WEDNESDAY

THURSDAY

FRIDAY

SATURDAY

SUNDAY

Time of day

NEUTRON THERAPY PROTON THERAPY ISOTOPE PRODUCTION NUCLEAR PHYSICS ENERGY CHANGE

CYCLOTRON OPERATING SCHEDULE

-1

0

1

0 60 120 180 240 300 360

Phase (degrees)

Am

plitu

de

main voltage

3th harmonic voltage

flat-top voltage

-1

0

1

0 60 120 180 240 300 360

Phase (degrees)

Am

plitu

de

main voltage

3th harmonic voltage

flat-top voltage

A higher-order harmonic is added to provide a flatter

accelerating voltage for less energy spread, smaller beam

widths and better beam extraction

FLAT-TOPPING SYSTEMS AT iTHEMBA LABS

Without flat-topping

SPC1 BUNCHER SSC18°°°° 12°°°°

320 µA

SPC1 SSC

With flat-topping

45°°°° 25°°°°

� TO IMPROVE BOTH THE BEAM QUALITY AND INTENSITY

OF THE 66 MeV p+ BEAM FOR ISOTOPE PRODUCTION

∼∼∼∼ 400 µµµµA

ADDITIONAL

BUNCHER

h = 2650 µµµµA h = 4

h = 2

BUNCHER

With flat-topping

120µA

99.7% transmission

The flat-top system of SPC1Capacitive

Coupling

Tune the 2nd

resonance of the

“rf cavity” to the

5th harmonic of

the fundamental

frequency

SPC1 SIDE VIEW

f0 = 16.31 MHz

for 66 MeV p+

Main Resonator

Two SPC1 flat-top resonators

Advantages of flat-topping :

•Higher beam intensity

•Better beam quality – less energy spread

(a) Beam orbit pattern with the

5th harmonic flat-top system(b) Beam orbit pattern without

the 5th harmonic flat-top system

S S C w i t h F L A T - T O P P I N G R E S O N A T O R

EEC

POSITION OF

FLAT-TOPPING

RESONATOR

Low energy inLow energy in

INJECTIONINJECTIONEXTRACTIONEXTRACTION

1.1.1.1. lower dee housinglower dee housinglower dee housinglower dee housing 2.2.2.2. acceleration gapacceleration gapacceleration gapacceleration gap 3.3.3.3. top of the upper top of the upper top of the upper top of the upper

deedeedeedee plateplateplateplate 4.4.4.4. beam gapbeam gapbeam gapbeam gap 5.5.5.5. shortshortshortshort----circuit plate at injectioncircuit plate at injectioncircuit plate at injectioncircuit plate at injection 6.6.6.6.

shortshortshortshort----circuit plate at extractioncircuit plate at extractioncircuit plate at extractioncircuit plate at extraction 7.7.7.7. and and and and 8.8.8.8. ports for coupling and ports for coupling and ports for coupling and ports for coupling and

tuningtuningtuningtuning components components components components 9.9.9.9. top of the bottom dee platetop of the bottom dee platetop of the bottom dee platetop of the bottom dee plate 10.10.10.10. plate for plate for plate for plate for

detuningdetuningdetuningdetuning of an unwanted resonance modeof an unwanted resonance modeof an unwanted resonance modeof an unwanted resonance mode....

The 3-D drawing of the SSC flat-top resonator

Installation of the flat-top resonator

Bombardment station for radionuclide production

Thick target radionuclide production

20 20 20 20 555516.016.016.016.061.5 61.5 61.5 61.5 →→→→ 20.020.020.020.0AgAgAgAg103103103103PdPdPdPd

202020201.51.51.51.52.62.62.62.628.6 28.6 28.6 28.6 →→→→ 21.021.021.021.0TlTlTlTl201201201201TlTlTlTl

61.5 61.5 61.5 61.5 →→→→ 25.525.525.525.5

61.5 61.5 61.5 61.5 →→→→ 40.040.040.040.0

62.6 62.6 62.6 62.6 →→→→ 47.647.647.647.6

61.5 61.5 61.5 61.5 →→→→ 39.439.439.439.4

62.6 62.6 62.6 62.6 →→→→ 57.757.757.757.7

34.0 34.0 34.0 34.0 →→→→ 2.42.42.42.4

62.6 62.6 62.6 62.6 →→→→ 39.439.439.439.4

34.3 34.3 34.3 34.3 →→→→ 18.118.118.118.1

60.7 60.7 60.7 60.7 →→→→ 38.738.738.738.7

Energy windowEnergy windowEnergy windowEnergy window

(MeV)(MeV)(MeV)(MeV)

20202020777715.015.015.015.0PrPrPrPr139139139139CeCeCeCe

20202020121212127.07.07.07.0MgMgMgMg22222222NaNaNaNa

2020202066667.07.07.07.0NaINaINaINaI123123123123IIII

2020202099998.68.68.68.6RbClRbClRbClRbCl82828282SrSrSrSr

1515151533331.31.31.31.3RbClRbClRbClRbCl81818181RbRbRbRb

20202020

20202020

4444

4444

5.0 5.0 5.0 5.0

5.05.05.05.0

69696969GaGaGaGa71717171Ga Ga Ga Ga

68686868GeGeGeGe

20202020

20202020

2222

6666

4.44.44.44.4

7.4 7.4 7.4 7.4

ZnZnZnZn

GeGeGeGe

67676767GaGaGaGa

Diameter of Diameter of Diameter of Diameter of

discdiscdiscdisc

(mm)(mm)(mm)(mm)

ThicknessThicknessThicknessThickness

(mm)(mm)(mm)(mm)

MassMassMassMass

(gram)(gram)(gram)(gram)

TargetTargetTargetTargetRadionuclideRadionuclideRadionuclideRadionuclide

3D drawing of the new vertical beam line

1. the horizontal beam line

2. the 90°°°° bending magnet

3. two quadrupole magnets

4. sweeper magnets

5. steerer magnet

6. vacuum chamber for diagnostic

equipment with a Faraday cup,

harp and capacitive probe for

current measurement

7. shielding lift mechanism for

target exchanges

8. 9. and 10. inner iron shield

11. target

12. water tanks with a 4%

ammonium pentaborate solution

13. iron shield

14. borated paraffin-wax shield

15. support structure.

The new vertical beam line for radionuclide production

The planned beam lines for supplying two targets, simultaneously,

with beam for radionuclide production. The main components are the

electrostatic channel EC, the septum magnet SPM, the bending magnet

BM1and the existing switcher magnet SW. The bending magnet BM2

deflects the beam downward into the vertical beam line. Q, SM and D

designate quadrupole magnets, steering magnets and diagnostic

vacuum chambers, respectively.

New beam line with beam splitting for radioisotope

production

Installation of the new high-power beam stop

Non-destructive beam position monitor

Positions at which BPMs have been installed

Beam position display with non-destructive beam position

monitors after automatic alignment at the second monitor

Beam Alignment on x– and y– axes

The scale ranges are from minus to plus 30 mm.

I would like to thank the IAEA for the financial support.

Enkosi, Ngiyabonga, Kea le boga

Thank you !