ECPM 2006, Nice, France, 2-4 November 2006 1 DESIGN STUDIES OF THE 300AMEV SUPERCONDUCTING CYCLOTRON...

ECPM 2006, Nice, France, 2-4 November 2006 1

DESIGN STUDIES OF THE 300AMEV SUPERCONDUCTING

CYCLOTRON FOR HADRONTHERAPY

Mario Maggiore

Laboratori Nazionali del SudCatania, Italy


OUTLINE

INTRODUCTION

MAGNETIC CIRCUIT

PRELIMINARY EXTRACTION RESULTS

INJECTION STUDY

CAVITY DESIGN

CONCLUSIONS


The 300 AMeV choice

At the end of 2005 the SCENT project has been completed. The preliminary studies of a superconducting cyclotron able to accelerate ions with mass to charge ratio of 0,5 up to energy of 250A MeV were carried out by the Accelerator R&D group of LNS.

In the March 2006, we have investigated the possibility to increase the extraction energy of the carbon ions up to 300 AMeV, keeping unchanged the main parameter of the machine. Moreover, we tried to extract the proton beam by the stripping process at the energy of 250 AMeV.

Today…”The agreement between the Italian National Institute for Nuclear Physics and the Belgian firm Iba for the marketing, in biomedical field, of the first superconductive cyclotron producing protons and carbon ions as well, has been made official today. The innovative project, that will developed by the Infn Southern National Laboratories and realized with the contribution of the Iba specific twenty-year experience in the field of cyclotrons for medical applications, was conceived for the hospital centres of oncological hadrontherapy.” Medical News Today, 23 July 2006


Why 300AMeV is better than 250AMeV (carbon ions) ?

Courtesy of HIMAC

C12 @ 300 AMeV 174 mm depth

C12 @ 250 AMeV

75 % of targets


Two machines not quite similar…

250 AMeV (p, 12C6+)300 AMeV (12C6+)

250MeV (p)

Pole Radius 1325 mm

B average (Rext) 3.9 tesla 4.2 tesla

Yoke diameter 4900 mm 5100 mm

Yoke height 2900 mm

Hill gap 50 mm 30 mm

Valley gap 1050 mm 900 mm(variable)

Max spiral angle 73 deg 80 deg

Weight 340 tons 420 tons

Current density 41 amp/mm2 45 amp/mm2

Extraction Syst.2 ED placed in the

hills + stripping 2 ED placed in the

valleys + stripping

Number of cavities 4

RF frequency(h=4) 93 MHz 97 MHz


Magnetic circuit design

A wider valley (45 deg) allows to get an higher energy gain per turn and to place a wide ED (43 deg) in order to keep relatively low the local electric field and make easy the extraction process.

0 10 20 30 40 50 60 70 80 90 100 110 120 1300

8

16

24

32

40

48

56

64

72

80

R 0( )

deg

R 1( ) 8 deg

deg

R

But…

andSpiral angle versus radius

flutter


Preliminary extraction results

-1-0,8-0,6-0,4-0,2

00,20,40,60,8

1

0 100 200 300 400

[cm

]

[degree]-1

-0,8-0,6-0,4-0,2

00,20,40,60,8

1

0 100 200 300 400

[cm

]

[degree]

-1,25

-0,75

-0,25

0,25

0,75

1,25

0 50 100 150 200 250 300 350 400

[cm

]

[Degree]-1,25

-0,75

-0,25

0,25

0,75

1,25

0 50 100 150 200 250 300 350 400

[cm

]

[Degree]

ED1 ED2

Radial env.

Vertical env.

MC

Protons by stripping @ 246 MeV

Carbon by ED (E=92KV/cm) @ 300A MeV

Beam envelopes

C12 @ 300AMeV

p @ 246 MeV


Central region design

0 1 2 3 4 5 6 73.16 10

4

3.18 104

3.2 104

3.22 104

3.24 104

radius (cm)B

(ga

uss)

Einj=25 AKeV

Vinflect= 14 KV

gapinflect= 6 mm

Einflect= 23KV/cm

Bo=3.22 tesla

Vdee = 70 KV

Egap= 90 KV/cm

SEE POSTER SESSION

CENTRAL REGION DESIGN OF THE 300 AMeV SUPERCONDUCTING CYCLOTRONL. Calabretta, D. Battaglia, D. Campo, M. Maggiore, LAC Piazza, D. Rifuggiato


Cavity Design

fo= 97.65 MHz

Q= 9200

<V>max=100KV

Rsh = 42.55 KΏ

Ploss=68 kW/cav

Nstem= 4

Height= 84 cm

Length =230 cm

Width = 43 deg


The fine tuning system

0 20 40 60 80 100 120 1400

5

10

15

20

25

diffj

j

Work in progress


Estimation of the forces acting on the trim rods

F ...1.2 o

Bmax2 Bmin2 r2

600 kg !

20 cm

=5 cm


Pole cap deformation due to the magnetic forces

Applied load: 3000 tons

Max displacement: 0.1 mm


Coils parameters

Coil Parameters

Size 150x210 mm2

Current density 45 amp/mm2

Inner Radius 1420 mm

Distance from the M.P.

70 mm

Energy Stored 35 MJ

Nominal Current (I)

900÷1000 amp

Total current (NI) 1.4 Mamp

Max Magnetic field 4.4 tesla

Axial Force -9.09 MN

Average Hoop Stress (peak)

156 (284) MPa


Conclusion

The studies done so far show that the energy range of 300 AMeV for Carbon ions, can be achieved keeping the main structural parameters of the SCENT machine.

We shown that it is possible to extract the proton beams by stripping at the energy of 250 MeV.

Despite the high magnetic field and the low injection energy, we designed the central region working with four DEEs @ 70KV.

More detailed design studies concerning the RF cavities, the dynamic’s beam, the fine tuning system and other, are in progress.


Next ICCA @ Catania

For any information visit our web site: http://www.lns.infn.it/Cyclotrons2007/


0 15 30 45 60 75 90 105 120 135 1503 10

4

3.15 104

3.3 104

3.45 104

3.6 104

3.75 104

3.9 104

4.05 104

4.2 104

4.35 104

4.5 104

Bmedio R 0( )

Bmedio R 1( )

R

0 15 30 45 60 75 90 105 120 135 1500

0.006

0.012

0.018

0.024

0.03

0.036

0.042

0.048

0.054

0.06

flutter R 0( )

flutter R 1( )

R

100 150 200 250 3000

0.2

0.4

0.6

0.8

1

1.2

1.4

energy per nucleon (AMeV)

beta

tron

fre

quen

cy tu

nes

-0,4

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

0,4 0,6 0,8 1 1,2 1,4 1,6

ECPM 2006, Nice, France, 2-4 November 2006 1 DESIGN STUDIES OF THE 300AMEV SUPERCONDUCTING CYCLOTRON...

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Transcript of ECPM 2006, Nice, France, 2-4 November 2006 1 DESIGN STUDIES OF THE 300AMEV SUPERCONDUCTING CYCLOTRON...