S-Band side coupled drift tube linac

LUIGI PICARDI – UTAPRAD ENEA Frascati

International School on Hadrontherapy «Edwin McMillan»

2nd Workshop on Hadron Beam Therapy of Cancer

Erice, Sicily, Italy May 20, 2011 - May 27, 2011

LUIGI PICARDI - Il Progetto TOP-IMPLART2nd Workshop on Hadron Beam Therapy of Cancer

Erice, Sicily, Italy May 20, 2011 - May 27, 2011 1

The ENEA Accelerator

Laboratory is in ENEA

Frascati Research Centre.

It grew up as an extension of

the accelerator group that

built in the fifties the 1 GeV

Just an introduction

built in the fifties the 1 GeV

Frascati Electrosynchrotron,

and is indeed housed just in

the same old building.

Today it is a part of

“Application of Radiation”

Technical Unit UT APRAD

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In late sixties the competences in accelerator physics in Frascati area were split

between INFN and CNEN (now ENEA) , two big scientific institutions, and after

the synchrotron shut down in 1974, some of them who still stayed in CNEN

were addressed to the development of accelerator for applications in medical

and industrial fields.

Working together with other laboratories in ENEA Casaccia which have expertise

in Radiobiology and Radiation Metrology and with other italian scientific

institutions like National Institute of Health (ISS), INFN, and research Hospitals

Small electron accelerators

institutions like National Institute of Health (ISS), INFN, and research Hospitals

and Universities, the knowhow in the accelerator field was transferred

in the years ‘80 – ’90 to an Italian

company named HITESYS with the

site in Aprilia close to Rome. The

company was then able to built a

Intra Operative Radiation Therapy

(IORT) accelerator named NOVAC7

(the first machine installed in an

hospital in 1997)

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IORT: IntraOperative Radiation Therapy

SORDINA in north Italy close Treviso which produces the LIAC accelerator, similar to the NOVAC

In 2001 the company Hitesys split in two companies NRT company in Aprilia that now is produced Novac 7,

accelerator, similar to the NOVAC

More than 40 machines NOVAC7 and LIAC, are running in hospitals in Italy, Europe, and recently USA and in other countries.

ENEA is always ready to promote new developments.

NOVAC7 LIAC(NRT) (Sordina)

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In 1993 ENEA joins the Hadrontherapy Collaboration setup by Ugo Amaldi in 1991. From the beginning the problem of very huge and costly hadrontherapy facilities was underlined. The comparisonbetween the performance-raising X-rays radiotherapy to the nevertheless excellent protontherapy was immediately evident.

ENEA Accelerator Lab on Protontherapy

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Protontherapy, and more, hadrontherapy shows high plant costs, and a very late mortage . ENEA coordinated therefore a study on the development of compact accelerators in which two compact synchrotrons, a SC cyclotron and a 3 GHz linear accelerator were studied and compared.

ENEA Accelerator Lab on Protontherapy

In particular, in 1994-95 ENEA proposed the development of a 3 GHz linear accelerator studied in collaboration with CERN and INFN that focused the attention on the development of al linear machine as an alternative to circular machines.

The main difference with a similar proposal by Hamm et al., in 1991 was in the segment 7 – 70 MeV where, instead of a 425 MHz DTL, a 2.998 GHz new structure, called SCDTL, was foreseen.

ENEA patented this structure in Europe in 1995 CouplingCavity

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ENEA patented this structure in Europe in 1995

RF input

Cavity

AcceleratingTank

PMQ

The ENEA linear accelerator proposal had the characteristic that only a small part, the low energy injector was at a frequency different from 3 GHz. Therefore a strong commitment of italian companies involved in the IORT linac business could be foreseen. Moreover, in the original ENEA-CERN design the injector was a 5 MeV RFQ made of three coupled segments, and the construction could be thought to be carried on in Italy as well.

ENEA Accelerator Lab on Protontherapy

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be carried on in Italy as well.

DTL (425 MHz) vs SCDTL (3 GHz)SCDTL comes from the willing of compacting the size of DTL structures. Protontherapy requires to accelerate a very low current , that for a linac means no space charge problems and allows the use of high frequency operation. On the left the 425 MHz Drift Tube Linac structure and on the right the 3GHz Side Coupled DTL.

28.31

Ep>1500 MeV or Ee>2 MeV

Ep=200 MeV

50.00

SCL tanks with 15 accelerating gaps for different proton energies

SCDTL vs CCL structure

Transition to SCL

The SCDTL substitutes the commonly used CCL (Coupled Cavity linac) in the intermediate energy (7-65 MeV) part of the protontherapy Linac. It shows indeed a higher shunt impedance in the low-velocity part of the Linac.

25.33

6.35

12.35

18.31

Ep=70 MeV

Ep=30 MeV

Ep=7 MeV

Ep=200 MeV

Ep=150 MeV

123.5

24.70

61.8

SCDTL tanks with 15 accelerating gaps for different proton energies

36.62

179.1

LIBO

to SCL Structure

SCDTL Structure

PMQ

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It consists of short DTL tanks coupled together by side cavities. The DTLs are short tanks, each having 4 to 7 cells of βλ length, and the side cavity extends in a space left free on the axis for the accommodation of a very short (3 cm long, 2 cm o.d., 6-7 mm i.d.) PMQ (Permanent Magnet Quadrupole) for transverse focusing

1998-2005 The proposal of a Linear accelerator was selected

The TOP Project

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Linear accelerator was selected by th TOP (Terapia Oncologica con Protoni) Project at National Institute of Health (ISS), and a collaboration started for setting up the facility in the ISS area in Rome. The main achievements

have been:

7 MeV injector, acquired from AccSys Company

Realization some SCDTL prototipes

DEVELOPMENT OF THE TOP LINAC

SCDTL: NEW stems

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With respect to first prototypes the stem and drift tubewere machined from a solid piece. Two parallel 1.5 mmdiameter holes were drilled trough the 60 mm longrectangular stem with smoothed edges, for the coolantflow. Each stem is then TIG welded to the tank outersurface to provide for vacuum/coolant tightness. The lossin Shunt impedance due to the large flat stems is lessthan 10%. With this system also the construction cost issubstantially lowered.

180

200

DEVELOPMENT OF THE TOP LINAC

SCDTL module #1 measurements

All tanks and coupling cavities of the first module (7-12 MeV, 1 m long, 9 DTL tanks, 5 cells per tank) were built. With the structure correctly

2940 2960 2980 3000 3020 3040 3060 30800

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40

60

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120

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160

Frequency, MHz

u.a

.

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tank) were built. With the structure correctly tuned at the proper frequency the electric field was adjusted with tuning screws in the coupling cells to obtain the axial distribution uniform within ±2% among the 11 average tank fields and ±5% among the 55 cells fields

Power fed to structure:= 1.206 MW

• 2008: • SPARKLE Project for an installation

at Casarano (Le)• Design and build a SCDTL linear booster

for a commercial cyclotron (IBA Cyclone18/9)

• Scope: upgrade the energy up to 24 MeV

• Aim: demonstrate cyclotron-linac matching for a potential protontherapy

PROTON LINAC DEVELOPMENT

matching for a potential protontherapy plant in situ.

Progetto SPARKLE – Casarano (Le)

The project was found very useful for upgrading the SCDTL structure design

ForwardReflected

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1.2Fin21

ORIGINALE

SMOOTHED

AverFin21e21

0

500

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2000

13.5 14 14.5 15 15.5 16 16.5 17 17.5

ReflectedFw-Refl

Pow

er, k

W

PFN Voltage, kV

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0 500 1000 1500 2000 2500

ISPAN Project 2009 – 2011 (Ongoing) 570 kEuro grant from Regione Lazio– FILAS Setup of a Radiobiology facility in Frascati with 2 beam outputs:A 17 MeV horizontal beam for small animal irradiation A 3-7 MeV vertical beam pointing upwards for cells irradiationLeaders: NRT and CECOM companiesCo- Leaders ENEA and ISS

The ISPAN Project

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The ISPAN Project

Two SCDTL structures that bring the energy to 17.5 MeVMachining is under wayOperation is foreseen for the end of 2011.

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Tank 1 and Tank 9 of Module 1

In 2008 the TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTherapy) was setup in collaboration with con ISS e IFO, with the aim of building a protontherapy linac to be housed in the largest oncological hospital in Rome, IFO.

In 2010 it was approved the Funding of the project with a 11 M€ grant from Regione Lazio, Innovation Department

The TOP- IMPLART Project

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TOP-IMPLART Logo

PHASE 1 Final Objective: A protonherapy centre based on a 230 MeV accelerator setup in two phases. Involved Institutes: ENEA (technical units: APRAD, BIORAD), ISS, IFO

The TOP- IMPLART Project

Involved Companies : NRT,

CECOM, ADAM, TSC, …

Fundings: First phase, 11 M€got from Regione Lazio, Innovation Department, construction of the accelerator up to 150 MeV, in Frascati ENEA centre.

Total cost estimate 40-45 ML

LINAC2LINAC1INIETTORE

SCDTL CCL1 CCL2

7 MeV 40 MeV 150 MeV 230 MeV

Energia

PHASE 2

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IMPLART-150

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IMPLART-150+ Beam Delivery

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IMPLART-230

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IMPLART-230 + 3 Beam delivery

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TOP IMPLART Layout

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IMPLART-150 Accelerator

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IMPLART-150 Accelerator

2630 MeV

CCL low velocity structure mechanical design

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Preferred For E<70 MeV

Preferred For E>70 MeV

Example of beam dynamics analysis

Analysis of beam transmission and losses

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Analysis of beam Emittance Continuous Beam Energy variation

Example of beam dynamics analysis

Analysis of BeamTranport Line acceptance

The beam optics has been designed in order to have an horizontal dispersive focus halfway between the two dipoles, where a movable slit/collimator is placed in order to control the energy spread accepted by the treatment. The dispersion in this location is about 7.5 mm per % momentum spread.With a slit of 15 mm of horizontal half width corresponding to a momentum acceptance of about ±2% (energy acceptance about ± 3.8 MeV at 150 MeV and about ±3.5 MeV at 85 MeV) the

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± ±at 150 MeV and about ±3.5 MeV at 85 MeV) the

rms energy spread values plotted in figure 9b vs average energy are achieved and in the whole energy range the computed intensity ripple due to various jitters is ±2%.

The quadrupoles EMQ1 and EMQ2 make the horizontal focus halfway the two bending magnets according to the beam Twiss parameters at the linac output that change with the energy, the EMQ3/EMQ6 gradient controls the vertical envelope and can be kept constant whilst the EMQ4/EMQ5 gradient provides the final dispersion-less condition. Finally the four quadrupoles EMQ7, EMQ8,EMQ9 and EMQ10 give at the input of the scanning beam system a parallel beam with a spot between 4 and 10 mm of FWHM.

Machine parameters for the first phase

Composition of 392 pulses each 7x7 spot and 8 slices

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Characteristics are:Modularity, Technology similar to the conventional Radiotherapy eletron machines, Active and fast energy variation, Pulse to pulse current variation, very low emittance beam, etc…

IFO HOSPITAL in ROME

Final layout (at IFO Hospital, Rome)

Final layout (at IFO Hospital, Rome)

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A study is undergoing leaded by a Bari Company (ITEL) to design a special treatment chair/bed for positioning the patient. The bedhas to be assisted by a special orientable TAC. The scope is trying to avoid the use of the gantry, substituting its movement with patientalignment and with one or two fixed beams.

Single Output facility

In a Green field situation, the low beam losses (35% transmission) and the low average energy of the lost particles allow thinking of a locally shielded accelerator, with single output beam, able to scan the energy from max (180-200 MeV) to min (60 MeV) electronically

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The heavy shielding would only be necessary for the treatment room. This arrangement seems to be the optimized setup for the lowest cost protontherapy plant

Aim of TOP-IMPLART Project are

Conclusions

Setting up a proton therapy facility highly innovative and compact in the Rome area in collaboration with prestigious academic institutions with scientific and clinical expertise

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Promote the development of a marketable product and transferring the know-how to Italian industries, similarly to what done in the field of IORT, in order to increase the Italian technological potential and in particular the Lazio one, in the field of 'High technology applied to the biomedical sector’