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
LUIGI PICARDI - Il Progetto TOP-IMPLART
2nd Workshop on Hadron Beam Therapy of Cancer
Erice, Sicily, Italy May 20, 2011 - May 27, 2011
May 20, 2011 - May 27, 2011
1
Just an introduction
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
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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Small electron accelerators
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
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
In 2001 the company Hitesys split in
two companies
NRT company in Aprilia that now is
produced Novac 7,
SORDINA in north Italy close
Treviso which produces the LIAC
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
(NRT)
LIAC
(Sordina)
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ENEA Accelerator Lab on Protontherapy
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 comparison
between the performance-raising X-rays radiotherapy to the
nevertheless excellent protontherapy was immediately evident.
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.
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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
PMQ
Coupling
Cavity
Accelerating
Tank
RF input
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ENEA Accelerator Lab on Protontherapy
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 ENEACERN 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.
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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.
SCDTL vs CCL structure
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.
SCL tanks with 15 accelerating gaps for different proton energies
50.00
Ep>1500 MeV or Ee>2 MeV
Transition
to SCL
LIB
Structure
28.31
Ep=200 MeV
25.33
O
Ep=150 MeV
18.31
36.62
Ep=70 MeV
179.1
12.35
24.70
Ep=30 MeV
123.5
6.35
Ep=7 MeV
61.8
SCDTL tanks with 15 accelerating gaps for different proton energies
SCDTL Structure
PMQ
It consists of short DTL tanks coupled
together by side cavities. The DTLs are short
tanks, each having 4 to 7 cells of  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
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The TOP Project
1998-2005 The proposal of a
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
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DEVELOPMENT OF THE TOP LINAC
SCDTL: NEW stems
With respect to first prototypes the stem and drift tube
were machined from a solid piece. Two parallel 1.5 mm
diameter holes were drilled trough the 60 mm long
rectangular stem with smoothed edges, for the coolant
flow. Each stem is then TIG welded to the tank outer
surface to provide for vacuum/coolant tightness. The loss
in Shunt impedance due to the large flat stems is less
than 10%. With this system also the construction cost is
substantially lowered.
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DEVELOPMENT OF THE TOP LINAC
SCDTL module #1 measurements
200
180
160
140
120
u.a.
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
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
100
80
60
40
20
0
2940
2960
2980
3000
3020
Frequency, MHz
3040
3060
3080
Power fed to structure:
= 1.206 MW
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PROTON LINAC DEVELOPMENT
•
•
•
•
•
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
plant in situ.
Progetto SPARKLE – Casarano (Le)
The project was found very useful for upgrading the SCDTL structure design
Fin21
1.2
ORIGINALE
SMOOTHED
AverFin21e21
Forward
Reflected
Fw-Refl
1
0.8
0.6
2000
0.4
0.2
0
500
1000
1500
2000
2500
1500
Power, kW
0
1000
500
0
13.5
14
14.5
15
15.5
16
PFN Voltage, kV
16.5
17
17.5
The ISPAN Project
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 irradiation
Leaders: NRT and CECOM companies
Co- Leaders ENEA and ISS
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The ISPAN Project
Two SCDTL structures that bring the energy to 17.5 MeV
Machining is under way
Operation is foreseen for the end of 2011.
Tank 1 and Tank 9 of Module 1
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The TOP- IMPLART Project
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
TOP-IMPLART Logo
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The TOP- IMPLART Project
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
Involved Companies : NRT,
CECOM, ADAM, TSC, …
PHASE 2 Fundings: First phase, 11 M€
SCDTL
7 MeV
LINAC2
LINAC1
INIETTORE
40 MeV
got from Regione Lazio,
Innovation Department,
construction of the accelerator
up to 150 MeV, in Frascati
ENEA centre.
CCL1
150 MeV
CCL2
230 MeV
Energia
Total cost estimate 40-45 ML
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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
30 MeV
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CCL low velocity structure mechanical design
Preferred
For E<70 MeV
Preferred
For E>70 MeV
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Example of beam dynamics analysis
Analysis of beam transmission and losses
Analysis of beam Emittance
Continuous Beam Energy variation
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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
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.
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Machine parameters for the first phase
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…
Composition of 392 pulses
each 7x7 spot and 8
slices
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Final layout (at IFO Hospital, Rome)
IFO HOSPITAL in ROME
Final layout (at IFO Hospital, Rome)
A study is undergoing leaded by a Bari
Company (ITEL) to design a special treatment
chair/bed for positioning the patient. The bed
has to be assisted by a special orientable TAC.
The scope is trying to avoid the use of the
gantry, substituting its movement with patient
alignment and with one or two fixed beams.
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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
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
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Conclusions
Aim of TOP-IMPLART Project are
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
Promote the development
of a marketable product and transferring the knowhow 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’
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