PL7 – 003 Years of experience in ENEA Frascati Accelerator LAB Paolo Nenzi on behalf of ENEA Frascati Team AccSys Pleasanton (CA), USA 11 December 2014.

PL7 – 003 Years of experience in ENEA Frascati Accelerator LAB

Paolo Nenzi on behalf of ENEA Frascati Team

AccSys Pleasanton (CA), USA 11 December 2014

Outline

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• ENEA Frascati Accelerator lab• History • UTAPRAD Technical unit

• A short introduction to hadrontherapy and protontherapy• Comparison with conventional radiotherapy

• The TOP-IMPLART Project• Description of the project and LINAC structure• Project schedule• Actual Layout of the TOP-IMPLART LINAC• Development of a single room facility

• Our experience with PL7-003• Features• Special requirements• Modifications• PL7 Operation: our way• Remarks

• Discussion

The ENEA Accelerator Laboratory is in located in the ENEA Frascati Research Centre.

It grew up as an extension of the accelerator group that built the 1 GeV Frascati Electrosynchrotron in the fifties, and is housed in the same hystorical building.

Today it is a part of “Technical Unit for the Development of Applications of Radiation (UTAPRAD)”.

An introduction on Accelerator Development in ENEA

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UTAPRAD

• UTAPRAD is Directed by Dr. Roberta Fantoni, is formed by 95 staff members, and is addressed to the development of applications of radiations.

• UTAPRAD is aimed to research and technological services, by means implementation of technologies for the application of ionizing and not-ionizing radiations, the development of particle accelerators of optoelectronics and photonics.

• Its role specifically includes technologies for physical diagnostics in the fields of: environmental and health protection, cultural heritage preservation, security and development of accelerators for medical applications.

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HADRONTHERAPY AND PROTONTHERAPY

Very short introduction to

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Hadron therapy and Protontherapy

• Hadrontherapy = radiotherapy with protons and ions.

• Protontherapy = radiotherapy with protons.

• Advantages:

• patial selectivity that implies a conformal therapy.

• Less irradiation of surrounding healty tissue

Bragg’s peak

Dose delivery limited by the Bragg’s peak depth

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Dose difference between the IMRT and IMPT

7 fields with IMRT 2 fields with IMPTComparison between IMRT and IMPT

IMPT employs techniques similar to those exploted in IMRT (Intensity Modulated RadioTherapy) to obtain conformal dose concentrations in the tissue. IMPT allows for more conformality with less dose concentrations in surrounding tissue.

Intensity Modulated Proton Therapy (IMPT)

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THE TOP-IMPLART PROJECTDescription of

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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.

930MeV Prototype (first milestone) TOP-IMPLART layout (230MeV, 3 beam lines)

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Aims 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 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’

The TOP-IMPLART project

• Modularity: • the accelerator is composed by a

sequence of subsystems optimized for medical use.

• the system can be built in successive phases matching funding flow and allowing fast return of investment from SSN (public health) or private insurance plans.

• Technical characteristics: • 3 GHz RF: compactness, well-known

technology.• Pulsed operation: possibility of XYZ-

SCAN for Intensity Modulated ProtonTherapy (IMPT).

• Beam with high optical quality: smaller magnets.

• Italian project: • Italian design and patents • Italian SMEs are involved in the

development of the prototype in ENEA .

• Long term goal of developing an italian company or consortium of SMEs to build medical accelerators.

The TOP-IMPLART project

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The structure of TOP-IMPLART LINAC showing modularity in the accelerating structures and in the RF distribution. All the RF sources are 10MW peak power (10 kW average) TH2157A klystron tubes. This guarantees more than 30% power margin. Duty cycle will be lower than 5e-4.

The TOP-IMPLART project

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PL7 and TOP IMPLART important dates

• 1999:– Tender with JPAW Acc Works and Northrop Grumman

• 2000: – Injector order placed on March 7th

• 2001: – Factory Acceptance Tests

– Delivery on May 10th

• 2005:– End of site preparation and granting of authorizations (started in 1994)

– Injector installation and operation

• 2008:– TOP-IMPLART project presented to Regione Lazio

• 2010:– Ragione Lazio approved funding the project with a grant of 11M€

• 2013:– Selections for recruiting new personel for the project (physicists, engineers and

technicians). Recruiting completed in Dec 2013. 11 people assigned to the project: 4 physicists, 3 engineers, 2 technicians, 1 administrative assistant, and 1 PhD student (electromagnetism track)

• 2014:– Installation and commissioning of first 3GHz SCDTL structure 13

PL7 and TOP IMPLART important dates

• 2015:– First quarter: installation and commissioning of the first three SCDTL

accelerating sections to reach 27MeV

– Second quarter: installation and commissioning of the fourth SCDTL to reach 35MeV

– Final part of the funding (6.5 M€) will be released from Regione Lazio. Condition for release is reaching an energy of (about) 30MeV

• 2016:– Energy of clinical interest will be reached

• 2017:– 150 MeV milestone

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ACTUAL LAYOUT OF TOP-IMPLART LINAC

Description of the

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Actual LayoutRadiobiology line 3-7 MeV

11.6 MeV

Injector16

Beam spot fuorescent screen dia =20 mmBeam size 2 mm

TOP-IMPLART injector is a commercial LINAC manufactured by AccSys-Hitachi (4.6 m long). It is composed by:

• Duoplasmatron source with current limiter (focusing + perture) to 30 uA• 3 MeV RFQ operating at 425 MHz• DTL up to 7 MeV at 425 MHzPulsed current:• Pulse width (20-100 μs)• Pulse rep. freq. 0-200 Hz

The injector

Current can be varied in the 0 – 30 μA varying Einzel lens voltage (pulsed operation underway

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PL7 – 003 and LEBT

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Panoramic (distorted) picture of the injector and LEBT (Low Energy Beam Transfer)

The vertical extraction line, situated in the middle of the LEBT is dedicated to in-vitro radiobiology experiments.

Steel holder (=13mm) contains cells (6µm thickness) on Mylar (60µm thickness) over their culture medium.

Scatterer (gold foil, 2µm thickness)Aluminum collimator ( =2 mm)

Kapton window (50µm thickness)

69 c

m90° magnet

Vertical line

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SCDTL-1 Module

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Made by CECOM (Guidonia, Roma)

SCDTL-1 Module

SCDTL-1Accelerating tanks number

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Length 1.1 mPipe radius (proton beam hole radius)

2 mm

Input power 1.3 MWStarting energy 7 MeVEnding energy 11.6 MeV

tank PMQ dissassembly

PMQ

Tank interior 21

0

0.2

0.4

0.6

0.8

1

1.2

630 660 690 720 750 780 810 840

Tran

smis

sion

Al (um)

Measurements

computed transmission curve for 11.6 MeV

5 6 7 8 9 10 11 120

1000

2000

3000

4000

5000

6000

energy(MeV)

43% of the beam has an energy greater then 11 MeV. Energy peak is around 11.63 MeV

Accelerated beam current =15 µA

11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 120

100

200

300

400

500

600

700

800

900

1000

energy(MeV)

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Experimental verification of SCDTL-1 performances

Energy measurement obtained from range measurement in Aluminum.

Transmission curve vs Al thickness.

11.6

TOP-IMPLART SINGLE ROOM FACILITY

New development:

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Single Output facility

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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, The heavy shielding would only be necessary for the treatment room

PL7 - 003Our experience with

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• Proton source: – Duoplasmatron Source 30 keV

• Acceleration– RFQ 3 MeV– DTL 4 MeV

• Control Software:– LINCON 1.1 written by Marianne Hamm on Labview 6.1, running on

Windows 98– LabView source available– We have an updated version of the software running on a newer PC.– We tested the new combination but we never used it because of many

controls are unconsinstent to settings– Alternative to optical control boards ? (Group3 are obsolete)

Features of PL7-003

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• Pulse Current:– Availability of Low and High current for different

applications:• Radioisotope production : 8 mA per pulse• Protontherapy linac injector: 100-10-1 μA per pulse

– Retractable (1 mm dia) copper aperture at RFQ input

• Pulsed Einzel Lens current to modulate output current:– Hard tube pulser designed by George Engemann(?) never

worked

• Reduced DTL pulse:– 3GHz LINAC works with a 4μs pulse– Need for a DTL pulse of up to 7 us

Special requirements for our PL7-003

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• We ended high current operation of the injector. – Only low current is available now.

• Beam aperture has been changed and slightly increased to reach 200 uA beam current.

Modifications applied to our PL7-003

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• We have manufactured a new Einzel Lens for the injector in our laboratory as ACCSYS did non repair it.

Modifications applied to our PL7-003

Old Einzel Lens New Einzel Lens

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• The following modifications have been planned to give better control to injector current and eventually suppress it for one or more pulse.

• Current control is important for medical applications.

• We have commissioned to a SME company an High Voltage pulsed source for the Einzel:– The pulser has been delivered to our facility and is currently under HV test.

• An external enabling arc discharge is in development. • We are evaluating the possibility of inserting a chopper (10kV, 4cm) in front of the

Einzel lens. – Hints ?

• (?) Negative pulse on Pierce electrode (?)• We would like to set and read injector variables from our control system (LabView

2014) to integrate it into the higher level control system.– How we can do this ?

Planned or undwerway Modifications to our PL7-003

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• We always operate PL7-003 at low current (200 uA) with external trigger using a PRF in the 10 – 50 Hz range

• Cavity fields:– RFQ Cavity field 4 -4.25 (Standard 4.11)– DTL Cavity Field 4.7 – 5.35 (standard 5.2 – 5.34)

• Remark: it is impossible, of course, to make reflected power vanish both in RFQ and DTL – We asked Accsys several times to adjust coupling coefficient

by loop rotation, without uccess. – Never mind, we can still operate this way: we can loose some

power.

PL7-003 operation: Our Way

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• We found that the PL7 machine has been well done.– Electronics systems are well explained in the schematics (This is very important for such kind

of machines). – We experienced some complexity and redundancy in controls and interlocks that sometimes

seems to cause strange faults

• The old control systems (LINCON 1.1) it is functional and well designed.– The drawback is that is not possible to interface it with an higher level control system– We need an open system.

• Arc is not properly stable for very accurate and stable operation at low currents– How we can improve arc stability at low currents ?

• Feedback loops are hard to adjust:– There is no written explanation of procedure,– Potentiometers on the boards have no clear mark of their function

• Sometimes at high rep rate DF yellow light prevents operation– We could not trace back to the cause

• We need for an electronic maintenance training course

Remarks

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ENDComing to the

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Thank you for attention!

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Merry Christmas and happy 2015

… from TOP-IMPLART teame

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Discussion

Some point for discussion

1. differences between actual machines and the one we have.2. Understanding the AM loop and how to tune it3. Tube testing system4. Latest developments on the control software: latest release, controller

boards, source availability5. Ask John Sexton about a possible visit to us6. Request for offer for a maintenance course for the PL77. Are you using FPGA boards on newer machines ?8. Have you a working Einzel Lens pulsed source ? We have a design from

George Engemann but we do not know if it works and how to operate it9. New development in duoplasmatron source10.Visit to factory