1 Paola Sala INFN Milano For the FLUKA collaboration Roma, 1-03-2007 FLUKA: status and plans.

1

Paola SalaINFN Milano

For the FLUKA collaborationRoma, 1-03-2007

FLUKA: status and plansFLUKA: status and plans

Paola Sala, Roma 01-03-2007 2

Outline

Status, validation and perspectives of ion interaction models

Beta-emitter activation: comparison with data Coupling to CT : work in progress and examples Low energy neutrons: ongoing developments Coupling of radiobiological models : tools

already exist

Info: http://www.fluka.org


Heavy ion interaction models in Fluka

DPMJET-III for energies ≥ 5 GeV/nDPMJET (R. Engel, J. Ranft and S. Roesler) Nucleus-Nucleus interaction modelEnergy range: from 5-10 GeV/n up to the highest Cosmic Ray energies (1018-1020 eV)Used in many Cosmic Ray shower codesBased on the Dual Parton Model and the Glauber model, like the high-energy FLUKA hadron-nucleus event generator

Modified and improved version of rQMD-2.4 for 0.1 < E < 5 GeV/nrQMD-2.4 (H. Sorge et al.) Cascade-Relativistic QMD modelEnergy range: from 0.1 GeV/n up to several hundred GeV/nSuccessfully applied to relativistic A-A particle production

New QMD model for 0.03 < E < 0.5 GeV/nBME (BoltzmannMasterEquation) for E< 0.1 GeV/n

FLUKA implementation of BME from E.Gadioli et al (Milan)Now under test for A≤ 16

Standard FLUKA evaporation/fission/fragmentation used in both Target/Projectile final deexcitation Projectile-like evaporation is responsible for the most energetic fragmentsElectromagnetic dissociation


FLUKA with modified RQMD-2.4

Fragment charge cross section for 1.05 GeV/n Fe ions on Al (left) and Cu

(right). : FLUKA, : PRC 56, 388 (1997), : PRC42, 5208 (1990), : PRC 19, 1309 (1979)


FLUKA fragmentation results

Fragment charge cross section for 750 MeV/n U ions on Pb.

Data (stars) from J. Benlliure, P. Ambruster et al., Eur. Phys. J. A2, 193-198 (1988).

Fission products have been excluded like in the experimental analysis


The new QMD model

New model developed for FLUKA, based on Quantum Molecular Dynamics :

2 and 3-body forces + Coulomb -> nuclear potential dynamically evolving during collision -> nuclear compression, fragment formation

semi-classical (molecular) motion of nucleons with nucleon-nucleon interaction terms Quantum effects: nucleons as wave packets, Pauli blocking,

stochastic scattering, particle production (not implemented)Status: Model developed and coupled to FLUKA equilibrium stage Comparison with thin target experimental data in progress Initialization database ready up to Z<83, First implementation in the full FLUKA scheme working Tests on thick target experimental data started Energy range: from few tens of MeV/A up to 500-600 MeV/A


The new QMD model: (data PRC64 (2001) 034607)

QMD + FLUKA EXP dataRQMD + FLUKA


The new QMD model: examples (proc.Cospar2006 )

12C 290MeV/A

On C, Cu, Pb

Ne 400MeV/A

On C, Cu, Pb

5, 10, 20, 30, 40, 60 and 80 deg, (multiplied by powers of 10)

Dots: data Iwata et al. PRC64, (2001), 054609

Histo: fluka


The new QMD model: examples

Charge distribution from simulations ( histograms) compared to experimental data (grey points) by the AMPHORA detector at SARA. The results of simulations are extremely sensitive to the implementation of experimental cuts, as can be seen comparing the yellow line, obtained imposing a multiplicity cut of Mz > 5 at the end of the fast stage of the reaction, described by QMD, to the red line, obtained adding at the end of the FLUKA stage of the simulation a multiplicity cut of Mz > 10 and taking into account the acceptance of the detector.


The new QMD model:future

Completion of the initialization database Better description of nucleon-nucleon elastic

scattering, with non-isotropic angular distribution

Pion production …tests, tests, tests…….


The BME (Boltzmann Master Equation) theory

It describes the thermalization of the composite system formed in A–A collisions at E < 100MeV/n, via nucleon–nucleon scattering and emission into the continuum of single nucleons and nucleons bound in clusters (M. Cavinato et al., Nucl. Phys. A 643, 15 (1998); 679, 753 (2001))

exp. data from E. Holub et al., Phys. Rev. C 28, 252 (1983)


THE BME – FLUKA INTERFACEfor nucleus – nucleus interactions below 100 MeV/n

A preliminary version of the BME-FLUKA event generator considering two different reaction mechanisms, is presently under test

1. COMPLETE FUSION

PCF = CF /R

preequilibrium

according to the BME theory

FLUKA evaporation

In order to get the multiplicities of the pre-equilibrium particles and their double differential spectra, the BME theory is applied to a few representative systems at different bombarding energies and the results are parameterized.

2. PERIPHERAL COLLISION

P = 1 − PCF

three body mechanism

or

“inelastic scattering” (for high b)

The complete fusion cross section decreases with increasing bombarding energy. We integrate the nuclear densities of the projectile and the target over their overlapping region, as a function of the impact parameter, and obtain an excited “middle source” and two fragments (projectile and target-like). The kinematics is suggested by break-up studies.

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BME – FLUKA interfaceStudied reaction: 12C+12C @ 200 MeV

Andrea Mairani

Milan, December 2006

In collaboration with Dr. F. Cerutti, Dr. A. Ferrari, Prof. E. Gadioli

New results and comparison with i-Themba expt. Data

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OUTLINE

Experimental investigation:

•Experimental data for Intermediate Mass Fragment (IMF) emission, 12C+12C @ 200 MeV, experiment performed at iThemba Labs

•Bragg Curve Detector (low E threshold, about 1 MeV/u, - no isotope separation, data however still under evaluation)

•Silicon detector telescope (about 5 MeV/u energy threshold – isotope identification)

Theoretical analysis:

•Benchmark of new FLUKA-BME interface (complete fusion mechanism): reproduction of Fluorine and heaviest Oxygen isotopes

•Measurement of Beta+ emitter cross section (15O,13N,11C)

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Theoretical Analysis

•12C+12C ion pair is included in BME-FLUKA database

•The pre-equilibrium emission is obtained using the “interpolated” parameters

•Benchmark only of the COMPLETE FUSION mechanism

•Coalescence IMF emission, not yet included in FLUKA, is obtained with a “full BME run”

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19F and 20F spectra

Exp data (iThemba) BME (light particles) + FLUKA -> evaporative

residues

Experimental

energy threshold

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15O spectra – β+ emitter

Exp data IMF emission(“fullBME”) BME(light particles)+FLUKA -> ev residues

Total Total

predictionprediction

σσ((1515O)O)

about 16 mbabout 16 mb

12.8 12.8 + + 2.62.6 mbmb

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WORK IN PROGESS AND FUTURE DEVELOPMENTS

Experimental investigation:

•Completion of experimental data analysis for 12C+12C @ 200 MeV (2006) and starting analysis at 400 MeV (2006)

•New experiment: 16O+12C (2007)•New ion source (2007-2008), possible experiments at about 50-60 MeV/u

Theoretical analysis:

•Generalize the BME-FLUKA interface for ion pairs not included in the database

•Develop and benchmark the already included peripheral process (projectile and target break-up – Li, Be, B exp data @ iThemba labs)

•Include the IMF emission in the preequilibrium stage


Full transport + RQMD

+ BME+ ionization

: bragg peaks


Bragg peaks vs exp. data: 20Ne @ 670 MeV/n

Dose vs depth distribution for 670 MeV/n 20Ne ions on a water phantom.The green line is

the FLUKA prediction

The symbols are exp data from LBL

and GSI

Exp. Data Jpn.J.Med.Phys. 18,

1,1998Fragmentation products

mostly α’s and p’s


12C Bragg peaks vs exp. data

• Experiment: circles (270 AMeV) and triangles (330 AMeV)

• FLUKA: lines

Sommerer et al: Phys. Med. Biol. 51 2006

Zoom: 270 AMeVBlue: no spreadGreen: 0.15% Energy spread (σ)


In-beam PET: ion beam fragmentation

Final goal: simulation of β+ emitters generated during the irradiationIn-beam treatment plan verification with PET

Work in progress: FLUKA validation (F.Sommerer) Comparison with experimental data on

fragment production (Schall et al.) 12C, 14N, 16O beams, 675 MeV/A Adjustable water column 0-25.5 cm Z spectra of escaping fragments for Z4 Cumulative yield of light fragments Simulation: corrections applied for angular acceptance and

for material in the beam upstream the water target Comparison with experimental data on +-

emitter production (Fiedler et. al.)


Fragmentation of therapeutic beamsProduction of light fragments (mostly α’s) as a function of depth in water

Dashed: FLUKA-total

Dotted: FLUKA with angular correction acceptance

Solid : FLUKA with all corrections

Stars : experimental data


12C induced +-Activity

+ -active fragments: 11C (20.4min), 15O (122s), 10C (19s), 13N (10min), 8B (0.8s), 9C (0.1s), 14O (71s), 13O (9ms), 12N (11ms)

Courtesy of F. Fiedler

* Fiedler F. et al., The Feasibility of In-Beam PET for Therapeutic Beams of 3He, 2005 IEEE Nuclear Science Symposium Conference Record

Experiment*: 12C beams with 337.5 AMeV on different targets, activity measured during irradiation 556s (red) and 10 minutes after irradiation, for 10 minutes (blue)

After 10 minutes dominated by 11C

*)

Measuring only in pauses between spills.


+-Activity after Irradiation

water

PMMA

graphite

Measured 10 – 20 min after irradiation, therefore dominated by 11C Further work:• processing with same software

than experiment• profiles during irradiation


New data

New data recently ( one week ago) taken with 16O

Bragg peak + emission

comparison of different beams test of MC

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HIT Betriebs GmbH amUniversitätsklinikum Heidelbergmit beschränkter Haftung

www.med.uni-heidelberg.de/hit

CT-based Calculations of Dose and Positron Emitter Distributions in Proton Therapy

using the FLUKA Monte Carlo code Katia Parodi, Ph.D.1,‡,*

1 Massachusetts General Hospital, Boston, USA‡ Previously at Forschungszentrum Rossendorf, Dresden, Germany

*Now at Heidelberg Ion Therapy Centre, Heidelberg, Germany

Workshop on Monte Carlo in Treatment Planning

Catania, Italy, 31.10.2006 (NOTE: part of the presented slides are not included due to unpublished material)

Massachusetts General Hospitaland Harvard Medical School

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CT-based MC calculation of dose and +emitters

The FLUKA MC code (http://www.fluka.org)

- Reliable nuclear models- Already applied to proton therapy: Dosimetric/radiobiological studies

(Biaggi et al NIM B 159, 1999)

In-beam PET phantom experiments(Parodi et al PMB 47, 2002, Parodi et al IEEE, 52 2005)

- Import of raw CT scans with optimized algorithms for efficient transport in voxel geometries(Andersen et al Radiat. Prot. Dosimetry 116, 2005) T

he

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The FLUKA implementation (II) CT information• Segmentation into 27 materials

Soft tissue

Air, Lung,Adipose tissue

Skeletal tissue

…Extended for HU > 1600 to include Ti (HU ~ 3000) (Parodi et al, MP, in press)

24 from Schneider et al PMB 45, 2000

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The FLUKA implementation (II) CT information• Nominal mean density for each HU interval (Jiang and Paganetti MP 31, 2004) • But real density varies continuously with HU value

Schneider et al PMB 45, 2000

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Results I: phantom experiments 1 SOBP @ 8 Gy in PMMA with 2 Ti rods, tmeas= 60 min, T ~ 14 min

PET/CT Measurement MC

p beam

Parodi et al MP (in press)

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Results I: phantom experimentsRange reduction due to metallic rods

50 % fall-offsagree within 1 mm

p beam

Parodi et al MP (in press)

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Results I: phantom experiments

Meas 60 minSimu Dose MCDose TP (Focus)

Meas 60 minSimu Dose MCDose TP

Meas 60 minSimu Dose MCDose TP

PET/CT Meas

Shadowing effect

Better description than TPParodi et al MP (in press)

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MC Dose

1 Field

2 Field

TP Dose

Results II: Clinical studyClival Chordoma, 0.96 GyE / field, T1 ~ 26 min, T2 ~ 16 min

K. Parodi et al IJROBP (submitted)

MC PET Meas. PET

Agreement within 1-2 mmFor position of distal max.And 50 % fall-off


Thermal neutron pointwise treatment

At present FLUKA uses one thermal groupone thermal group for neutrons, extending from 10-5 eV to 0.414 eV: it is fine for most applications, not for all

The new cross section librarynew cross section library will contain some 30 thermal 30 thermal groupsgroups, however…

… for some applications a truly pointwise treatmentpointwise treatment of thermal neutrons could be a must

.. For some applications a fully correlated pointwise treatment could be a must : done for H, Ar, and partially for 10B, 6Li, Xe, Cd

WARNING : Pointwise does NOT mean correlated:Both multigroup and pointwise codes use the international

evaluated databases (e.g. ENDF) which contain only inclusive distributions of reaction products

To obtain exclusive, correlated final states ad-hoc models and algorithms have to be developed


Thermal neutron pointwise treatment

A new fully pointwise free gas thermal treatmentpointwise free gas thermal treatment has been implemented in FLUKA: in principle can be applied to whichever materialwhichever material (if preprocessed, presently applied to 1H, 6Li and 40Ar) at whichever temperaturewhichever temperature

This treatment make use of the best physics approach with no approximation and full account of thermal full account of thermal motionmotion (no isotropic assumption for lab scattering)

A special bound hydrogenbound hydrogen treatment for water water at 293 K has been also developed (based on the ENDF S(S(αα,,ββ)) treatment) and it is under test

The correlated treatment of neutron reactions will be extended to all “biological” targets


Coupling to radiobiological models

Energy deposition and dose can be calculated on geometry-independent meshes through standard FLUKA scoring utilities

Tools have been developed by the FLUKA collaboration to weight the energy deposition events by

Particle type Particle energy (or LET)

Weighting is applied run-time, can be linear or quadratic

Needs a data-base for biological effects


END

1 Paola Sala INFN Milano For the FLUKA collaboration Roma, 1-03-2007 FLUKA: status and plans.

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Transcript of 1 Paola Sala INFN Milano For the FLUKA collaboration Roma, 1-03-2007 FLUKA: status and plans.