1st adamas workshop, gsi, 2012r.pleskac18/12/2012 mosaic detector: experiments for therapy and space...

1st ADAMAS Workshop, GSI, 2012R.Pleskac 18/12/2012

Mosaic Detector:Experiments for Therapy and Space Research

R.Pleskac

GSI / Biophysics


OverviewOverview

Hadrontherapy & Space ResearchSignificance of nuclear fragmentationCave A measurements(Bragg curves, nuclear fragmentation, microdosimetry, beam widening)FIRST experiment(double-differential cross-section for Z particles)

Mosaic DetectorRequirementsDesignTime Line


Significance of nuclear fragmentation Significance of nuclear fragmentation in RT with light ionsin RT with light ions

Carbon ion therapy

100-400 MeV/u

I. Pshenichnov

High-energy carbon beam stopping in water

Nuclear fragmentation Loss of primary ions depth-dose, RBE

Total reaction cross section 1-2 b

Buildup of secondary fragments dose-tail, lateral dose

Exp. Investigations (physical characterization)– LBL Berkeley Ne 670 MeV/u 1970’s W. Schimmerling – NIRS/HIMAC Chiba C, light ions 1990’s T. Kanai – GSI Biophysics C, light ions 1990’s


Before treatmentBefore treatment

Definition and delineation of target volume (CT,MRI,PET)

transform patient CT-data to water-equivalent path length of ions

Treatment planning: - find best entrance ports - optimization (absorbed dose [Gy]) physical model - biological optim. (RBE (LET(Z,E),dose …) [GyE])

Verify dose distribution in water phantom (tolerable deviation < 5%)

Patient positioning

Patient treatment Bragg curves + Bragg curves +

fragmentation datafragmentation data


Mechanical accuracy:1 μm for relative thickness

0.1 mm absolute

Precision Bragg curve measurementsPrecision Bragg curve measurements

Comparison of absolute B.P. positions measured at GSI and HIT synchrotrons at the same nominal beam energies:

→ agreement within < 2 ‰ rel. deviation

The present data base includesprecise B.P. position data forp, 3He, 7Li, 12C, 16O


Bragg curves of Bragg curves of 12C waterC water

peak-width and height are affected by– straggling – fragmentation

increasing tail dose

© D.Schardt


Microdosimetry Microdosimetry in-phantomin-phantom measurements measurements

Tissue-equivalent proportional chamber (TEPC)

Sensitive volume

120 mb TE-gas


Beam Widening –Beam Widening –- Film Stack in Water Acquarium- Film Stack in Water Acquarium

Photo© G.Martino

Irradiated GaF Chromic filmsStack of films placed in the water-phantom aligned with the beam axis


Fragmentation studies

- Fragment buildup in thick targets

- Neutrons

- Microdosimetry


Fragmentation SetupFragmentation Setup

Angular distribution setup → Beam energy of 120 MeV/u→ Cylindrical water target (diameter of 150 mm)→ Telescope positionned at 0°, 20°, 30°, 60°, 90° and 120°

The ΔE–E telescope detector

Loss of primary ions setup→ beam energy of 300 MeV/u→ Target: 0, 1, …, 7 large water flasks→ Telescope positionned at 0°


Signal processing & Data Acquisition (DAQ) systemSignal processing & Data Acquisition (DAQ) system

Number of primary ions N0→ big ionization chamber

Number of fragments N→ ΔE-E telescope

Trigger→ START and/or BaF2 detector

DAQ→ GSI Multi Branch System (MBS)→ Aug 2007 – CAMAC CVC based DAQ→ Feb 2009 – CAMAC GTBC based DAQ→ Aug 2012 – VME based DAQ

RAW DATA→ List Mode Data (LMD) files

DATA ANALYSIS→ on event-by-event basis→ ROOT program (online / offline)→ ΔE-E scatter plot → "banana" cuts → identification of fragments


Identification of FragmentsIdentification of Fragments

7Li at 120 MeV/u: ΔE-E scatter plot

p

d

t3He

4He

γ+n

ΔE (plastic)

E (

BaF

2)


Loss of primary ions and fragment buildupLoss of primary ions and fragment buildup

Loss of carbon Ions by

nuclear reactions

E. Haettner et al., GSI 2005

Buildup of secondary fragments

Surviving fraction


Spectral dataSpectral data

E. Haettner et al., GSI 2005

Buildup of secondary

fragments

Fragment energy spectra 4mm behind B.P.

E0 12C

He energy spectra at angles 0° - 6°

E0 12C

Comparison with

PHITS-code


FIRST – experimental setup in cave CFIRST – experimental setup in cave C

IR – START scintillatorIR – Beam MonitorIR – TargetIR – Si Pixel Vertex DetectorIR- KENTROSALADIN MagnetTP-MUSIC IVTOF wallLAND

→ Beam diagnostics→ New detectors in interaction region (IR) → ALADIN dipole→ MUSIC + ToF Wall→ LAND

Measurable→ Double-differential cross-section for Z particles

Experiment in August 2011(carbon beam fragmented on thick targets)

→ C + C (5 mm) at 400 MeV/u→ C + Au (0.5 mm) at 400 MeV/u

→ coincidence measurement→ on event-by-event basis


Future Experiments at GSI: Irradiation facilitiesFuture Experiments at GSI: Irradiation facilities

Cave B (rear part)Preparation of FIRST

E = 0.1 – 2 GeV/u

Medical cave

Cave AFragmentation ExperimentsSpace research

E < 15 MeV/uCave CFIRST experiment


Mosaic DetectorMosaic Detector

new GSI mosaic detector

(based on n_ToF design)n_ToF mosaic detector


Requirements / GeometryRequirements / Geometry

Purpose:Beam monitor (counter) + START/STOP for ToF + Energy lossParticles: protons – carbon – iron - HIIntensities: 1e0 – 1e8/sec(replacing existing START plastic scintillator)

sCVD:4,5 x 4,5 mm2 x 300 μmactive area 4,0 x 4,0 mm2 (~ 80 % of total area)

Mosaic detector:3 x 3 sCVDtotal area 13,5 x 13,5 mm2 (beam spot 5 – 10 mm FWHM)9 x C2 + 1 x C6 preamplifiers


CharacteristicsCharacteristics

Signalsprotons - oxygen at 500 MeV: → 3.2 – 350 fC3.2 fC / 4 ns = 0.8 μA → 0.8 μA * 50 Ω = 40 μV40 dB current amplifier (f = 100) → 40 μV * 100 = 4 mVprotons: S/B = 4 mV / 2.5 mV = 1.6oxygen: S/B = 200 mV / 3.2 mV = 62.5

protons: using quick charge amplifier (4 mV/fC) → 3.2 fC * 4 mV/fC = 12.8 mV → S/B = 12.8 mV / 0.6 mV (noice) = 21.3

Time Resolutioncase of 16O: 1 ns / 100 ps = 10 pscase of protons: 3.5 ns / 21.3 ns = 150 ps


Proton / Carbon InteractionProton / Carbon Interaction

Ionization for protons at 200 – 500 MeV

Ionization for carbon at 1 – 10 GeV →

150 – 600 fC (150 – 600 MIP)


n_ToF PCB Design (1)n_ToF PCB Design (1)


n_ToF PCB Design (2)n_ToF PCB Design (2)

Top layer Bottom layer

Readout lines


Time lineTime line

January 2013 – assembling February 2013 – final testing End of February 2013 - delivering


THANK YOU FOR YOUR ATTENTION !THANK YOU FOR YOUR ATTENTION !

1st adamas workshop, gsi, 2012r.pleskac18/12/2012 mosaic detector: experiments for therapy and space...

Documents

adamas workshop

pleskac18122012 beam

pleskac18122012 microdosimetry

microdosimetry slide

beam axis slide

water phantom

pleskac gsi biophysics

schardt slide