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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Mosaic Detector: Experiments for Therapy and Space Research R.Pleskac GSI / Biophysics
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Overview Hadrontherapy & Space Research Significance of nuclear fragmentation Cave A measurements (Bragg curves, nuclear fragmentation, microdosimetry, beam widening) FIRST experiment (double-differential cross-section for Z particles) Mosaic Detector Requirements Design Time Line
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Significance of nuclear fragmentation in 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
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Before 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 + fragmentation data fragmentation data
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Mechanical accuracy: 1 μm for relative thickness 0.1 mm absolute Precision 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 includes precise B.P. position data for p, 3 He, 7 Li, 12 C, 16 O
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Bragg curves of C water Bragg curves of 12 C water peak-width and height are affected by –straggling –fragmentation increasing tail dose © D.Schardt
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Microdosimetry in-phantom measurements Tissue-equivalent proportional chamber (TEPC) Sensitive volume 120 mb TE-gas
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Beam Widening – - Film Stack in Water Acquarium Photo© G.Martino Irradiated GaF Chromic films Stack of films placed in the water- phantom aligned with the beam axis
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Fragmentation studies - Fragment buildup in thick targets - Neutrons - Microdosimetry
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Fragmentation 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°
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Signal processing & Data Acquisition (DAQ) system Number of primary ions N0 → big ionization chamber Number of fragments N → ΔE-E telescope Trigger → START and/or BaF 2 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
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Identification of Fragments 7 Li at 120 MeV/u: ΔE-E scatter plot p d t 3He 4He γ+n ΔE (plastic) E (BaF2)
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Loss 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
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Spectral data E. Haettner et al., GSI 2005 Buildup of secondary fragments Fragment energy spectra 4mm behind B.P. E 0 12 C He energy spectra at angles 0° - 6° E 0 12 C Comparison with PHITS-code
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 FIRST – experimental setup in cave C IR – START scintillator IR – Beam Monitor IR – Target IR – Si Pixel Vertex Detector IR- KENTROS ALADIN Magnet TP-MUSIC IV TOF wall LAND → 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
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Future Experiments at GSI: Irradiation facilities Cave B (rear part) Preparation of FIRST E = 0.1 – 2 GeV/u Medical cave Cave A Fragmentation Experiments Space research E < 15 MeV/u Cave C FIRST experiment
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Mosaic Detector new GSI mosaic detector (based on n_ToF design) n_ToF mosaic detector
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Requirements / Geometry Purpose: Beam monitor (counter) + START/STOP for ToF + Energy loss Particles: protons – carbon – iron - HI Intensities: 1e0 – 1e8/sec (replacing existing START plastic scintillator) sCVD: 4,5 x 4,5 mm2 x 300 μm active area 4,0 x 4,0 mm2 (~ 80 % of total area) Mosaic detector: 3 x 3 sCVD total area 13,5 x 13,5 mm2 (beam spot 5 – 10 mm FWHM) 9 x C2 + 1 x C6 preamplifiers
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Characteristics Signals protons - oxygen at 500 MeV: → 3.2 – 350 fC 3.2 fC / 4 ns = 0.8 μA → 0.8 μA * 50 Ω = 40 μV 40 dB current amplifier (f = 100) → 40 μV * 100 = 4 mV protons: S/B = 4 mV / 2.5 mV = 1.6 oxygen: 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 Resolution case of 16O: 1 ns / 100 ps = 10 ps case of protons: 3.5 ns / 21.3 ns = 150 ps
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Proton / Carbon Interaction Ionization for protons at 200 – 500 MeV Ionization for carbon at 1 – 10 GeV → 150 – 600 fC (150 – 600 MIP)
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 n_ToF PCB Design (1)
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 n_ToF PCB Design (2) Top layerBottom layer Readout lines
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 Time line January 2013 – assembling February 2013 – final testing End of February 2013 - delivering
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1st ADAMAS Workshop, GSI, 2012R.Pleskac18/12/2012 THANK YOU FOR YOUR ATTENTION !
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