Analysis of Carbon Ion Fragmentation and Angular Fragment Distributions using a flexible set-up

Transcription

1 Analysis of Carbon Ion Fragmentation and Angular Fragment Distributions using a flexible set-up G. Arico1,2, B. Hartmann2, J. Jakubek3, S. Pospisil3, O. Jäkel1,2,4, M. Martisikova1,2 1 University Clinic Heidelberg, Heidelberg, Germany 2 German Cancer Research Center, Heidelberg, Germany 3 Institute of Experimental and Applied Physics, Prague, Czech Republic 4 Heidelberg Ion-Beam Therapy Center, Heidelberg, Germany PTCOG 53 Shanghai 2014

2 PAge22 Carbon ion radiotherapy Carbon ions may undergo nuclear fragmentation processes in the patient Fragments also contribute to the delivered dose Aim: Investigation of the fragment spectra higher accuracy in the physical beam models Phys. Med. Biol.58 (2013) doi: / /58/23/8265

3 PAge33 A highly flexible set-up Semiconductor Timepix detector Single particle detection Fast data acquisition Advantages: Easy to handle device Particle arrival time measurements Particle energy loss measurements Llopart X., Nucl. Instr. Meth. A 581 (2007) Hartmann B. (2013), PhD thesis, Univ Heidelberg

4 PAge44 Collected signal for a carbon ion beam crossing PMMA (tacquisition = 1 ms) cluster { Cluster size Cluster signal Cluster signal [KeV] Semiconductor Timepix detector

5 PAge55 Different ion species can be identified Hartmann B. (2013), PhD thesis, Univ Heidelberg

6 PAge66 Purpose 1: Fragmentation in different materials Setup: TARGET 12 Energy loss measurements Different targets with same water equivalent thickness Same relative position of detector and Bragg peak Timepix detector C Schematic Bragg curve Comparisons: PMMA and water PMMA, bone and lung

7 Fragmentation in different materials Water PMMA PAge77 Result: PMMA can replace water in nuclear fragmentation studies (N. Matsufuji, Phys. Med. Biol. 48 (2003) )

8 Fragmentation in different materials Lung Bone PMMA PAge88 Result: Larger discrepancies were measured

9 PAge99 Correlation of fragments with the respective ion Purpose 2: Correlation of fragments with the respective primary ion Setup: TARGET 12 C Fragment Schematic Bragg curve Two synchronized detectors Time coincidence measurements Target: 5 cm PMMA Analysis: Reference clock Lateral particle distributions

10 PAge10 10 Correlation of fragments with the respective ion Beam Profile (tmeasurement ~ 40 min) Relative distance with respect to the primary carbon ion position

11 Correlation of fragments with the respective ion PAge11 11 with respect to the primary carbon ion position

12 Correlation of fragments with the respective ion PAge12 12 with respect to the primary carbon ion position or with respect to the mean beam position Result: Time coincidence measurements enable higher accuracy

13 PAge13 13 Conclusions: The presented highly flexible set-ups, implementing Timepix detectors, are successfully used to: identify and quantify fragments arising in carbon ion beams carbon ion correlate the fragments to the primary Energy Measurements PMMA can be used in place of water in ion spectroscopy Time Measurements Higher precision in lateral particle distributions analysis Up to 6 fragments from a single carbon ion

14 PAge14 14 Outlook: layers for particle tracking Several detector Improve physical beam models (MC and TPS) Research carried out in frame of the MediPix Collaboration Experiments performed at the Heidelberg Ion-Beam Therapy Center

15 Thank you for your attention! Further information on