1. Carbon ion fragmentation study for medical applications Protons (hadrons in general) especially suitable for deep-sited tumors (brain, neck base, prostate) and fat people G. De Lellis Napoli University

2. Dose modulation From the overlap of close peaks (close energies), conformational Profile is obtained The patient is rotated so to avoid a long exposure time of the healthy tissues Size of the sick part

3. Carbon beam Same energy deposit profile as protons but with larger energy loss per unit length one ionization every ~ 10nm (DNA helix ~ 2nm)

4. Charge and mass measurement Density of energy along the track path  Z 2 Multiple scattering or magnetic field provides either p  or p From the combined measurement, we can get p and the mass  A,Z

5. Exposure of an ECC to 400 Mev/u Carbon ions ECC structure: 219 OPERA-like emulsions and 219 Lexan sheets (  = 1.15 g/cm 3 ) 1 mm thick (73 consecutive “cells”) exposed to 400 Mev/u Carbon ions Cell structure LEXAN R0R1R2 R0: sheet normally developed after the exposure R1: sheet refreshed after the exposure (3 days, 30 0 C, 98% R.H.) R2: sheet refreshed after the exposure (3 days, 38 0 C, 98% R.H.)

6. Carbon exposure at HIMAC (NIRS-Chiba)

7. C ions angular spectrum Slope X Slope Y slope X (3  ) slope Y (3  ) P1 -0.150 ±0.004 -0.003 ±0.005 P2 -0.017 ±0.004 -0.002 ±0.005 P3 0.134 ±0.004 -0.001 ±0.005 3.4 cm 2 scanning in each sheet (all sheets scanned)

8. Track volume: sum of the areas of the clusters belonging to the track BG, mip Z > 1 p Upstream sheet Downstream sheet (about 5 cm) p  Z > 2 one sheet – R0 type one sheet – R1 type Downstream sheet (about 5 cm) Upstream sheet

9. R0 vs R1 and R1 vs R2 scatter plot H He

10. R1 versus R2 He Li Be B C 20 to 30 sheets 5 to 10 sheets

11. Charge identification Z = 2 Z = 3 Z = 4 5 R1 VS 5 R2 (2 cm)10 R1 VS 10 R2 (4 cm) 15 R1 VS 15 R2 (6 cm) 20 R1 VS 20 R2 (8 cm) Z = 4 Z = 3 Z = 2 Z = 5 Z = 6

12. Charge separation

13. Charge separation versus the number of segments Helium-Lithium Lithium-Beryllium

14. Charge separation versus the number of segments Boron-CarbonBeryllium-Boron

15. Charge identification efficiency

16. One vertex C 3 cm Vertex analysis

17. Impact parameter distribution

18. Track multiplicity at interaction vertex

19. Charge distribution of secondary particles charge reconstruction efficiency Inefficiency  Charge = 0 Charge efficiency = (2848-27)/2848 = 99.1±0.2%

20. Sum of the charge at the interaction vertex

21. Carbon interactions Bragg peak Contamination at the percent level

22. Angular distribution of secondary particles

23. Particle ranges for different charges

24. Ranges and interaction lengths for stopping and interacting particles

25. Elastic scattering angle ~ 6% Contamination

26. Conclusions The charge identification works well up to the Carbon The charge separation capability is about 5 sigma for protons and helium already with less than 10 plates where other detectors fail The separation between boron and carbon requires 30 plates to reach 2.5 sigma The vertex reconstruction works with impact parameters of 10 µm or less Elastic and anelastic scattering are well separated Outlooks Improve the identification capability for short tracks Measure the momentum for isotope discrimination