Proposal for a new INFN experiment Proposal for a new INFN experiment on fragmentation for hadrontherapy applications G. Battistoni

Target fragmentation & proton RBE Currently the contribution of target fragments and of the increasing RBE near the PB is implicit (ICRU reccommendation RBE=1.1) Lately has been pointed out possible impact of variable proton RBE on clinical NCTP values RBE=1.1 Variable RBE Wedenberg 2014 Med Phys

What about Target Fragmentation? Target fragmentation in proton therapy: gives contribution also outside the tumor region! Cell killed by ionization Recoil fragment generated About 10% of biological effect in the entrance channel due to secondary fragments Largest contributions of recoil fragments expected from He, C, Be, O, N These might be the source of an RBE>1.1 more damage than expected to healthy tissues!! R=1/40 R=1/8 250 MeV proton beam in water Entrance channel 0.5 KeV/mum and 0.2 Gy -> about 3% cell killing Bragg peak 2.5 keV/mum and 2 Gy ‘_ about 60% cell killing Cancers 2015,7 Tommasino & Durante

p➜ X (C,O) scattering @200 MeV p-N elastic interaction and the light fragment production (p,d,t) are quite well known. More uncertainty on He fragments.Missing data on heavy fragments (A>4), largely unknown.Available nuclear models in MC code not yet reliable Very low energy, very short range fragments!! Cancers 2015,7 Tommasino & Durante Analitic model results on p+O

p scattering on Brain tissue @200 MeV MC (FLUKA) prediction of production of heavy fragments for 200 MeV p on “BRAIN” : production of He & C dN/dlog(E[GeV]) 4He 12C dN/dlog(E[GeV]) 15 μm range 15 μm range for RBE: the knowledge of dσ/dE is mandatory!! Ekin tot (GeV) Ekin tot (GeV)

Radiobiology desiderata To implement sound radiobiological models the requirements is a improvement of the knowledge of the p-> patient (i.e. p-> H,C,O that are the 98% of human body mass ) interaction at 100-250 MeV. Measure the heavy fragment (Z>2) production cross section with maximum uncertainty of 5% Measure the fragment energy spectrum (i.e. ds/dE) with an energy resolution of the order of 1 MeV/A Charge ID at the level of 2-3% Isotopic ID at the level of 5% Not needed accurate angular measurement If possible study also the light ions productions

A new exp. is being proposed FOOT: FragmentatiOn Of Target Rm1, Rm2, LNF, Bo, Mi, To, Pi, Na, TIFPA, LNS To perform a fragmentation measurement in the Inverse Kinematics Approach: 100 – 300 MeV/u C,O,N beams against a H-rich target Detector designed for: Z-id, A-id, Energy, Angle C CH2 The fragmentation cross section on H can be obtained by subtraction.

DE/DX & TOF measurement The FOOT Detector BGO calorimeter Combines magnetic, TOF and calorimetric measurements Beam monitor Drift chamber ~ 1.5 m Start counter DE/DX & TOF measurement Plastic scint Drift Chamber Permanent Magnet (0.8 T)

Interaction region Silicon Pixel Vertex Detector Permanent Magnet (0.8 T) C or CH2 Target Permanent Magnet (0.8 T) 0.75 cm Silicon Pixel Vertex Detector 0.75 cm

Hallbach geometry for Magnet Hallback geometry provides uniform transverse magnetic field in a cylindrical geometry: B field proportional to ln(Rout/Rin) B=0.8T Thick=8cm Rin=3.5 cm

Complementary approach for the measurement of light fragments P and He fragments are emitted with a broader angular distribution with respect to heavier fragments P and He fragment can have long range, can easily punch through the calorimeter Difficult to cover all Z,A with a single detector design In order to contain light fragments calorimeter should be quite thick: if a separate system can be used for lighter Z fragments we can build a cheaper absorption detector Complementary equipment to be inserted between target and magnet for low Z fragments: Emulsion Cloud Chamber

Courtesy of G. De Lellis

ECC structure ECC structure: Not homogeneous structure 6 consecutive emulsion films 56 nuclear emulsion layers (300 m) interleaved with 56 lead plates (1 mm) 12.5cm 10.2cm film 62 6 consecutive emulsions film 57 film 56 1 mm lead layer 300 μm nuclear emulsion film 2 film 1

Beam exposure of ECC test to be proposed @CNAO 30°≤ α ≤ 90° Beam (p or C-12) PMMA ECC

N.B. Emulsion can track light ions at large angle, up to tgθ ~ 3 Courtesy of G. De Lellis

Beams & Facilities Possible facility: CNAO, HIT, HIMAC, GSI, BNL, (LNS) CNAO: Experimental room would be ok: 16O beam would be necessary GSI : uncertain (NO) beam availability HIT: ~ok, experimental room a bit small HIMAC, BNL : ok, but expensive and with logistic difficulties MED-AUSTRON ?? Not yet explored, could be an opportunity LNS : ok for low energy (80 MeV/nucl) Time schedule for data taking: 2019-2020

Other proposal: Aachen experiment Experimental tests performed at the Cooler Synchrotron (COSY) facility

Other possible future experiments about fra gmentation A big question mark on the possibility of the carbon beam at Archede

Altra proposta INFN correlata con FOOT MoVe IT: Modeling and Verification for Ion beam Treatment planning Project to coordinate INFN expertise in the field of modeling and radiobiology for exploiting this information in producing advanced, biologically adapted treatment planning, and new devices for its verification. New implementations in the TPS involve target fragmentation, radiobiological effectiveness (RBE) and treatment of intra-tumor heterogeneity, such as hypoxia. Output of the project, beyond scientific publications, will be permanent infrastructures in INFN-LNS, CNAO, and TIFPA, novel TPS software algorithms, and patented irradiation devices. XPR Trento, Napoli, LNS, Torino, Milano, CNAO