@misc{oai:repo.qst.go.jp:00078078,
 author = {Chacon, Andrew and Mohammadi, Akram and Howell, N. and Middleton, R. and Fraser, B. and N. Wyatt and Harley Rutherford and R. Franklin, D. and Takyu, Sodai and Nishikido, Fumihiko and Hirayama, Ryoichi and Yamaya, Taiga and Matsufuji, Naruhiro and Rosenfeld, A. and Guatelli, S. and Safavi naeini, Mitra and Chacon, Andrew and Mohammadi, Akram and Rutherford, Harley and Takyu, Sodai and Nishikido, Fumihiko and Hirayama, Ryoichi and Yamaya, Taiga and Matsufuji, Naruhiro and Safavi naeini, Mitra},
 month = {Oct},
 note = {During heavy ion therapy, some particles in the beam undergo atomic nuclear inelastic collisions with other nuclei in the target, resulting in the production of a range of nuclear fragments, including neutrons. The neutron component is moderated by matter in the target, causing them to lose energy and thermalise. These neutrons are of particular interest as they offer the potential for therapeutic applications via neutron capture. Accurate and reliable quantification of the thermal neutron fluence produced during particle therapy will provide valuable information regarding the feasibility of therapeutic exploitation of this thermal neutron field. However, measurement of thermal neutron fluence is extremely challenging due to the intense and diverse mixed radiation field in the target volume. In this work, we present the results of experimental quantification of thermal neutron fluence, performed using the gold activation method, during carbon and helium beam therapy. Geant4 Monte Carlo simulations were used to validate the approach, establishing that the activation of gold is almost exclusively due to neutron capture, and that nearly all gamma photons detected in the vicinity of 411 keV result from the decay of the activated gold. The  method was then applied to experimentally measure the fluence of thermal neutrons per Gy(RBE) of delivered dose during carbon and helium beam therapy, both inside and outside of the beam in a poly(methyl methacrylate) (PMMA) phantom. Thermal neutron fluence was measured at four different depths: at the entrance, distal edge, middle of the SOBP and in the tail region of the spread-out Bragg peak (SOBP). o our knowledge, this is the first time that this method has been used in particle therapy., The 2019 IEEE Nuclear Science Symposium (NSS) and Medical Imaging Conference (MIC)},
 title = {Experimental quantification of internally generated thermal neutron fluence in heavy ion therapy},
 year = {2019}
}