For the physical characterization of neutron beam, dosimetric measurements had been performed to obtain physical data of KCCH cyclotron-produced neutrons for clinical use. The results are presented and compared with the data of other institutions from the literatures. The central aixs percent depth dose, build-up curves and open and wedge isodose curve values are intermediate between that of a 4 and 6 MV X-ray. The build-up level of maximum dose was at 1.35 cm and entrance dose was approximately 40%. Flatness of the beam was 9% at Dmax and less than+/-3% at the depth of 80% isodose line. Penumbra begond the 20% line is wider than corresponding photon beam. The output factors ranged 0.894 for 6 x 6 cm field to 1.187 for 30 x 30 cm field. gamma contamination of neutron beam was 4.9% at 2 cm depth in 10 x10 cm field.
Cyclotrons ; Neutrons*