Abstarct: In this study, we tried to design a photoneutron source baxsed on an electron LINAC. Therefore, we used the emitted electrons from 5 and 10 MeV electron LINAC. It is good to mention that many studies have been done on these neutron sources recently and also, we can use them for many applications, include boron neutron capture therapy (BNCT), neutron activation, explosives, and narcotics detection and etc. Actually, in this thesis, we designed and optimized the electron-gamma-neutron convertor for 5 and 10 MeV electron LINAC. In this convertor, the energetic electrons collide with a high atomic number of elements such as tungsten and produce a continuous spectrum photons (bremsstrahlung). Then these photons collide with a photonuclear target such as beryllium or deuterium and produce neutron (photoneutron). Therefore, we can obtain a good neutron flux for any application that needs a neutron source. We could reach to 4.7882×108 and 3.6×108 (n/cm2.mA.s) total neutron flux and thermal neutron flux, respectively. In the present work, we used these neutron sources for thermal neutron activation for the detection of explosives (TNT, PETN, RDX, HMX, NG, EGDN). Also, we verified our results with other works and we reached a good agreement with them, as well. We showed that these neutron sources have good potential for thermal neutron activation and explosives detection. In addition, we did good investigations about gamma shielding for these neutron sources and also, we investigated the dosimetry around of convertor in brief. Of course, it should be noted that we studied buildup factors as an important parameter for gamma-ray shielding. It is good to mention that all simulations and investigations have been done by the Monte Carlo method via MCNPX code. Finally, as mentioned above, we can suggest our design for explosives detection and thermal neutron activation.