A white light neutron source can be produced if a thick target is bombarded by an intense proton beam of 70 MeV. With metal tungsten as a target material, the calculations are made by using the SPEC and DDCS programs. The calculated results show that the reactions occur for 4.6% of incident 70-MeV protons before stopping in a thick W target. The total neutron intensity produced by a 70-MeV and 200-A proton beam is 1.01 × 1014/s. The average neutron energy is 4.19 MeV. The neutron intensity >10 MeV is 1.15 × 1013/s, of which most is emitted in the forward small-angle region. This kind of white light neutron source is very useful in practice.