A neutron beam source generator is provided, which includes an accelerator connecting to a beryllium target through a channel, a filter and a collimator. The beryllium target is disposed at an end of the channel and adjacent to the filter. The filter is disposed between the beryllium target and the collimator. The channel and the beryllium target have an angle α therebetween, and the angle α is between 0° and 90°. The channel and the direction normal to the surface of the filter have an angle β therebetween, and the angle β is between 0° and 90°. The cross-section of the channel is not circular.
