Python script is a modification of the script at https://cyclotron.lbl.gov/base-rad-effects/neutrons, and calculates the beamtime necessary to achieve a fluence of 1e14 neutrons, based on a target of finite size (3x5mm, but can be specified in the script), distance from the deuteron breakup source (2.5cm, but can be specified in the script), and deuteron current (4uA, but can be specified in the script).