Everybody is staring at “Igor”, spellbound. The white box will be ready in a moment. The measurement of its neutron radiation is expected to reveal: has there been any radioactive material put aside? International experts have used the portable detector in the exercise “Nuclear Disarmament Verification” (NuDiVe) at the Jülich Institute of Energy and Climate Research (IEK-6), in which they tested new methods for monitoring nuclear disarmament. The procedures could clarify in the future whether a nuclear warhead has been properly destroyed. Until now, this proof has hardly been possible because inspectors are not allowed to inspect weapons systems directly. This is intended to protect a state’s military know-how.