What is the cheapest possible neutron detector? Are there any cheap detectors (for students)? What is the cheapest possible X-ray detector? What is the cheapest possible vacuum pump? How noisy are they? I mean: Does the pumping noise disturb the wall neighbours? Are there any other ways to tell that the nuclear FUSION reaction has happened except the neutron gain? How much does deuterium cost? Is it the only possible fusionable matter in the market a student can buy?