Neutron star between 10 and 10 (100 million to 1 quadrillion) times as strong as that of the Earth. The gravitational field at the neutron star's surface is about (200 billion) times that of the Earth. As the star's core collapses, its rotation rate increases as a result of conservation of angular momentum, hence newly formed neutron stars rotate at up to several hundred times per second. Some neutron stars emit beams of electromagnetic radiation that make them detectable as pulsars. Indeed, the discovery of pulsars by Jocelyn Bell Burnell in 1967 was the first observational suggestion that neutron stars exist. The
Fast neutron therapy be directed from virtually any angle, allowing sparing of normal tissue and maximum radiation dose to the tumor. During treatment, only the patient remains inside the treatment room (called a vault) and the therapists will remotely control the treatment, viewing the patient via video cameras. Each delivery of a set neutron beam geometry is referred to as a treatment field or beam. The treatment delivery is planned to deliver the radiation as effectively as possible, and usually results in fields that conform to the shape of the gross target, with any extension to cover microscopic disease. The neutron therapy facility